Merge branch 'nitehu-feature/cache-folder-setting' into develop

dependencies.gradle

@@ -27,12 +27,12 @@ ext.versions = [
 
         junit4               : "4.12",
         junit5               : "5.3.1",
-        mockito              : "2.16.0",
+        mockito              : "3.5.5",
         mockitoKotlin        : "1.5.0",
         kluent               : "1.35",
         apacheCodecs         : "1.10",
         testRunner           : "1.0.1",
-        robolectric          : "3.8",
+        robolectric          : "4.4",
         dexter               : "6.1.2",
 ]
 

gradle_scripts/android-module-bootstrap.gradle

@@ -69,6 +69,6 @@ jacoco {
 }
 
 ext {
-    jacocoExclude = []
+    jacocoExclude = ['jdk.internal.*']
 }
 

gradle_scripts/kotlin-module-bootstrap.gradle

@@ -30,7 +30,7 @@ jacoco {
 
 ext {
     // override it in the module
-    jacocoExclude = []
+    jacocoExclude = ['jdk.internal.*']
 }
 
 jacocoTestReport {

ultrasonic/build.gradle

@@ -99,7 +99,8 @@ ext {
             '**/R$*.class',
             '**/R.class',
             '**/BuildConfig.class',
-            '**/di/**'
+            '**/di/**',
+            'jdk.internal.*'
     ]
 }
 
@@ -109,4 +110,5 @@ jacoco {
 
 tasks.withType(Test) {
     jacoco.includeNoLocationClasses = true
+    jacoco.excludes += jacocoExclude
 }

ultrasonic/src/main/java/org/moire/ultrasonic/fragment/SettingsFragment.java

@@ -15,6 +15,8 @@ import org.moire.ultrasonic.activity.ServerSettingsActivity;
 import org.moire.ultrasonic.activity.SubsonicTabActivity;
 import org.moire.ultrasonic.featureflags.Feature;
 import org.moire.ultrasonic.featureflags.FeatureStorage;
+import org.moire.ultrasonic.filepicker.FilePickerDialog;
+import org.moire.ultrasonic.filepicker.OnFileSelectedListener;
 import org.moire.ultrasonic.provider.SearchSuggestionProvider;
 import org.moire.ultrasonic.service.MediaPlayerController;
 import org.moire.ultrasonic.util.*;
@@ -37,7 +39,7 @@ public class SettingsFragment extends PreferenceFragment
     private ListPreference maxBitrateWifi;
     private ListPreference maxBitrateMobile;
     private ListPreference cacheSize;
-    private EditTextPreference cacheLocation;
+    private Preference cacheLocation;
     private ListPreference preloadCount;
     private ListPreference bufferLength;
     private ListPreference incrementTime;
@@ -85,7 +87,7 @@ public class SettingsFragment extends PreferenceFragment
         maxBitrateWifi = (ListPreference) findPreference(Constants.PREFERENCES_KEY_MAX_BITRATE_WIFI);
         maxBitrateMobile = (ListPreference) findPreference(Constants.PREFERENCES_KEY_MAX_BITRATE_MOBILE);
         cacheSize = (ListPreference) findPreference(Constants.PREFERENCES_KEY_CACHE_SIZE);
-        cacheLocation = (EditTextPreference) findPreference(Constants.PREFERENCES_KEY_CACHE_LOCATION);
+        cacheLocation = findPreference(Constants.PREFERENCES_KEY_CACHE_LOCATION);
         preloadCount = (ListPreference) findPreference(Constants.PREFERENCES_KEY_PRELOAD_COUNT);
         bufferLength = (ListPreference) findPreference(Constants.PREFERENCES_KEY_BUFFER_LENGTH);
         incrementTime = (ListPreference) findPreference(Constants.PREFERENCES_KEY_INCREMENT_TIME);
@@ -113,6 +115,7 @@ public class SettingsFragment extends PreferenceFragment
         setupClearSearchPreference();
         setupGaplessControlSettingsV14();
         setupFeatureFlagsPreferences();
+        setupCacheLocationPreference();
 
         // After API26 foreground services must be used for music playback, and they must have a notification
         if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.O) {
@@ -155,8 +158,6 @@ public class SettingsFragment extends PreferenceFragment
             setHideMedia(sharedPreferences.getBoolean(key, false));
         } else if (Constants.PREFERENCES_KEY_MEDIA_BUTTONS.equals(key)) {
             setMediaButtonsEnabled(sharedPreferences.getBoolean(key, true));
-        } else if (Constants.PREFERENCES_KEY_CACHE_LOCATION.equals(key)) {
-            setCacheLocation(sharedPreferences.getString(key, ""));
         } else if (Constants.PREFERENCES_KEY_SEND_BLUETOOTH_NOTIFICATIONS.equals(key)) {
             setBluetoothPreferences(sharedPreferences.getBoolean(key, true));
         } else if (Constants.PREFERENCES_KEY_IMAGE_LOADER_CONCURRENCY.equals(key)) {
@@ -164,6 +165,40 @@ public class SettingsFragment extends PreferenceFragment
         }
     }
 
+    private void setupCacheLocationPreference() {
+        cacheLocation.setSummary(settings.getString(Constants.PREFERENCES_KEY_CACHE_LOCATION,
+            FileUtil.getDefaultMusicDirectory(getActivity()).getPath()));
+
+        cacheLocation.setOnPreferenceClickListener(new Preference.OnPreferenceClickListener() {
+            @Override
+            public boolean onPreferenceClick(Preference preference) {
+            // If the user tries to change the cache location, we must first check to see if we have write access.
+            PermissionUtil.requestInitialPermission(getActivity(), new PermissionUtil.PermissionRequestFinishedCallback() {
+                    @Override
+                    public void onPermissionRequestFinished(boolean hasPermission) {
+                        if (hasPermission) {
+                            FilePickerDialog filePickerDialog = FilePickerDialog.Companion.createFilePickerDialog(getActivity());
+                            filePickerDialog.setDefaultDirectory(FileUtil.getDefaultMusicDirectory(getActivity()).getPath());
+                            filePickerDialog.setInitialDirectory(cacheLocation.getSummary().toString());
+                            filePickerDialog.setOnFileSelectedListener(new OnFileSelectedListener() {
+                                @Override
+                                public void onFileSelected(File file, String path) {
+                                    SharedPreferences.Editor editor = cacheLocation.getEditor();
+                                    editor.putString(Constants.PREFERENCES_KEY_CACHE_LOCATION, path);
+                                    editor.commit();
+
+                                    setCacheLocation(path);
+                                }
+                            });
+                            filePickerDialog.show();
+                        }
+                    }
+                });
+            return true;
+            }
+        });
+    }
+
     private void setupClearSearchPreference() {
         Preference clearSearchPreference = findPreference(Constants.PREFERENCES_KEY_CLEAR_SEARCH_HISTORY);
 
