#527 Change from polling to using DownloadService events

4 files changed, 369 insertions, 436 deletions

diff --git a/app/src/main/java/github/daneren2005/dsub/activity/SubsonicActivity.java b/app/src/main/java/github/daneren2005/dsub/activity/SubsonicActivity.java
index 33d978bf..1492c778 100644
--- a/app/src/main/java/github/daneren2005/dsub/activity/SubsonicActivity.java
+++ b/app/src/main/java/github/daneren2005/dsub/activity/SubsonicActivity.java
@@ -29,6 +29,7 @@ import android.media.AudioManager;
 import android.os.Build;
 import android.os.Bundle;
 import android.os.Environment;
+import android.os.Handler;
 import android.support.design.widget.NavigationView;
 import android.support.v7.app.ActionBarDrawerToggle;
 import android.support.v4.app.Fragment;
@@ -82,6 +83,7 @@ public class SubsonicActivity extends AppCompatActivity implements OnItemSelecte
 	private static final int MENU_GROUP_SERVER = 10;
 	private static final int MENU_ITEM_SERVER_BASE = 100;
 
+	private final List<Runnable> afterServiceAvailable = new ArrayList<>();
 	private boolean drawerIdle = true;
 	private boolean destroyed = false;
 	private boolean finished = false;
@@ -91,6 +93,7 @@ public class SubsonicActivity extends AppCompatActivity implements OnItemSelecte
 	protected View secondaryContainer;
 	protected boolean tv = false;
 	protected boolean touchscreen = true;
+	protected Handler handler = new Handler();
 	Spinner actionBarSpinner;
 	ArrayAdapter<CharSequence> spinnerAdapter;
 	ViewGroup rootView;
@@ -871,13 +874,28 @@ public class SubsonicActivity extends AppCompatActivity implements OnItemSelecte
 		for (int i = 0; i < 5; i++) {
 			DownloadService downloadService = DownloadService.getInstance();
 			if (downloadService != null) {
-				return downloadService;
+				break;
 			}
 			Log.w(TAG, "DownloadService not running. Attempting to start it.");
 			startService(new Intent(this, DownloadService.class));
 			Util.sleepQuietly(50L);
 		}
-		return DownloadService.getInstance();
+
+		final DownloadService downloadService = DownloadService.getInstance();
+		if(downloadService != null && afterServiceAvailable.size() > 0) {
+			for(Runnable runnable: afterServiceAvailable) {
+				handler.post(runnable);
+			}
+			afterServiceAvailable.clear();
+		}
+		return downloadService;
+	}
+	public void runWhenServiceAvailable(Runnable runnable) {
+		if(getDownloadService() != null) {
+			runnable.run();
+		} else {
+			afterServiceAvailable.add(runnable);
+		}
 	}
 
 	public static String getThemeName() {
diff --git a/app/src/main/java/github/daneren2005/dsub/activity/SubsonicFragmentActivity.java b/app/src/main/java/github/daneren2005/dsub/activity/SubsonicFragmentActivity.java
index f0685a5f..e5144f6f 100644
--- a/app/src/main/java/github/daneren2005/dsub/activity/SubsonicFragmentActivity.java
+++ b/app/src/main/java/github/daneren2005/dsub/activity/SubsonicFragmentActivity.java
@@ -45,6 +45,7 @@ import com.sothree.slidinguppanel.SlidingUpPanelLayout;
 
 import java.io.File;
 import java.util.Date;
+import java.util.List;
 import java.util.concurrent.Executors;
 import java.util.concurrent.ScheduledExecutorService;
 import java.util.concurrent.TimeUnit;
@@ -82,13 +83,12 @@ import github.daneren2005.dsub.view.ChangeLog;
 /**
  * Created by Scott on 10/14/13.
  */
-public class SubsonicFragmentActivity extends SubsonicActivity {
+public class SubsonicFragmentActivity extends SubsonicActivity implements DownloadService.OnSongChangedListener {
 	private static String TAG = SubsonicFragmentActivity.class.getSimpleName();
 	private static boolean infoDialogDisplayed;
 	private static boolean sessionInitialized = false;
 	private static long ALLOWED_SKEW = 30000L;
 
-	private Handler handler = new Handler();
 	private SlidingUpPanelLayout slideUpPanel;
 	private SlidingUpPanelLayout.PanelSlideListener panelSlideListener;
 	private NowPlayingFragment nowPlayingFragment;
@@ -96,7 +96,6 @@ public class SubsonicFragmentActivity extends SubsonicActivity {
 	private Toolbar mainToolbar;
 	private Toolbar nowPlayingToolbar;
 
-	private ScheduledExecutorService executorService;
 	private View bottomBar;
 	private ImageView coverArtView;
 	private TextView trackView;
@@ -292,11 +291,6 @@ public class SubsonicFragmentActivity extends SubsonicActivity {
 						getDownloadService().previous();
 						return null;
 					}
-
-					@Override
-					protected void done(Void result) {
-						update();
-					}
 				}.execute();
 			}
 		});
@@ -317,11 +311,6 @@ public class SubsonicFragmentActivity extends SubsonicActivity {
 
 						return null;
 					}
-
-					@Override
-					protected void done(Void result) {
-						update();
-					}
 				}.execute();
 			}
 		});
@@ -340,11 +329,6 @@ public class SubsonicFragmentActivity extends SubsonicActivity {
 						getDownloadService().next();
 						return null;
 					}
-
-					@Override
-					protected void done(Void result) {
-						update();
-					}
 				}.execute();
 			}
 		});
@@ -406,18 +390,6 @@ public class SubsonicFragmentActivity extends SubsonicActivity {
 	public void onResume() {
 		super.onResume();
 
