Add .ifNotNull extension function as a more readable alternative to ?.let

ultrasonic/src/main/kotlin/org/moire/ultrasonic/domain/APIPlaylistConverter.kt

@@ -6,6 +6,7 @@ package org.moire.ultrasonic.domain
 import java.text.SimpleDateFormat
 import kotlin.LazyThreadSafetyMode.NONE
 import org.moire.ultrasonic.api.subsonic.models.Playlist as APIPlaylist
+import org.moire.ultrasonic.util.Util.ifNotNull
 
 internal val playlistDateFormat by lazy(NONE) { SimpleDateFormat.getInstance() }
 
@@ -17,7 +18,7 @@ fun APIPlaylist.toMusicDirectoryDomainEntity(): MusicDirectory = MusicDirectory(
 fun APIPlaylist.toDomainEntity(): Playlist = Playlist(
     this.id, this.name, this.owner,
     this.comment, this.songCount.toString(),
-    this.created?.let { playlistDateFormat.format(it.time) } ?: "",
+    this.created.ifNotNull { playlistDateFormat.format(it.time) } ?: "",
     public
 )
 

ultrasonic/src/main/kotlin/org/moire/ultrasonic/domain/APIShareConverter.kt

@@ -5,6 +5,7 @@ package org.moire.ultrasonic.domain
 import java.text.SimpleDateFormat
 import kotlin.LazyThreadSafetyMode.NONE
 import org.moire.ultrasonic.api.subsonic.models.Share as APIShare
+import org.moire.ultrasonic.util.Util.ifNotNull
 
 internal val shareTimeFormat by lazy(NONE) { SimpleDateFormat.getInstance() }
 
@@ -13,11 +14,11 @@ fun List<APIShare>.toDomainEntitiesList(): List<Share> = this.map {
 }
 
 fun APIShare.toDomainEntity(): Share = Share(
-    created = this@toDomainEntity.created?.let { shareTimeFormat.format(it.time) },
+    created = this@toDomainEntity.created.ifNotNull { shareTimeFormat.format(it.time) },
     description = this@toDomainEntity.description,
-    expires = this@toDomainEntity.expires?.let { shareTimeFormat.format(it.time) },
+    expires = this@toDomainEntity.expires.ifNotNull { shareTimeFormat.format(it.time) },
     id = this@toDomainEntity.id,
-    lastVisited = this@toDomainEntity.lastVisited?.let { shareTimeFormat.format(it.time) },
+    lastVisited = this@toDomainEntity.lastVisited.ifNotNull { shareTimeFormat.format(it.time) },
     url = this@toDomainEntity.url,
     username = this@toDomainEntity.username,
     visitCount = this@toDomainEntity.visitCount.toLong(),

ultrasonic/src/main/kotlin/org/moire/ultrasonic/fragment/TrackCollectionFragment.kt

@@ -211,7 +211,7 @@ class TrackCollectionFragment : Fragment() {
 
     val handler = CoroutineExceptionHandler { _, exception ->
         Handler(Looper.getMainLooper()).post {
-            context?.let { CommunicationErrorHandler.handleError(exception, it) }
+            CommunicationErrorHandler.handleError(exception, context)
         }
         refreshAlbumListView!!.isRefreshing = false
     }

ultrasonic/src/main/kotlin/org/moire/ultrasonic/service/CommunicationErrorHandler.kt

@@ -39,9 +39,11 @@ import timber.log.Timber
  */
 class CommunicationErrorHandler {
     companion object {
-        fun handleError(error: Throwable?, context: Context) {
+        fun handleError(error: Throwable?, context: Context?) {
             Timber.w(error)
 
+            if (context == null) return
+
             AlertDialog.Builder(context)
                 .setIcon(android.R.drawable.ic_dialog_alert)
                 .setTitle(R.string.error_label)

ultrasonic/src/main/kotlin/org/moire/ultrasonic/service/MediaPlayerLifecycleSupport.kt

@@ -22,6 +22,7 @@ import org.moire.ultrasonic.domain.PlayerState
 import org.moire.ultrasonic.util.CacheCleaner
 import org.moire.ultrasonic.util.Constants
 import org.moire.ultrasonic.util.Settings
+import org.moire.ultrasonic.util.Util.ifNotNull
 import timber.log.Timber
 
