loading doesn't cause unavoidable lag (removed excessive blocking);

switched to a blocking queue list to manage album cover loading; threads
that should be daemons are daemons now;

core/src/zero1hd/rhythmbullet/audio/MusicList.java

@@ -149,6 +149,7 @@ public class MusicList extends Observable {
 		
 		@Override
 		public void run() {
+			Gdx.app.debug("MusicList", "recursive async search beginning.");
 			Array<FileHandle> obtainedAudioFiles = recursiveMusicSearch(directory);
 			Sort.instance().sort(obtainedAudioFiles, compare);
 			if (work) {
@@ -164,6 +165,7 @@ public class MusicList extends Observable {
 			if (thread == null) {
 				work = true;
 				thread = new Thread(this, threadName);
+				thread.setDaemon(true);
 				thread.start();
 				return true;
 			} else {

core/src/zero1hd/rhythmbullet/audio/MusicMetadataController.java

@@ -40,6 +40,10 @@ public class MusicMetadataController extends Observable implements Disposable, O
 		}
 	}
 	
+	/**
+	 * if there is the same amount of metadata as there is music in the music list.
+	 * @return whether or not both sizes are equal.
+	 */
 	public boolean isDone() {
 		return (metadataArray.size == musicList.getMusicArray().size);
 	}
@@ -52,16 +56,12 @@ public class MusicMetadataController extends Observable implements Disposable, O
 	}
 	
 	public int size() {
-		synchronized (loadingThread) {
 		return metadataArray.size;
 	}
-	}
 	
 	public AudioMetadata getMetadata(int index) {
-		synchronized (loadingThread) {
 		return metadataArray.get(index);
 	}
-	}
 	
 	
 	public AudioMetadata getInfo(FileHandle filehandle) {
@@ -80,28 +80,25 @@ public class MusicMetadataController extends Observable implements Disposable, O
 		@Override
 		public void run() {
 			Gdx.app.debug(name, "loading...");
+			clear();
 			searching = true;
-			for (int i = 0; i < metadataArray.size; i++) {
+			Array<AudioMetadata> tempMetadataArray = new Array<>();
-				metadataArray.get(i).dispose();
-			}
-			metadataArray.clear();
 			for (int i = 0; i < musicList.getTotal() && work; i++) {
 				FileHandle musicFile = musicList.getMusicArray().get(i);
-				synchronized (this) {
 				switch (SupportedFormats.valueOf(musicFile.extension().toUpperCase())) {
 				case MP3:
-						metadataArray.add(new MP3Metadata(musicFile));
+					tempMetadataArray.add(new MP3Metadata(musicFile));
 					break;
 				case WAV:
-						metadataArray.add(new WAVMetadata(musicFile));
+					tempMetadataArray.add(new WAVMetadata(musicFile));
 					break;
 				default:
 					break;
+				}
+			}
 			
-					}
-				}
-			}
 			if (work) {
+				metadataArray = tempMetadataArray;
 				searching = false;
 				Gdx.app.debug(name, "load complete.");
 				setChanged();
@@ -130,4 +127,11 @@ public class MusicMetadataController extends Observable implements Disposable, O
 			loadAudioMetadata();
 		}
 	}
+	
+	public void clear() {
+		for (int i = 0; i < metadataArray.size; i++) {
+			metadataArray.get(i).dispose();
+		}
+		metadataArray.clear();
+	}
 }

desktop/src/zero1hd/rhythmbullet/desktop/screens/main/MusicSelectionPage.java

@@ -2,6 +2,7 @@ package zero1hd.rhythmbullet.desktop.screens.main;
 
 import java.util.Observable;
 import java.util.Observer;
+import java.util.concurrent.LinkedBlockingQueue;
 
 import com.badlogic.gdx.Gdx;
 import com.badlogic.gdx.Input.Keys;
@@ -178,6 +179,7 @@ public class MusicSelectionPage extends Page implements Observer {
 	private synchronized void updateList(float delta) {
 		if (mc.getMusicList().isSearched()) {
 			if (mc.getMusicList().getTotal() != 0) {
+				if (mmc.isDone() && !mmc.isSearching()) {
 					if (selectables.size() != mmc.size()) {
 						MusicSelectable selectable = new MusicSelectable(mmc.getMetadata(selectables.size()));
 						selectables.add(selectable);
@@ -196,6 +198,8 @@ public class MusicSelectionPage extends Page implements Observer {
 							}
 						}
 					}
+				}
+
 			} else {
 				//TODO: Error message reporting empty music list or something
 			}
@@ -219,6 +223,7 @@ public class MusicSelectionPage extends Page implements Observer {
 	@Override
 	public void dispose() {
 		mc.getMusicList().deleteObserver(this);
+		selectionLoaderThread.stop();
 		super.dispose();
 	}
 	