@@ -315,7 +350,6 @@ public class SettingsFragment extends PreferenceFragment
         maxBitrateWifi.setSummary(maxBitrateWifi.getEntry());
         maxBitrateMobile.setSummary(maxBitrateMobile.getEntry());
         cacheSize.setSummary(cacheSize.getEntry());
-        cacheLocation.setSummary(cacheLocation.getText());
         preloadCount.setSummary(preloadCount.getEntry());
         bufferLength.setSummary(bufferLength.getEntry());
         incrementTime.setSummary(incrementTime.getEntry());
@@ -396,14 +430,16 @@ public class SettingsFragment extends PreferenceFragment
         if (!FileUtil.ensureDirectoryExistsAndIsReadWritable(dir)) {
             PermissionUtil.handlePermissionFailed(getActivity(), new PermissionUtil.PermissionRequestFinishedCallback() {
                 @Override
-                public void onPermissionRequestFinished() {
+                public void onPermissionRequestFinished(boolean hasPermission) {
                     String currentPath = settings.getString(Constants.PREFERENCES_KEY_CACHE_LOCATION,
                             FileUtil.getDefaultMusicDirectory(getActivity()).getPath());
                     cacheLocation.setSummary(currentPath);
-                    cacheLocation.setText(currentPath);
                 }
             });
         }
+        else {
+            cacheLocation.setSummary(path);
+        }
 
         // Clear download queue.
         mediaPlayerControllerLazy.getValue().clear();

ultrasonic/src/main/java/org/moire/ultrasonic/util/PermissionUtil.java

@@ -5,6 +5,8 @@ import android.content.Context;
 import android.content.DialogInterface;
 import android.content.Intent;
 import android.net.Uri;
+import android.os.Handler;
+import android.os.Looper;
 import android.util.Log;
 
 import androidx.appcompat.app.AlertDialog;
@@ -34,7 +36,7 @@ public class PermissionUtil {
     private static final String TAG = FileUtil.class.getSimpleName();
 
     public interface PermissionRequestFinishedCallback {
-        void onPermissionRequestFinished();
+        void onPermissionRequestFinished(boolean hasPermission);
     }
 
     /**
@@ -55,27 +57,79 @@ public class PermissionUtil {
         if (currentCachePath.compareTo(defaultCachePath) == 0) return;
 
         // We must get the context of the Main Activity for the dialogs, as this function may be called from a background thread where displaying dialogs is not available
-        Context mainContext = MainActivity.getInstance();
+        final Context mainContext = MainActivity.getInstance();
 
         if ((PermissionChecker.checkSelfPermission(context, Manifest.permission.WRITE_EXTERNAL_STORAGE) == PERMISSION_DENIED) ||
                 (PermissionChecker.checkSelfPermission(context, Manifest.permission.READ_EXTERNAL_STORAGE) == PERMISSION_DENIED)) {
             // While we request permission, the Music Directory is temporarily reset to its default location
             setCacheLocation(context, FileUtil.getDefaultMusicDirectory(context).getPath());
-            requestPermission(mainContext, currentCachePath, callback);
+            requestFailedPermission(mainContext, currentCachePath, callback);
         } else {
             setCacheLocation(context, FileUtil.getDefaultMusicDirectory(context).getPath());
-            showWarning(mainContext, context.getString(R.string.permissions_message_box_title), context.getString(R.string.permissions_access_error), null);
-            callback.onPermissionRequestFinished();
+            new Handler(Looper.getMainLooper()).post(new Runnable() {
+                @Override
+                public void run() {
+                    showWarning(mainContext, context.getString(R.string.permissions_message_box_title), context.getString(R.string.permissions_access_error), null);
+                }
+            });
+            callback.onPermissionRequestFinished(false);
         }
     }
 
+    /**
+     * This function requests permission to access the filesystem.
+     * It can be used to request the permission initially, e.g. when the user decides to use a non-default folder for the cache
+     * @param context context for the operation
+     * @param callback callback function to execute after the permission request is finished
+     */
+    public static void requestInitialPermission(final Context context, final PermissionRequestFinishedCallback callback) {
+        Dexter.withContext(context)
+                .withPermissions(
+                        Manifest.permission.WRITE_EXTERNAL_STORAGE,
+                        Manifest.permission.READ_EXTERNAL_STORAGE)
+                .withListener(new MultiplePermissionsListener() {
+                    @Override
+                    public void onPermissionsChecked(MultiplePermissionsReport report) {
+                        if (report.areAllPermissionsGranted()) {
+                            Log.i(TAG, "Permission granted to read / write external storage");
+                            if (callback != null) callback.onPermissionRequestFinished(true);
+                            return;
+                        }
+
+                        if (report.isAnyPermissionPermanentlyDenied()) {
+                            Log.i(TAG, "Found permanently denied permission to read / write external storage, offering settings");
+                            showSettingsDialog(context);
+                            if (callback != null) callback.onPermissionRequestFinished(false);
+                            return;
+                        }
+
+                        Log.i(TAG, "At least one permission is missing to read / write external storage");
+                        showWarning(context, context.getString(R.string.permissions_message_box_title),
+                                context.getString(R.string.permissions_rationale_description_initial), null);
+                        if (callback != null) callback.onPermissionRequestFinished(false);
+                    }
+
+                    @Override
+                    public void onPermissionRationaleShouldBeShown(List<PermissionRequest> permissions, PermissionToken token) {
+                        showWarning(context, context.getString(R.string.permissions_rationale_title),
+                                context.getString(R.string.permissions_rationale_description_initial), token);
+                    }
+                }).withErrorListener(new PermissionRequestErrorListener() {
+            @Override
+            public void onError(DexterError error) {
+                Log.e(TAG, String.format("An error has occurred during checking permissions with Dexter: %s", error.toString()));
+            }
+        })
+                .check();
+    }
+
     private static void setCacheLocation(Context context, String cacheLocation) {
         Util.getPreferences(context).edit()
                 .putString(Constants.PREFERENCES_KEY_CACHE_LOCATION, cacheLocation)
                 .apply();
     }
 
-    private static void requestPermission(final Context context, final String cacheLocation, final PermissionRequestFinishedCallback callback) {
+    private static void requestFailedPermission(final Context context, final String cacheLocation, final PermissionRequestFinishedCallback callback) {
         Dexter.withContext(context)
                 .withPermissions(
                         Manifest.permission.WRITE_EXTERNAL_STORAGE,
@@ -86,14 +140,14 @@ public class PermissionUtil {
                         if (report.areAllPermissionsGranted()) {
                             Log.i(TAG, String.format("Permission granted to use cache directory %s", cacheLocation));
                             setCacheLocation(context, cacheLocation);
-                            if (callback != null) callback.onPermissionRequestFinished();
+                            if (callback != null) callback.onPermissionRequestFinished(true);
                             return;
                         }
 
                         if (report.isAnyPermissionPermanentlyDenied()) {
                             Log.i(TAG, String.format("Found permanently denied permission to use cache directory %s, offering settings", cacheLocation));
                             showSettingsDialog(context);
-                            if (callback != null) callback.onPermissionRequestFinished();
+                            if (callback != null) callback.onPermissionRequestFinished(false);
                             return;
                         }
 
@@ -101,13 +155,13 @@ public class PermissionUtil {
                         setCacheLocation(context, FileUtil.getDefaultMusicDirectory(context).getPath());
                         showWarning(context, context.getString(R.string.permissions_message_box_title),
                                 context.getString(R.string.permissions_permission_missing), null);
-                        if (callback != null) callback.onPermissionRequestFinished();
+                        if (callback != null) callback.onPermissionRequestFinished(false);
                     }
 