 /**
@@ -113,7 +114,7 @@ class MediaPlayerLifecycleSupport : KoinComponent {
         if (intentAction == Constants.CMD_PROCESS_KEYCODE) {
             if (intent.extras != null) {
                 val event = intent.extras!![Intent.EXTRA_KEY_EVENT] as KeyEvent?
-                event?.let { handleKeyEvent(it) }
+                event.ifNotNull { handleKeyEvent(it) }
             }
         } else {
             handleUltrasonicIntent(intentAction)

ultrasonic/src/main/kotlin/org/moire/ultrasonic/subsonic/ShareHandler.kt

@@ -26,6 +26,7 @@ import org.moire.ultrasonic.util.Settings
 import org.moire.ultrasonic.util.ShareDetails
 import org.moire.ultrasonic.util.TimeSpan
 import org.moire.ultrasonic.util.TimeSpanPicker
+import org.moire.ultrasonic.util.Util.ifNotNull
 
 /**
  * This class handles sharing items in the media library
@@ -79,7 +80,7 @@ class ShareHandler(val context: Context) {
 
                 if (!shareDetails.ShareOnServer && shareDetails.Entries.size == 1) return null
                 if (shareDetails.Entries.isEmpty()) {
-                    fragment.arguments?.getString(Constants.INTENT_EXTRA_NAME_ID)?.let {
+                    fragment.arguments?.getString(Constants.INTENT_EXTRA_NAME_ID).ifNotNull {
                         ids.add(it)
                     }
                 } else {

ultrasonic/src/main/kotlin/org/moire/ultrasonic/util/MediaSessionHandler.kt

@@ -28,6 +28,7 @@ import org.moire.ultrasonic.receiver.MediaButtonIntentReceiver
 import org.moire.ultrasonic.service.DownloadFile
 import org.moire.ultrasonic.service.RxBus
 import org.moire.ultrasonic.service.plusAssign
+import org.moire.ultrasonic.util.Util.ifNotNull
 import timber.log.Timber
 
 private const val INTENT_CODE_MEDIA_BUTTON = 161
@@ -150,7 +151,7 @@ class MediaSessionHandler : KoinComponent {
                 // This probably won't be necessary once we implement more
                 // of the modern media APIs, like the MediaController etc.
                 val event = mediaButtonEvent.extras!!["android.intent.extra.KEY_EVENT"] as KeyEvent?
-                event?.let { RxBus.mediaButtonEventPublisher.onNext(it) }
+                event.ifNotNull { RxBus.mediaButtonEventPublisher.onNext(it) }
                 return true
             }
 
@@ -257,13 +258,10 @@ class MediaSessionHandler : KoinComponent {
 
         val index = cachedPlaylist?.indexOf(currentPlaying)
         cachedPlayingIndex = if (index == null || index < 0) null else index.toLong()
-        cachedPlaylist?.let { setMediaSessionQueue(it) }
+        cachedPlaylist.ifNotNull { setMediaSessionQueue(it) }
 
-        if (
+        if (cachedPlaylist != null && !Settings.shouldDisableNowPlayingListSending)
-            cachedPlayingIndex != null && cachedPlaylist != null &&
+            cachedPlayingIndex.ifNotNull { playbackStateBuilder.setActiveQueueItemId(it) }
-            !Settings.shouldDisableNowPlayingListSending
-        )
-            cachedPlayingIndex?.let { playbackStateBuilder.setActiveQueueItemId(it) }
 
         // Save the playback state
         mediaSession?.setPlaybackState(playbackStateBuilder.build())
@@ -296,11 +294,8 @@ class MediaSessionHandler : KoinComponent {
         playbackStateBuilder.setState(playbackState!!, cachedPosition, 1.0f)
         playbackStateBuilder.setActions(playbackActions!!)
 
-        if (
+        if (cachedPlaylist != null && !Settings.shouldDisableNowPlayingListSending)
-            cachedPlayingIndex != null && cachedPlaylist != null &&
+            cachedPlayingIndex.ifNotNull { playbackStateBuilder.setActiveQueueItemId(it) }
-            !Settings.shouldDisableNowPlayingListSending
-        )
-            playbackStateBuilder.setActiveQueueItemId(cachedPlayingIndex!!)
 
         mediaSession?.setPlaybackState(playbackStateBuilder.build())
     }

ultrasonic/src/main/kotlin/org/moire/ultrasonic/util/Util.kt

@@ -538,7 +538,6 @@ object Util {
     }
 
     /**
-     *
      * Broadcasts the given song info as the new song being played.
      */
     fun broadcastNewTrackInfo(context: Context, song: MusicDirectory.Entry?) {
@@ -957,6 +956,14 @@ object Util {
         return context.getSystemService(Context.CONNECTIVITY_SERVICE) as ConnectivityManager
     }
 
+    /**
+     * Executes the given block if this is not null.
+     * @return: the return of the block, or null if this is null
+     */
+    fun <T : Any, R> T?.ifNotNull(block: (T) -> R): R? {
+        return this?.let(block)
+    }
+
     data class NetworkInfo(
         var connected: Boolean = false,
         var unmetered: Boolean = false