diff --git a/ext/clementine-spotifyblob/spotifyclient.h b/ext/clementine-spotifyblob/spotifyclient.h
index 47afbfd3b..f93af662c 100644
--- a/ext/clementine-spotifyblob/spotifyclient.h
+++ b/ext/clementine-spotifyblob/spotifyclient.h
@@ -39,7 +39,7 @@ class SpotifyClient : public AbstractMessageHandler<pb::spotify::Message> {
   Q_OBJECT
 
  public:
-  SpotifyClient(QObject* parent = 0);
+  SpotifyClient(QObject* parent = nullptr);
   ~SpotifyClient();
 
   static const int kSpotifyImageIDSize;
diff --git a/ext/libclementine-common/core/messagereply.h b/ext/libclementine-common/core/messagereply.h
index 1523709b8..72904e765 100644
--- a/ext/libclementine-common/core/messagereply.h
+++ b/ext/libclementine-common/core/messagereply.h
@@ -30,7 +30,7 @@ class _MessageReplyBase : public QObject {
   Q_OBJECT
 
  public:
-  _MessageReplyBase(QObject* parent = 0);
+  _MessageReplyBase(QObject* parent = nullptr);
 
   virtual int id() const = 0;
   bool is_finished() const { return finished_; }
@@ -58,7 +58,7 @@ signals:
 template <typename MessageType>
 class MessageReply : public _MessageReplyBase {
  public:
-  MessageReply(const MessageType& request_message, QObject* parent = 0);
+  MessageReply(const MessageType& request_message, QObject* parent = nullptr);
 
   int id() const { return request_message_.id(); }
   const MessageType& request_message() const { return request_message_; }
diff --git a/ext/libclementine-common/core/workerpool.h b/ext/libclementine-common/core/workerpool.h
index 343e31c1d..49fe099c0 100644
--- a/ext/libclementine-common/core/workerpool.h
+++ b/ext/libclementine-common/core/workerpool.h
@@ -38,7 +38,7 @@ class _WorkerPoolBase : public QObject {
   Q_OBJECT
 
  public:
-  _WorkerPoolBase(QObject* parent = 0);
+  _WorkerPoolBase(QObject* parent = nullptr);
 
 signals:
   // Emitted when a worker failed to start.  This usually happens when the
@@ -60,7 +60,7 @@ signals:
 template <typename HandlerType>
 class WorkerPool : public _WorkerPoolBase {
  public:
-  WorkerPool(QObject* parent = 0);
+  WorkerPool(QObject* parent = nullptr);
   ~WorkerPool();
 
   typedef typename HandlerType::MessageType MessageType;
diff --git a/src/core/backgroundstreams.h b/src/core/backgroundstreams.h
index 208fe3c10..d768569c5 100644
--- a/src/core/backgroundstreams.h
+++ b/src/core/backgroundstreams.h
@@ -13,7 +13,7 @@ class QAction;
 class BackgroundStreams : public QObject {
   Q_OBJECT
  public:
-  explicit BackgroundStreams(EngineBase* engine, QObject* parent = 0);
+  explicit BackgroundStreams(EngineBase* engine, QObject* parent = nullptr);
   ~BackgroundStreams();
 
   void LoadStreams();
diff --git a/src/core/boundfuturewatcher.h b/src/core/boundfuturewatcher.h
index 5c68a06b3..ba238ad84 100644
--- a/src/core/boundfuturewatcher.h
+++ b/src/core/boundfuturewatcher.h
@@ -8,7 +8,7 @@
 template <typename T, typename D>
 class BoundFutureWatcher : public QFutureWatcher<T>, boost::noncopyable {
  public:
-  BoundFutureWatcher(const D& data, QObject* parent = 0)
+  BoundFutureWatcher(const D& data, QObject* parent = nullptr)
       : QFutureWatcher<T>(parent), data_(data) {}
 
   ~BoundFutureWatcher() {}
diff --git a/src/core/database.h b/src/core/database.h
index 36a6a9714..6b1442f65 100644
--- a/src/core/database.h
+++ b/src/core/database.h
@@ -42,7 +42,7 @@ class Database : public QObject {
   Q_OBJECT
 
  public:
-  Database(Application* app, QObject* parent = 0,
+  Database(Application* app, QObject* parent = nullptr,
            const QString& database_name = QString());
 
   struct AttachedDatabase {
@@ -175,7 +175,7 @@ signals:
 
 class MemoryDatabase : public Database {
  public:
-  MemoryDatabase(Application* app, QObject* parent = 0)
+  MemoryDatabase(Application* app, QObject* parent = nullptr)
       : Database(app, parent, ":memory:") {}
   ~MemoryDatabase() {
     // Make sure Qt doesn't reuse the same database
diff --git a/src/core/filesystemwatcherinterface.h b/src/core/filesystemwatcherinterface.h
index 78bacf055..22a91ec23 100644
--- a/src/core/filesystemwatcherinterface.h
+++ b/src/core/filesystemwatcherinterface.h
@@ -23,13 +23,13 @@
 class FileSystemWatcherInterface : public QObject {
   Q_OBJECT
  public:
-  FileSystemWatcherInterface(QObject* parent = 0);
+  FileSystemWatcherInterface(QObject* parent = nullptr);
   virtual void Init() {}
   virtual void AddPath(const QString& path) = 0;
   virtual void RemovePath(const QString& path) = 0;
   virtual void Clear() = 0;
 
-  static FileSystemWatcherInterface* Create(QObject* parent = 0);
+  static FileSystemWatcherInterface* Create(QObject* parent = nullptr);
 
 signals:
   void PathChanged(const QString& path);
diff --git a/src/core/globalshortcutbackend.h b/src/core/globalshortcutbackend.h
index 96a305633..3393e9861 100644
--- a/src/core/globalshortcutbackend.h
+++ b/src/core/globalshortcutbackend.h
@@ -26,7 +26,7 @@ class GlobalShortcutBackend : public QObject {
   Q_OBJECT
 
  public:
-  GlobalShortcutBackend(GlobalShortcuts* parent = 0);
+  GlobalShortcutBackend(GlobalShortcuts* parent = nullptr);
   virtual ~GlobalShortcutBackend() {}
 
   bool is_active() const { return active_; }
diff --git a/src/core/globalshortcuts.h b/src/core/globalshortcuts.h
index 1dcaf9d3c..113ad35fb 100644
--- a/src/core/globalshortcuts.h
+++ b/src/core/globalshortcuts.h
@@ -33,7 +33,7 @@ class GlobalShortcuts : public QWidget {
   Q_OBJECT
 
  public:
-  GlobalShortcuts(QWidget* parent = 0);
+  GlobalShortcuts(QWidget* parent = nullptr);
 
   static const char* kSettingsGroup;
 
diff --git a/src/core/macfslistener.h b/src/core/macfslistener.h
index 327fa0c09..de816dfbf 100644
--- a/src/core/macfslistener.h
+++ b/src/core/macfslistener.h
@@ -30,7 +30,7 @@ class MacFSListener : public FileSystemWatcherInterface {
   Q_OBJECT
 
  public:
-  explicit MacFSListener(QObject* parent = 0);
+  explicit MacFSListener(QObject* parent = nullptr);
   void Init();
   void AddPath(const QString& path);
   void RemovePath(const QString& path);
diff --git a/src/core/mergedproxymodel.h b/src/core/mergedproxymodel.h
index b24e49c59..24dbe47c3 100644
--- a/src/core/mergedproxymodel.h
+++ b/src/core/mergedproxymodel.h
@@ -30,7 +30,7 @@ class MergedProxyModel : public QAbstractProxyModel {
   Q_OBJECT
 
  public:
-  MergedProxyModel(QObject* parent = 0);
+  MergedProxyModel(QObject* parent = nullptr);
   ~MergedProxyModel();
 
   // Make another model appear as a child of the given item in the source model.
diff --git a/src/core/modelfuturewatcher.h b/src/core/modelfuturewatcher.h
index ea97c9889..171e74892 100644
--- a/src/core/modelfuturewatcher.h
+++ b/src/core/modelfuturewatcher.h
@@ -7,7 +7,7 @@
 template <typename T>
 class ModelFutureWatcher : public QFutureWatcher<T> {
  public:
-  ModelFutureWatcher(const QModelIndex& index, QObject* parent = 0)
+  ModelFutureWatcher(const QModelIndex& index, QObject* parent = nullptr)
       : QFutureWatcher<T>(parent), index_(index) {}
 
   ~ModelFutureWatcher() {}
diff --git a/src/core/mpris.h b/src/core/mpris.h
index b613b5aa3..bb260e6b8 100644
--- a/src/core/mpris.h
+++ b/src/core/mpris.h
@@ -31,7 +31,7 @@ class Mpris : public QObject {
   Q_OBJECT
 
  public:
-  Mpris(Application* app, QObject* parent = 0);
+  Mpris(Application* app, QObject* parent = nullptr);
 
 signals:
   void RaiseMainWindow();
diff --git a/src/core/mpris1.h b/src/core/mpris1.h
index 62cf2bdf8..e43e1d560 100644
--- a/src/core/mpris1.h
+++ b/src/core/mpris1.h
@@ -78,7 +78,7 @@ class Mpris1 : public QObject {
   Q_OBJECT
 
  public:
-  Mpris1(Application* app, QObject* parent = 0,
+  Mpris1(Application* app, QObject* parent = nullptr,
          const QString& dbus_service_name = QString());
   ~Mpris1();
 
@@ -102,7 +102,7 @@ class Mpris1Root : public QObject {
   Q_OBJECT
 
  public:
-  Mpris1Root(Application* app, QObject* parent = 0);
+  Mpris1Root(Application* app, QObject* parent = nullptr);
 
   QString Identity();
   void Quit();
@@ -116,7 +116,7 @@ class Mpris1Player : public QObject {
   Q_OBJECT
 
  public:
-  Mpris1Player(Application* app, QObject* parent = 0);
+  Mpris1Player(Application* app, QObject* parent = nullptr);
 
   void Pause();
   void Stop();
@@ -171,7 +171,7 @@ class Mpris1TrackList : public QObject {
   Q_OBJECT
 
  public:
-  Mpris1TrackList(Application* app, QObject* parent = 0);
+  Mpris1TrackList(Application* app, QObject* parent = nullptr);
 
   int AddTrack(const QString&, bool);
   void DelTrack(int index);
diff --git a/src/core/mpris2.h b/src/core/mpris2.h
index 1ced809ff..4732fe575 100644
--- a/src/core/mpris2.h
+++ b/src/core/mpris2.h
@@ -102,7 +102,7 @@ class Mpris2 : public QObject {
   Q_PROPERTY(QStringList Orderings READ Orderings)
   Q_PROPERTY(MaybePlaylist ActivePlaylist READ ActivePlaylist)
 
-  Mpris2(Application* app, Mpris1* mpris1, QObject* parent = 0);
+  Mpris2(Application* app, Mpris1* mpris1, QObject* parent = nullptr);
 
   // Root Properties
   bool CanQuit() const;
diff --git a/src/core/network.h b/src/core/network.h
index 588e84f69..4e5ab20da 100644
--- a/src/core/network.h
+++ b/src/core/network.h
@@ -48,7 +48,7 @@ class NetworkAccessManager : public QNetworkAccessManager {
   Q_OBJECT
 
  public:
-  NetworkAccessManager(QObject* parent = 0);
+  NetworkAccessManager(QObject* parent = nullptr);
 
  protected:
   QNetworkReply* createRequest(Operation op, const QNetworkRequest& request,
@@ -104,7 +104,7 @@ class NetworkTimeouts : public QObject {
   Q_OBJECT
 
  public:
-  NetworkTimeouts(int timeout_msec, QObject* parent = 0);
+  NetworkTimeouts(int timeout_msec, QObject* parent = nullptr);
 
   // TODO: Template this to avoid code duplication.
   void AddReply(QNetworkReply* reply);
diff --git a/src/core/organiseformat.h b/src/core/organiseformat.h
index 2b4f3febe..29a775bed 100644
--- a/src/core/organiseformat.h
+++ b/src/core/organiseformat.h
@@ -48,7 +48,7 @@ class OrganiseFormat {
 
   class Validator : public QValidator {
    public:
-    explicit Validator(QObject* parent = 0);
+    explicit Validator(QObject* parent = nullptr);
     QValidator::State validate(QString& format, int& pos) const;
   };
 
@@ -61,7 +61,7 @@ class OrganiseFormat {
     static const QRgb kInvalidTagColorDark;
     static const QRgb kBlockColorDark;
 
-    explicit SyntaxHighlighter(QObject* parent = 0);
+    explicit SyntaxHighlighter(QObject* parent = nullptr);
     explicit SyntaxHighlighter(QTextEdit* parent);
     explicit SyntaxHighlighter(QTextDocument* parent);
     void highlightBlock(const QString& format);
diff --git a/src/core/player.h b/src/core/player.h
index 257d11256..bcbbecb1a 100644
--- a/src/core/player.h
+++ b/src/core/player.h
@@ -37,7 +37,7 @@ class PlayerInterface : public QObject {
   Q_OBJECT
 
  public:
-  PlayerInterface(QObject* parent = 0) : QObject(parent) {}
+  PlayerInterface(QObject* parent = nullptr) : QObject(parent) {}
 
   virtual EngineBase* engine() const = 0;
   virtual Engine::State GetState() const = 0;
@@ -107,7 +107,7 @@ class Player : public PlayerInterface {
   Q_OBJECT
 
  public:
-  Player(Application* app, QObject* parent = 0);
+  Player(Application* app, QObject* parent = nullptr);
   ~Player();
 
   void Init();
diff --git a/src/core/qxtglobalshortcutbackend.h b/src/core/qxtglobalshortcutbackend.h
index 4a51f840e..bbe65c5cd 100644
--- a/src/core/qxtglobalshortcutbackend.h
+++ b/src/core/qxtglobalshortcutbackend.h
@@ -24,7 +24,7 @@ class QxtGlobalShortcut;
 
 class QxtGlobalShortcutBackend : public GlobalShortcutBackend {
  public:
-  QxtGlobalShortcutBackend(GlobalShortcuts* parent = 0);
+  QxtGlobalShortcutBackend(GlobalShortcuts* parent = nullptr);
 
  protected:
   bool DoRegister();
diff --git a/src/core/simpletreemodel.h b/src/core/simpletreemodel.h
index 8dc0e3998..247ee4916 100644
--- a/src/core/simpletreemodel.h
+++ b/src/core/simpletreemodel.h
@@ -25,7 +25,7 @@ class QModelIndex;
 template <typename T>
 class SimpleTreeModel : public QAbstractItemModel {
  public:
-  SimpleTreeModel(T* root = 0, QObject* parent = 0);
+  SimpleTreeModel(T* root = 0, QObject* parent = nullptr);
   virtual ~SimpleTreeModel() {}
 
