media library prefs: do not poll.

It took a couple of years, but the Timer is finally history.

app/src/main/java/ch/blinkenlights/android/medialibrary/LibraryObserver.java

@@ -26,8 +26,9 @@ public class LibraryObserver {
 	 * by the receiver
 	 */
 	public enum Type {
-		SONG,     // Change affected song items.
+		SONG,          // Change affected song items.
-		PLAYLIST, // Change affected playlists.
+		PLAYLIST,      // Change affected playlists.
+		SCAN_PROGRESS, // Information about an ongoing scan.
 	}
 	/**
 	 * Special hint values

app/src/main/java/ch/blinkenlights/android/medialibrary/MediaScanner.java

@@ -178,7 +178,7 @@ public class MediaScanner implements Handler.Callback {
 		MediaLibrary.Preferences prefs = MediaLibrary.getPreferences(mContext);
 		MediaScanPlan.Statistics stats = mScanPlan.getStatistics();
 
-		progress.isRunning = (stats.lastFile != null);
+		progress.isRunning = mScanPlan.hasNextStep();
 		progress.lastFile = stats.lastFile;
 		progress.seen = stats.seen;
 		progress.changed = stats.changed;
@@ -225,6 +225,7 @@ public class MediaScanner implements Handler.Callback {
 				// for this scan.
 				mHandler.removeMessages(MSG_NOTIFY_CHANGE);
 				MediaLibrary.notifyObserver(LibraryObserver.Type.SONG, LibraryObserver.Value.UNKNOWN, false);
+				MediaLibrary.notifyObserver(LibraryObserver.Type.SCAN_PROGRESS, LibraryObserver.Value.UNKNOWN, false);
 
 				updateNotification(false);
 				break;
@@ -247,6 +248,7 @@ public class MediaScanner implements Handler.Callback {
 				if (changed && !mHandler.hasMessages(MSG_NOTIFY_CHANGE)) {
 					mHandler.sendMessageDelayed(mHandler.obtainMessage(MSG_NOTIFY_CHANGE), 500);
 				}
+				MediaLibrary.notifyObserver(LibraryObserver.Type.SCAN_PROGRESS, LibraryObserver.Value.UNKNOWN, true);
 				updateNotification(true);
 				break;
 			}
@@ -814,6 +816,13 @@ public class MediaScanner implements Handler.Callback {
 			mStats.reset();
 			return next;
 		}
+
+		/**
+		 * Returns true if the scan plan has a step to execute
+		 */
+		boolean hasNextStep() {
+			return mSteps.size() > 0;
+		}
 	}
 }
 

app/src/main/java/ch/blinkenlights/android/vanilla/PlaybackService.java

@@ -1948,6 +1948,9 @@ public final class PlaybackService extends Service
 		@Override
 		public void onChange(LibraryObserver.Type type, long id, boolean ongoing)
 		{
+			if (type != LibraryObserver.Type.SONG && type != LibraryObserver.Type.PLAYLIST)
+				return;
+
 			MediaUtils.onMediaChange();
 			onMediaChange();
 		}

app/src/main/java/ch/blinkenlights/android/vanilla/PreferencesMediaLibrary.java

@@ -1,5 +1,5 @@
 /*
- * Copyright (C) 2017-2018 Adrian Ulrich <adrian@blinkenlights.ch>
+ * Copyright (C) 2017-2021 Adrian Ulrich <adrian@blinkenlights.ch>
  *
  * This program is free software: you can redistribute it and/or modify
  * it under the terms of the GNU General Public License as published by
@@ -39,15 +39,7 @@ import android.widget.ProgressBar;
 import android.widget.TextView;
 import android.widget.Toast;
 