-		Runnable runnable = new Runnable() {
-			@Override
-			public void run() {
-				handler.post(new Runnable() {
-					@Override
-					public void run() {
-						update();
-					}
-				});
-			}
-		};
-
 		if(getIntent().hasExtra(Constants.INTENT_EXTRA_VIEW_ALBUM)) {
 			SubsonicFragment fragment = new SelectDirectoryFragment();
 			Bundle args = new Bundle();
@@ -437,15 +409,21 @@ public class SubsonicFragmentActivity extends SubsonicActivity {
 		}
 
 		createAccount();
-
-		executorService = Executors.newSingleThreadScheduledExecutor();
-		executorService.scheduleWithFixedDelay(runnable, 0L, 1000L, TimeUnit.MILLISECONDS);
+		runWhenServiceAvailable(new Runnable() {
+			@Override
+			public void run() {
+				getDownloadService().addOnSongChangedListener(SubsonicFragmentActivity.this, true);
+			}
+		});
 	}
 
 	@Override
 	public void onPause() {
 		super.onPause();
-		executorService.shutdown();
+		DownloadService downloadService = getDownloadService();
+		if(downloadService != null) {
+			downloadService.removeOnSongChangeListener(this);
+		}
 	}
 
 	@Override
@@ -638,54 +616,6 @@ public class SubsonicFragmentActivity extends SubsonicActivity {
 		}
 	}
 
-	private void update() {
-		DownloadService downloadService = getDownloadService();
-		if (downloadService == null) {
-			return;
-		}
-
-		DownloadFile current = downloadService.getCurrentPlaying();
-		PlayerState state = downloadService.getPlayerState();
-		if(current == currentPlaying && state == currentState) {
-			if(current == null && slideUpPanel.getPanelState() == SlidingUpPanelLayout.PanelState.COLLAPSED) {
-				slideUpPanel.setPanelState(SlidingUpPanelLayout.PanelState.HIDDEN);
-			}
-			return;
-		} else {
-			currentPlaying = current;
-			currentState = state;
-		}
-
-		MusicDirectory.Entry song = null;
-		if (current != null) {
-			song = current.getSong();
-			trackView.setText(song.getTitle());
-			artistView.setText(song.getArtist());
-
-			if(slideUpPanel.getPanelState() == SlidingUpPanelLayout.PanelState.HIDDEN) {
-				slideUpPanel.setPanelState(SlidingUpPanelLayout.PanelState.COLLAPSED);
-			}
-		} else if(slideUpPanel.getPanelState() == SlidingUpPanelLayout.PanelState.COLLAPSED) {
-			slideUpPanel.setPanelState(SlidingUpPanelLayout.PanelState.HIDDEN);
-		}
-
-		if (coverArtView != null) {
-			int height = coverArtView.getHeight();
-			if (height <= 0) {
-				int[] attrs = new int[]{R.attr.actionBarSize};
-				TypedArray typedArray = this.obtainStyledAttributes(attrs);
-				height = typedArray.getDimensionPixelSize(0, 0);
-				typedArray.recycle();
-			}
-			getImageLoader().loadImage(coverArtView, song, false, height, false);
-		}
-
-		int[] attrs = new int[]{(state == PlayerState.STARTED) ? R.attr.actionbar_pause : R.attr.actionbar_start};
-		TypedArray typedArray = this.obtainStyledAttributes(attrs);
-		startButton.setImageResource(typedArray.getResourceId(0, 0));
-		typedArray.recycle();
-	}
-
 	public void checkUpdates() {
 		try {
 			String version = getPackageManager().getPackageInfo(getPackageName(), 0).versionName;
@@ -892,4 +822,62 @@ public class SubsonicFragmentActivity extends SubsonicActivity {
 	public Toolbar getActiveToolbar() {
 		return slideUpPanel.getPanelState() == SlidingUpPanelLayout.PanelState.EXPANDED ? nowPlayingToolbar : mainToolbar;
 	}
+
+	@Override
+	public void onSongChanged(DownloadFile currentPlaying, int currentPlayingIndex) {
+		DownloadService downloadService = getDownloadService();
+		PlayerState state = downloadService.getPlayerState();
+		if(currentPlaying == this.currentPlaying && state == currentState) {
+			if(currentPlaying == null && slideUpPanel.getPanelState() == SlidingUpPanelLayout.PanelState.COLLAPSED) {
+				slideUpPanel.setPanelState(SlidingUpPanelLayout.PanelState.HIDDEN);
+			}
+			return;
+		} else {
+			this.currentPlaying = currentPlaying;
+		}
+
+		MusicDirectory.Entry song = null;
+		if (currentPlaying != null) {
+			song = currentPlaying.getSong();
+			trackView.setText(song.getTitle());
+			artistView.setText(song.getArtist());
+
+			if(slideUpPanel.getPanelState() == SlidingUpPanelLayout.PanelState.HIDDEN) {
+				slideUpPanel.setPanelState(SlidingUpPanelLayout.PanelState.COLLAPSED);
+			}
+		} else if(slideUpPanel.getPanelState() == SlidingUpPanelLayout.PanelState.COLLAPSED) {
+			slideUpPanel.setPanelState(SlidingUpPanelLayout.PanelState.HIDDEN);
+		}
+
+		if (coverArtView != null) {
+			int height = coverArtView.getHeight();
+			if (height <= 0) {
+				int[] attrs = new int[]{R.attr.actionBarSize};
+				TypedArray typedArray = this.obtainStyledAttributes(attrs);
+				height = typedArray.getDimensionPixelSize(0, 0);
+				typedArray.recycle();
+			}
+			getImageLoader().loadImage(coverArtView, song, false, height, false);
+		}
+	}
+
+	@Override
+	public void onSongsChanged(List<DownloadFile> songs, DownloadFile currentPlaying, int currentPlayingIndex) {
+		if(this.currentPlaying != currentPlaying) {
+			onSongChanged(currentPlaying, currentPlayingIndex);
+		}
+	}
+
+	@Override
+	public void onSongProgress(DownloadFile currentPlaying, int millisPlayed, Integer duration, boolean isSeekable) {
+
+	}
+
+	@Override
+	public void onStateUpdate(DownloadFile downloadFile, PlayerState playerState) {
+		int[] attrs = new int[]{(playerState == PlayerState.STARTED) ? R.attr.actionbar_pause : R.attr.actionbar_start};
+		TypedArray typedArray = this.obtainStyledAttributes(attrs);
+		startButton.setImageResource(typedArray.getResourceId(0, 0));
+		typedArray.recycle();
+	}
 }
diff --git a/app/src/main/java/github/daneren2005/dsub/fragments/NowPlayingFragment.java b/app/src/main/java/github/daneren2005/dsub/fragments/NowPlayingFragment.java
index 1b652f57..a75470e9 100644
--- a/app/src/main/java/github/daneren2005/dsub/fragments/NowPlayingFragment.java
+++ b/app/src/main/java/github/daneren2005/dsub/fragments/NowPlayingFragment.java
@@ -66,6 +66,7 @@ import github.daneren2005.dsub.domain.RepeatMode;
 import github.daneren2005.dsub.domain.ServerInfo;
 import github.daneren2005.dsub.service.DownloadFile;
 import github.daneren2005.dsub.service.DownloadService;
+import github.daneren2005.dsub.service.DownloadService.OnSongChangedListener;
 import github.daneren2005.dsub.service.MusicService;
 import github.daneren2005.dsub.service.MusicServiceFactory;
 import github.daneren2005.dsub.service.OfflineException;
@@ -86,11 +87,10 @@ import java.util.ArrayList;
 import java.util.concurrent.ScheduledFuture;
 import github.daneren2005.dsub.activity.SubsonicActivity;
 
