Merge branch 'fixAppend' into 'develop'

Fix EndlessScrolling in genre listings

Closes #1223

See merge request ultrasonic/ultrasonic!1050

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

@@ -91,7 +91,6 @@ open class TrackCollectionFragment(
     private val rxBusSubscription: CompositeDisposable = CompositeDisposable()
 
     private var sortOrder = initialOrder
-    private var offset: Int? = null
 
     /**
      * The id of the main layout
@@ -188,13 +187,12 @@ open class TrackCollectionFragment(
 
     private fun loadMoreTracks() {
         if (displayRandom() || navArgs.genreName != null) {
-            offset = navArgs.offset + navArgs.size
-            getLiveData(refresh = true, append = true)
+            getLiveData(append = true)
         }
     }
 
     internal open fun handleRefresh() {
-        getLiveData(true)
+        getLiveData(refresh = true)
     }
 
     internal open fun setupButtons(view: View) {
@@ -553,7 +551,7 @@ open class TrackCollectionFragment(
         val getVideos = navArgs.getVideos
         val getRandomTracks = displayRandom()
         val size = if (navArgs.size < 0) Settings.maxSongs else navArgs.size
-        val offset = offset ?: navArgs.offset
+        val offset = navArgs.offset
         val refresh2 = navArgs.refresh || refresh
 
         listModel.viewModelScope.launch(handler) {
@@ -685,7 +683,7 @@ open class TrackCollectionFragment(
 
     override fun setOrderType(newOrder: SortOrder) {
         sortOrder = newOrder
-        getLiveData(true)
+        getLiveData(refresh = true)
     }
 
     override var viewCapabilities: ViewCapabilities = ViewCapabilities(

ultrasonic/src/main/kotlin/org/moire/ultrasonic/model/TrackCollectionModel.kt

@@ -27,6 +27,7 @@ import org.moire.ultrasonic.util.Util
 class TrackCollectionModel(application: Application) : GenericListModel(application) {
 
     val currentList: MutableLiveData<List<MusicDirectory.Child>> = MutableLiveData()
+    private var loadedUntil: Int = 0
 
     /*
     * Especially when dealing with indexes, this method can return Albums, Entries or a mix of both!
@@ -37,7 +38,6 @@ class TrackCollectionModel(application: Application) : GenericListModel(applicat
         name: String?
     ) {
         withContext(Dispatchers.IO) {
-
             val service = MusicServiceFactory.getMusicService()
             val musicDirectory = service.getMusicDirectory(id, name, refresh)
             currentListIsSortable = true
@@ -57,11 +57,19 @@ class TrackCollectionModel(application: Application) : GenericListModel(applicat
     }
 
     suspend fun getSongsForGenre(genre: String, count: Int, offset: Int, append: Boolean) {
+        // Handle the logic for endless scrolling:
+        // If appending the existing list, set the offset from where to load
+        var newOffset = offset
+        if (append) newOffset += (count + loadedUntil)
+
         withContext(Dispatchers.IO) {
             val service = MusicServiceFactory.getMusicService()
-            val musicDirectory = service.getSongsByGenre(genre, count, offset)
+            val musicDirectory = service.getSongsByGenre(genre, count, newOffset)
             currentListIsSortable = false
             updateList(musicDirectory, append)
+
+            // Update current offset
+            loadedUntil = newOffset
         }
     }
 
@@ -96,7 +104,6 @@ class TrackCollectionModel(application: Application) : GenericListModel(applicat
     }
 
     suspend fun getRandom(size: Int, append: Boolean) {
-
         withContext(Dispatchers.IO) {
             val service = MusicServiceFactory.getMusicService()
             val musicDirectory = service.getRandomSongs(size)