   // QAbstractItemModel
diff --git a/src/core/songloader.h b/src/core/songloader.h
index 1eafe353b..733530f8d 100644
--- a/src/core/songloader.h
+++ b/src/core/songloader.h
@@ -41,7 +41,7 @@ class SongLoader : public QObject {
   Q_OBJECT
  public:
   SongLoader(LibraryBackendInterface* library, const Player* player,
-             QObject* parent = 0);
+             QObject* parent = nullptr);
   ~SongLoader();
 
   enum Result { Success, Error, WillLoadAsync, };
diff --git a/src/core/stylesheetloader.h b/src/core/stylesheetloader.h
index 622e0c9c8..ff889fa12 100644
--- a/src/core/stylesheetloader.h
+++ b/src/core/stylesheetloader.h
@@ -25,7 +25,7 @@
 
 class StyleSheetLoader : public QObject {
  public:
-  StyleSheetLoader(QObject* parent = 0);
+  StyleSheetLoader(QObject* parent = nullptr);
 
   // Sets the given stylesheet on the given widget.
   // If the stylesheet contains strings like %palette-[role], these get replaced
diff --git a/src/core/tagreaderclient.h b/src/core/tagreaderclient.h
index 7a83aa324..3fa14d975 100644
--- a/src/core/tagreaderclient.h
+++ b/src/core/tagreaderclient.h
@@ -32,7 +32,7 @@ class TagReaderClient : public QObject {
   Q_OBJECT
 
  public:
-  TagReaderClient(QObject* parent = 0);
+  TagReaderClient(QObject* parent = nullptr);
 
   typedef AbstractMessageHandler<pb::tagreader::Message> HandlerType;
   typedef HandlerType::ReplyType ReplyType;
diff --git a/src/core/taskmanager.h b/src/core/taskmanager.h
index b743f4777..36c34d677 100644
--- a/src/core/taskmanager.h
+++ b/src/core/taskmanager.h
@@ -26,7 +26,7 @@ class TaskManager : public QObject {
   Q_OBJECT
 
  public:
-  TaskManager(QObject* parent = 0);
+  TaskManager(QObject* parent = nullptr);
 
   struct Task {
     int id;
diff --git a/src/core/urlhandler.h b/src/core/urlhandler.h
index 649426f8f..03e77fc04 100644
--- a/src/core/urlhandler.h
+++ b/src/core/urlhandler.h
@@ -26,7 +26,7 @@ class UrlHandler : public QObject {
   Q_OBJECT
 
  public:
-  UrlHandler(QObject* parent = 0);
+  UrlHandler(QObject* parent = nullptr);
 
   // The URL scheme that this handler handles.
   virtual QString scheme() const = 0;
diff --git a/src/covers/albumcoverexporter.h b/src/covers/albumcoverexporter.h
index 2194f94bc..7626fd934 100644
--- a/src/covers/albumcoverexporter.h
+++ b/src/covers/albumcoverexporter.h
@@ -32,7 +32,7 @@ class AlbumCoverExporter : public QObject {
   Q_OBJECT
 
  public:
-  AlbumCoverExporter(QObject* parent = 0);
+  AlbumCoverExporter(QObject* parent = nullptr);
   virtual ~AlbumCoverExporter() {}
 
   static const int kMaxConcurrentRequests;
diff --git a/src/covers/albumcoverfetcher.h b/src/covers/albumcoverfetcher.h
index 4b4cb0b8c..217904bd8 100644
--- a/src/covers/albumcoverfetcher.h
+++ b/src/covers/albumcoverfetcher.h
@@ -78,7 +78,7 @@ class AlbumCoverFetcher : public QObject {
   Q_OBJECT
 
  public:
-  AlbumCoverFetcher(CoverProviders* cover_providers, QObject* parent = 0,
+  AlbumCoverFetcher(CoverProviders* cover_providers, QObject* parent = nullptr,
                     QNetworkAccessManager* network = 0);
   virtual ~AlbumCoverFetcher() {}
 
diff --git a/src/covers/albumcoverloader.h b/src/covers/albumcoverloader.h
index 0ff4a384a..c81c14d41 100644
--- a/src/covers/albumcoverloader.h
+++ b/src/covers/albumcoverloader.h
@@ -34,7 +34,7 @@ class AlbumCoverLoader : public QObject {
   Q_OBJECT
 
  public:
-  AlbumCoverLoader(QObject* parent = 0);
+  AlbumCoverLoader(QObject* parent = nullptr);
 
   void Stop() { stop_requested_ = true; }
 
diff --git a/src/covers/coversearchstatisticsdialog.h b/src/covers/coversearchstatisticsdialog.h
index f3e552ad1..43ec7ea16 100644
--- a/src/covers/coversearchstatisticsdialog.h
+++ b/src/covers/coversearchstatisticsdialog.h
@@ -30,7 +30,7 @@ class CoverSearchStatisticsDialog : public QDialog {
   Q_OBJECT
 
  public:
-  CoverSearchStatisticsDialog(QWidget* parent = 0);
+  CoverSearchStatisticsDialog(QWidget* parent = nullptr);
   ~CoverSearchStatisticsDialog();
 
   void Show(const CoverSearchStatistics& statistics);
diff --git a/src/covers/currentartloader.h b/src/covers/currentartloader.h
index cea049325..3d4de4178 100644
--- a/src/covers/currentartloader.h
+++ b/src/covers/currentartloader.h
@@ -34,7 +34,7 @@ class CurrentArtLoader : public QObject {
   Q_OBJECT
 
  public:
-  CurrentArtLoader(Application* app, QObject* parent = 0);
+  CurrentArtLoader(Application* app, QObject* parent = nullptr);
   ~CurrentArtLoader();
 
   const AlbumCoverLoaderOptions& options() const { return options_; }
diff --git a/src/covers/kittenloader.h b/src/covers/kittenloader.h
index cae0e3274..94f2489d2 100644
--- a/src/covers/kittenloader.h
+++ b/src/covers/kittenloader.h
@@ -11,7 +11,7 @@ class QNetworkReply;
 class KittenLoader : public AlbumCoverLoader {
   Q_OBJECT
  public:
-  KittenLoader(QObject* parent = 0);
+  KittenLoader(QObject* parent = nullptr);
 
   virtual quint64 LoadKitten(const AlbumCoverLoaderOptions& options);
 
diff --git a/src/covers/musicbrainzcoverprovider.h b/src/covers/musicbrainzcoverprovider.h
index 9a462bb3e..df706a533 100644
--- a/src/covers/musicbrainzcoverprovider.h
+++ b/src/covers/musicbrainzcoverprovider.h
@@ -28,7 +28,7 @@ class QNetworkReply;
 class MusicbrainzCoverProvider : public CoverProvider {
   Q_OBJECT
  public:
-  MusicbrainzCoverProvider(QObject* parent = 0);
+  MusicbrainzCoverProvider(QObject* parent = nullptr);
 
   // CoverProvider
   virtual bool StartSearch(const QString& artist, const QString& album, int id);
diff --git a/src/devices/devicedatabasebackend.h b/src/devices/devicedatabasebackend.h
index ca0d2fd88..f4d5848d4 100644
--- a/src/devices/devicedatabasebackend.h
+++ b/src/devices/devicedatabasebackend.h
@@ -29,7 +29,7 @@ class DeviceDatabaseBackend : public QObject {
   Q_OBJECT
 
  public:
-  Q_INVOKABLE DeviceDatabaseBackend(QObject* parent = 0);
+  Q_INVOKABLE DeviceDatabaseBackend(QObject* parent = nullptr);
 
   struct Device {
     Device() : id_(-1) {}
diff --git a/src/devices/devicemanager.h b/src/devices/devicemanager.h
index 720e794a7..64ec0edf1 100644
--- a/src/devices/devicemanager.h
+++ b/src/devices/devicemanager.h
@@ -39,7 +39,7 @@ class DeviceManager : public QAbstractListModel {
   Q_OBJECT
 
  public:
-  DeviceManager(Application* app, QObject* parent = 0);
+  DeviceManager(Application* app, QObject* parent = nullptr);
   ~DeviceManager();
 
   enum Role {
diff --git a/src/devices/deviceproperties.h b/src/devices/deviceproperties.h
index e797cdb5c..4e3534041 100644
--- a/src/devices/deviceproperties.h
+++ b/src/devices/deviceproperties.h
@@ -30,7 +30,7 @@ class DeviceProperties : public QDialog {
   Q_OBJECT
 
  public:
-  DeviceProperties(QWidget* parent = 0);
+  DeviceProperties(QWidget* parent = nullptr);
   ~DeviceProperties();
 
   void SetDeviceManager(DeviceManager* manager);
diff --git a/src/devices/deviceview.h b/src/devices/deviceview.h
index b2025cdde..92858c787 100644
--- a/src/devices/deviceview.h
+++ b/src/devices/deviceview.h
@@ -48,7 +48,7 @@ class DeviceView : public AutoExpandingTreeView {
   Q_OBJECT
 
  public:
-  DeviceView(QWidget* parent = 0);
+  DeviceView(QWidget* parent = nullptr);
   ~DeviceView();
 
   void SetApplication(Application* app);
diff --git a/src/devices/deviceviewcontainer.h b/src/devices/deviceviewcontainer.h
index 897f6f0d2..97d377b28 100644
--- a/src/devices/deviceviewcontainer.h
+++ b/src/devices/deviceviewcontainer.h
@@ -30,7 +30,7 @@ class DeviceViewContainer : public QWidget {
   Q_OBJECT
 
  public:
-  explicit DeviceViewContainer(QWidget* parent = 0);
+  explicit DeviceViewContainer(QWidget* parent = nullptr);
   ~DeviceViewContainer();
 
   DeviceView* view() const;
diff --git a/src/engines/gstelementdeleter.h b/src/engines/gstelementdeleter.h
index 4b08262e0..00b548c49 100644
--- a/src/engines/gstelementdeleter.h
+++ b/src/engines/gstelementdeleter.h
@@ -26,7 +26,7 @@ class GstElementDeleter : public QObject {
   Q_OBJECT
 
  public:
-  GstElementDeleter(QObject* parent = 0);
+  GstElementDeleter(QObject* parent = nullptr);
 
   // If you call this function with any gstreamer element, the element will get
   // deleted in the main thread.  This is useful if you need to delete an
diff --git a/src/globalsearch/globalsearch.h b/src/globalsearch/globalsearch.h
index 53d644f28..3004569b8 100644
--- a/src/globalsearch/globalsearch.h
+++ b/src/globalsearch/globalsearch.h
@@ -32,7 +32,7 @@ class GlobalSearch : public QObject {
   Q_OBJECT
 
  public:
-  GlobalSearch(Application* app, QObject* parent = 0);
+  GlobalSearch(Application* app, QObject* parent = nullptr);
 
   static const int kDelayedSearchTimeoutMs;
   static const char* kSettingsGroup;
diff --git a/src/globalsearch/globalsearchmodel.h b/src/globalsearch/globalsearchmodel.h
index cb286fdba..d0765f70d 100644
--- a/src/globalsearch/globalsearchmodel.h
+++ b/src/globalsearch/globalsearchmodel.h
@@ -31,7 +31,7 @@ class GlobalSearchModel : public QStandardItemModel {
   Q_OBJECT
 
  public:
-  GlobalSearchModel(GlobalSearch* engine, QObject* parent = 0);
+  GlobalSearchModel(GlobalSearch* engine, QObject* parent = nullptr);
 
   enum Role {
     Role_Result = LibraryModel::LastRole,
diff --git a/src/globalsearch/globalsearchsortmodel.h b/src/globalsearch/globalsearchsortmodel.h
index 19a5cedee..20f99c5b5 100644
--- a/src/globalsearch/globalsearchsortmodel.h
+++ b/src/globalsearch/globalsearchsortmodel.h
@@ -22,7 +22,7 @@
 
 class GlobalSearchSortModel : public QSortFilterProxyModel {
  public:
-  GlobalSearchSortModel(QObject* parent = 0);
+  GlobalSearchSortModel(QObject* parent = nullptr);
 
  protected:
   bool lessThan(const QModelIndex& left, const QModelIndex& right) const;
diff --git a/src/globalsearch/globalsearchview.h b/src/globalsearch/globalsearchview.h
index 41d9d0186..4c376bdc5 100644
--- a/src/globalsearch/globalsearchview.h
+++ b/src/globalsearch/globalsearchview.h
@@ -41,7 +41,7 @@ class GlobalSearchView : public QWidget {
   Q_OBJECT
 
  public:
-  GlobalSearchView(Application* app, QWidget* parent = 0);
+  GlobalSearchView(Application* app, QWidget* parent = nullptr);
   ~GlobalSearchView();
 
   static const int kSwapModelsTimeoutMsec;
diff --git a/src/globalsearch/groovesharksearchprovider.h b/src/globalsearch/groovesharksearchprovider.h
index 892c3e04b..4fe3bc0d3 100644
--- a/src/globalsearch/groovesharksearchprovider.h
+++ b/src/globalsearch/groovesharksearchprovider.h
@@ -28,7 +28,7 @@ class GroovesharkSearchProvider : public SearchProvider {
   Q_OBJECT
 
  public:
-  explicit GroovesharkSearchProvider(Application* app, QObject* parent = 0);
+  explicit GroovesharkSearchProvider(Application* app, QObject* parent = nullptr);
   void Init(GroovesharkService* service);
 
   // SearchProvider
diff --git a/src/globalsearch/librarysearchprovider.h b/src/globalsearch/librarysearchprovider.h
index 389845029..2b7ceb11f 100644
--- a/src/globalsearch/librarysearchprovider.h
+++ b/src/globalsearch/librarysearchprovider.h
@@ -27,7 +27,7 @@ class LibrarySearchProvider : public BlockingSearchProvider {
   LibrarySearchProvider(LibraryBackendInterface* backend, const QString& name,
                         const QString& id, const QIcon& icon,
                         bool enabled_by_default, Application* app,
-                        QObject* parent = 0);
+                        QObject* parent = nullptr);
 
   ResultList Search(int id, const QString& query);
   MimeData* LoadTracks(const ResultList& results);
diff --git a/src/globalsearch/searchprovider.h b/src/globalsearch/searchprovider.h
index 92f6d387d..6c8460efe 100644
--- a/src/globalsearch/searchprovider.h
+++ b/src/globalsearch/searchprovider.h
@@ -32,7 +32,7 @@ class SearchProvider : public QObject {
   Q_OBJECT
 
  public:
-  SearchProvider(Application* app, QObject* parent = 0);
+  SearchProvider(Application* app, QObject* parent = nullptr);
 
   static const int kArtHeight;
 