-public class NowPlayingFragment extends SubsonicFragment implements OnGestureListener, SectionAdapter.OnItemClickedListener<DownloadFile> {
+public class NowPlayingFragment extends SubsonicFragment implements OnGestureListener, SectionAdapter.OnItemClickedListener<DownloadFile>, OnSongChangedListener {
 	private static final String TAG = NowPlayingFragment.class.getSimpleName();
 	private static final int PERCENTAGE_OF_SCREEN_FOR_SWIPE = 10;
 	private static final int INCREMENT_TIME = 5000;
-	private static final int SERVICE_BACKOFF = 200;
 
 	private static final int ACTION_PREVIOUS = 1;
 	private static final int ACTION_NEXT = 2;
@@ -126,13 +126,11 @@ public class NowPlayingFragment extends SubsonicFragment implements OnGestureLis
 	private ScheduledFuture<?> hideControlsFuture;
 	private List<DownloadFile> songList;
 	private DownloadFileAdapter songListAdapter;
-	private SilentBackgroundTask<Void> onProgressChangedTask;
-	private SilentBackgroundTask<Void> onCurrentChangedTask;
-	private SilentBackgroundTask<Void> onDownloadListChangedTask;
 	private boolean seekInProgress = false;
 	private boolean startFlipped = false;
 	private boolean scrollWhenLoaded = false;
 	private int lastY = 0;
+	private int currentPlayingSize = 0;
 
 	/**
 	 * Called when the activity is first created.
@@ -280,12 +278,6 @@ public class NowPlayingFragment extends SubsonicFragment implements OnGestureLis
 						getDownloadService().previous();
 						return null;
 					}
-
-					@Override
-					protected void done(Void result) {
-						onCurrentChanged();
-						onProgressChanged();
-					}
 				}.execute();
 				setControlsVisible(true);
 			}
@@ -306,14 +298,6 @@ public class NowPlayingFragment extends SubsonicFragment implements OnGestureLis
 						getDownloadService().next();
 						return true;
 					}
-
-					@Override
-					protected void done(Boolean result) {
-						if (result) {
-							onCurrentChanged();
-							onProgressChanged();
-						}
-					}
 				}.execute();
 				setControlsVisible(true);
 			}
@@ -333,12 +317,6 @@ public class NowPlayingFragment extends SubsonicFragment implements OnGestureLis
 						getDownloadService().pause();
 						return null;
 					}
-
-					@Override
-					protected void done(Void result) {
-						onCurrentChanged();
-						onProgressChanged();
-					}
 				}.execute();
 			}
 		});
@@ -352,12 +330,6 @@ public class NowPlayingFragment extends SubsonicFragment implements OnGestureLis
 						getDownloadService().reset();
 						return null;
 					}
-
-					@Override
-					protected void done(Void result) {
-						onCurrentChanged();
-						onProgressChanged();
-					}
 				}.execute();
 			}
 		});
@@ -372,12 +344,6 @@ public class NowPlayingFragment extends SubsonicFragment implements OnGestureLis
 						start();
 						return null;
 					}
-
-					@Override
-					protected void done(Void result) {
-						onCurrentChanged();
-						onProgressChanged();
-					}
 				}.execute();
 			}
 		});
@@ -387,7 +353,6 @@ public class NowPlayingFragment extends SubsonicFragment implements OnGestureLis
 			public void onClick(View view) {
 				RepeatMode repeatMode = getDownloadService().getRepeatMode().next();
 				getDownloadService().setRepeatMode(repeatMode);
-				onDownloadListChanged();
 				switch (repeatMode) {
 					case OFF:
 						Util.toast(context, R.string.download_repeat_off);
@@ -523,7 +488,6 @@ public class NowPlayingFragment extends SubsonicFragment implements OnGestureLis
 					@Override
 					protected void done(Void result) {
 						seekInProgress = false;
-						NowPlayingFragment.this.onProgressChanged();
 					}
 				}.execute();
 			}
@@ -811,24 +775,10 @@ public class NowPlayingFragment extends SubsonicFragment implements OnGestureLis
 	}
 	private void onResumeHandlers() {
 		final Handler handler = new Handler();
-		Runnable runnable = new Runnable() {
-			@Override
-			public void run() {
-				handler.post(new Runnable() {
-					@Override
-					public void run() {
-						update();
-					}
-				});
-			}
-		};
-
 		executorService = Executors.newSingleThreadScheduledExecutor();
-		executorService.scheduleWithFixedDelay(runnable, 0L, 1000L, TimeUnit.MILLISECONDS);
-
 		setControlsVisible(true);
 