                     @Override
                     public void onPermissionRationaleShouldBeShown(List<PermissionRequest> permissions, PermissionToken token) {
                         showWarning(context, context.getString(R.string.permissions_rationale_title),
-                                context.getString(R.string.permissions_rationale_description), token);
+                                context.getString(R.string.permissions_rationale_description_failed), token);
                     }
                 }).withErrorListener(new PermissionRequestErrorListener() {
             @Override

ultrasonic/src/main/kotlin/org/moire/ultrasonic/filepicker/FilePickerAdapter.kt

@@ -0,0 +1,287 @@
+package org.moire.ultrasonic.filepicker
+
+import android.content.Context
+import android.graphics.drawable.Drawable
+import android.os.Environment
+import android.text.TextUtils
+import android.util.Log
+import android.view.LayoutInflater
+import android.view.View
+import android.view.ViewGroup
+import android.widget.ImageView
+import android.widget.TextView
+import androidx.appcompat.app.AlertDialog
+import androidx.appcompat.widget.AppCompatEditText
+import androidx.recyclerview.widget.RecyclerView
+import java.io.File
+import java.util.LinkedList
+import kotlin.Comparator
+import org.moire.ultrasonic.R
+import org.moire.ultrasonic.util.Util
+
+/**
+ * Adapter for the RecyclerView which handles listing, navigating and picking files
+ * @author this implementation is loosely based on the work of Yogesh Sundaresan,
+ * original license: http://www.apache.org/licenses/LICENSE-2.0
+ */
+internal class FilePickerAdapter : RecyclerView.Adapter<FilePickerAdapter.FileListHolder> {
+
+    private var data: MutableList<FileListItem> = LinkedList()
+    var defaultDirectory: File = Environment.getExternalStorageDirectory()
+    var initialDirectory: File = Environment.getExternalStorageDirectory()
+    lateinit var selectedDirectoryChanged: (String, Boolean) -> Unit
+    var selectedDirectory: File = defaultDirectory
+        private set
+
+    private var context: Context? = null
+    private var listerView: FilePickerView? = null
+    private var isRealDirectory: Boolean = false
+
+    private val physicalPaths: Array<String>
+        get() = arrayOf(
+            "/storage/sdcard0", "/storage/sdcard1", "/storage/extsdcard",
+            "/storage/sdcard0/external_sdcard", "/mnt/extsdcard", "/mnt/sdcard/external_sd",
+            "/mnt/external_sd", "/mnt/media_rw/sdcard1", "/removable/microsd", "/mnt/emmc",
+            "/storage/external_SD", "/storage/ext_sd", "/storage/removable/sdcard1",
+            "/data/sdext", "/data/sdext2", "/data/sdext3", "/data/sdext4", "/sdcard1",
+            "/sdcard2", "/storage/microsd", "/data/user"
+        )
+
+    private var folderIcon: Drawable? = null
+    private var upIcon: Drawable? = null
+    private var sdIcon: Drawable? = null
+
+    constructor(defaultDir: File, view: FilePickerView) : this(view) {
+        this.defaultDirectory = defaultDir
+        selectedDirectory = defaultDir
+    }
+
+    constructor(view: FilePickerView) {
+        this.context = view.context
+        listerView = view
+
+        upIcon = Util.getDrawableFromAttribute(context, R.attr.filepicker_subdirectory_up)
+        folderIcon = Util.getDrawableFromAttribute(context, R.attr.filepicker_folder)
+        sdIcon = Util.getDrawableFromAttribute(context, R.attr.filepicker_sd_card)
+    }
+
+    fun start() {
+        fileLister(initialDirectory)
+    }
+
+    private fun fileLister(currentDirectory: File) {
+        var fileList = LinkedList<FileListItem>()
+        var storages: List<File>? = null
+        var storagePaths: List<String>? = null
+        if (android.os.Build.VERSION.SDK_INT >= android.os.Build.VERSION_CODES.KITKAT) {
+            storages = context!!.getExternalFilesDirs(null).filterNotNull()
+            storagePaths = storages.map { i -> i.absolutePath }
+        }
+
+        if (currentDirectory.absolutePath == "/" ||
+            currentDirectory.absolutePath == "/storage" ||
+            currentDirectory.absolutePath == "/storage/emulated" ||
+            currentDirectory.absolutePath == "/mnt"
+        ) {
+            isRealDirectory = false
+            fileList = if (
+                android.os.Build.VERSION.SDK_INT >= android.os.Build.VERSION_CODES.KITKAT
+            ) {
+                getKitKatStorageItems(storages!!)
+            } else {
+                getStorageItems()
+            }
+        } else {
+            isRealDirectory = true
+            val files = currentDirectory.listFiles()
+            files?.forEach { file ->
+                if (file.isDirectory) {
+                    fileList.add(FileListItem(file, file.name, folderIcon!!))
+                }
+            }
+        }
+
+        data = LinkedList(fileList)
+
+        data.sortWith(
+            Comparator { f1, f2 ->
+                if (f1.file!!.isDirectory && f2.file!!.isDirectory)
+                    f1.name.compareTo(f2.name, ignoreCase = true)
+                else if (f1.file!!.isDirectory && !f2.file!!.isDirectory)
+                    -1
+                else if (!f1.file!!.isDirectory && f2.file!!.isDirectory)
+                    1
+                else if (!f1.file!!.isDirectory && !f2.file!!.isDirectory)
+                    f1.name.compareTo(f2.name, ignoreCase = true)
+                else
+                    0
+            }
+        )
+
+        selectedDirectory = currentDirectory
+        selectedDirectoryChanged.invoke(
+            if (isRealDirectory) selectedDirectory.absolutePath
+            else context!!.getString(R.string.filepicker_available_drives),
+            isRealDirectory
+        )
+
+        // Add the "Up" navigation to the list
+        if (currentDirectory.absolutePath != "/" && isRealDirectory) {
+            // If we are on KitKat or later, only the default App folder is usable, so we can't
+            // navigate the SD card. Jump to the root if "Up" is selected.
+            if (android.os.Build.VERSION.SDK_INT >= android.os.Build.VERSION_CODES.KITKAT) {
+                if (storagePaths!!.indexOf(currentDirectory.absolutePath) > 0)
+                    data.add(0, FileListItem(File("/"), "..", upIcon!!))
+                else
+                    data.add(0, FileListItem(selectedDirectory.parentFile!!, "..", upIcon!!))
+            } else {
+                data.add(0, FileListItem(selectedDirectory.parentFile!!, "..", upIcon!!))
+            }
+        }
+
+        notifyDataSetChanged()
+        listerView!!.scrollToPosition(0)
+    }
+
+    private fun getStorageItems(): LinkedList<FileListItem> {
+        val fileList = LinkedList<FileListItem>()
+        var s = System.getenv("EXTERNAL_STORAGE")
+        if (!TextUtils.isEmpty(s)) {
+            val f = File(s!!)
+            fileList.add(FileListItem(f, f.name, sdIcon!!))
+        } else {
+            val paths = physicalPaths
+            for (path in paths) {
+                val f = File(path)
+                if (f.exists())
+                    fileList.add(FileListItem(f, f.name, sdIcon!!))
+            }
+        }
+        s = System.getenv("SECONDARY_STORAGE")
+        if (s != null && !TextUtils.isEmpty(s)) {
+            val rawSecondaryStorages =
+                s.split(File.pathSeparator.toRegex()).dropLastWhile { it.isEmpty() }.toTypedArray()
+            for (path in rawSecondaryStorages) {
+                val f = File(path)
+                if (f.exists())
+                    fileList.add(FileListItem(f, f.name, sdIcon!!))
+            }
+        }
+        return fileList
+    }
+
+    private fun getKitKatStorageItems(storages: List<File>): LinkedList<FileListItem> {
+        val fileList = LinkedList<FileListItem>()
+        if (storages.isNotEmpty()) {
+            for ((index, file) in storages.withIndex()) {
+                var path = file.absolutePath
+                path = path.replace("/Android/data/([a-zA-Z_][.\\w]*)/files".toRegex(), "")
+                if (index == 0) {
+                    fileList.add(
+                        FileListItem(
+                            File(path),
+                            context!!.getString(R.string.filepicker_internal, path),
+                            sdIcon!!
+                        )
+                    )
+                } else {
+                    fileList.add(
+                        FileListItem(
+                            file,
+                            context!!.getString(R.string.filepicker_default_app_folder, path),
+                            sdIcon!!
+                        )
+                    )
+                }
+            }
+        }
+        return fileList
+    }
+
+    override fun onCreateViewHolder(parent: ViewGroup, viewType: Int): FileListHolder {
+        return FileListHolder(
+            LayoutInflater.from(context).inflate(
+                R.layout.filepicker_item_file_lister, listerView, false
+            )
+        )
+    }
+
+    override fun onBindViewHolder(holder: FileListHolder, position: Int) {
+        val actualFile = data[position]
+
+        holder.name.text = actualFile.name
+        holder.icon.setImageDrawable(actualFile.icon)
+    }
+
+    override fun getItemCount(): Int {
+        return data.size
+    }
+
+    fun goToDefault() {
+        fileLister(defaultDirectory)
+    }
+
+    fun createNewFolder() {
+        val view = View.inflate(context, R.layout.filepicker_dialog_create_folder, null)
+        val editText = view.findViewById<AppCompatEditText>(R.id.edittext)
+        val builder = AlertDialog.Builder(context!!)
+            .setView(view)
+            .setTitle(context!!.getString(R.string.filepicker_enter_folder_name))
+            .setPositiveButton(context!!.getString(R.string.filepicker_create)) { _, _ -> }
+        val dialog = builder.create()
+        dialog.show()
+
+        dialog.getButton(AlertDialog.BUTTON_POSITIVE).setOnClickListener {
+            val name = editText.text!!.toString()
+
+            if (TextUtils.isEmpty(name)) {
+                Util.toast(context!!, context!!.getString(R.string.filepicker_name_invalid))
+            } else {
+                val file = File(selectedDirectory, name)
+
+                if (file.exists()) {
+                    Util.toast(context!!, context!!.getString(R.string.filepicker_already_exists))
+                } else {
+                    dialog.dismiss()
+                    if (file.mkdirs()) {
+                        fileLister(file)
+                    } else {
+                        Util.toast(
+                            context!!,
+                            context!!.getString(R.string.filepicker_create_folder_failed)
+                        )
+                    }
+                }
+            }
+        }
+    }
+
+    internal inner class FileListItem(
+        fileParameter: File,
+        nameParameter: String,
+        iconParameter: Drawable
+    ) {
+        var file: File? = fileParameter
+        var name: String = nameParameter
+        var icon: Drawable? = iconParameter
+    }
+
+    internal inner class FileListHolder(
+        itemView: View
+    ) : RecyclerView.ViewHolder(itemView), View.OnClickListener {
+
+        var name: TextView = itemView.findViewById(R.id.name)
+        var icon: ImageView = itemView.findViewById(R.id.icon)
+
+        init {
+            itemView.findViewById<View>(R.id.layout).setOnClickListener(this)
+        }
+
+        override fun onClick(v: View) {
+            val clickedFile = data[adapterPosition]
+            selectedDirectory = clickedFile.file!!
+            fileLister(clickedFile.file!!)
+            Log.d("FileLister", clickedFile.file!!.absolutePath)
+        }
+    }
+}