@@ -199,7 +199,7 @@ class BlockingSearchProvider : public SearchProvider {
   Q_OBJECT
 
  public:
-  BlockingSearchProvider(Application* app, QObject* parent = 0);
+  BlockingSearchProvider(Application* app, QObject* parent = nullptr);
 
   void SearchAsync(int id, const QString& query);
   virtual ResultList Search(int id, const QString& query) = 0;
diff --git a/src/globalsearch/searchproviderstatuswidget.h b/src/globalsearch/searchproviderstatuswidget.h
index 3bf871d2a..16946715a 100644
--- a/src/globalsearch/searchproviderstatuswidget.h
+++ b/src/globalsearch/searchproviderstatuswidget.h
@@ -27,7 +27,7 @@ class Ui_SearchProviderStatusWidget;
 class SearchProviderStatusWidget : public QWidget {
  public:
   SearchProviderStatusWidget(const QIcon& warning_icon, GlobalSearch* engine,
-                             SearchProvider* provider, QWidget* parent = 0);
+                             SearchProvider* provider, QWidget* parent = nullptr);
   ~SearchProviderStatusWidget();
 
   bool eventFilter(QObject* object, QEvent* event);
diff --git a/src/globalsearch/soundcloudsearchprovider.h b/src/globalsearch/soundcloudsearchprovider.h
index 7ef38a334..062b69c55 100644
--- a/src/globalsearch/soundcloudsearchprovider.h
+++ b/src/globalsearch/soundcloudsearchprovider.h
@@ -28,7 +28,7 @@ class SoundCloudSearchProvider : public SearchProvider {
   Q_OBJECT
 
  public:
-  explicit SoundCloudSearchProvider(Application* app, QObject* parent = 0);
+  explicit SoundCloudSearchProvider(Application* app, QObject* parent = nullptr);
   void Init(SoundCloudService* service);
 
   // SearchProvider
diff --git a/src/globalsearch/spotifysearchprovider.h b/src/globalsearch/spotifysearchprovider.h
index 90b7f11a0..66dd5b4a8 100644
--- a/src/globalsearch/spotifysearchprovider.h
+++ b/src/globalsearch/spotifysearchprovider.h
@@ -28,7 +28,7 @@ class SpotifySearchProvider : public SearchProvider {
   Q_OBJECT
 
  public:
-  SpotifySearchProvider(Application* app, QObject* parent = 0);
+  SpotifySearchProvider(Application* app, QObject* parent = nullptr);
 
   void SearchAsync(int id, const QString& query);
   void LoadArtAsync(int id, const Result& result);
diff --git a/src/globalsearch/suggestionwidget.h b/src/globalsearch/suggestionwidget.h
index 771a05ca8..0b8e329e7 100644
--- a/src/globalsearch/suggestionwidget.h
+++ b/src/globalsearch/suggestionwidget.h
@@ -26,7 +26,7 @@ class SuggestionWidget : public QWidget {
   Q_OBJECT
 
  public:
-  SuggestionWidget(const QIcon& search_icon, QWidget* parent = 0);
+  SuggestionWidget(const QIcon& search_icon, QWidget* parent = nullptr);
   ~SuggestionWidget();
 
   bool eventFilter(QObject* object, QEvent* event);
diff --git a/src/internet/boxsettingspage.h b/src/internet/boxsettingspage.h
index 5c094dd18..d0f6c6130 100644
--- a/src/internet/boxsettingspage.h
+++ b/src/internet/boxsettingspage.h
@@ -30,7 +30,7 @@ class BoxSettingsPage : public SettingsPage {
   Q_OBJECT
 
  public:
-  BoxSettingsPage(SettingsDialog* parent = 0);
+  BoxSettingsPage(SettingsDialog* parent = nullptr);
   ~BoxSettingsPage();
 
   void Load();
diff --git a/src/internet/boxurlhandler.h b/src/internet/boxurlhandler.h
index c004bbbca..563942bcd 100644
--- a/src/internet/boxurlhandler.h
+++ b/src/internet/boxurlhandler.h
@@ -8,7 +8,7 @@ class BoxService;
 class BoxUrlHandler : public UrlHandler {
   Q_OBJECT
  public:
-  BoxUrlHandler(BoxService* service, QObject* parent = 0);
+  BoxUrlHandler(BoxService* service, QObject* parent = nullptr);
 
   QString scheme() const { return "box"; }
   QIcon icon() const { return QIcon(":/providers/box.png"); }
diff --git a/src/internet/digitallyimportedclient.h b/src/internet/digitallyimportedclient.h
index dbd0692e1..0a8364280 100644
--- a/src/internet/digitallyimportedclient.h
+++ b/src/internet/digitallyimportedclient.h
@@ -31,7 +31,7 @@ class DigitallyImportedClient : public QObject {
   Q_OBJECT
 
  public:
-  DigitallyImportedClient(const QString& service_name, QObject* parent = 0);
+  DigitallyImportedClient(const QString& service_name, QObject* parent = nullptr);
 
   static const char* kApiUsername;
   static const char* kApiPassword;
diff --git a/src/internet/dropboxauthenticator.h b/src/internet/dropboxauthenticator.h
index 7457390b4..bd3a71809 100644
--- a/src/internet/dropboxauthenticator.h
+++ b/src/internet/dropboxauthenticator.h
@@ -11,7 +11,7 @@ class QNetworkReply;
 class DropboxAuthenticator : public QObject {
   Q_OBJECT
  public:
-  explicit DropboxAuthenticator(QObject* parent = 0);
+  explicit DropboxAuthenticator(QObject* parent = nullptr);
   void StartAuthorisation();
 
   const QString& access_token() const { return access_token_; }
diff --git a/src/internet/dropboxsettingspage.h b/src/internet/dropboxsettingspage.h
index a0712246b..f03f97e0a 100644
--- a/src/internet/dropboxsettingspage.h
+++ b/src/internet/dropboxsettingspage.h
@@ -31,7 +31,7 @@ class DropboxSettingsPage : public SettingsPage {
   Q_OBJECT
 
  public:
-  DropboxSettingsPage(SettingsDialog* parent = 0);
+  DropboxSettingsPage(SettingsDialog* parent = nullptr);
   ~DropboxSettingsPage();
 
   void Load();
diff --git a/src/internet/dropboxurlhandler.h b/src/internet/dropboxurlhandler.h
index c234251ca..f86734f64 100644
--- a/src/internet/dropboxurlhandler.h
+++ b/src/internet/dropboxurlhandler.h
@@ -8,7 +8,7 @@ class DropboxService;
 class DropboxUrlHandler : public UrlHandler {
   Q_OBJECT
  public:
-  DropboxUrlHandler(DropboxService* service, QObject* parent = 0);
+  DropboxUrlHandler(DropboxService* service, QObject* parent = nullptr);
 
   QString scheme() const { return "dropbox"; }
   QIcon icon() const { return QIcon(":providers/dropbox.png"); }
diff --git a/src/internet/geolocator.h b/src/internet/geolocator.h
index af8e4bf8e..d0690aecc 100644
--- a/src/internet/geolocator.h
+++ b/src/internet/geolocator.h
@@ -25,7 +25,7 @@
 class Geolocator : public QObject {
   Q_OBJECT
  public:
-  explicit Geolocator(QObject* parent = 0);
+  explicit Geolocator(QObject* parent = nullptr);
 
   void Geolocate();
 
diff --git a/src/internet/googledriveclient.h b/src/internet/googledriveclient.h
index 07212698a..3708f55e6 100644
--- a/src/internet/googledriveclient.h
+++ b/src/internet/googledriveclient.h
@@ -134,7 +134,7 @@ class Client : public QObject {
   Q_OBJECT
 
  public:
-  Client(QObject* parent = 0);
+  Client(QObject* parent = nullptr);
 
   bool is_authenticated() const;
   const QString& access_token() const { return access_token_; }
diff --git a/src/internet/googledrivesettingspage.h b/src/internet/googledrivesettingspage.h
index 7cd8088e9..37da9cb46 100644
--- a/src/internet/googledrivesettingspage.h
+++ b/src/internet/googledrivesettingspage.h
@@ -30,7 +30,7 @@ class GoogleDriveSettingsPage : public SettingsPage {
   Q_OBJECT
 
  public:
-  GoogleDriveSettingsPage(SettingsDialog* parent = 0);
+  GoogleDriveSettingsPage(SettingsDialog* parent = nullptr);
   ~GoogleDriveSettingsPage();
 
   void Load();
diff --git a/src/internet/googledriveurlhandler.h b/src/internet/googledriveurlhandler.h
index 46b1bebea..a4f9a4bf7 100644
--- a/src/internet/googledriveurlhandler.h
+++ b/src/internet/googledriveurlhandler.h
@@ -8,7 +8,7 @@ class GoogleDriveService;
 class GoogleDriveUrlHandler : public UrlHandler {
   Q_OBJECT
  public:
-  GoogleDriveUrlHandler(GoogleDriveService* service, QObject* parent = 0);
+  GoogleDriveUrlHandler(GoogleDriveService* service, QObject* parent = nullptr);
 
   QString scheme() const { return "googledrive"; }
   QIcon icon() const { return QIcon(":providers/googledrive.png"); }
diff --git a/src/internet/icecastbackend.h b/src/internet/icecastbackend.h
index f67203f45..3e3115488 100644
--- a/src/internet/icecastbackend.h
+++ b/src/internet/icecastbackend.h
@@ -29,7 +29,7 @@ class IcecastBackend : public QObject {
   Q_OBJECT
 
  public:
-  IcecastBackend(QObject* parent = 0);
+  IcecastBackend(QObject* parent = nullptr);
   void Init(Database* db);
 
   static const char* kTableName;
diff --git a/src/internet/icecastfilterwidget.h b/src/internet/icecastfilterwidget.h
index 44a8a5296..c6c019d44 100644
--- a/src/internet/icecastfilterwidget.h
+++ b/src/internet/icecastfilterwidget.h
@@ -33,7 +33,7 @@ class IcecastFilterWidget : public QWidget {
   Q_OBJECT
 
  public:
-  IcecastFilterWidget(QWidget* parent = 0);
+  IcecastFilterWidget(QWidget* parent = nullptr);
   ~IcecastFilterWidget();
 
   static const char* kSettingsGroup;
diff --git a/src/internet/icecastmodel.h b/src/internet/icecastmodel.h
index e25fb94df..02bbe8a00 100644
--- a/src/internet/icecastmodel.h
+++ b/src/internet/icecastmodel.h
@@ -30,7 +30,7 @@ class IcecastModel : public SimpleTreeModel<IcecastItem> {
   Q_OBJECT
 
  public:
-  IcecastModel(IcecastBackend* backend, QObject* parent = 0);
+  IcecastModel(IcecastBackend* backend, QObject* parent = nullptr);
   ~IcecastModel();
 
   // These values get saved in QSettings - don't change them
diff --git a/src/internet/internetmodel.h b/src/internet/internetmodel.h
index 14433c1d1..794cbd94a 100644
--- a/src/internet/internetmodel.h
+++ b/src/internet/internetmodel.h
@@ -42,7 +42,7 @@ class InternetModel : public QStandardItemModel {
   Q_OBJECT
 
  public:
-  InternetModel(Application* app, QObject* parent = 0);
+  InternetModel(Application* app, QObject* parent = nullptr);
 
   enum Role {
     // Services can use this role to distinguish between different types of
diff --git a/src/internet/internetview.h b/src/internet/internetview.h
index 5188deab3..ef5d7be2b 100644
--- a/src/internet/internetview.h
+++ b/src/internet/internetview.h
@@ -24,7 +24,7 @@ class InternetView : public AutoExpandingTreeView {
   Q_OBJECT
 
  public:
-  InternetView(QWidget* parent = 0);
+  InternetView(QWidget* parent = nullptr);
 
   // QWidget
   void contextMenuEvent(QContextMenuEvent* e);
diff --git a/src/internet/internetviewcontainer.h b/src/internet/internetviewcontainer.h
index 748c67074..f57f4b177 100644
--- a/src/internet/internetviewcontainer.h
+++ b/src/internet/internetviewcontainer.h
@@ -34,7 +34,7 @@ class InternetViewContainer : public QWidget {
   Q_OBJECT
 
  public:
-  InternetViewContainer(QWidget* parent = 0);
+  InternetViewContainer(QWidget* parent = nullptr);
   ~InternetViewContainer();
 
   static const int kAnimationDuration;
diff --git a/src/internet/lastfmstationdialog.h b/src/internet/lastfmstationdialog.h
index de2ce3990..a59e126f7 100644
--- a/src/internet/lastfmstationdialog.h
+++ b/src/internet/lastfmstationdialog.h
@@ -26,7 +26,7 @@ class LastFMStationDialog : public QDialog {
   Q_OBJECT
 
  public:
-  LastFMStationDialog(QWidget* parent = 0);
+  LastFMStationDialog(QWidget* parent = nullptr);
   ~LastFMStationDialog();
 
   enum Type { Artist, Tag, Custom, };
diff --git a/src/internet/localredirectserver.h b/src/internet/localredirectserver.h
index 77138a242..c919dbbf7 100644
--- a/src/internet/localredirectserver.h
+++ b/src/internet/localredirectserver.h
@@ -11,7 +11,7 @@ class QTcpSocket;
 class LocalRedirectServer : public QObject {
   Q_OBJECT
  public:
-  LocalRedirectServer(QObject* parent = 0);
+  LocalRedirectServer(QObject* parent = nullptr);
 
   // Causes the server to listen for _one_ request.
   void Listen();
diff --git a/src/internet/magnatunedownloaddialog.h b/src/internet/magnatunedownloaddialog.h
index d9743f5f9..89ecdd3b0 100644
--- a/src/internet/magnatunedownloaddialog.h
+++ b/src/internet/magnatunedownloaddialog.h
@@ -35,7 +35,7 @@ class QXmlStreamReader;
 class MagnatuneDownloadDialog : public QDialog {
   Q_OBJECT
  public:
-  MagnatuneDownloadDialog(MagnatuneService* service, QWidget* parent = 0);
+  MagnatuneDownloadDialog(MagnatuneService* service, QWidget* parent = nullptr);
   ~MagnatuneDownloadDialog();
 
   void Show(const SongList& songs);
diff --git a/src/internet/oauthenticator.h b/src/internet/oauthenticator.h
index 0e5cbbd3e..349495374 100644
--- a/src/internet/oauthenticator.h
+++ b/src/internet/oauthenticator.h
@@ -21,7 +21,7 @@ class OAuthenticator : public QObject {
   };
 
   OAuthenticator(const QString& client_id, const QString& client_secret,
-                 RedirectStyle redirect, QObject* parent = 0);
+                 RedirectStyle redirect, QObject* parent = nullptr);
   void StartAuthorisation(const QString& oauth_endpoint,
                           const QString& token_endpoint, const QString& scope);
   void RefreshAuthorisation(const QString& token_endpoint,
diff --git a/src/internet/skydriveurlhandler.h b/src/internet/skydriveurlhandler.h
index dc3ce04b4..1e7e61d15 100644
--- a/src/internet/skydriveurlhandler.h
+++ b/src/internet/skydriveurlhandler.h
@@ -8,7 +8,7 @@ class SkydriveService;
 class SkydriveUrlHandler : public UrlHandler {
   Q_OBJECT
  public:
-  SkydriveUrlHandler(SkydriveService* service, QObject* parent = 0);
+  SkydriveUrlHandler(SkydriveService* service, QObject* parent = nullptr);
 