-		DownloadService downloadService = getDownloadService();
+		final DownloadService downloadService = getDownloadService();
 		if (downloadService == null || downloadService.getCurrentPlaying() == null || startFlipped) {
 			playlistFlipper.setDisplayedChild(1);
 		}
@@ -843,24 +793,17 @@ public class NowPlayingFragment extends SubsonicFragment implements OnGestureLis
 		if(currentPlaying == null && downloadService != null && currentPlaying == downloadService.getCurrentPlaying()) {
 			getImageLoader().loadImage(albumArtImageView, (Entry) null, true, false);
 		}
-		if(downloadService != null) {
-			downloadService.startRemoteScan();
-		} else {
-			// Make sure to call remote scan once the service is ready
-			final Runnable waitForService = new Runnable() {
-				@Override
-				public void run() {
-					DownloadService service = getDownloadService();
-					if(service != null) {
-						service.startRemoteScan();
-					} else {
-						handler.postDelayed(this, SERVICE_BACKOFF);
-					}
-				}
-			};
 
-			handler.postDelayed(waitForService, SERVICE_BACKOFF);
-		}
+		context.runWhenServiceAvailable(new Runnable() {
+			@Override
+			public void run() {
+				if(primaryFragment) {
+					DownloadService downloadService = getDownloadService();
+					downloadService.startRemoteScan();
+					downloadService.addOnSongChangedListener(NowPlayingFragment.this, true);
+				}
+			}
+		});
 	}
 
 	@Override
@@ -870,11 +813,11 @@ public class NowPlayingFragment extends SubsonicFragment implements OnGestureLis
 	}
 	private void onPauseHandlers() {
 		if(executorService != null) {
-			executorService.shutdown();
-			if (getDownloadService() != null) {
-				getDownloadService().stopRemoteScan();
+			DownloadService downloadService = getDownloadService();
+			if (downloadService != null) {
+				downloadService.stopRemoteScan();
+				downloadService.removeOnSongChangeListener(this);
 			}
-			executorService = null;
 			playlistFlipper.setDisplayedChild(0);
 		}
 	}
@@ -983,24 +926,10 @@ public class NowPlayingFragment extends SubsonicFragment implements OnGestureLis
 	}
 
 	private void update() {
-		if (getDownloadService() == null) {
-			return;
-		}
-
-		if (currentRevision != getDownloadService().getDownloadListUpdateRevision()) {
-			onDownloadListChanged();
-		}
-
-		if (currentPlaying != getDownloadService().getCurrentPlaying()) {
-			onCurrentChanged();
-		}
-
 		if(startFlipped) {
 			startFlipped = false;
 			scrollToCurrent();
 		}
-
-		onProgressChanged();
 	}
 
