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);
 	}
@@ -52,15 +56,11 @@ public class MusicMetadataController extends Observable implements Disposable, O
 	}
 	
 	public int size() {
-		synchronized (loadingThread) {
-			return metadataArray.size;
-		}
+		return metadataArray.size;
 	}
 	
 	public AudioMetadata getMetadata(int index) {
-		synchronized (loadingThread) {
-			return metadataArray.get(index);
-		}
+		return metadataArray.get(index);
 	}
 	
 	
@@ -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++) {
-				metadataArray.get(i).dispose();
-			}
-			metadataArray.clear();
+			Array<AudioMetadata> tempMetadataArray = new Array<>();
 			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));
-						break;
-					case WAV:
-						metadataArray.add(new WAVMetadata(musicFile));
-						break;
-					default:
-						break;
-					
-					}
+				switch (SupportedFormats.valueOf(musicFile.extension().toUpperCase())) {
+				case MP3:
+					tempMetadataArray.add(new MP3Metadata(musicFile));
+					break;
+				case WAV:
+					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();
+	}
 }