@@ -231,13 +236,15 @@ public class MusicSelectionPage extends Page implements Observer {
 				selectables.setChecked(mc.getCurrentMusicFileHandle());
 			}
 		} else if (o == mc.getMusicList()) {
-			synchronized (this) {
 			if (arg == mc.getMusicList().states.LOADING) {
+				synchronized (this) {
 					vGroup.clear();
 					selectables.clear();
 					musicInfoTable.setToDefault();
+					selectionLoaderThread.clear();
 				}
 			}
+
 		}
 	}
 	
@@ -250,31 +257,23 @@ public class MusicSelectionPage extends Page implements Observer {
 	
 	private class musicSelectionLoaderThread implements Runnable {
 		private Thread thread;
-		private Array<AudioMetadata> queueList;
  		private String name = "Music-Selection-Loader-Thread";
 		private volatile boolean work = true;
-		
+		private LinkedBlockingQueue<AudioMetadata> queue;
 		public musicSelectionLoaderThread() {
-			queueList = new Array<>();
+			queue = new LinkedBlockingQueue<>();
 		}
 		
 		@Override
 		public void run() {
 			while (work) {
-				while (queueList.size != 0) {
 				AudioMetadata metadata;
-					synchronized (this) {
+				try {
-						metadata = queueList.pop();
+					metadata = queue.take();
 					metadata.loadAlbumCover();
 					simpleDebug("Loading " + metadata.getTitle());
-					}
-				}
-				synchronized (this) {
-					try {
-						wait();
 				} catch (InterruptedException e) {
-						e.printStackTrace();
+					simpleDebug("Thread was interupted.");
-					}
 				}
 			}
 		}
@@ -282,21 +281,25 @@ public class MusicSelectionPage extends Page implements Observer {
 		public boolean start() {
 			if (thread == null) {
 				thread = new Thread(this, name);
+				thread.setDaemon(true);
 				thread.start();
 				return true;
-			} else {
-				synchronized (this) {
-					notify();
-				}
 			}
 			return false;
 		}
 		
-		public void queue(AudioMetadata metadata) {
+		public void stop() {
-			if (!queueList.contains(metadata, true)) {
+			clear();
-				queueList.add(metadata);
+			thread.interrupt();
-				start();
+			work = false;
 		}
+		
+		public void clear() {
+			queue.clear();
+		}
+		
+		public void queue(AudioMetadata metadata) {
+			queue.add(metadata);
 		}
 		
 	}
@@ -348,7 +351,7 @@ public class MusicSelectionPage extends Page implements Observer {
 			actualCoords.x = getX() + getParent().getX();
 			actualCoords.y = getY() + getParent().getY();
 
-			if ((actualCoords.y < 0 - getHeight() || actualCoords.y > getStage().getHeight() || actualCoords.x < 0 - getWidth() || actualCoords.x > getStage().getWidth()) && selectables.getChecked() != this) {
+			if ((actualCoords.y < 0 - getHeight() - getStage().getHeight()*1.5f || actualCoords.y > getStage().getHeight()*1.5f) && selectables.getChecked() != this) {
 				offScreenAct(delta);
 			} else {
 				onScreenAct(delta);
@@ -365,10 +368,9 @@ public class MusicSelectionPage extends Page implements Observer {
 			if (offScreen) {
 				offScreen = false;
 				timeSinceChanged = 0;
-			} else if (timeSinceChanged < 0.75f) {
+			} else if (timeSinceChanged < 0.075f) {
 				timeSinceChanged += delta;
-			}
+			} else {
-			if (timeSinceChanged >= 0.75f) {
 				if (!frameUsed && metadata.getAlbumCover() != null && !albumArtDisplayed) {
 					updateAlbumArtImage(metadata.getAlbumCover());
 					albumArtDisplayed = true;