 	protected void startTimer() {
@@ -1098,258 +1027,6 @@ public class NowPlayingFragment extends SubsonicFragment implements OnGestureLis
 			}
 		}
 	}
-	private void onDownloadListChanged() {
-		onDownloadListChanged(false);
-	}
-	private void onDownloadListChanged(final boolean refresh) {
-		final DownloadService downloadService = getDownloadService();
-		if (downloadService == null || onDownloadListChangedTask != null) {
-			return;
-		}
-
-		onDownloadListChangedTask = new SilentBackgroundTask<Void>(context) {
-			int currentPlayingIndex;
-			int size;
-
-			@Override
-			protected Void doInBackground() throws Throwable {
-				currentPlayingIndex = downloadService.getCurrentPlayingIndex() + 1;
-				size = downloadService.size();
-
-				return null;
-			}
-
-			@Override
-			protected void done(Void result) {
-				List<DownloadFile> list;
-				list = downloadService.getSongs();
-
-				if(downloadService.isShufflePlayEnabled()) {
-					emptyTextView.setText(R.string.download_shuffle_loading);
-				}
-				else {
-					emptyTextView.setText(R.string.download_empty);
-				}
-
-				if(songListAdapter == null || refresh) {
-					songList = new ArrayList<>();
-					songList.addAll(list);
-					playlistView.setAdapter(songListAdapter = new DownloadFileAdapter(context, songList, NowPlayingFragment.this));
-				} else {
-					songList.clear();
-					songList.addAll(list);
-					songListAdapter.notifyDataSetChanged();
-				}
-
-				emptyTextView.setVisibility(list.isEmpty() ? View.VISIBLE : View.GONE);
-				currentRevision = downloadService.getDownloadListUpdateRevision();
-
-				switch (downloadService.getRepeatMode()) {
-					case OFF:
-						if("light".equals(SubsonicActivity.getThemeName()) | "light_fullscreen".equals(SubsonicActivity.getThemeName())) {
-							repeatButton.setImageResource(R.drawable.media_repeat_off_light);
-						} else {
-							repeatButton.setImageResource(R.drawable.media_repeat_off);
-						}
-						break;
-					case ALL:
-						repeatButton.setImageResource(R.drawable.media_repeat_all);
-						break;
-					case SINGLE:
-						repeatButton.setImageResource(R.drawable.media_repeat_single);
-						break;
-					default:
-						break;
-				}
-
-				if(scrollWhenLoaded) {
-					scrollToCurrent();
-					scrollWhenLoaded = false;
-				}
-
-				setSubtitle(context.getResources().getString(R.string.download_playing_out_of, currentPlayingIndex, size));
-				onDownloadListChangedTask = null;
-				if(onCurrentChangedTask != null) {
-					onCurrentChangedTask.execute();
-				} else if(onProgressChangedTask != null) {
-					onProgressChangedTask.execute();
-				}
-			}
-		};
-		onDownloadListChangedTask.execute();
-	}
-
-	private void onCurrentChanged() {
-		final DownloadService downloadService = getDownloadService();
-		if (downloadService == null  || onCurrentChangedTask != null) {
-			return;
-		}
-
-		onCurrentChangedTask = new SilentBackgroundTask<Void>(context) {
-			int currentPlayingIndex;
-			int currentPlayingSize;
-
-			@Override
-			protected Void doInBackground() throws Throwable {
-				currentPlaying = downloadService.getCurrentPlaying();
-				currentPlayingIndex = downloadService.getCurrentPlayingIndex() + 1;
-				currentPlayingSize = downloadService.size();
-				return null;
-			}
-
-			@Override
-			protected void done(Void result) {
-				if (currentPlaying != null) {
-					Entry song = currentPlaying.getSong();
-					songTitleTextView.setText(song.getTitle());
-					getImageLoader().loadImage(albumArtImageView, song, true, true);
-					starButton.setImageResource(song.isStarred() ? android.R.drawable.btn_star_big_on : android.R.drawable.btn_star_big_off);
-					setSubtitle(context.getResources().getString(R.string.download_playing_out_of, currentPlayingIndex, currentPlayingSize));
-
-					int badRating, goodRating, bookmark;
-					if(song.getRating() == 1) {
-						badRating = R.drawable.ic_action_rating_bad_selected;
-					} else if(context.getResources().getConfiguration().orientation == Configuration.ORIENTATION_PORTRAIT) {
-						badRating = R.drawable.ic_action_rating_bad_dark;
-					} else {
-						badRating = Util.getAttribute(context, R.attr.rating_bad);
-					}
-					rateBadButton.setImageResource(badRating);
-
-					if(song.getRating() == 5) {
-						goodRating = R.drawable.ic_action_rating_good_selected;
-					} else if(context.getResources().getConfiguration().orientation == Configuration.ORIENTATION_PORTRAIT) {