   QString scheme() const { return "skydrive"; }
   QIcon icon() const { return QIcon(":providers/skydrive.png"); }
diff --git a/src/internet/spotifyblobdownloader.h b/src/internet/spotifyblobdownloader.h
index c9ed9efba..974cdff88 100644
--- a/src/internet/spotifyblobdownloader.h
+++ b/src/internet/spotifyblobdownloader.h
@@ -29,7 +29,7 @@ class SpotifyBlobDownloader : public QObject {
 
  public:
   SpotifyBlobDownloader(const QString& version, const QString& path,
-                        QObject* parent = 0);
+                        QObject* parent = nullptr);
   ~SpotifyBlobDownloader();
 
   static const char* kSignatureSuffix;
diff --git a/src/internet/spotifyserver.h b/src/internet/spotifyserver.h
index a235504f6..3474a6b1d 100644
--- a/src/internet/spotifyserver.h
+++ b/src/internet/spotifyserver.h
@@ -31,7 +31,7 @@ class SpotifyServer : public AbstractMessageHandler<pb::spotify::Message> {
   Q_OBJECT
 
  public:
-  SpotifyServer(QObject* parent = 0);
+  SpotifyServer(QObject* parent = nullptr);
 
   void Init();
   void Login(const QString& username, const QString& password,
diff --git a/src/internet/subsonicservice.h b/src/internet/subsonicservice.h
index 4deb88644..d05d90ab2 100644
--- a/src/internet/subsonicservice.h
+++ b/src/internet/subsonicservice.h
@@ -140,7 +140,7 @@ class SubsonicLibraryScanner : public QObject {
   Q_OBJECT
 
  public:
-  SubsonicLibraryScanner(SubsonicService* service, QObject* parent = 0);
+  SubsonicLibraryScanner(SubsonicService* service, QObject* parent = nullptr);
   ~SubsonicLibraryScanner();
 
   void Scan();
diff --git a/src/internet/ubuntuoneauthenticator.h b/src/internet/ubuntuoneauthenticator.h
index a61f40a36..6ac777127 100644
--- a/src/internet/ubuntuoneauthenticator.h
+++ b/src/internet/ubuntuoneauthenticator.h
@@ -9,7 +9,7 @@ class NetworkAccessManager;
 class UbuntuOneAuthenticator : public QObject {
   Q_OBJECT
  public:
-  explicit UbuntuOneAuthenticator(QObject* parent = 0);
+  explicit UbuntuOneAuthenticator(QObject* parent = nullptr);
   void StartAuthorisation(const QString& email, const QString& password);
 
   bool success() const { return success_; }
diff --git a/src/internet/ubuntuonesettingspage.h b/src/internet/ubuntuonesettingspage.h
index c0ab99467..0dc702849 100644
--- a/src/internet/ubuntuonesettingspage.h
+++ b/src/internet/ubuntuonesettingspage.h
@@ -10,7 +10,7 @@ class Ui_UbuntuOneSettingsPage;
 class UbuntuOneSettingsPage : public SettingsPage {
   Q_OBJECT
  public:
-  UbuntuOneSettingsPage(SettingsDialog* parent = 0);
+  UbuntuOneSettingsPage(SettingsDialog* parent = nullptr);
 
   void Load();
   void Save();
diff --git a/src/internet/ubuntuoneurlhandler.h b/src/internet/ubuntuoneurlhandler.h
index e36396148..a4e9a39bf 100644
--- a/src/internet/ubuntuoneurlhandler.h
+++ b/src/internet/ubuntuoneurlhandler.h
@@ -8,7 +8,7 @@ class UbuntuOneService;
 class UbuntuOneUrlHandler : public UrlHandler {
   Q_OBJECT
  public:
-  UbuntuOneUrlHandler(UbuntuOneService* service, QObject* parent = 0);
+  UbuntuOneUrlHandler(UbuntuOneService* service, QObject* parent = nullptr);
 
   QString scheme() const { return "ubuntuonefile"; }
   QIcon icon() const { return QIcon(":providers/ubuntuone.png"); }
diff --git a/src/library/librarybackend.h b/src/library/librarybackend.h
index 9a3bb458b..907fe29a1 100644
--- a/src/library/librarybackend.h
+++ b/src/library/librarybackend.h
@@ -36,7 +36,7 @@ class LibraryBackendInterface : public QObject {
   Q_OBJECT
 
  public:
-  LibraryBackendInterface(QObject* parent = 0) : QObject(parent) {}
+  LibraryBackendInterface(QObject* parent = nullptr) : QObject(parent) {}
   virtual ~LibraryBackendInterface() {}
 
   struct Album {
@@ -121,7 +121,7 @@ class LibraryBackend : public LibraryBackendInterface {
  public:
   static const char* kSettingsGroup;
 
-  Q_INVOKABLE LibraryBackend(QObject* parent = 0);
+  Q_INVOKABLE LibraryBackend(QObject* parent = nullptr);
   void Init(Database* db, const QString& songs_table, const QString& dirs_table,
             const QString& subdirs_table, const QString& fts_table);
 
diff --git a/src/library/librarydirectorymodel.h b/src/library/librarydirectorymodel.h
index 92494828c..f9a937ad2 100644
--- a/src/library/librarydirectorymodel.h
+++ b/src/library/librarydirectorymodel.h
@@ -32,7 +32,7 @@ class LibraryDirectoryModel : public QStandardItemModel {
   Q_OBJECT
 
  public:
-  LibraryDirectoryModel(LibraryBackend* backend, QObject* parent = 0);
+  LibraryDirectoryModel(LibraryBackend* backend, QObject* parent = nullptr);
   ~LibraryDirectoryModel();
 
   // To be called by GUIs
diff --git a/src/library/libraryfilterwidget.h b/src/library/libraryfilterwidget.h
index 426c5ab39..3241606b3 100644
--- a/src/library/libraryfilterwidget.h
+++ b/src/library/libraryfilterwidget.h
@@ -38,7 +38,7 @@ class LibraryFilterWidget : public QWidget {
   Q_OBJECT
 
  public:
-  LibraryFilterWidget(QWidget* parent = 0);
+  LibraryFilterWidget(QWidget* parent = nullptr);
   ~LibraryFilterWidget();
 
   static const int kFilterDelay = 500;  // msec
diff --git a/src/library/librarymodel.h b/src/library/librarymodel.h
index ee41ed002..302f8ace7 100644
--- a/src/library/librarymodel.h
+++ b/src/library/librarymodel.h
@@ -47,7 +47,7 @@ class LibraryModel : public SimpleTreeModel<LibraryItem> {
   Q_ENUMS(GroupBy);
 
  public:
-  LibraryModel(LibraryBackend* backend, Application* app, QObject* parent = 0);
+  LibraryModel(LibraryBackend* backend, Application* app, QObject* parent = nullptr);
   ~LibraryModel();
 
   static const char* kSmartPlaylistsMimeType;
diff --git a/src/library/libraryview.h b/src/library/libraryview.h
index 6e229b658..3fbf0cb93 100644
--- a/src/library/libraryview.h
+++ b/src/library/libraryview.h
@@ -53,7 +53,7 @@ class LibraryView : public AutoExpandingTreeView {
   Q_OBJECT
 
  public:
-  LibraryView(QWidget* parent = 0);
+  LibraryView(QWidget* parent = nullptr);
   ~LibraryView();
 
   static const char* kSettingsGroup;
diff --git a/src/library/libraryviewcontainer.h b/src/library/libraryviewcontainer.h
index 751756da6..6989fdafe 100644
--- a/src/library/libraryviewcontainer.h
+++ b/src/library/libraryviewcontainer.h
@@ -28,7 +28,7 @@ class LibraryViewContainer : public QWidget {
   Q_OBJECT
 
  public:
-  LibraryViewContainer(QWidget* parent = 0);
+  LibraryViewContainer(QWidget* parent = nullptr);
   ~LibraryViewContainer();
 
   LibraryFilterWidget* filter() const;
diff --git a/src/library/librarywatcher.h b/src/library/librarywatcher.h
index a1abb8bf4..81059d171 100644
--- a/src/library/librarywatcher.h
+++ b/src/library/librarywatcher.h
@@ -38,7 +38,7 @@ class LibraryWatcher : public QObject {
   Q_OBJECT
 
  public:
-  LibraryWatcher(QObject* parent = 0);
+  LibraryWatcher(QObject* parent = nullptr);
 
   static const char* kSettingsGroup;
 
diff --git a/src/moodbar/moodbarcontroller.h b/src/moodbar/moodbarcontroller.h
index b695aedf8..c3b672088 100644
--- a/src/moodbar/moodbarcontroller.h
+++ b/src/moodbar/moodbarcontroller.h
@@ -30,7 +30,7 @@ class MoodbarController : public QObject {
   Q_OBJECT
 
  public:
-  MoodbarController(Application* app, QObject* parent = 0);
+  MoodbarController(Application* app, QObject* parent = nullptr);
 
 signals:
   void CurrentMoodbarDataChanged(const QByteArray& data);
diff --git a/src/moodbar/moodbaritemdelegate.h b/src/moodbar/moodbaritemdelegate.h
index dc3df6bbb..53e435058 100644
--- a/src/moodbar/moodbaritemdelegate.h
+++ b/src/moodbar/moodbaritemdelegate.h
@@ -36,7 +36,7 @@ class MoodbarItemDelegate : public QItemDelegate {
 
  public:
   MoodbarItemDelegate(Application* app, PlaylistView* view,
-                      QObject* parent = 0);
+                      QObject* parent = nullptr);
 
   void paint(QPainter* painter, const QStyleOptionViewItem& option,
              const QModelIndex& index) const;
diff --git a/src/moodbar/moodbarloader.h b/src/moodbar/moodbarloader.h
index 0dd0d953a..52fea6ae0 100644
--- a/src/moodbar/moodbarloader.h
+++ b/src/moodbar/moodbarloader.h
@@ -32,7 +32,7 @@ class MoodbarLoader : public QObject {
   Q_OBJECT
 
  public:
-  MoodbarLoader(Application* app, QObject* parent = 0);
+  MoodbarLoader(Application* app, QObject* parent = nullptr);
   ~MoodbarLoader();
 
   enum Result {
diff --git a/src/musicbrainz/acoustidclient.h b/src/musicbrainz/acoustidclient.h
index 5b27d9bb3..36b3bc50c 100644
--- a/src/musicbrainz/acoustidclient.h
+++ b/src/musicbrainz/acoustidclient.h
@@ -38,7 +38,7 @@ class AcoustidClient : public QObject {
   // the Finished signal - they have no meaning to AcoustidClient.
 
  public:
-  AcoustidClient(QObject* parent = 0);
+  AcoustidClient(QObject* parent = nullptr);
 
   // Network requests will be aborted after this interval.
   void SetTimeout(int msec);
diff --git a/src/musicbrainz/musicbrainzclient.h b/src/musicbrainz/musicbrainzclient.h
index a16182224..cdaf20094 100644
--- a/src/musicbrainz/musicbrainzclient.h
+++ b/src/musicbrainz/musicbrainzclient.h
@@ -38,7 +38,7 @@ class MusicBrainzClient : public QObject {
   // the Finished signal - they have no meaning to MusicBrainzClient.
 
  public:
-  MusicBrainzClient(QObject* parent = 0);
+  MusicBrainzClient(QObject* parent = nullptr);
 
   struct Result {
     Result() : duration_msec_(0), track_(0), year_(-1) {}
diff --git a/src/musicbrainz/tagfetcher.h b/src/musicbrainz/tagfetcher.h
index 85a5656e1..18bb90ef9 100644
--- a/src/musicbrainz/tagfetcher.h
+++ b/src/musicbrainz/tagfetcher.h
@@ -33,7 +33,7 @@ class TagFetcher : public QObject {
   // MusicBrainzClient.
 
  public:
-  TagFetcher(QObject* parent = 0);
+  TagFetcher(QObject* parent = nullptr);
 
   void StartFetch(const SongList& songs);
 
diff --git a/src/networkremote/networkremote.h b/src/networkremote/networkremote.h
index 06c8afb73..ba455bc23 100644
--- a/src/networkremote/networkremote.h
+++ b/src/networkremote/networkremote.h
@@ -18,7 +18,7 @@ class NetworkRemote : public QObject {
   static const char* kSettingsGroup;
   static const quint16 kDefaultServerPort;
 
-  explicit NetworkRemote(Application* app, QObject* parent = 0);
+  explicit NetworkRemote(Application* app, QObject* parent = nullptr);
   ~NetworkRemote();
 
  public slots:
diff --git a/src/playlist/dynamicplaylistcontrols.h b/src/playlist/dynamicplaylistcontrols.h
index 9ef5e521f..e1212563e 100644
--- a/src/playlist/dynamicplaylistcontrols.h
+++ b/src/playlist/dynamicplaylistcontrols.h
@@ -26,7 +26,7 @@ class DynamicPlaylistControls : public QWidget {
   Q_OBJECT
 
  public:
-  DynamicPlaylistControls(QWidget* parent = 0);
+  DynamicPlaylistControls(QWidget* parent = nullptr);
   ~DynamicPlaylistControls();
 
 signals:
diff --git a/src/playlist/playlist.h b/src/playlist/playlist.h
index 5ff8fc1b1..998f52acd 100644
--- a/src/playlist/playlist.h
+++ b/src/playlist/playlist.h
@@ -78,7 +78,7 @@ class Playlist : public QAbstractListModel {
   Playlist(PlaylistBackend* backend, TaskManager* task_manager,
            LibraryBackend* library, int id,
            const QString& special_type = QString(), bool favorite = false,
-           QObject* parent = 0);
+           QObject* parent = nullptr);
   ~Playlist();
 
   void SkipTracks(const QModelIndexList& source_indexes);
diff --git a/src/playlist/playlistbackend.h b/src/playlist/playlistbackend.h
index e0d941578..1d7c10179 100644
--- a/src/playlist/playlistbackend.h
+++ b/src/playlist/playlistbackend.h
@@ -34,7 +34,7 @@ class PlaylistBackend : public QObject {
   Q_OBJECT
 
  public:
-  Q_INVOKABLE PlaylistBackend(Application* app, QObject* parent = 0);
+  Q_INVOKABLE PlaylistBackend(Application* app, QObject* parent = nullptr);
 
   struct Playlist {
     Playlist() : id(-1), favorite(false), last_played(0) {}
diff --git a/src/playlist/playlistcontainer.h b/src/playlist/playlistcontainer.h
index e3a680ae8..b0b8b8ba8 100644
--- a/src/playlist/playlistcontainer.h
+++ b/src/playlist/playlistcontainer.h
@@ -36,7 +36,7 @@ class PlaylistContainer : public QWidget {
   Q_OBJECT
 
  public:
-  PlaylistContainer(QWidget* parent = 0);
+  PlaylistContainer(QWidget* parent = nullptr);
   ~PlaylistContainer();
 
   static const char* kSettingsGroup;
diff --git a/src/playlist/playlistfilter.h b/src/playlist/playlistfilter.h
index ae1ee03af..fad98b423 100644
--- a/src/playlist/playlistfilter.h
+++ b/src/playlist/playlistfilter.h
@@ -31,7 +31,7 @@ class PlaylistFilter : public QSortFilterProxyModel {
   Q_OBJECT
 
  public:
-  PlaylistFilter(QObject* parent = 0);
+  PlaylistFilter(QObject* parent = nullptr);
   ~PlaylistFilter();
 
