Fix viewer review findings

- Reels paging: drop page callbacks after destroy or a replaced playlist
- Scope Glide loads to views and clear them in onDestroy (no deprecated Glide.with(Activity))
- Stop the player in onStop, re-prepare in onStart
- Photo timer uses real elapsed time and starts when the photo is on screen
- Reels: continue past the old last post when a new page arrives; "No reels" when empty
- Likes: ordered single-thread executor, newer toggle wins on error, no "null" in toast
- Note the unbounded frame grab limitation

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

2 files changed, 59 insertions, 14 deletions

diff --git a/app/src/main/java/mygram/droid/MainActivity.java b/app/src/main/java/mygram/droid/MainActivity.java
index 7578f05..3292f90 100644
--- a/app/src/main/java/mygram/droid/MainActivity.java
+++ b/app/src/main/java/mygram/droid/MainActivity.java
@@ -124,7 +124,7 @@ public final class MainActivity extends Activity {
 				return;
 			ready = true;
 			// Foldergram's logo is AGPLv3: loaded from the instance after login, never bundled.
-			Glide.with(this).load(Api.resolve(Prefs.server(), "/icon-192.png")).error(R.drawable.ic_home).into(logo);
+			Glide.with(logo).load(Api.resolve(Prefs.server(), "/icon-192.png")).error(R.drawable.ic_home).into(logo);
 			backgrounds = posts;
 			handler.removeCallbacks(rotate);
 			rotateBackground();
@@ -235,7 +235,7 @@ public final class MainActivity extends Activity {
 		back.animate().cancel();
 		back.setAlpha(0f);
 		back.bringToFront();
-		Glide.with(this).load(p.media.get(0).thumbnailUrl).listener(new RequestListener<Drawable>() {
+		Glide.with(back).load(p.media.get(0).thumbnailUrl).listener(new RequestListener<Drawable>() {
 			@Override
 			public boolean onLoadFailed(GlideException e, Object model, Target<Drawable> target, boolean first) {
 				return false;
diff --git a/app/src/main/java/mygram/droid/ViewerActivity.java b/app/src/main/java/mygram/droid/ViewerActivity.java
index e422104..098f817 100644
--- a/app/src/main/java/mygram/droid/ViewerActivity.java
+++ b/app/src/main/java/mygram/droid/ViewerActivity.java
@@ -21,6 +21,7 @@ import android.media.MediaMetadataRetriever;
 import android.os.Bundle;
 import android.os.Handler;
 import android.os.Looper;
+import android.os.SystemClock;
 import android.view.Gravity;
 import android.view.KeyEvent;
 import android.view.View;
@@ -47,6 +48,7 @@ import com.bumptech.glide.request.RequestListener;
 import com.bumptech.glide.request.target.Target;
 
 import java.util.HashMap;
+import java.util.List;
 import java.util.concurrent.ExecutorService;
 import java.util.concurrent.Executors;
 import java.util.concurrent.ThreadLocalRandom;
@@ -59,6 +61,8 @@ public final class ViewerActivity extends Activity {
 	private static final long SEEK_MS = 10_000, TICK_MS = 100;
 	/** Frame grabs block on the network; keep them off the API pool. */
 	private static final ExecutorService FRAMES = Executors.newSingleThreadExecutor();
+	/** One thread, so like toggles reach the server in order. */
+	private static final ExecutorService LIKES = Executors.newSingleThreadExecutor();
 	private static final ViewGroup.LayoutParams FILL = new ViewGroup.LayoutParams(
 			ViewGroup.LayoutParams.MATCH_PARENT, ViewGroup.LayoutParams.MATCH_PARENT);
 
@@ -73,8 +77,8 @@ public final class ViewerActivity extends Activity {
 	private int index, slide;
 	/** Bumped on every slide change; late callbacks for older slides are dropped. */
 	private volatile int generation;
-	private boolean paused, failed, loadingMore;
-	private long photoElapsed;
+	private boolean paused, failed, loadingMore, parkedAtEnd;
+	private long photoElapsed, lastTick;
 