ultrasonic/src/main/kotlin/org/moire/ultrasonic/filepicker/FilePickerDialog.kt

@@ -0,0 +1,116 @@
+package org.moire.ultrasonic.filepicker
+
+import android.content.Context
+import android.content.DialogInterface.BUTTON_NEGATIVE
+import android.content.DialogInterface.BUTTON_NEUTRAL
+import android.content.DialogInterface.BUTTON_POSITIVE
+import android.view.LayoutInflater
+import android.widget.Button
+import android.widget.TextView
+import androidx.appcompat.app.AlertDialog
+import org.moire.ultrasonic.R
+
+/**
+ * This dialog can be used to pick a file / folder from the filesystem.
+ * Currently only supports folders.
+ * @author this implementation is loosely based on the work of Yogesh Sundaresan,
+ * original license: http://www.apache.org/licenses/LICENSE-2.0
+ */
+class FilePickerDialog {
+
+    private var alertDialog: AlertDialog? = null
+    private var filePickerView: FilePickerView? = null
+    private var onFileSelectedListener: OnFileSelectedListener? = null
+    private var currentPath: TextView? = null
+    private var newFolderButton: Button? = null
+
+    private constructor(context: Context) {
+        alertDialog = AlertDialog.Builder(context).create()
+        initialize(context)
+    }
+
+    private constructor(context: Context, themeResId: Int) {
+        alertDialog = AlertDialog.Builder(context, themeResId).create()
+        initialize(context)
+    }
+
+    private fun initialize(context: Context) {
+        val view = LayoutInflater.from(context).inflate(R.layout.filepicker_dialog_main, null)
+
+        alertDialog!!.setView(view)
+        filePickerView = view.findViewById(R.id.file_list_view)
+        currentPath = view.findViewById(R.id.current_path)
+
+        newFolderButton = view.findViewById(R.id.filepicker_create_folder)
+        newFolderButton!!.setOnClickListener { filePickerView!!.createNewFolder() }
+
+        alertDialog!!.setTitle(context.getString(R.string.filepicker_select_folder))
+
+        alertDialog!!.setButton(BUTTON_POSITIVE, context.getString(R.string.filepicker_select)) {
+            dialogInterface, _ ->
+            dialogInterface.dismiss()
+            if (onFileSelectedListener != null)
+                onFileSelectedListener!!.onFileSelected(
+                    filePickerView!!.selected, filePickerView!!.selected.absolutePath
+                )
+        }
+        alertDialog!!.setButton(BUTTON_NEUTRAL, context.getString(R.string.filepicker_default)) {
+            _, _ ->
+            filePickerView!!.goToDefaultDirectory()
+        }
+        alertDialog!!.setButton(BUTTON_NEGATIVE, context.getString(R.string.common_cancel)) {
+            dialogInterface, _ ->
+            dialogInterface.dismiss()
+        }
+    }
+
+    /**
+     * Display the FilePickerDialog
+     */
+    fun show() {
+        filePickerView!!.start { currentDirectory, isRealPath ->
+            run {
+                currentPath?.text = currentDirectory
+                newFolderButton!!.isEnabled = isRealPath
+            }
+        }
+        alertDialog!!.show()
+        alertDialog!!.getButton(BUTTON_NEUTRAL).setOnClickListener {
+            filePickerView!!.goToDefaultDirectory()
+        }
+    }
+
+    /**
+     * Listener to know which file/directory is selected
+     *
+     * @param onFileSelectedListener Instance of the Listener
+     */
+    fun setOnFileSelectedListener(onFileSelectedListener: OnFileSelectedListener) {
+        this.onFileSelectedListener = onFileSelectedListener
+    }
+
+    /**
+     * Set the initial directory to show the list of files in that directory
+     *
+     * @param path String denoting to the directory
+     */
+    fun setDefaultDirectory(path: String) {
+        filePickerView!!.setDefaultDirectory(path)
+    }
+
+    fun setInitialDirectory(path: String) {
+        filePickerView!!.setInitialDirectory(path)
+    }
+
+    companion object {
+        /**
+         * Creates a default instance of FilePickerDialog
+         *
+         * @param context Context of the App
+         * @return Instance of FileListerDialog
+         */
+        fun createFilePickerDialog(context: Context): FilePickerDialog {
+            return FilePickerDialog(context)
+        }
+    }
+}