   // QAbstractItemModel
diff --git a/src/playlist/playlistheader.h b/src/playlist/playlistheader.h
index bdd1039ad..a2e2e3d2f 100644
--- a/src/playlist/playlistheader.h
+++ b/src/playlist/playlistheader.h
@@ -30,7 +30,7 @@ class PlaylistHeader : public StretchHeaderView {
 
  public:
   PlaylistHeader(Qt::Orientation orientation, PlaylistView* view,
-                 QWidget* parent = 0);
+                 QWidget* parent = nullptr);
 
   // QWidget
   void contextMenuEvent(QContextMenuEvent* e);
diff --git a/src/playlist/playlistlistcontainer.h b/src/playlist/playlistlistcontainer.h
index b9b4dcd27..2c1cc8486 100644
--- a/src/playlist/playlistlistcontainer.h
+++ b/src/playlist/playlistlistcontainer.h
@@ -35,7 +35,7 @@ class PlaylistListContainer : public QWidget {
   Q_OBJECT
 
  public:
-  PlaylistListContainer(QWidget* parent = 0);
+  PlaylistListContainer(QWidget* parent = nullptr);
   ~PlaylistListContainer();
 
   void SetApplication(Application* app);
diff --git a/src/playlist/playlistlistmodel.h b/src/playlist/playlistlistmodel.h
index 109dc1e0b..0c8dcccb7 100644
--- a/src/playlist/playlistlistmodel.h
+++ b/src/playlist/playlistlistmodel.h
@@ -7,7 +7,7 @@ class PlaylistListModel : public QStandardItemModel {
   Q_OBJECT
 
  public:
-  PlaylistListModel(QObject* parent = 0);
+  PlaylistListModel(QObject* parent = nullptr);
 
   enum Types { Type_Folder, Type_Playlist };
 
diff --git a/src/playlist/playlistmanager.h b/src/playlist/playlistmanager.h
index f20f37e3b..a3eeeace0 100644
--- a/src/playlist/playlistmanager.h
+++ b/src/playlist/playlistmanager.h
@@ -135,7 +135,7 @@ class PlaylistManager : public PlaylistManagerInterface {
   Q_OBJECT
 
  public:
-  PlaylistManager(Application* app, QObject* parent = 0);
+  PlaylistManager(Application* app, QObject* parent = nullptr);
   ~PlaylistManager();
 
   int current_id() const { return current_; }
diff --git a/src/playlist/playlistsequence.h b/src/playlist/playlistsequence.h
index c607d740e..a5b841a78 100644
--- a/src/playlist/playlistsequence.h
+++ b/src/playlist/playlistsequence.h
@@ -32,7 +32,7 @@ class PlaylistSequence : public QWidget {
   Q_OBJECT
 
  public:
-  PlaylistSequence(QWidget* parent = 0, SettingsProvider* settings = 0);
+  PlaylistSequence(QWidget* parent = nullptr, SettingsProvider* settings = 0);
   ~PlaylistSequence();
 
   enum RepeatMode {
diff --git a/src/playlist/playlisttabbar.h b/src/playlist/playlisttabbar.h
index 5cd1081ac..3b795367c 100644
--- a/src/playlist/playlisttabbar.h
+++ b/src/playlist/playlisttabbar.h
@@ -31,7 +31,7 @@ class PlaylistTabBar : public QTabBar {
   Q_OBJECT
 
  public:
-  PlaylistTabBar(QWidget* parent = 0);
+  PlaylistTabBar(QWidget* parent = nullptr);
 
   static const int kDragHoverTimeout = 500;
   static const char* kSettingsGroup;
diff --git a/src/playlist/playlistview.h b/src/playlist/playlistview.h
index df444053a..fedc207e0 100644
--- a/src/playlist/playlistview.h
+++ b/src/playlist/playlistview.h
@@ -59,7 +59,7 @@ class PlaylistView : public QTreeView {
  public:
   enum BackgroundImageType { Default, None, Custom, AlbumCover };
 
-  PlaylistView(QWidget* parent = 0);
+  PlaylistView(QWidget* parent = nullptr);
 
   static const int kStateVersion;
   // Constants for settings: are persistent, values should not be changed
diff --git a/src/playlist/queue.h b/src/playlist/queue.h
index 56c66d3f3..de1edefd2 100644
--- a/src/playlist/queue.h
+++ b/src/playlist/queue.h
@@ -26,7 +26,7 @@ class Queue : public QAbstractProxyModel {
   Q_OBJECT
 
  public:
-  Queue(QObject* parent = 0);
+  Queue(QObject* parent = nullptr);
 
   static const char* kRowsMimetype;
 
diff --git a/src/playlist/queuemanager.h b/src/playlist/queuemanager.h
index 1457eb94e..34643d964 100644
--- a/src/playlist/queuemanager.h
+++ b/src/playlist/queuemanager.h
@@ -30,7 +30,7 @@ class QueueManager : public QDialog {
   Q_OBJECT
 
  public:
-  QueueManager(QWidget* parent = 0);
+  QueueManager(QWidget* parent = nullptr);
   ~QueueManager();
 
   void SetPlaylistManager(PlaylistManager* manager);
diff --git a/src/playlistparsers/asxiniparser.h b/src/playlistparsers/asxiniparser.h
index 73de87d59..cb15e52ef 100644
--- a/src/playlistparsers/asxiniparser.h
+++ b/src/playlistparsers/asxiniparser.h
@@ -24,7 +24,7 @@ class AsxIniParser : public ParserBase {
   Q_OBJECT
 
  public:
-  AsxIniParser(LibraryBackendInterface* library, QObject* parent = 0);
+  AsxIniParser(LibraryBackendInterface* library, QObject* parent = nullptr);
 
   QString name() const { return "ASX/INI"; }
   QStringList file_extensions() const { return QStringList() << "asxini"; }
diff --git a/src/playlistparsers/asxparser.h b/src/playlistparsers/asxparser.h
index fa643d579..681eab17a 100644
--- a/src/playlistparsers/asxparser.h
+++ b/src/playlistparsers/asxparser.h
@@ -24,7 +24,7 @@ class ASXParser : public XMLParser {
   Q_OBJECT
 
  public:
-  ASXParser(LibraryBackendInterface* library, QObject* parent = 0);
+  ASXParser(LibraryBackendInterface* library, QObject* parent = nullptr);
 
   QString name() const { return "ASX"; }
   QStringList file_extensions() const { return QStringList() << "asx"; }
diff --git a/src/playlistparsers/cueparser.h b/src/playlistparsers/cueparser.h
index 2ba8f5826..0f07b0b11 100644
--- a/src/playlistparsers/cueparser.h
+++ b/src/playlistparsers/cueparser.h
@@ -43,7 +43,7 @@ class CueParser : public ParserBase {
   static const char* kGenre;
   static const char* kDate;
 
-  CueParser(LibraryBackendInterface* library, QObject* parent = 0);
+  CueParser(LibraryBackendInterface* library, QObject* parent = nullptr);
 
   QString name() const { return "CUE"; }
   QStringList file_extensions() const { return QStringList() << "cue"; }
diff --git a/src/playlistparsers/m3uparser.h b/src/playlistparsers/m3uparser.h
index 53ef2185f..431e5728b 100644
--- a/src/playlistparsers/m3uparser.h
+++ b/src/playlistparsers/m3uparser.h
@@ -28,7 +28,7 @@ class M3UParser : public ParserBase {
   Q_OBJECT
 
  public:
-  M3UParser(LibraryBackendInterface* library, QObject* parent = 0);
+  M3UParser(LibraryBackendInterface* library, QObject* parent = nullptr);
 
   QString name() const { return "M3U"; }
   QStringList file_extensions() const {
diff --git a/src/playlistparsers/parserbase.h b/src/playlistparsers/parserbase.h
index ca91d168d..9b01dd546 100644
--- a/src/playlistparsers/parserbase.h
+++ b/src/playlistparsers/parserbase.h
@@ -29,7 +29,7 @@ class ParserBase : public QObject {
   Q_OBJECT
 
  public:
-  ParserBase(LibraryBackendInterface* library, QObject* parent = 0);
+  ParserBase(LibraryBackendInterface* library, QObject* parent = nullptr);
 
   virtual QString name() const = 0;
   virtual QStringList file_extensions() const = 0;
diff --git a/src/playlistparsers/playlistparser.h b/src/playlistparsers/playlistparser.h
index 00a82a9f3..6e42c7210 100644
--- a/src/playlistparsers/playlistparser.h
+++ b/src/playlistparsers/playlistparser.h
@@ -30,7 +30,7 @@ class PlaylistParser : public QObject {
   Q_OBJECT
 
  public:
-  PlaylistParser(LibraryBackendInterface* library, QObject* parent = 0);
+  PlaylistParser(LibraryBackendInterface* library, QObject* parent = nullptr);
 
   static const int kMagicSize;
 
diff --git a/src/playlistparsers/plsparser.h b/src/playlistparsers/plsparser.h
index ddc8e8c2d..4fc10b6aa 100644
--- a/src/playlistparsers/plsparser.h
+++ b/src/playlistparsers/plsparser.h
@@ -24,7 +24,7 @@ class PLSParser : public ParserBase {
   Q_OBJECT
 
  public:
-  PLSParser(LibraryBackendInterface* library, QObject* parent = 0);
+  PLSParser(LibraryBackendInterface* library, QObject* parent = nullptr);
 
   QString name() const { return "PLS"; }
   QStringList file_extensions() const { return QStringList() << "pls"; }
diff --git a/src/playlistparsers/wplparser.h b/src/playlistparsers/wplparser.h
index 7853fbefa..2b0bd3ec1 100644
--- a/src/playlistparsers/wplparser.h
+++ b/src/playlistparsers/wplparser.h
@@ -22,7 +22,7 @@
 
 class WplParser : public XMLParser {
  public:
-  WplParser(LibraryBackendInterface* library, QObject* parent = 0);
+  WplParser(LibraryBackendInterface* library, QObject* parent = nullptr);
 
   QString name() const { return "WPL"; }
   QStringList file_extensions() const { return QStringList() << "wpl"; }
diff --git a/src/playlistparsers/xspfparser.h b/src/playlistparsers/xspfparser.h
index 5d9e5c975..0102c1288 100644
--- a/src/playlistparsers/xspfparser.h
+++ b/src/playlistparsers/xspfparser.h
@@ -29,7 +29,7 @@ class XSPFParser : public XMLParser {
   Q_OBJECT
 
  public:
-  XSPFParser(LibraryBackendInterface* library, QObject* parent = 0);
+  XSPFParser(LibraryBackendInterface* library, QObject* parent = nullptr);
 
   QString name() const { return "XSPF"; }
   QStringList file_extensions() const { return QStringList() << "xspf"; }
diff --git a/src/smartplaylists/searchpreview.h b/src/smartplaylists/searchpreview.h
index 6878f16fe..b7b84c3e9 100644
--- a/src/smartplaylists/searchpreview.h
+++ b/src/smartplaylists/searchpreview.h
@@ -34,7 +34,7 @@ class SearchPreview : public QWidget {
   Q_OBJECT
 
  public:
-  SearchPreview(QWidget* parent = 0);
+  SearchPreview(QWidget* parent = nullptr);
   ~SearchPreview();
 
   void set_application(Application* app);
diff --git a/src/songinfo/artistinfoview.h b/src/songinfo/artistinfoview.h
index b25a8788c..b4cab03ea 100644
--- a/src/songinfo/artistinfoview.h
+++ b/src/songinfo/artistinfoview.h
@@ -32,7 +32,7 @@ class ArtistInfoView : public SongInfoBase {
   Q_OBJECT
 
  public:
-  ArtistInfoView(QWidget* parent = 0);
+  ArtistInfoView(QWidget* parent = nullptr);
   ~ArtistInfoView();
 
  protected:
diff --git a/src/songinfo/collapsibleinfoheader.h b/src/songinfo/collapsibleinfoheader.h
index 388197ad8..65b0bc15a 100644
--- a/src/songinfo/collapsibleinfoheader.h
+++ b/src/songinfo/collapsibleinfoheader.h
@@ -28,7 +28,7 @@ class CollapsibleInfoHeader : public QWidget {
   Q_PROPERTY(float opacity READ opacity WRITE set_opacity);
 
  public:
-  CollapsibleInfoHeader(QWidget* parent = 0);
+  CollapsibleInfoHeader(QWidget* parent = nullptr);
 
   static const int kHeight;
   static const int kIconSize;
diff --git a/src/songinfo/collapsibleinfopane.h b/src/songinfo/collapsibleinfopane.h
index 36305aafa..1445cc5ba 100644
--- a/src/songinfo/collapsibleinfopane.h
+++ b/src/songinfo/collapsibleinfopane.h
@@ -51,7 +51,7 @@ class CollapsibleInfoPane : public QWidget {
     QObject* content_object_;
   };
 