-						goodRating = R.drawable.ic_action_rating_good_dark;
-					} else {
-						goodRating = Util.getAttribute(context, R.attr.rating_good);
-					}
-					rateGoodButton.setImageResource(goodRating);
-
-					if(song.getBookmark() != null) {
-						bookmark = R.drawable.ic_menu_bookmark_selected;
-					} else if(context.getResources().getConfiguration().orientation == Configuration.ORIENTATION_PORTRAIT) {
-						bookmark = R.drawable.ic_menu_bookmark_dark;
-					} else {
-						bookmark = Util.getAttribute(context, R.attr.bookmark);
-					}
-					bookmarkButton.setImageResource(bookmark);
-				} else {
-					songTitleTextView.setText(null);
-					getImageLoader().loadImage(albumArtImageView, (Entry) null, true, false);
-					starButton.setImageResource(android.R.drawable.btn_star_big_off);
-					setSubtitle(null);
-				}
-				onCurrentChangedTask = null;
-				if(onProgressChangedTask != null) {
-					onProgressChangedTask.execute();
-				}
-			}
-		};
-
-		if(onDownloadListChangedTask == null) {
-			onCurrentChangedTask.execute();
-		}
-	}
-
-	private void onProgressChanged() {
-		// Make sure to only be trying to run one of these at a time
-		if (getDownloadService() == null || onProgressChangedTask != null) {
-			return;
-		}
-
-		onProgressChangedTask = new SilentBackgroundTask<Void>(context) {
-			DownloadService downloadService;
-			int millisPlayed;
-			Integer duration;
-			PlayerState playerState;
-			boolean isSeekable;
-
-			@Override
-			protected Void doInBackground() throws Throwable {
-				downloadService = getDownloadService();
-				millisPlayed = Math.max(0, downloadService.getPlayerPosition());
-				duration = downloadService.getPlayerDuration();
-				playerState = getDownloadService().getPlayerState();
-				isSeekable = downloadService.isSeekable();
-				return null;
-			}
-
-			@Override
-			protected void done(Void result) {
-				if (currentPlaying != null) {
-					int millisTotal = duration == null ? 0 : duration;
-
-					positionTextView.setText(Util.formatDuration(millisPlayed / 1000));
-					if(millisTotal > 0) {
-						durationTextView.setText(Util.formatDuration(millisTotal / 1000));
-					} else {
-						durationTextView.setText("-:--");
-					}
-					progressBar.setMax(millisTotal == 0 ? 100 : millisTotal); // Work-around for apparent bug.
-					if(!seekInProgress) {
-						progressBar.setProgress(millisPlayed);
-					}
-					progressBar.setEnabled(isSeekable);
-				} else {
-					positionTextView.setText("0:00");
-					durationTextView.setText("-:--");
-					progressBar.setProgress(0);
-					progressBar.setEnabled(false);
-				}
-
-				switch (playerState) {
-					case DOWNLOADING:
-						if(currentPlaying != null) {
-							if(Util.isWifiRequiredForDownload(context)) {
-								statusTextView.setText(context.getResources().getString(R.string.download_playerstate_mobile_disabled));
-							} else {
-								long bytes = currentPlaying.getPartialFile().length();
-								statusTextView.setText(context.getResources().getString(R.string.download_playerstate_downloading, Util.formatLocalizedBytes(bytes, context)));
-							}
-						}
-						break;
-					case PREPARING:
-						statusTextView.setText(R.string.download_playerstate_buffering);
-						break;
-					default:
-						if(currentPlaying != null) {
-							String artist = "";
-							if(currentPlaying.getSong().getArtist() != null) {
-								artist = currentPlaying.getSong().getArtist() + " - ";
-							}
-							statusTextView.setText(artist + currentPlaying.getSong().getAlbum());
-						} else {
-							statusTextView.setText(null);
-						}
-						break;
-				}
-
-				switch (playerState) {
-					case STARTED:
-						pauseButton.setVisibility(View.VISIBLE);
-						stopButton.setVisibility(View.INVISIBLE);
-						startButton.setVisibility(View.INVISIBLE);
-						break;
-					case DOWNLOADING:
-					case PREPARING:
-						pauseButton.setVisibility(View.INVISIBLE);
-						stopButton.setVisibility(View.VISIBLE);
-						startButton.setVisibility(View.INVISIBLE);
-						break;
-					default:
-						pauseButton.setVisibility(View.INVISIBLE);
-						stopButton.setVisibility(View.INVISIBLE);
-						startButton.setVisibility(View.VISIBLE);
-						break;
-				}
-
-				onProgressChangedTask = null;
-			}
-		};
-		if(onDownloadListChangedTask == null && onCurrentChangedTask == null) {
-			onProgressChangedTask.execute();
-		}
-	}
 