ultrasonic/src/main/kotlin/org/moire/ultrasonic/filepicker/FilePickerView.kt

@@ -0,0 +1,67 @@
+package org.moire.ultrasonic.filepicker
+
+import android.content.Context
+import android.util.AttributeSet
+import androidx.recyclerview.widget.LinearLayoutManager
+import androidx.recyclerview.widget.RecyclerView
+import java.io.File
+
+/**
+ * RecyclerView containing the file list of a directory
+ * @author this implementation is loosely based on the work of Yogesh Sundaresan,
+ * original license: http://www.apache.org/licenses/LICENSE-2.0
+ */
+internal class FilePickerView : RecyclerView {
+
+    private var adapter: FilePickerAdapter? = null
+
+    val selected: File
+        get() = adapter!!.selectedDirectory
+
+    constructor(context: Context) : super(context) {
+        initialize()
+    }
+
+    constructor(context: Context, attrs: AttributeSet?) : super(context, attrs) {
+        initialize()
+    }
+
+    constructor(
+        context: Context,
+        attrs: AttributeSet?,
+        defStyle: Int
+    ) : super(context, attrs, defStyle) {
+        initialize()
+    }
+
+    private fun initialize() {
+        layoutManager = LinearLayoutManager(context, VERTICAL, false)
+        adapter = FilePickerAdapter(this)
+    }
+
+    fun start(selectedDirectoryChangedListener: (String, Boolean) -> Unit) {
+        setAdapter(adapter)
+        adapter?.selectedDirectoryChanged = selectedDirectoryChangedListener
+        adapter!!.start()
+    }
+
+    fun setDefaultDirectory(file: File) {
+        adapter!!.defaultDirectory = file
+    }
+
+    fun setDefaultDirectory(path: String) {
+        setDefaultDirectory(File(path))
+    }
+
+    fun setInitialDirectory(path: String) {
+        adapter!!.initialDirectory = File(path)
+    }
+
+    fun goToDefaultDirectory() {
+        adapter!!.goToDefault()
+    }
+
+    fun createNewFolder() {
+        adapter!!.createNewFolder()
+    }
+}

ultrasonic/src/main/kotlin/org/moire/ultrasonic/filepicker/OnFileSelectedListener.kt

@@ -0,0 +1,7 @@
+package org.moire.ultrasonic.filepicker
+
+import java.io.File
+
+interface OnFileSelectedListener {
+    fun onFileSelected(file: File?, path: String?)
+}

ultrasonic/src/main/res/layout/filepicker_dialog_create_folder.xml

@@ -0,0 +1,21 @@
+<?xml version="1.0" encoding="utf-8"?>
+<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
+    android:layout_width="match_parent"
+    android:layout_height="match_parent"
+    android:orientation="vertical"
+    android:padding="10dp">
+
+    <com.google.android.material.textfield.TextInputLayout
+        android:layout_width="match_parent"
+        android:layout_height="wrap_content">
+
+        <androidx.appcompat.widget.AppCompatEditText
+            android:id="@+id/edittext"
+            android:layout_width="match_parent"
+            android:layout_height="wrap_content"
+            android:imeOptions="actionDone"
+            android:inputType="text"
+            android:maxLines="1" />
+    </com.google.android.material.textfield.TextInputLayout>
+
+</LinearLayout>

ultrasonic/src/main/res/layout/filepicker_dialog_main.xml

@@ -0,0 +1,43 @@
+<?xml version="1.0" encoding="utf-8"?>
+<RelativeLayout xmlns:a="http://schemas.android.com/apk/res/android"
+    a:layout_width="match_parent"
+    a:layout_height="match_parent"
+    a:orientation="vertical">
+
+    <TextView
+        a:id="@+id/current_path"
+        a:layout_width="match_parent"
+        a:layout_height="wrap_content"
+        a:layout_alignParentTop="true"
+        a:layout_margin="20dp"
+        a:gravity="center_vertical"
+        a:text=""
+        a:textSize="18sp" />
+
+    <org.moire.ultrasonic.filepicker.FilePickerView
+        a:id="@+id/file_list_view"
+        a:layout_width="match_parent"
+        a:layout_height="match_parent"
+        a:layout_below="@id/current_path"
+        a:layout_above="@id/filepicker_create_folder"
+        a:scrollbars="vertical" />
+
+    <Button
+        a:id="@+id/filepicker_create_folder"
+        style="@style/Widget.AppCompat.Button.ButtonBar.AlertDialog"
+        a:layout_width="wrap_content"
+        a:layout_height="wrap_content"
+        a:layout_alignParentBottom="true"
+        a:layout_marginStart="10dp"
+        a:layout_marginLeft="10dp"
+        a:layout_marginTop="10dp"
+        a:layout_marginEnd="10dp"
+        a:layout_marginRight="10dp"
+        a:layout_marginBottom="10dp"
+        a:drawableStart="?attr/filepicker_create_new_folder"
+        a:drawableLeft="?attr/filepicker_create_new_folder"
+        a:drawablePadding="10dp"
+        a:gravity="start|center_vertical"
+        a:text="@string/filepicker.create_folder" />
+
+</RelativeLayout>

ultrasonic/src/main/res/layout/filepicker_item_file_lister.xml

@@ -0,0 +1,26 @@
+<?xml version="1.0" encoding="utf-8"?>
+<LinearLayout xmlns:a="http://schemas.android.com/apk/res/android"
+    a:id="@+id/layout"
+    a:padding="5dp"
+    a:layout_width="match_parent"
+    a:layout_height="wrap_content"
+    a:minHeight="?android:attr/listPreferredItemHeight"
+    a:orientation="horizontal">
+
+    <ImageView
+        a:id="@+id/icon"
+        a:layout_width="36dp"
+        a:layout_height="36dp"
+        a:layout_gravity="center_vertical" />
+
+    <TextView
+        a:id="@+id/name"
+        a:layout_width="wrap_content"
+        a:layout_height="wrap_content"
+        a:layout_gravity="center_vertical"
+        a:layout_marginStart="20dp"
+        a:layout_marginLeft="20dp"
+        a:gravity="center_vertical"
+        a:text=""
+        a:textSize="18sp" />
+</LinearLayout>