-  CollapsibleInfoPane(const Data& data, QWidget* parent = 0);
+  CollapsibleInfoPane(const Data& data, QWidget* parent = nullptr);
 
   const Data& data() const { return data_; }
 
diff --git a/src/songinfo/songinfobase.h b/src/songinfo/songinfobase.h
index 0ff87354b..13f0f4cc9 100644
--- a/src/songinfo/songinfobase.h
+++ b/src/songinfo/songinfobase.h
@@ -38,7 +38,7 @@ class SongInfoBase : public QWidget {
   Q_OBJECT
 
  public:
-  SongInfoBase(QWidget* parent = 0);
+  SongInfoBase(QWidget* parent = nullptr);
 
   static const char* kSettingsGroup;
 
diff --git a/src/songinfo/songinfofetcher.h b/src/songinfo/songinfofetcher.h
index 9e0decf3d..7366b5bd6 100644
--- a/src/songinfo/songinfofetcher.h
+++ b/src/songinfo/songinfofetcher.h
@@ -33,7 +33,7 @@ class SongInfoFetcher : public QObject {
   Q_OBJECT
 
  public:
-  SongInfoFetcher(QObject* parent = 0);
+  SongInfoFetcher(QObject* parent = nullptr);
 
   struct Result {
     QList<QUrl> images_;
diff --git a/src/songinfo/songinfotextview.h b/src/songinfo/songinfotextview.h
index 27f5c6683..c858c8e0a 100644
--- a/src/songinfo/songinfotextview.h
+++ b/src/songinfo/songinfotextview.h
@@ -24,7 +24,7 @@ class SongInfoTextView : public QTextBrowser {
   Q_OBJECT
 
  public:
-  SongInfoTextView(QWidget* parent = 0);
+  SongInfoTextView(QWidget* parent = nullptr);
 
   static const qreal kDefaultFontSize;
   static const char* kSettingsGroup;
diff --git a/src/songinfo/songinfoview.h b/src/songinfo/songinfoview.h
index da42d80ec..e8e32780b 100644
--- a/src/songinfo/songinfoview.h
+++ b/src/songinfo/songinfoview.h
@@ -29,7 +29,7 @@ class SongInfoView : public SongInfoBase {
   Q_OBJECT
 
  public:
-  SongInfoView(QWidget* parent = 0);
+  SongInfoView(QWidget* parent = nullptr);
   ~SongInfoView();
 
   static const char* kSettingsGroup;
diff --git a/src/songinfo/songkickconcertwidget.h b/src/songinfo/songkickconcertwidget.h
index fdd2f73ca..abef19fbd 100644
--- a/src/songinfo/songkickconcertwidget.h
+++ b/src/songinfo/songkickconcertwidget.h
@@ -30,7 +30,7 @@ class SongKickConcertWidget : public QWidget {
   Q_OBJECT
 
  public:
-  SongKickConcertWidget(QWidget* parent = 0);
+  SongKickConcertWidget(QWidget* parent = nullptr);
   ~SongKickConcertWidget();
 
   static const int kStaticMapWidth;
diff --git a/src/songinfo/songplaystats.h b/src/songinfo/songplaystats.h
index c57fd6ee9..6f08be087 100644
--- a/src/songinfo/songplaystats.h
+++ b/src/songinfo/songplaystats.h
@@ -25,7 +25,7 @@ class SongPlayStats : public QWidget {
   Q_OBJECT
 
  public:
-  SongPlayStats(QWidget* parent = 0);
+  SongPlayStats(QWidget* parent = nullptr);
 
   static const int kIconSize;
   static const int kLineSpacing;
diff --git a/src/songinfo/tagwidget.h b/src/songinfo/tagwidget.h
index 81cb4b458..f1867ac81 100644
--- a/src/songinfo/tagwidget.h
+++ b/src/songinfo/tagwidget.h
@@ -70,7 +70,7 @@ class TagWidget : public QWidget {
  public:
   enum Type { Type_Tags, Type_Artists, };
 
-  TagWidget(Type type, QWidget* parent = 0);
+  TagWidget(Type type, QWidget* parent = nullptr);
 
   void SetIcon(const QIcon& icon) { icon_ = icon; }
   void AddTag(const QString& tag);
diff --git a/src/songinfo/ultimatelyricslyric.h b/src/songinfo/ultimatelyricslyric.h
index bca5a9d79..46a6bab74 100644
--- a/src/songinfo/ultimatelyricslyric.h
+++ b/src/songinfo/ultimatelyricslyric.h
@@ -25,7 +25,7 @@ class UltimateLyricsLyric : public QTextDocument {
   Q_OBJECT
 
  public:
-  UltimateLyricsLyric(QObject* parent = 0);
+  UltimateLyricsLyric(QObject* parent = nullptr);
 
   void SetHtml(const QString& html);
 };
diff --git a/src/songinfo/ultimatelyricsreader.h b/src/songinfo/ultimatelyricsreader.h
index 2bfb474e7..cfa8cfb14 100644
--- a/src/songinfo/ultimatelyricsreader.h
+++ b/src/songinfo/ultimatelyricsreader.h
@@ -30,7 +30,7 @@ class UltimateLyricsReader : public QObject {
   Q_OBJECT
 
  public:
-  UltimateLyricsReader(QObject* parent = 0);
+  UltimateLyricsReader(QObject* parent = nullptr);
 
   QList<SongInfoProvider*> Parse(const QString& filename) const;
   QList<SongInfoProvider*> ParseDevice(QIODevice* device) const;
diff --git a/src/transcoder/transcodedialog.h b/src/transcoder/transcodedialog.h
index de422cc77..d68a92e6e 100644
--- a/src/transcoder/transcodedialog.h
+++ b/src/transcoder/transcodedialog.h
@@ -31,7 +31,7 @@ class TranscodeDialog : public QDialog {
   Q_OBJECT
 
  public:
-  TranscodeDialog(QWidget* parent = 0);
+  TranscodeDialog(QWidget* parent = nullptr);
   ~TranscodeDialog();
 
   static const char* kSettingsGroup;
diff --git a/src/transcoder/transcoder.h b/src/transcoder/transcoder.h
index ad9367833..3e4f91a14 100644
--- a/src/transcoder/transcoder.h
+++ b/src/transcoder/transcoder.h
@@ -47,7 +47,7 @@ class Transcoder : public QObject {
   Q_OBJECT
 
  public:
-  Transcoder(QObject* parent = 0);
+  Transcoder(QObject* parent = nullptr);
 
   static TranscoderPreset PresetForFileType(Song::FileType type);
   static QList<TranscoderPreset> GetAllPresets();
diff --git a/src/transcoder/transcoderoptionsaac.h b/src/transcoder/transcoderoptionsaac.h
index 24b01d8b1..f1680e47a 100644
--- a/src/transcoder/transcoderoptionsaac.h
+++ b/src/transcoder/transcoderoptionsaac.h
@@ -24,7 +24,7 @@ class Ui_TranscoderOptionsAAC;
 
 class TranscoderOptionsAAC : public TranscoderOptionsInterface {
  public:
-  TranscoderOptionsAAC(QWidget* parent = 0);
+  TranscoderOptionsAAC(QWidget* parent = nullptr);
   ~TranscoderOptionsAAC();
 
   void Load();
diff --git a/src/transcoder/transcoderoptionsdialog.h b/src/transcoder/transcoderoptionsdialog.h
index 93377d30c..5afefa7dc 100644
--- a/src/transcoder/transcoderoptionsdialog.h
+++ b/src/transcoder/transcoderoptionsdialog.h
@@ -29,7 +29,7 @@ class TranscoderOptionsDialog : public QDialog {
   Q_OBJECT
 
  public:
-  TranscoderOptionsDialog(Song::FileType type, QWidget* parent = 0);
+  TranscoderOptionsDialog(Song::FileType type, QWidget* parent = nullptr);
   ~TranscoderOptionsDialog();
 
   bool is_valid() const { return options_; }
diff --git a/src/transcoder/transcoderoptionsflac.h b/src/transcoder/transcoderoptionsflac.h
index db390a70f..b5e416e8b 100644
--- a/src/transcoder/transcoderoptionsflac.h
+++ b/src/transcoder/transcoderoptionsflac.h
@@ -24,7 +24,7 @@ class Ui_TranscoderOptionsFlac;
 
 class TranscoderOptionsFlac : public TranscoderOptionsInterface {
  public:
-  TranscoderOptionsFlac(QWidget* parent = 0);
+  TranscoderOptionsFlac(QWidget* parent = nullptr);
   ~TranscoderOptionsFlac();
 
   void Load();
diff --git a/src/transcoder/transcoderoptionsmp3.h b/src/transcoder/transcoderoptionsmp3.h
index 776cc7b21..927da28f8 100644
--- a/src/transcoder/transcoderoptionsmp3.h
+++ b/src/transcoder/transcoderoptionsmp3.h
@@ -26,7 +26,7 @@ class TranscoderOptionsMP3 : public TranscoderOptionsInterface {
   Q_OBJECT
 
  public:
-  TranscoderOptionsMP3(QWidget* parent = 0);
+  TranscoderOptionsMP3(QWidget* parent = nullptr);
   ~TranscoderOptionsMP3();
 
   void Load();
diff --git a/src/transcoder/transcoderoptionsopus.h b/src/transcoder/transcoderoptionsopus.h
index a4e1d557f..384ffea56 100644
--- a/src/transcoder/transcoderoptionsopus.h
+++ b/src/transcoder/transcoderoptionsopus.h
@@ -24,7 +24,7 @@ class Ui_TranscoderOptionsOpus;
 
 class TranscoderOptionsOpus : public TranscoderOptionsInterface {
  public:
-  TranscoderOptionsOpus(QWidget* parent = 0);
+  TranscoderOptionsOpus(QWidget* parent = nullptr);
   ~TranscoderOptionsOpus();
 
   void Load();
diff --git a/src/transcoder/transcoderoptionsspeex.h b/src/transcoder/transcoderoptionsspeex.h
index 2fe512e6d..fe0465814 100644
--- a/src/transcoder/transcoderoptionsspeex.h
+++ b/src/transcoder/transcoderoptionsspeex.h
@@ -24,7 +24,7 @@ class Ui_TranscoderOptionsSpeex;
 
 class TranscoderOptionsSpeex : public TranscoderOptionsInterface {
  public:
-  TranscoderOptionsSpeex(QWidget* parent = 0);
+  TranscoderOptionsSpeex(QWidget* parent = nullptr);
   ~TranscoderOptionsSpeex();
 
   void Load();
diff --git a/src/transcoder/transcoderoptionsvorbis.h b/src/transcoder/transcoderoptionsvorbis.h
index 05de8f1c5..d849fd528 100644
--- a/src/transcoder/transcoderoptionsvorbis.h
+++ b/src/transcoder/transcoderoptionsvorbis.h
@@ -24,7 +24,7 @@ class Ui_TranscoderOptionsVorbis;
 
 class TranscoderOptionsVorbis : public TranscoderOptionsInterface {
  public:
-  TranscoderOptionsVorbis(QWidget* parent = 0);
+  TranscoderOptionsVorbis(QWidget* parent = nullptr);
   ~TranscoderOptionsVorbis();
 
   void Load();
diff --git a/src/transcoder/transcoderoptionswma.h b/src/transcoder/transcoderoptionswma.h
index b1d4cfbec..2e4d97617 100644
--- a/src/transcoder/transcoderoptionswma.h
+++ b/src/transcoder/transcoderoptionswma.h
@@ -24,7 +24,7 @@ class Ui_TranscoderOptionsWma;
 
 class TranscoderOptionsWma : public TranscoderOptionsInterface {
  public:
-  TranscoderOptionsWma(QWidget* parent = 0);
+  TranscoderOptionsWma(QWidget* parent = nullptr);
   ~TranscoderOptionsWma();
 
   void Load();
diff --git a/src/ui/about.h b/src/ui/about.h
index 1a9730815..97aa7bd36 100644
--- a/src/ui/about.h
+++ b/src/ui/about.h
@@ -25,7 +25,7 @@
 class About : public QDialog {
   Q_OBJECT
  public:
-  About(QWidget* parent = 0);
+  About(QWidget* parent = nullptr);
 
   static const char* kUrl;
 
diff --git a/src/ui/addstreamdialog.h b/src/ui/addstreamdialog.h
index b0c1220f4..f076d36f0 100644
--- a/src/ui/addstreamdialog.h
+++ b/src/ui/addstreamdialog.h
@@ -28,7 +28,7 @@ class AddStreamDialog : public QDialog {
   Q_OBJECT
 
  public:
-  AddStreamDialog(QWidget* parent = 0);
+  AddStreamDialog(QWidget* parent = nullptr);
   ~AddStreamDialog();
 
   void set_url(const QUrl& url);
diff --git a/src/ui/albumcoverchoicecontroller.h b/src/ui/albumcoverchoicecontroller.h
index e1561b48f..c71a4f5c7 100644
--- a/src/ui/albumcoverchoicecontroller.h
+++ b/src/ui/albumcoverchoicecontroller.h
@@ -41,7 +41,7 @@ class AlbumCoverChoiceController : public QWidget {
   static const char* kSaveImageFileFilter;
   static const char* kAllFilesFilter;
 
-  AlbumCoverChoiceController(QWidget* parent = 0);
+  AlbumCoverChoiceController(QWidget* parent = nullptr);
   ~AlbumCoverChoiceController();
 
   void SetApplication(Application* app);
diff --git a/src/ui/albumcoverexport.h b/src/ui/albumcoverexport.h
index d5531a7bb..9cac2a3c0 100644
--- a/src/ui/albumcoverexport.h
+++ b/src/ui/albumcoverexport.h
@@ -27,7 +27,7 @@ class AlbumCoverExport : public QDialog {
   Q_OBJECT
 
  public:
-  AlbumCoverExport(QWidget* parent = 0);
+  AlbumCoverExport(QWidget* parent = nullptr);
   ~AlbumCoverExport();
 
   enum OverwriteMode {
diff --git a/src/ui/albumcovermanager.h b/src/ui/albumcovermanager.h
index 5efa126f6..26b77f9c4 100644
--- a/src/ui/albumcovermanager.h
+++ b/src/ui/albumcovermanager.h
@@ -48,7 +48,7 @@ class AlbumCoverManager : public QMainWindow {
   Q_OBJECT
  public:
   AlbumCoverManager(Application* app, LibraryBackend* library_backend,
-                    QWidget* parent = 0, QNetworkAccessManager* network = 0);
+                    QWidget* parent = nullptr, QNetworkAccessManager* network = 0);
   ~AlbumCoverManager();
 
   static const char* kSettingsGroup;
diff --git a/src/ui/albumcovermanagerlist.h b/src/ui/albumcovermanagerlist.h
index 41078e129..3862dd9e4 100644
--- a/src/ui/albumcovermanagerlist.h
+++ b/src/ui/albumcovermanagerlist.h
@@ -25,7 +25,7 @@ class AlbumCoverManager;
 class AlbumCoverManagerList : public QListWidget {
   Q_OBJECT
  public:
-  AlbumCoverManagerList(QWidget* parent = 0);
+  AlbumCoverManagerList(QWidget* parent = nullptr);
 
   void set_cover_manager(AlbumCoverManager* manager) { manager_ = manager; }
 
diff --git a/src/ui/console.h b/src/ui/console.h
index 2ba5b8532..fcd5c9b6b 100644
--- a/src/ui/console.h
+++ b/src/ui/console.h
@@ -10,7 +10,7 @@ class Application;
 class Console : public QDialog {
   Q_OBJECT
  public:
-  Console(Application* app, QWidget* parent = 0);
+  Console(Application* app, QWidget* parent = nullptr);
 
  private slots:
   void RunQuery();
diff --git a/src/ui/coverfromurldialog.h b/src/ui/coverfromurldialog.h
index c3eb065bd..4087dc342 100644
--- a/src/ui/coverfromurldialog.h
+++ b/src/ui/coverfromurldialog.h
@@ -30,7 +30,7 @@ class CoverFromURLDialog : public QDialog {
   Q_OBJECT
 
  public:
-  CoverFromURLDialog(QWidget* parent = 0);
+  CoverFromURLDialog(QWidget* parent = nullptr);
   ~CoverFromURLDialog();
 