 	private void changeProgress(final int ms) {
 		final DownloadService downloadService = getDownloadService();
@@ -1528,11 +1205,6 @@ public class NowPlayingFragment extends SubsonicFragment implements OnGestureLis
 							downloadService.seekTo(downloadService.getPlayerPosition() - DownloadService.REWIND);
 							break;
 					}
-
-					onProgressChanged();
-					if(performAction == ACTION_NEXT || performAction == ACTION_PREVIOUS) {
-						onCurrentChanged();
-					}
 					return null;
 				}
 			}.execute();
@@ -1568,11 +1240,180 @@ public class NowPlayingFragment extends SubsonicFragment implements OnGestureLis
 			@Override
 			protected Void doInBackground() throws Throwable {
 				getDownloadService().play(item);
-
-				onCurrentChanged();
-				onProgressChanged();
 				return null;
 			}
 		}.execute();
 	}
+
+	@Override
+	public void onSongChanged(DownloadFile currentPlaying, int currentPlayingIndex) {
+		this.currentPlaying = currentPlaying;
+		if (currentPlaying != null) {
+			Entry song = currentPlaying.getSong();
+			songTitleTextView.setText(song.getTitle());
+			getImageLoader().loadImage(albumArtImageView, song, true, true);
+			starButton.setImageResource(song.isStarred() ? android.R.drawable.btn_star_big_on : android.R.drawable.btn_star_big_off);
+			setSubtitle(context.getResources().getString(R.string.download_playing_out_of, currentPlayingIndex, currentPlayingSize));
+
+			int badRating, goodRating, bookmark;
+			if(song.getRating() == 1) {
+				badRating = R.drawable.ic_action_rating_bad_selected;
+			} else if(context.getResources().getConfiguration().orientation == Configuration.ORIENTATION_PORTRAIT) {
+				badRating = R.drawable.ic_action_rating_bad_dark;
+			} else {
+				badRating = Util.getAttribute(context, R.attr.rating_bad);
+			}
+			rateBadButton.setImageResource(badRating);
+
+			if(song.getRating() == 5) {
+				goodRating = R.drawable.ic_action_rating_good_selected;
+			} else if(context.getResources().getConfiguration().orientation == Configuration.ORIENTATION_PORTRAIT) {
+				goodRating = R.drawable.ic_action_rating_good_dark;
+			} else {
+				goodRating = Util.getAttribute(context, R.attr.rating_good);
+			}
+			rateGoodButton.setImageResource(goodRating);
+
+			if(song.getBookmark() != null) {
+				bookmark = R.drawable.ic_menu_bookmark_selected;
+			} else if(context.getResources().getConfiguration().orientation == Configuration.ORIENTATION_PORTRAIT) {
+				bookmark = R.drawable.ic_menu_bookmark_dark;
+			} else {
+				bookmark = Util.getAttribute(context, R.attr.bookmark);
+			}
+			bookmarkButton.setImageResource(bookmark);
+		} else {
+			songTitleTextView.setText(null);
+			getImageLoader().loadImage(albumArtImageView, null, true, false);
+			starButton.setImageResource(android.R.drawable.btn_star_big_off);
+			setSubtitle(null);
+		}
+	}
+
+	@Override
+	public void onSongsChanged(List<DownloadFile> songs, DownloadFile currentPlaying, int currentPlayingIndex) {
+		currentPlayingSize = songs.size();
+
+		DownloadService downloadService = getDownloadService();
+		if(downloadService.isShufflePlayEnabled()) {
+			emptyTextView.setText(R.string.download_shuffle_loading);
+		}
+		else {
+			emptyTextView.setText(R.string.download_empty);
+		}
+
+		if(songListAdapter == null) {
+			songList = new ArrayList<>();
+			songList.addAll(songs);
+			playlistView.setAdapter(songListAdapter = new DownloadFileAdapter(context, songList, NowPlayingFragment.this));
+		} else {
+			songList.clear();
+			songList.addAll(songs);
+			songListAdapter.notifyDataSetChanged();
+		}
+
+		emptyTextView.setVisibility(songs.isEmpty() ? View.VISIBLE : View.GONE);
+		currentRevision = downloadService.getDownloadListUpdateRevision();
+
+		switch (downloadService.getRepeatMode()) {
+			case OFF:
+				if("light".equals(SubsonicActivity.getThemeName()) | "light_fullscreen".equals(SubsonicActivity.getThemeName())) {
+					repeatButton.setImageResource(R.drawable.media_repeat_off_light);
+				} else {
+					repeatButton.setImageResource(R.drawable.media_repeat_off);
+				}
+				break;
+			case ALL:
+				repeatButton.setImageResource(R.drawable.media_repeat_all);
+				break;
+			case SINGLE:
+				repeatButton.setImageResource(R.drawable.media_repeat_single);
+				break;
+			default:
+				break;
+		}
+
+		if(scrollWhenLoaded) {
+			scrollToCurrent();
+			scrollWhenLoaded = false;
+		}
+
+		setSubtitle(context.getResources().getString(R.string.download_playing_out_of, currentPlayingIndex, currentPlayingSize));
+		if(this.currentPlaying != currentPlaying) {
+			onSongChanged(currentPlaying, currentPlayingIndex);
+		}
+	}
+
+	@Override
+	public void onSongProgress(DownloadFile currentPlaying, int millisPlayed, Integer duration, boolean isSeekable) {
+		if (currentPlaying != null) {
+			int millisTotal = duration == null ? 0 : duration;
+
+			positionTextView.setText(Util.formatDuration(millisPlayed / 1000));
+			if(millisTotal > 0) {
+				durationTextView.setText(Util.formatDuration(millisTotal / 1000));
+			} else {
+				durationTextView.setText("-:--");
+			}
+			progressBar.setMax(millisTotal == 0 ? 100 : millisTotal); // Work-around for apparent bug.
+			if(!seekInProgress) {
+				progressBar.setProgress(millisPlayed);
+			}
+			progressBar.setEnabled(isSeekable);
+		} else {
+			positionTextView.setText("0:00");
+			durationTextView.setText("-:--");
+			progressBar.setProgress(0);
+			progressBar.setEnabled(false);
+		}
+	}
+
+	@Override
+	public void onStateUpdate(DownloadFile downloadFile, PlayerState playerState) {
+		switch (playerState) {
+			case DOWNLOADING:
+				if(currentPlaying != null) {
+					if(Util.isWifiRequiredForDownload(context)) {
+						statusTextView.setText(context.getResources().getString(R.string.download_playerstate_mobile_disabled));
+					} else {
+						long bytes = currentPlaying.getPartialFile().length();
+						statusTextView.setText(context.getResources().getString(R.string.download_playerstate_downloading, Util.formatLocalizedBytes(bytes, context)));
+					}
+				}
+				break;
+			case PREPARING:
+				statusTextView.setText(R.string.download_playerstate_buffering);
+				break;
+			default:
+				if(currentPlaying != null) {
+					String artist = "";
+					if(currentPlaying.getSong().getArtist() != null) {
+						artist = currentPlaying.getSong().getArtist() + " - ";
+					}
+					statusTextView.setText(artist + currentPlaying.getSong().getAlbum());
+				} else {
+					statusTextView.setText(null);
+				}
+				break;
+		}
+
+		switch (playerState) {
+			case STARTED:
+				pauseButton.setVisibility(View.VISIBLE);
+				stopButton.setVisibility(View.INVISIBLE);
+				startButton.setVisibility(View.INVISIBLE);
+				break;
+			case DOWNLOADING:
+			case PREPARING:
+				pauseButton.setVisibility(View.INVISIBLE);
+				stopButton.setVisibility(View.VISIBLE);
+				startButton.setVisibility(View.INVISIBLE);
+				break;
+			default:
+				pauseButton.setVisibility(View.INVISIBLE);
+				stopButton.setVisibility(View.INVISIBLE);
+				startButton.setVisibility(View.VISIBLE);
+				break;
+		}
+	}
 }
diff --git a/app/src/main/java/github/daneren2005/dsub/service/DownloadService.java b/app/src/main/java/github/daneren2005/dsub/service/DownloadService.java
index 2e3217d2..cd22fb69 100644
--- a/app/src/main/java/github/daneren2005/dsub/service/DownloadService.java
+++ b/app/src/main/java/github/daneren2005/dsub/service/DownloadService.java
@@ -139,6 +139,7 @@ public class DownloadService extends Service {
 	private boolean removePlayed;
 	private boolean shufflePlay;
 	private boolean artistRadio;
+	private final List<OnSongChangedListener> onSongChangedListeners = new ArrayList<>();
 	private long revision;
 	private static DownloadService instance;
 	private String suggestedPlaylistName;
@@ -362,7 +363,6 @@ public class DownloadService extends Service {
 				}
 			}
 			setNextPlaying();
-			revision++;
 		} else {
 			int size = size();
 			int index = getCurrentPlayingIndex();
@@ -378,8 +378,9 @@ public class DownloadService extends Service {
 			if(!autoplay && (size - 1) == index) {
 				setNextPlaying();
 			}
-			revision++;
 		}
+		revision++;
+		onSongsChanged();
 		updateRemotePlaylist();
 