ultrasonic/src/main/res/values-de/strings.xml

@@ -399,10 +399,24 @@
     <string name="permissions.message_box_title">Warning</string>
     <string name="permissions.permission_missing">Ultrasonic needs read/write permission to the music cache directory. Cache directory was reset to its default value.</string>
     <string name="permissions.rationale_title">Permission request</string>
-    <string name="permissions.rationale_description">Ultrasonic needs read/write permission to the music cache directory.\nPlease allow Ultrasonic to access the filesystem.</string>
+    <string name="permissions.rationale_description_failed">Ultrasonic needs read/write permission to the music cache directory.\nPlease allow Ultrasonic to access the filesystem.</string>
     <string name="permissions.permanent_denial_title">Permissions permanently denied</string>
-    <string name="permissions.permanent_denial_description">Ultrasonic needs Read/Write access to the cache location. You can grant them in app settings. If you reject this request, the cache location will be reset to its default value.</string>
+    <string name="permissions.permanent_denial_description">Ultrasonic needs Read/Write access to the cache location. You can grant them in app settings. If you reject this request, the default folder will be used as the cache location.</string>
     <string name="permissions.open_settings">Open settings</string>
+    <string name="permissions.rationale_description_initial">To be able to change the cache location, Ultrasonic needs read/write permission to the filesystem.</string>
+
+    <string name="filepicker.select_folder">Select a folder</string>
+    <string name="filepicker.create_folder">Create new folder</string>
+    <string name="filepicker.create_folder_failed">Failed to create new folder</string>
+    <string name="filepicker.internal">%1$s (Internal)</string>
+    <string name="filepicker.default_app_folder">Default app folder on %1$s (External)</string>
+    <string name="filepicker.enter_folder_name">Enter the folder name</string>
+    <string name="filepicker.create">Create</string>
+    <string name="filepicker.name_invalid">Please enter a valid folder name</string>
+    <string name="filepicker.already_exists">This folder already exists.\nPlease provide another name for the folder</string>
+    <string name="filepicker.select">Select</string>
+    <string name="filepicker.default">Use default</string>
+    <string name="filepicker.available_drives">Available drives:</string>
 
     <plurals name="select_album_n_songs">
         <item quantity="one">1 Titel</item>

ultrasonic/src/main/res/values-es/strings.xml

@@ -400,10 +400,24 @@
     <string name="permissions.message_box_title">Atención</string>
     <string name="permissions.permission_missing">Ultrasonic necesita permiso de lectura / escritura para el directorio caché de música. El directorio caché se restableció a su valor predeterminado.</string>
     <string name="permissions.rationale_title">Solicitud de permisos</string>
-    <string name="permissions.rationale_description">Ultrasonic necesita permiso de lectura / escritura para el directorio caché de música. Por favor permite a Ultrasonic acceder al sistema de ficheros.</string>
+    <string name="permissions.rationale_description_failed">Ultrasonic necesita permiso de lectura / escritura para el directorio caché de música. Por favor permite a Ultrasonic acceder al sistema de ficheros.</string>
     <string name="permissions.permanent_denial_title">Permisos denegados permanentemente</string>
     <string name="permissions.permanent_denial_description">Ultrasonic necesita acceso de lectura / escritura a la ubicación de la caché. Puedes otorgarlos en la configuración de la aplicación. Si rechazas esta solicitud, la ubicación de la caché se restablecerá a su valor predeterminado.</string>
     <string name="permissions.open_settings">Abrir configuración</string>
+    <string name="permissions.rationale_description_initial">To be able to change the cache location, Ultrasonic needs read/write permission to the filesystem.</string>
+
+    <string name="filepicker.select_folder">Select a folder</string>
+    <string name="filepicker.create_folder">Create new folder</string>
+    <string name="filepicker.create_folder_failed">Failed to create new folder</string>
+    <string name="filepicker.internal">%1$s (Internal)</string>
+    <string name="filepicker.default_app_folder">Default app folder on %1$s (External)</string>
+    <string name="filepicker.enter_folder_name">Enter the folder name</string>
+    <string name="filepicker.create">Create</string>
+    <string name="filepicker.name_invalid">Please enter a valid folder name</string>
+    <string name="filepicker.already_exists">This folder already exists.\nPlease provide another name for the folder</string>
+    <string name="filepicker.select">Select</string>
+    <string name="filepicker.default">Use default</string>
+    <string name="filepicker.available_drives">Available drives:</string>
 
     <plurals name="select_album_n_songs">
         <item quantity="one">1 canción</item>

ultrasonic/src/main/res/values-fr/strings.xml

@@ -400,10 +400,24 @@
     <string name="permissions.message_box_title">Warning</string>
     <string name="permissions.permission_missing">Ultrasonic needs read/write permission to the music cache directory. Cache directory was reset to its default value.</string>
     <string name="permissions.rationale_title">Permission request</string>
-    <string name="permissions.rationale_description">Ultrasonic needs read/write permission to the music cache directory.\nPlease allow Ultrasonic to access the filesystem.</string>
+    <string name="permissions.rationale_description_failed">Ultrasonic needs read/write permission to the music cache directory.\nPlease allow Ultrasonic to access the filesystem.</string>
     <string name="permissions.permanent_denial_title">Permissions permanently denied</string>
-    <string name="permissions.permanent_denial_description">Ultrasonic needs Read/Write access to the cache location. You can grant them in app settings. If you reject this request, the cache location will be reset to its default value.</string>
+    <string name="permissions.permanent_denial_description">Ultrasonic needs Read/Write access to the cache location. You can grant them in app settings. If you reject this request, the default folder will be used as the cache location.</string>
     <string name="permissions.open_settings">Open settings</string>
+    <string name="permissions.rationale_description_initial">To be able to change the cache location, Ultrasonic needs read/write permission to the filesystem.</string>
+
+    <string name="filepicker.select_folder">Select a folder</string>
+    <string name="filepicker.create_folder">Create new folder</string>
+    <string name="filepicker.create_folder_failed">Failed to create new folder</string>
+    <string name="filepicker.internal">%1$s (Internal)</string>
+    <string name="filepicker.default_app_folder">Default app folder on %1$s (External)</string>
+    <string name="filepicker.enter_folder_name">Enter the folder name</string>
+    <string name="filepicker.create">Create</string>
+    <string name="filepicker.name_invalid">Please enter a valid folder name</string>
+    <string name="filepicker.already_exists">This folder already exists.\nPlease provide another name for the folder</string>
+    <string name="filepicker.select">Select</string>
+    <string name="filepicker.default">Use default</string>
+    <string name="filepicker.available_drives">Available drives:</string>
 
     <plurals name="select_album_n_songs">
         <item quantity="one">Un titre</item>

ultrasonic/src/main/res/values-hu/strings.xml

@@ -400,10 +400,24 @@
     <string name="permissions.message_box_title">Figyelem</string>
     <string name="permissions.permission_missing">Az Ultrasonic működéséhez írás/olvasás hozzáférés szükséges a zenei fájl gyorsítótárhoz. A gyorsítótár helye visszaállítva az alapbeállításra.</string>
     <string name="permissions.rationale_title">Jogosultság kérés</string>
-    <string name="permissions.rationale_description">Az Ultrasonic működéséhez írás/olvasás hozzáférés szükséges a zenei fájl gyorsítótárhoz.\nKérjük, engedélyezd a hozzáférést a fájlrendszerhez.</string>
+    <string name="permissions.rationale_description_failed">Az Ultrasonic működéséhez írás/olvasás hozzáférés szükséges a zenei fájl gyorsítótárhoz.\nKérlek, adj hozzáférést az Ultrasonicnak a fájlrendszerhez.</string>
     <string name="permissions.permanent_denial_title">A jogosultság visszautasítva</string>
     <string name="permissions.permanent_denial_description">Az Ultrasonic működéséhez írás/olvasás hozzáférés szükséges a zenei fájl gyorsítótárhoz. Ez a beállítás az alkalmazásbeállítások között módosítható. Ha elutasítod ezt a kérést, a gyorsítótár helye visszaáll az alapbeállításra.</string>
     <string name="permissions.open_settings">Beállítások megnyitása</string>
+    <string name="permissions.rationale_description_initial">A gyorsítótár helyének megváltoztatásához az Ultrasonicnak írás/olvasás hozzáférésre van szüksége a fájlrendszerhez.</string>
+
+    <string name="filepicker.select_folder">Mappa kiválasztása</string>
+    <string name="filepicker.create_folder">Új mappa létrehozása</string>
+    <string name="filepicker.create_folder_failed">Az új mappa létrehozása nem sikerült</string>
+    <string name="filepicker.internal">%1$s (Belső)</string>
+    <string name="filepicker.default_app_folder">Alapértelmezett alkalmazásmappa a %1$s tárolón (Külső)</string>
+    <string name="filepicker.enter_folder_name">A mappa neve</string>
+    <string name="filepicker.create">Létrehoz</string>
+    <string name="filepicker.name_invalid">Kérjük, adj meg egy érvényes mappanevet</string>
+    <string name="filepicker.already_exists">Ilyen nevű mappa már létezik.\nKérjük, adj meg más nevet.</string>
+    <string name="filepicker.select">Választ</string>
+    <string name="filepicker.default">Alapért.</string>
+    <string name="filepicker.available_drives">Elérhető tárolók:</string>
 