   // Opens the dialog. This returns an image found at the URL chosen by user
diff --git a/src/ui/edittagdialog.h b/src/ui/edittagdialog.h
index 8c18e6f5d..6f03f903b 100644
--- a/src/ui/edittagdialog.h
+++ b/src/ui/edittagdialog.h
@@ -43,7 +43,7 @@ class EditTagDialog : public QDialog {
   Q_OBJECT
 
  public:
-  EditTagDialog(Application* app, QWidget* parent = 0);
+  EditTagDialog(Application* app, QWidget* parent = nullptr);
   ~EditTagDialog();
 
   static const char* kHintText;
diff --git a/src/ui/equalizer.h b/src/ui/equalizer.h
index 30b20f280..1fb7befc2 100644
--- a/src/ui/equalizer.h
+++ b/src/ui/equalizer.h
@@ -29,7 +29,7 @@ class Equalizer : public QDialog {
   Q_OBJECT
 
  public:
-  Equalizer(QWidget* parent = 0);
+  Equalizer(QWidget* parent = nullptr);
   ~Equalizer();
 
   static const int kBands = 10;
diff --git a/src/ui/globalshortcutgrabber.h b/src/ui/globalshortcutgrabber.h
index 74319b7f5..180685fb5 100644
--- a/src/ui/globalshortcutgrabber.h
+++ b/src/ui/globalshortcutgrabber.h
@@ -33,7 +33,7 @@ class GlobalShortcutGrabber : public QDialog {
   Q_OBJECT
 
  public:
-  GlobalShortcutGrabber(QWidget* parent = 0);
+  GlobalShortcutGrabber(QWidget* parent = nullptr);
   ~GlobalShortcutGrabber();
 
   QKeySequence GetKey(const QString& name);
diff --git a/src/ui/macsystemtrayicon.h b/src/ui/macsystemtrayicon.h
index 3b9741c31..6fa5b5898 100644
--- a/src/ui/macsystemtrayicon.h
+++ b/src/ui/macsystemtrayicon.h
@@ -28,7 +28,7 @@ class MacSystemTrayIcon : public SystemTrayIcon {
   Q_OBJECT
 
  public:
-  MacSystemTrayIcon(QObject* parent = 0);
+  MacSystemTrayIcon(QObject* parent = nullptr);
   ~MacSystemTrayIcon();
 
   void SetupMenu(QAction* previous, QAction* play, QAction* stop,
diff --git a/src/ui/mainwindow.h b/src/ui/mainwindow.h
index 5a2343daa..427c21f66 100644
--- a/src/ui/mainwindow.h
+++ b/src/ui/mainwindow.h
@@ -89,7 +89,7 @@ class MainWindow : public QMainWindow, public PlatformInterface {
 
  public:
   MainWindow(Application* app, SystemTrayIcon* tray_icon, OSD* osd,
-             QWidget* parent = 0);
+             QWidget* parent = nullptr);
   ~MainWindow();
 
   static const char* kSettingsGroup;
diff --git a/src/ui/organisedialog.h b/src/ui/organisedialog.h
index 9eb764ded..d38664c7b 100644
--- a/src/ui/organisedialog.h
+++ b/src/ui/organisedialog.h
@@ -41,7 +41,7 @@ class OrganiseDialog : public QDialog {
   Q_OBJECT
 
  public:
-  OrganiseDialog(TaskManager* task_manager, QWidget* parent = 0);
+  OrganiseDialog(TaskManager* task_manager, QWidget* parent = nullptr);
   ~OrganiseDialog();
 
   static const char* kDefaultFormat;
diff --git a/src/ui/organiseerrordialog.h b/src/ui/organiseerrordialog.h
index 117a47e62..e250d683c 100644
--- a/src/ui/organiseerrordialog.h
+++ b/src/ui/organiseerrordialog.h
@@ -28,7 +28,7 @@ class OrganiseErrorDialog : public QDialog {
   Q_OBJECT
 
  public:
-  OrganiseErrorDialog(QWidget* parent = 0);
+  OrganiseErrorDialog(QWidget* parent = nullptr);
   ~OrganiseErrorDialog();
 
   enum OperationType { Type_Copy, Type_Delete, };
diff --git a/src/ui/qtsystemtrayicon.h b/src/ui/qtsystemtrayicon.h
index 710a839ce..b3d8fbc5e 100644
--- a/src/ui/qtsystemtrayicon.h
+++ b/src/ui/qtsystemtrayicon.h
@@ -26,7 +26,7 @@ class QtSystemTrayIcon : public SystemTrayIcon {
   Q_OBJECT
 
  public:
-  QtSystemTrayIcon(QObject* parent = 0);
+  QtSystemTrayIcon(QObject* parent = nullptr);
   ~QtSystemTrayIcon();
 
   void SetupMenu(QAction* previous, QAction* play, QAction* stop,
diff --git a/src/ui/ripcd.h b/src/ui/ripcd.h
index 779889c53..cd6e2591e 100644
--- a/src/ui/ripcd.h
+++ b/src/ui/ripcd.h
@@ -34,7 +34,7 @@ class RipCD : public QDialog {
   Q_OBJECT
 
  public:
-  explicit RipCD(QWidget* parent = 0);
+  explicit RipCD(QWidget* parent = nullptr);
   ~RipCD();
   bool CDIOIsValid() const;
 
diff --git a/src/ui/settingsdialog.h b/src/ui/settingsdialog.h
index 583fc47c5..32c2f9dc2 100644
--- a/src/ui/settingsdialog.h
+++ b/src/ui/settingsdialog.h
@@ -54,7 +54,7 @@ class SettingsDialog : public QDialog {
 
  public:
   SettingsDialog(Application* app, BackgroundStreams* streams,
-                 QWidget* parent = 0);
+                 QWidget* parent = nullptr);
   ~SettingsDialog();
 
   enum Page {
diff --git a/src/ui/standarditemiconloader.h b/src/ui/standarditemiconloader.h
index 999dd2b34..4e0439367 100644
--- a/src/ui/standarditemiconloader.h
+++ b/src/ui/standarditemiconloader.h
@@ -36,7 +36,7 @@ class StandardItemIconLoader : public QObject {
   Q_OBJECT
 
  public:
-  StandardItemIconLoader(AlbumCoverLoader* cover_loader, QObject* parent = 0);
+  StandardItemIconLoader(AlbumCoverLoader* cover_loader, QObject* parent = nullptr);
 
   AlbumCoverLoaderOptions* options() { return &cover_options_; }
 
diff --git a/src/ui/systemtrayicon.h b/src/ui/systemtrayicon.h
index 4c68b6420..cdeac88d0 100644
--- a/src/ui/systemtrayicon.h
+++ b/src/ui/systemtrayicon.h
@@ -28,7 +28,7 @@ class SystemTrayIcon : public QObject {
   Q_OBJECT
 
  public:
-  SystemTrayIcon(QObject* parent = 0);
+  SystemTrayIcon(QObject* parent = nullptr);
 
   // Called once to create the icon's context menu
   virtual void SetupMenu(QAction* previous, QAction* play, QAction* stop,
@@ -48,7 +48,7 @@ class SystemTrayIcon : public QObject {
   virtual void SetNowPlaying(const Song& song, const QString& image_path) {}
   virtual void ClearNowPlaying() {}
 
-  static SystemTrayIcon* CreateSystemTrayIcon(QObject* parent = 0);
+  static SystemTrayIcon* CreateSystemTrayIcon(QObject* parent = nullptr);
 
  public slots:
   void SetProgress(int percentage);
diff --git a/src/ui/trackselectiondialog.h b/src/ui/trackselectiondialog.h
index f95b57852..9ce76ea45 100644
--- a/src/ui/trackselectiondialog.h
+++ b/src/ui/trackselectiondialog.h
@@ -31,7 +31,7 @@ class TrackSelectionDialog : public QDialog {
   Q_OBJECT
 
  public:
-  TrackSelectionDialog(QWidget* parent = 0);
+  TrackSelectionDialog(QWidget* parent = nullptr);
   ~TrackSelectionDialog();
 
   void set_save_on_close(bool save_on_close) { save_on_close_ = save_on_close; }
diff --git a/src/visualisations/projectmpresetmodel.h b/src/visualisations/projectmpresetmodel.h
index d4575475b..efa42f334 100644
--- a/src/visualisations/projectmpresetmodel.h
+++ b/src/visualisations/projectmpresetmodel.h
@@ -28,7 +28,7 @@ class ProjectMPresetModel : public QAbstractItemModel {
   friend class ProjectMVisualisation;
 
  public:
-  ProjectMPresetModel(ProjectMVisualisation* vis, QObject* parent = 0);
+  ProjectMPresetModel(ProjectMVisualisation* vis, QObject* parent = nullptr);
 
   enum { Role_Url = Qt::UserRole, };
 
diff --git a/src/visualisations/projectmvisualisation.h b/src/visualisations/projectmvisualisation.h
index ec1266f54..918f0c77f 100644
--- a/src/visualisations/projectmvisualisation.h
+++ b/src/visualisations/projectmvisualisation.h
@@ -35,7 +35,7 @@ class QTemporaryFile;
 class ProjectMVisualisation : public QGraphicsScene, public BufferConsumer {
   Q_OBJECT
  public:
-  ProjectMVisualisation(QObject* parent = 0);
+  ProjectMVisualisation(QObject* parent = nullptr);
   ~ProjectMVisualisation();
 
   enum Mode { Random = 0, FromList = 1, };
diff --git a/src/visualisations/visualisationcontainer.h b/src/visualisations/visualisationcontainer.h
index 6154d4251..926b3913e 100644
--- a/src/visualisations/visualisationcontainer.h
+++ b/src/visualisations/visualisationcontainer.h
@@ -36,7 +36,7 @@ class VisualisationContainer : public QGraphicsView {
   Q_OBJECT
 
  public:
-  VisualisationContainer(QWidget* parent = 0);
+  VisualisationContainer(QWidget* parent = nullptr);
 
   static const int kLowFramerate;
   static const int kMediumFramerate;
diff --git a/src/visualisations/visualisationoverlay.h b/src/visualisations/visualisationoverlay.h
index aa13f4257..c6d05af9d 100644
--- a/src/visualisations/visualisationoverlay.h
+++ b/src/visualisations/visualisationoverlay.h
@@ -29,7 +29,7 @@ class VisualisationOverlay : public QWidget {
   Q_OBJECT
 
  public:
-  VisualisationOverlay(QWidget* parent = 0);
+  VisualisationOverlay(QWidget* parent = nullptr);
   ~VisualisationOverlay();
 
   static const int kFadeDuration;
diff --git a/src/visualisations/visualisationselector.h b/src/visualisations/visualisationselector.h
index a6732c24b..9a93afa63 100644
--- a/src/visualisations/visualisationselector.h
+++ b/src/visualisations/visualisationselector.h
@@ -26,7 +26,7 @@ class Ui_VisualisationSelector;
 class VisualisationSelector : public QDialog {
   Q_OBJECT
  public:
-  VisualisationSelector(QWidget* parent = 0);
+  VisualisationSelector(QWidget* parent = nullptr);
   ~VisualisationSelector();
 
   void SetVisualisation(ProjectMVisualisation* vis) { vis_ = vis; }
diff --git a/src/widgets/autoexpandingtreeview.h b/src/widgets/autoexpandingtreeview.h
index a113a174c..3c5de36d2 100644
--- a/src/widgets/autoexpandingtreeview.h
+++ b/src/widgets/autoexpandingtreeview.h
@@ -24,7 +24,7 @@ class AutoExpandingTreeView : public QTreeView {
   Q_OBJECT
 
  public:
-  AutoExpandingTreeView(QWidget* parent = 0);
+  AutoExpandingTreeView(QWidget* parent = nullptr);
 
   static const int kRowsToShow;
 
diff --git a/src/widgets/busyindicator.h b/src/widgets/busyindicator.h
index d4d62fc70..f9a8c7a0e 100644
--- a/src/widgets/busyindicator.h
+++ b/src/widgets/busyindicator.h
@@ -27,8 +27,8 @@ class BusyIndicator : public QWidget {
   Q_PROPERTY(QString text READ text WRITE set_text)
 
  public:
-  explicit BusyIndicator(const QString& text, QWidget* parent = 0);
-  explicit BusyIndicator(QWidget* parent = 0);
+  explicit BusyIndicator(const QString& text, QWidget* parent = nullptr);
+  explicit BusyIndicator(QWidget* parent = nullptr);
   ~BusyIndicator();
 
   QString text() const;
diff --git a/src/widgets/clickablelabel.h b/src/widgets/clickablelabel.h
index 9d8515055..230225d61 100644
--- a/src/widgets/clickablelabel.h
+++ b/src/widgets/clickablelabel.h
@@ -24,7 +24,7 @@ class ClickableLabel : public QLabel {
   Q_OBJECT
 
  public:
-  ClickableLabel(QWidget* parent = 0);
+  ClickableLabel(QWidget* parent = nullptr);
 
 signals:
   void Clicked();
diff --git a/src/widgets/elidedlabel.h b/src/widgets/elidedlabel.h
index 9d3bbf17e..54927f657 100644
--- a/src/widgets/elidedlabel.h
+++ b/src/widgets/elidedlabel.h
@@ -24,7 +24,7 @@ class ElidedLabel : public QLabel {
   Q_OBJECT
 
  public:
-  ElidedLabel(QWidget* parent = 0);
+  ElidedLabel(QWidget* parent = nullptr);
 
  public slots:
   void SetText(const QString& text);
diff --git a/src/widgets/equalizerslider.h b/src/widgets/equalizerslider.h
index 255d1e7ed..0c81236c6 100644
--- a/src/widgets/equalizerslider.h
+++ b/src/widgets/equalizerslider.h
@@ -27,7 +27,7 @@ class EqualizerSlider : public QWidget {
   Q_OBJECT
 
  public:
-  EqualizerSlider(const QString& label, QWidget* parent = 0);
+  EqualizerSlider(const QString& label, QWidget* parent = nullptr);
   ~EqualizerSlider();
 
   int value() const;
diff --git a/src/widgets/errordialog.h b/src/widgets/errordialog.h
index bfa59f711..e8b7b5e70 100644
--- a/src/widgets/errordialog.h
+++ b/src/widgets/errordialog.h
@@ -26,7 +26,7 @@ class ErrorDialog : public QDialog {
   Q_OBJECT
 
  public:
-  ErrorDialog(QWidget* parent = 0);
+  ErrorDialog(QWidget* parent = nullptr);
   ~ErrorDialog();
 
  public slots:
diff --git a/src/widgets/fancytabwidget.h b/src/widgets/fancytabwidget.h
index 375a292a0..a0a3dd80a 100644
--- a/src/widgets/fancytabwidget.h
+++ b/src/widgets/fancytabwidget.h
@@ -96,7 +96,7 @@ class FancyTabBar : public QWidget {
   Q_OBJECT
 
  public:
-  FancyTabBar(QWidget* parent = 0);
+  FancyTabBar(QWidget* parent = nullptr);
   ~FancyTabBar();
 
   void paintEvent(QPaintEvent* event);
@@ -145,7 +145,7 @@ class FancyTabWidget : public QWidget {
   Q_OBJECT
 
  public:
-  FancyTabWidget(QWidget* parent = 0);
+  FancyTabWidget(QWidget* parent = nullptr);
 