 		if(shuffle) {
@@ -543,6 +544,7 @@ public class DownloadService extends Service {
 			currentPlayingIndex = 0;
 		}
 		revision++;
+		onSongsChanged();
 		lifecycleSupport.serializeDownloadQueue();
 		updateRemotePlaylist();
 		setNextPlaying();
@@ -694,7 +696,7 @@ public class DownloadService extends Service {
 
 		reset();
 		downloadList.clear();
-		revision++;
+		onSongsChanged();
 		if (currentDownloading != null && !backgroundDownloadList.contains(currentDownloading)) {
 			currentDownloading.cancelDownload();
 			currentDownloading = null;
@@ -733,6 +735,7 @@ public class DownloadService extends Service {
 		currentPlayingIndex = downloadList.indexOf(currentPlaying);
 		backgroundDownloadList.remove(downloadFile);
 		revision++;
+		onSongsChanged();
 		lifecycleSupport.serializeDownloadQueue();
 		updateRemotePlaylist();
 		if(downloadFile == nextPlaying) {
@@ -789,6 +792,7 @@ public class DownloadService extends Service {
 			Util.broadcastNewTrackInfo(this, null);
 			Notifications.hidePlayingNotification(this, this, handler);
 		}
+		onSongChanged();
 	}
 
 	synchronized void setNextPlaying() {
@@ -1284,6 +1288,7 @@ public class DownloadService extends Service {
 			positionCache.stop();
 			positionCache = null;
 		}
+		onStateUpdate();
 	}
 
 	private class PositionCache implements Runnable {
@@ -1318,6 +1323,7 @@ public class DownloadService extends Service {
 							subtractNextPosition = 0;
 						}
 					}
+					onSongProgress();
 					Thread.sleep(1000L);
 				}
 				catch(Exception e) {
@@ -1989,10 +1995,16 @@ public class DownloadService extends Service {
 	}
 
 	private synchronized void checkRemovePlayed() {
+		boolean changed = false;
 		while(currentPlayingIndex > 0) {
 			downloadList.remove(0);
 			currentPlayingIndex = downloadList.indexOf(currentPlaying);
+			changed = true;
+		}
+
+		if(changed) {
 			revision++;
+			onSongsChanged();
 		}
 	}
 
@@ -2030,6 +2042,7 @@ public class DownloadService extends Service {
 		currentPlayingIndex = downloadList.indexOf(currentPlaying);
 
 		if (revisionBefore != revision) {
+			onSongsChanged();
 			updateRemotePlaylist();
 		}
 
@@ -2071,6 +2084,7 @@ public class DownloadService extends Service {
 		currentPlayingIndex = downloadList.indexOf(currentPlaying);
 
 		if (revisionBefore != revision) {
+			onSongsChanged();
 			updateRemotePlaylist();
 		}
 
@@ -2338,6 +2352,71 @@ public class DownloadService extends Service {
 		}
 	}
 
+	public void addOnSongChangedListener(OnSongChangedListener listener) {
+		addOnSongChangedListener(listener, false);
+	}
+	public void addOnSongChangedListener(OnSongChangedListener listener, boolean run) {
+		int index = onSongChangedListeners.indexOf(listener);
+		if(index == -1) {
+			onSongChangedListeners.add(listener);
+		}
+
+		if(run) {
+			onSongsChanged();
+			onSongProgress();
+			onStateUpdate();
+		}
+	}
+	public void removeOnSongChangeListener(OnSongChangedListener listener) {
+		int index = onSongChangedListeners.indexOf(listener);
+		if(index != -1) {
+			onSongChangedListeners.remove(index);
+		}
+	}
+
+	private void onSongChanged() {
+		for(final OnSongChangedListener listener: onSongChangedListeners) {
+			handler.post(new Runnable() {
+				@Override
+				public void run() {
+					listener.onSongChanged(currentPlaying, currentPlayingIndex);
+				}
+			});
+		}
+	}
+	private void onSongsChanged() {
+		for(final OnSongChangedListener listener: onSongChangedListeners) {
+			handler.post(new Runnable() {
+				@Override
+				public void run() {
+					listener.onSongsChanged(downloadList, currentPlaying, currentPlayingIndex);
+				}
+			});
+		}
+	}
+	private void onSongProgress() {
+		final Integer duration = getPlayerDuration();
+		final boolean isSeekable = isSeekable();
+		for(final OnSongChangedListener listener: onSongChangedListeners) {
+			handler.post(new Runnable() {
+				@Override
+				public void run() {
+					listener.onSongProgress(currentPlaying, cachedPosition, duration, isSeekable);
+				}
+			});
+		}
+	}
+	private void onStateUpdate() {
+		for(final OnSongChangedListener listener: onSongChangedListeners) {
+			handler.post(new Runnable() {
+				@Override
+				public void run() {
+					listener.onStateUpdate(currentPlaying, playerState);
+				}
+			});
+		}
+	}
+
 	private class BufferTask extends SilentBackgroundTask<Void> {
 		private final DownloadFile downloadFile;
 		private final int position;
@@ -2441,4 +2520,11 @@ public class DownloadService extends Service {
 			return "CheckCompletionTask (" + downloadFile + ")";
 		}
 	}
+
+	public interface OnSongChangedListener {
+		void onSongChanged(DownloadFile currentPlaying, int currentPlayingIndex);
+		void onSongsChanged(List<DownloadFile> songs, DownloadFile currentPlaying, int currentPlayingIndex);
+		void onSongProgress(DownloadFile currentPlaying, int millisPlayed, Integer duration, boolean isSeekable);
+		void onStateUpdate(DownloadFile downloadFile, PlayerState playerState);
+	}
 }