     <plurals name="select_album_n_songs">
         <item quantity="one">1 dal</item>

ultrasonic/src/main/res/values-nl/strings.xml

@@ -400,10 +400,24 @@
     <string name="permissions.message_box_title">Warning</string>
     <string name="permissions.permission_missing">Ultrasonic needs read/write permission to the music cache directory. Cache directory was reset to its default value.</string>
     <string name="permissions.rationale_title">Permission request</string>
-    <string name="permissions.rationale_description">Ultrasonic needs read/write permission to the music cache directory.\nPlease allow Ultrasonic to access the filesystem.</string>
+    <string name="permissions.rationale_description_failed">Ultrasonic needs read/write permission to the music cache directory.\nPlease allow Ultrasonic to access the filesystem.</string>
     <string name="permissions.permanent_denial_title">Permissions permanently denied</string>
-    <string name="permissions.permanent_denial_description">Ultrasonic needs Read/Write access to the cache location. You can grant them in app settings. If you reject this request, the cache location will be reset to its default value.</string>
+    <string name="permissions.permanent_denial_description">Ultrasonic needs Read/Write access to the cache location. You can grant them in app settings. If you reject this request, the default folder will be used as the cache location.</string>
     <string name="permissions.open_settings">Open settings</string>
+    <string name="permissions.rationale_description_initial">To be able to change the cache location, Ultrasonic needs read/write permission to the filesystem.</string>
+
+    <string name="filepicker.select_folder">Select a folder</string>
+    <string name="filepicker.create_folder">Create new folder</string>
+    <string name="filepicker.create_folder_failed">Failed to create new folder</string>
+    <string name="filepicker.internal">%1$s (Internal)</string>
+    <string name="filepicker.default_app_folder">Default app folder on %1$s (External)</string>
+    <string name="filepicker.enter_folder_name">Enter the folder name</string>
+    <string name="filepicker.create">Create</string>
+    <string name="filepicker.name_invalid">Please enter a valid folder name</string>
+    <string name="filepicker.already_exists">This folder already exists.\nPlease provide another name for the folder</string>
+    <string name="filepicker.select">Select</string>
+    <string name="filepicker.default">Use default</string>
+    <string name="filepicker.available_drives">Available drives:</string>
 
     <plurals name="select_album_n_songs">
         <item quantity="one">1 nummer</item>

ultrasonic/src/main/res/values-pl/strings.xml

@@ -400,10 +400,24 @@ ponieważ api Subsonic nie wspiera nowego sposobu autoryzacji dla użytkowników
     <string name="permissions.message_box_title">Warning</string>
     <string name="permissions.permission_missing">Ultrasonic needs read/write permission to the music cache directory. Cache directory was reset to its default value.</string>
     <string name="permissions.rationale_title">Permission request</string>
-    <string name="permissions.rationale_description">Ultrasonic needs read/write permission to the music cache directory.\nPlease allow Ultrasonic to access the filesystem.</string>
+    <string name="permissions.rationale_description_failed">Ultrasonic needs read/write permission to the music cache directory.\nPlease allow Ultrasonic to access the filesystem.</string>
     <string name="permissions.permanent_denial_title">Permissions permanently denied</string>
-    <string name="permissions.permanent_denial_description">Ultrasonic needs Read/Write access to the cache location. You can grant them in app settings. If you reject this request, the cache location will be reset to its default value.</string>
+    <string name="permissions.permanent_denial_description">Ultrasonic needs Read/Write access to the cache location. You can grant them in app settings. If you reject this request, the default folder will be used as the cache location.</string>
     <string name="permissions.open_settings">Open settings</string>
+    <string name="permissions.rationale_description_initial">To be able to change the cache location, Ultrasonic needs read/write permission to the filesystem.</string>
+
+    <string name="filepicker.select_folder">Select a folder</string>
+    <string name="filepicker.create_folder">Create new folder</string>
+    <string name="filepicker.create_folder_failed">Failed to create new folder</string>
+    <string name="filepicker.internal">%1$s (Internal)</string>
+    <string name="filepicker.default_app_folder">Default app folder on %1$s (External)</string>
+    <string name="filepicker.enter_folder_name">Enter the folder name</string>
+    <string name="filepicker.create">Create</string>
+    <string name="filepicker.name_invalid">Please enter a valid folder name</string>
+    <string name="filepicker.already_exists">This folder already exists.\nPlease provide another name for the folder</string>
+    <string name="filepicker.select">Select</string>
+    <string name="filepicker.default">Use default</string>
+    <string name="filepicker.available_drives">Available drives:</string>
 
     <plurals name="select_album_n_songs">
         <item quantity="one">1 utwór</item>

ultrasonic/src/main/res/values-pt-rBR/strings.xml

@@ -400,10 +400,24 @@
     <string name="permissions.message_box_title">Warning</string>
     <string name="permissions.permission_missing">Ultrasonic needs read/write permission to the music cache directory. Cache directory was reset to its default value.</string>
     <string name="permissions.rationale_title">Permission request</string>
-    <string name="permissions.rationale_description">Ultrasonic needs read/write permission to the music cache directory.\nPlease allow Ultrasonic to access the filesystem.</string>
+    <string name="permissions.rationale_description_failed">Ultrasonic needs read/write permission to the music cache directory.\nPlease allow Ultrasonic to access the filesystem.</string>
     <string name="permissions.permanent_denial_title">Permissions permanently denied</string>
-    <string name="permissions.permanent_denial_description">Ultrasonic needs Read/Write access to the cache location. You can grant them in app settings. If you reject this request, the cache location will be reset to its default value.</string>
+    <string name="permissions.permanent_denial_description">Ultrasonic needs Read/Write access to the cache location. You can grant them in app settings. If you reject this request, the default folder will be used as the cache location.</string>
     <string name="permissions.open_settings">Open settings</string>
+    <string name="permissions.rationale_description_initial">To be able to change the cache location, Ultrasonic needs read/write permission to the filesystem.</string>
+
+    <string name="filepicker.select_folder">Select a folder</string>
+    <string name="filepicker.create_folder">Create new folder</string>
+    <string name="filepicker.create_folder_failed">Failed to create new folder</string>
+    <string name="filepicker.internal">%1$s (Internal)</string>
+    <string name="filepicker.default_app_folder">Default app folder on %1$s (External)</string>
+    <string name="filepicker.enter_folder_name">Enter the folder name</string>
+    <string name="filepicker.create">Create</string>
+    <string name="filepicker.name_invalid">Please enter a valid folder name</string>
+    <string name="filepicker.already_exists">This folder already exists.\nPlease provide another name for the folder</string>
+    <string name="filepicker.select">Select</string>
+    <string name="filepicker.default">Use default</string>
+    <string name="filepicker.available_drives">Available drives:</string>
 