   // Values are persisted - only add to the end
   enum Mode {
diff --git a/src/widgets/favoritewidget.h b/src/widgets/favoritewidget.h
index d4ea15c93..417109eaf 100644
--- a/src/widgets/favoritewidget.h
+++ b/src/widgets/favoritewidget.h
@@ -24,7 +24,7 @@ class FavoriteWidget : public QWidget {
   Q_OBJECT
 
  public:
-  FavoriteWidget(int tab_id, bool favorite = false, QWidget* parent = 0);
+  FavoriteWidget(int tab_id, bool favorite = false, QWidget* parent = nullptr);
 
   // Change the value if different from the current one and then update display
   // and emit FavoriteStateChanged signal
diff --git a/src/widgets/fileview.h b/src/widgets/fileview.h
index 5f0178c90..608938366 100644
--- a/src/widgets/fileview.h
+++ b/src/widgets/fileview.h
@@ -39,7 +39,7 @@ class FileView : public QWidget {
   Q_OBJECT
 
  public:
-  FileView(QWidget* parent = 0);
+  FileView(QWidget* parent = nullptr);
   ~FileView();
 
   static const char* kFileFilter;
diff --git a/src/widgets/fileviewlist.h b/src/widgets/fileviewlist.h
index 0a8fe503d..98284c7eb 100644
--- a/src/widgets/fileviewlist.h
+++ b/src/widgets/fileviewlist.h
@@ -27,7 +27,7 @@ class FileViewList : public QListView {
   Q_OBJECT
 
  public:
-  FileViewList(QWidget* parent = 0);
+  FileViewList(QWidget* parent = nullptr);
 
   void mousePressEvent(QMouseEvent* e);
 
diff --git a/src/widgets/forcescrollperpixel.h b/src/widgets/forcescrollperpixel.h
index 5ff8d4e8c..1449104f2 100644
--- a/src/widgets/forcescrollperpixel.h
+++ b/src/widgets/forcescrollperpixel.h
@@ -26,7 +26,7 @@ class QAbstractItemView;
 // This helper class forces the mode back to ScrollPerPixel.
 class ForceScrollPerPixel : public QObject {
  public:
-  ForceScrollPerPixel(QAbstractItemView* item_view, QObject* parent = 0);
+  ForceScrollPerPixel(QAbstractItemView* item_view, QObject* parent = nullptr);
 
  protected:
   bool eventFilter(QObject* object, QEvent* event);
diff --git a/src/widgets/freespacebar.h b/src/widgets/freespacebar.h
index 0630724c5..b328c6875 100644
--- a/src/widgets/freespacebar.h
+++ b/src/widgets/freespacebar.h
@@ -24,7 +24,7 @@ class FreeSpaceBar : public QWidget {
   Q_OBJECT
 
  public:
-  FreeSpaceBar(QWidget* parent = 0);
+  FreeSpaceBar(QWidget* parent = nullptr);
 
   static const int kBarHeight;
   static const int kBarBorderRadius;
diff --git a/src/widgets/groupediconview.h b/src/widgets/groupediconview.h
index fefe9ca4e..42e08bf1f 100644
--- a/src/widgets/groupediconview.h
+++ b/src/widgets/groupediconview.h
@@ -40,7 +40,7 @@ class GroupedIconView : public QListView {
   Q_PROPERTY(QString header_text READ header_text WRITE set_header_text);
 
  public:
-  GroupedIconView(QWidget* parent = 0);
+  GroupedIconView(QWidget* parent = nullptr);
 
   enum Role { Role_Group = 1158300, };
 
diff --git a/src/widgets/lineedit.h b/src/widgets/lineedit.h
index 8a192a699..f9765d628 100644
--- a/src/widgets/lineedit.h
+++ b/src/widgets/lineedit.h
@@ -101,7 +101,7 @@ class LineEdit : public QLineEdit, public ExtendedEditor {
                  set_reset_button);
 
  public:
-  LineEdit(QWidget* parent = 0);
+  LineEdit(QWidget* parent = nullptr);
 
   // ExtendedEditor
   void set_focus() { QLineEdit::setFocus(); }
@@ -133,7 +133,7 @@ class TextEdit : public QPlainTextEdit, public ExtendedEditor {
                  set_reset_button);
 
  public:
-  TextEdit(QWidget* parent = 0);
+  TextEdit(QWidget* parent = nullptr);
 
   // ExtendedEditor
   void set_focus() { QPlainTextEdit::setFocus(); }
@@ -158,7 +158,7 @@ class SpinBox : public QSpinBox, public ExtendedEditor {
                  set_reset_button);
 
  public:
-  SpinBox(QWidget* parent = 0);
+  SpinBox(QWidget* parent = nullptr);
 
   // QSpinBox
   QString textFromValue(int val) const;
diff --git a/src/widgets/linetextedit.h b/src/widgets/linetextedit.h
index f66c981af..00ba03e14 100644
--- a/src/widgets/linetextedit.h
+++ b/src/widgets/linetextedit.h
@@ -24,7 +24,7 @@ class LineTextEdit : public QTextEdit {
   Q_OBJECT
 
  public:
-  LineTextEdit(QWidget* parent = 0);
+  LineTextEdit(QWidget* parent = nullptr);
 
   QSize sizeHint() const;
   QSize minimumSizeHint() const;
diff --git a/src/widgets/loginstatewidget.h b/src/widgets/loginstatewidget.h
index a4d3ed562..64d3e3018 100644
--- a/src/widgets/loginstatewidget.h
+++ b/src/widgets/loginstatewidget.h
@@ -27,7 +27,7 @@ class LoginStateWidget : public QWidget {
   Q_OBJECT
 
  public:
-  LoginStateWidget(QWidget* parent = 0);
+  LoginStateWidget(QWidget* parent = nullptr);
   ~LoginStateWidget();
 
   enum State { LoggedIn, LoginInProgress, LoggedOut };
diff --git a/src/widgets/multiloadingindicator.h b/src/widgets/multiloadingindicator.h
index 4f7fa0c00..0fa29ef56 100644
--- a/src/widgets/multiloadingindicator.h
+++ b/src/widgets/multiloadingindicator.h
@@ -27,7 +27,7 @@ class MultiLoadingIndicator : public QWidget {
   Q_OBJECT
 
  public:
-  MultiLoadingIndicator(QWidget* parent = 0);
+  MultiLoadingIndicator(QWidget* parent = nullptr);
 
   static const int kVerticalPadding;
   static const int kHorizontalPadding;
diff --git a/src/widgets/nowplayingwidget.h b/src/widgets/nowplayingwidget.h
index 62f9dd9f4..328dbc88e 100644
--- a/src/widgets/nowplayingwidget.h
+++ b/src/widgets/nowplayingwidget.h
@@ -42,7 +42,7 @@ class NowPlayingWidget : public QWidget {
   Q_OBJECT
 
  public:
-  NowPlayingWidget(QWidget* parent = 0);
+  NowPlayingWidget(QWidget* parent = nullptr);
   ~NowPlayingWidget();
 
   static const char* kSettingsGroup;
diff --git a/src/widgets/osd.h b/src/widgets/osd.h
index 151f721ab..8103fd5c5 100644
--- a/src/widgets/osd.h
+++ b/src/widgets/osd.h
@@ -47,7 +47,7 @@ class OSD : public QObject {
   Q_OBJECT
 
  public:
-  OSD(SystemTrayIcon* tray_icon, Application* app, QObject* parent = 0);
+  OSD(SystemTrayIcon* tray_icon, Application* app, QObject* parent = nullptr);
   ~OSD();
 
   static const char* kSettingsGroup;
diff --git a/src/widgets/osdpretty.h b/src/widgets/osdpretty.h
index b077ee1aa..50bf1eeda 100644
--- a/src/widgets/osdpretty.h
+++ b/src/widgets/osdpretty.h
@@ -30,7 +30,7 @@ class OSDPretty : public QWidget {
  public:
   enum Mode { Mode_Popup, Mode_Draggable, };
 
-  OSDPretty(Mode mode, QWidget* parent = 0);
+  OSDPretty(Mode mode, QWidget* parent = nullptr);
   ~OSDPretty();
 
   static const char* kSettingsGroup;
diff --git a/src/widgets/prettyimage.h b/src/widgets/prettyimage.h
index f6b062b44..1467e5850 100644
--- a/src/widgets/prettyimage.h
+++ b/src/widgets/prettyimage.h
@@ -30,7 +30,7 @@ class PrettyImage : public QWidget {
 
  public:
   PrettyImage(const QUrl& url, QNetworkAccessManager* network,
-              QWidget* parent = 0);
+              QWidget* parent = nullptr);
 
   static const int kTotalHeight;
   static const int kReflectionHeight;
diff --git a/src/widgets/prettyimageview.h b/src/widgets/prettyimageview.h
index fad801424..6b3b8d29e 100644
--- a/src/widgets/prettyimageview.h
+++ b/src/widgets/prettyimageview.h
@@ -33,7 +33,7 @@ class PrettyImageView : public QScrollArea {
   Q_OBJECT
 
  public:
-  PrettyImageView(QNetworkAccessManager* network, QWidget* parent = 0);
+  PrettyImageView(QNetworkAccessManager* network, QWidget* parent = nullptr);
 
   static const char* kSettingsGroup;
 
diff --git a/src/widgets/progressitemdelegate.h b/src/widgets/progressitemdelegate.h
index 95ec4843b..479585ec7 100644
--- a/src/widgets/progressitemdelegate.h
+++ b/src/widgets/progressitemdelegate.h
@@ -23,7 +23,7 @@
 class ProgressItemDelegate : public QStyledItemDelegate {
   Q_OBJECT
  public:
-  ProgressItemDelegate(QObject* parent = 0);
+  ProgressItemDelegate(QObject* parent = nullptr);
 
   void paint(QPainter* painter, const QStyleOptionViewItem& option,
              const QModelIndex& index) const;
diff --git a/src/widgets/ratingwidget.h b/src/widgets/ratingwidget.h
index 013da0867..cf2f51cb3 100644
--- a/src/widgets/ratingwidget.h
+++ b/src/widgets/ratingwidget.h
@@ -41,7 +41,7 @@ class RatingWidget : public QWidget {
   Q_PROPERTY(float rating READ rating WRITE set_rating);
 
  public:
-  RatingWidget(QWidget* parent = 0);
+  RatingWidget(QWidget* parent = nullptr);
 
   QSize sizeHint() const;
 
diff --git a/src/widgets/renametablineedit.h b/src/widgets/renametablineedit.h
index 7359f3777..51c39fea2 100644
--- a/src/widgets/renametablineedit.h
+++ b/src/widgets/renametablineedit.h
@@ -24,7 +24,7 @@ class RenameTabLineEdit : public QLineEdit {
   Q_OBJECT
 
  public:
-  RenameTabLineEdit(QWidget* parent = 0);
+  RenameTabLineEdit(QWidget* parent = nullptr);
 
 signals:
   void EditingCanceled();
diff --git a/src/widgets/stickyslider.h b/src/widgets/stickyslider.h
index 4401b8fb8..f04f0be4b 100644
--- a/src/widgets/stickyslider.h
+++ b/src/widgets/stickyslider.h
@@ -27,7 +27,7 @@ class StickySlider : public QSlider {
                  set_sticky_threshold);
 
  public:
-  StickySlider(QWidget* parent = 0);
+  StickySlider(QWidget* parent = nullptr);
 
   int sticky_center() const { return sticky_center_; }
   int sticky_threshold() const { return sticky_threshold_; }
diff --git a/src/widgets/stretchheaderview.h b/src/widgets/stretchheaderview.h
index e4f3afa4d..f3a6ae914 100644
--- a/src/widgets/stretchheaderview.h
+++ b/src/widgets/stretchheaderview.h
@@ -24,7 +24,7 @@ class StretchHeaderView : public QHeaderView {
   Q_OBJECT
 
  public:
-  StretchHeaderView(Qt::Orientation orientation, QWidget* parent = 0);
+  StretchHeaderView(Qt::Orientation orientation, QWidget* parent = nullptr);
 
   typedef double ColumnWidthType;
 
diff --git a/src/widgets/trackslider.h b/src/widgets/trackslider.h
index e8ff54925..e1cecd720 100644
--- a/src/widgets/trackslider.h
+++ b/src/widgets/trackslider.h
@@ -30,7 +30,7 @@ class TrackSlider : public QWidget {
   Q_OBJECT
 
  public:
-  TrackSlider(QWidget* parent = 0);
+  TrackSlider(QWidget* parent = nullptr);
   ~TrackSlider();
 
   void SetApplication(Application* app);
diff --git a/src/widgets/tracksliderslider.h b/src/widgets/tracksliderslider.h
index 57d383268..ca23180e8 100644
--- a/src/widgets/tracksliderslider.h
+++ b/src/widgets/tracksliderslider.h
@@ -27,7 +27,7 @@ class TrackSliderSlider : public QSlider {
   Q_OBJECT
 
  public:
-  TrackSliderSlider(QWidget* parent = 0);
+  TrackSliderSlider(QWidget* parent = nullptr);
 
  protected:
   void mousePressEvent(QMouseEvent* e);
diff --git a/src/wiimotedev/shortcuts.h b/src/wiimotedev/shortcuts.h
index b3310a722..7f19faa24 100644
--- a/src/wiimotedev/shortcuts.h
+++ b/src/wiimotedev/shortcuts.h
@@ -34,7 +34,7 @@ class WiimotedevShortcuts : public QObject {
   static const char* kActionsGroup;
   static const char* kSettingsGroup;
 
-  WiimotedevShortcuts(OSD* osd, QWidget* window, QObject* parent = 0);
+  WiimotedevShortcuts(OSD* osd, QWidget* window, QObject* parent = nullptr);
 
   enum Action {
     WiimotedevActiveDeactive = 0,