-import java.util.Timer;
+public class PreferencesMediaLibrary extends Fragment implements View.OnClickListener {
-import java.util.TimerTask;
-
-public class PreferencesMediaLibrary extends Fragment implements View.OnClickListener
-{
-	/**
-	 * The ugly timer which fires every 200ms
-	 */
-	private Timer mTimer;
 	/**
 	 * Our start button
 	 */
@@ -113,6 +105,20 @@ public class PreferencesMediaLibrary extends Fragment implements View.OnClickLis
 	 */
 	private String mInitialMediaFolders;
 
+	private final LibraryObserver mLibraryObserver = new LibraryObserver() {
+			@Override
+			public void onChange(LibraryObserver.Type type, long id, boolean ongoing) {
+				if (type != LibraryObserver.Type.SCAN_PROGRESS)
+					return;
+				getActivity().runOnUiThread(new Runnable() {
+						@Override
+						public void run() {
+							updateProgress();
+						}
+					});
+			}
+		};
+
 	@Override
 	public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
 		return inflater.inflate(R.layout.medialibrary_preferences, container, false);
@@ -149,18 +155,6 @@ public class PreferencesMediaLibrary extends Fragment implements View.OnClickLis
 	@Override
 	public void onResume() {
 		super.onResume();
-		mTimer = new Timer();
-		// Yep: its as ugly as it seems: we are POLLING
-		// the database.
-		mTimer.scheduleAtFixedRate((new TimerTask() {
-			@Override
-			public void run() {
-				getActivity().runOnUiThread(new Runnable(){
-					public void run() {
-						updateProgress();
-					}
-				});
-			}}), 0, 200);
 
 		// We got freshly created and user didn't have a chance
 		// to edit anything: remember this state
@@ -176,17 +170,15 @@ public class PreferencesMediaLibrary extends Fragment implements View.OnClickLis
 				mFullScanPending = true;
 		}
 
+		MediaLibrary.registerLibraryObserver(mLibraryObserver);
+		updateProgress();
 		updatePreferences(null);
 	}
 
 	@Override
 	public void onPause() {
 		super.onPause();
-		if (mTimer != null) {
+		MediaLibrary.unregisterLibraryObserver(mLibraryObserver);
-			mTimer.cancel();
-			mTimer = null;
-		}
-
 		// User exited this view -> scan if needed
 		if (mFullScanPending && !mIsEditingDirectories) {
 			MediaLibrary.startLibraryScan(getActivity(), true, true);
@@ -216,6 +208,7 @@ public class PreferencesMediaLibrary extends Fragment implements View.OnClickLis
 
 	private static final int MENU_DUMP_DB = 1;
 	private static final int MENU_FORCE_M3U_IMPORT = 2;
+
 	@Override
 	public void onCreateOptionsMenu(Menu menu, MenuInflater inflater) {
 		super.onCreateOptionsMenu(menu, inflater);
@@ -373,7 +366,6 @@ public class PreferencesMediaLibrary extends Fragment implements View.OnClickLis
 	 */
 	public void startButtonPressed(View view) {
 		MediaLibrary.startLibraryScan(getActivity(), mFullScanCheck.isChecked(), mDropDbCheck.isChecked());
-		updateProgress();
 	}
 
 	/**
@@ -383,7 +375,6 @@ public class PreferencesMediaLibrary extends Fragment implements View.OnClickLis
 	 */
 	public void cancelButtonPressed(View view) {
 		MediaLibrary.abortLibraryScan(getActivity());
-		updateProgress();
 	}
 
 	/**

app/src/main/java/ch/blinkenlights/android/vanilla/ScheduledLibraryUpdate.java

@@ -134,7 +134,7 @@ public class ScheduledLibraryUpdate extends JobService {
 	private final LibraryObserver mObserver = new LibraryObserver() {
 		@Override
 		public void onChange(LibraryObserver.Type type, long id, boolean ongoing) {
-			if (!ongoing) {
+			if (type == LibraryObserver.Type.SONG && !ongoing) {
 				jobFinished(mJobParams, false);
 				finalizeScan();
 			}