     <plurals name="select_album_n_songs">
         <item quantity="one">1 música</item>

ultrasonic/src/main/res/values-pt/strings.xml

@@ -400,10 +400,24 @@
     <string name="permissions.message_box_title">Warning</string>
     <string name="permissions.permission_missing">Ultrasonic needs read/write permission to the music cache directory. Cache directory was reset to its default value.</string>
     <string name="permissions.rationale_title">Permission request</string>
-    <string name="permissions.rationale_description">Ultrasonic needs read/write permission to the music cache directory.\nPlease allow Ultrasonic to access the filesystem.</string>
+    <string name="permissions.rationale_description_failed">Ultrasonic needs read/write permission to the music cache directory.\nPlease allow Ultrasonic to access the filesystem.</string>
     <string name="permissions.permanent_denial_title">Permissions permanently denied</string>
-    <string name="permissions.permanent_denial_description">Ultrasonic needs Read/Write access to the cache location. You can grant them in app settings. If you reject this request, the cache location will be reset to its default value.</string>
+    <string name="permissions.permanent_denial_description">Ultrasonic needs Read/Write access to the cache location. You can grant them in app settings. If you reject this request, the default folder will be used as the cache location.</string>
     <string name="permissions.open_settings">Open settings</string>
+    <string name="permissions.rationale_description_initial">To be able to change the cache location, Ultrasonic needs read/write permission to the filesystem.</string>
+
+    <string name="filepicker.select_folder">Select a folder</string>
+    <string name="filepicker.create_folder">Create new folder</string>
+    <string name="filepicker.create_folder_failed">Failed to create new folder</string>
+    <string name="filepicker.internal">%1$s (Internal)</string>
+    <string name="filepicker.default_app_folder">Default app folder on %1$s (External)</string>
+    <string name="filepicker.enter_folder_name">Enter the folder name</string>
+    <string name="filepicker.create">Create</string>
+    <string name="filepicker.name_invalid">Please enter a valid folder name</string>
+    <string name="filepicker.already_exists">This folder already exists.\nPlease provide another name for the folder</string>
+    <string name="filepicker.select">Select</string>
+    <string name="filepicker.default">Use default</string>
+    <string name="filepicker.available_drives">Available drives:</string>
 
     <plurals name="select_album_n_songs">
         <item quantity="one">%d música</item>

ultrasonic/src/main/res/values/strings.xml

@@ -404,10 +404,24 @@
     <string name="permissions.message_box_title">Warning</string>
     <string name="permissions.permission_missing">Ultrasonic needs read/write permission to the music cache directory. Cache directory was reset to its default value.</string>
     <string name="permissions.rationale_title">Permission request</string>
-    <string name="permissions.rationale_description">Ultrasonic needs read/write permission to the music cache directory.\nPlease allow Ultrasonic to access the filesystem.</string>
+    <string name="permissions.rationale_description_failed">Ultrasonic needs read/write permission to the music cache directory.\nPlease allow Ultrasonic to access the filesystem.</string>
     <string name="permissions.permanent_denial_title">Permissions permanently denied</string>
-    <string name="permissions.permanent_denial_description">Ultrasonic needs Read/Write access to the cache location. You can grant them in app settings. If you reject this request, the cache location will be reset to its default value.</string>
+    <string name="permissions.permanent_denial_description">Ultrasonic needs Read/Write access to the cache location. You can grant them in app settings. If you reject this request, the default folder will be used as the cache location.</string>
     <string name="permissions.open_settings">Open settings</string>
+    <string name="permissions.rationale_description_initial">To be able to change the cache location, Ultrasonic needs read/write permission to the filesystem.</string>
+
+    <string name="filepicker.select_folder">Select a folder</string>
+    <string name="filepicker.create_folder">Create new folder</string>
+    <string name="filepicker.create_folder_failed">Failed to create new folder</string>
+    <string name="filepicker.internal">%1$s (Internal)</string>
+    <string name="filepicker.default_app_folder">Default app folder on %1$s (External)</string>
+    <string name="filepicker.enter_folder_name">Enter the folder name</string>
+    <string name="filepicker.create">Create</string>
+    <string name="filepicker.name_invalid">Please enter a valid folder name</string>
+    <string name="filepicker.already_exists">This folder already exists.\nPlease provide another name for the folder</string>
+    <string name="filepicker.select">Select</string>
+    <string name="filepicker.default">Use default</string>
+    <string name="filepicker.available_drives">Available drives:</string>
 
     <plurals name="select_album_n_songs">
         <item quantity="one">1 song</item>

ultrasonic/src/main/res/values/styles.xml

@@ -92,6 +92,11 @@
     <attr name="check_mark_on" format="reference"/>
     <attr name="button_check_custom" format="reference"/>
     <attr name="color_background" format="reference"/>
+    <attr name="filepicker_create_new_folder" format="reference"/>
+    <attr name="filepicker_folder" format="reference"/>
+    <attr name="filepicker_subdirectory_left" format="reference"/>
+    <attr name="filepicker_subdirectory_up" format="reference"/>
+    <attr name="filepicker_sd_card" format="reference"/>
 
 </resources>
 

ultrasonic/src/main/res/values/themes.xml

@@ -1,6 +1,5 @@
 <?xml version="1.0" encoding="utf-8"?>
 <resources>
-
     <style name="UltraSonicTheme" parent="Theme.AppCompat">
         <item name="color_background">@color/background_color_dark</item>
         <item name="star_hollow">@drawable/ic_star_hollow_dark</item>
@@ -44,6 +43,10 @@
         <item name="chat_send">@drawable/ic_menu_chat_send_dark</item>
         <item name="bookmark">@drawable/ic_menu_bookmark_dark</item>
         <item name="button_check_custom">@drawable/btn_check_custom_dark</item>
+        <item name="filepicker_create_new_folder">@drawable/ic_create_new_folder_dark</item>
+        <item name="filepicker_folder">@drawable/ic_folder_dark</item>
+        <item name="filepicker_subdirectory_up">@drawable/ic_subdirectory_up_dark</item>
+        <item name="filepicker_sd_card">@drawable/ic_sd_storage_dark</item>
     </style>
 
     <style name="UltraSonicTheme.Light" parent="Theme.AppCompat.Light">
@@ -89,6 +92,9 @@
         <item name="chat_send">@drawable/ic_menu_chat_send_light</item>
         <item name="bookmark">@drawable/ic_menu_bookmark_light</item>
         <item name="button_check_custom">@drawable/btn_check_custom_light</item>
+        <item name="filepicker_create_new_folder">@drawable/ic_create_new_folder_light</item>
+        <item name="filepicker_folder">@drawable/ic_folder_light</item>
+        <item name="filepicker_subdirectory_up">@drawable/ic_subdirectory_up_light</item>
+        <item name="filepicker_sd_card">@drawable/ic_sd_storage_light</item>
     </style>
-
 </resources>

ultrasonic/src/main/res/xml/settings.xml

@@ -210,7 +210,7 @@
             a:entryValues="@array/cacheSizeValues"
             a:key="cacheSize"
             a:title="@string/settings.cache_size"/>
-        <EditTextPreference
+        <Preference
             a:key="cacheLocation"
             a:title="@string/settings.cache_location"/>
         <ListPreference