 	@Override
 	@OptIn(markerClass = UnstableApi.class)
@@ -168,12 +172,14 @@ public final class ViewerActivity extends Activity {
 		paused = false;
 		failed = false;
 		photoElapsed = 0;
+		lastTick = SystemClock.uptimeMillis();
+		parkedAtEnd = false;
 		message.setText("");
 		pauseIcon.setVisibility(View.GONE);
 		heart.setVisibility(Likes.has(post().id) ? View.VISIBLE : View.GONE);
-		Glide.with(this).load(m.video ? m.thumbnailUrl : m.previewUrl).override(200).into(backdrop);
+		Glide.with(backdrop).load(m.video ? m.thumbnailUrl : m.previewUrl).override(200).into(backdrop);
 		if (m.video) {
-			Glide.with(this).clear(photo);
+			Glide.with(photo).clear(photo);
 			video.setVisibility(View.VISIBLE);
 			player.setMediaItem(MediaItem.fromUri(m.previewUrl));
 			player.prepare();
@@ -182,7 +188,7 @@ public final class ViewerActivity extends Activity {
 		} else {
 			player.stop();
 			video.setVisibility(View.GONE);
-			Glide.with(this).load(m.previewUrl).listener(new RequestListener<Drawable>() {
+			Glide.with(photo).load(m.previewUrl).listener(new RequestListener<Drawable>() {
 				@Override
 				public boolean onLoadFailed(GlideException e, Object model, Target<Drawable> target, boolean first) {
 					if (gen == generation)
@@ -193,6 +199,8 @@ public final class ViewerActivity extends Activity {
 				@Override
 				public boolean onResourceReady(Drawable d, Object model, Target<Drawable> target, DataSource source,
 						boolean first) {
+					if (gen == generation)
+						photoElapsed = 0; // count from when the photo is on screen
 					return false;
 				}
 			}).into(photo);
@@ -200,6 +208,7 @@ public final class ViewerActivity extends Activity {
 		tick();
 	}
 
+	// ponytail: a grab already blocked in setDataSource is not interrupted, so a slow one delays the next post's frame; upgrade: a timeout or per-post cancellation.
 	/** Swaps the video backdrop for a frame from 20-80 % of the clip; ends are often black. */
 	private void randomFrame(Post.Media m, int gen) {
 		if (m.durationMs <= 0)
@@ -214,7 +223,7 @@ public final class ViewerActivity extends Activity {
 			}
 		}, frame -> {
 			if (frame != null && gen == generation) {
-				Glide.with(this).clear(backdrop);
+				Glide.with(backdrop).clear(backdrop);
 				backdrop.setImageBitmap(frame);
 			}
 		}, e -> {
@@ -229,8 +238,10 @@ public final class ViewerActivity extends Activity {
 			long d = player.getDuration();
 			progress.setProgress(d > 0 ? (int) (1000 * player.getCurrentPosition() / d) : 0);
 		} else {
+			long now = SystemClock.uptimeMillis();
 			if (!paused)
-				photoElapsed += TICK_MS;
+				photoElapsed += now - lastTick;
+			lastTick = now;
 			long total = Prefs.photoSeconds() * 1000L;
 			progress.setProgress((int) (1000 * Math.min(photoElapsed, total) / total));
 			if (photoElapsed >= total) {
@@ -248,6 +259,7 @@ public final class ViewerActivity extends Activity {
 		} else if (index < Playlist.posts.size() - 1) {
 			show(index + 1);
 		} else {
+			parkedAtEnd = true;
 			setPaused(true); // end of the list
 		}
 	}
@@ -262,6 +274,8 @@ public final class ViewerActivity extends Activity {
 
 	private void setPaused(boolean p) {
 		paused = p;
+		if (!p)
+			lastTick = SystemClock.uptimeMillis();
 		pauseIcon.setVisibility(p ? View.VISIBLE : View.GONE);
 		if (media().video && !failed) {
 			if (p)
@@ -293,15 +307,18 @@ public final class ViewerActivity extends Activity {
 			bigHeart.setVisibility(View.VISIBLE);
 			bigHeart.animate().alpha(0f).setDuration(700).withEndAction(() -> bigHeart.setVisibility(View.GONE)).start();
 		}
-		Api.async(() -> {
+		Api.async(LIKES, () -> {
 			Api.setLike(p.id, on);
 			return true;
 		}, ok -> {
 		}, e -> {
+			if (Likes.has(p.id) != on)
+				return; // a newer toggle wins
 			Likes.set(p.id, !on);
 			if (!Playlist.posts.isEmpty() && post() == p)
 				heart.setVisibility(on ? View.GONE : View.VISIBLE);
-			Toast.makeText(this, "Like failed: " + e.getMessage(), Toast.LENGTH_SHORT).show();
+			String msg = e.getMessage();
+			Toast.makeText(this, "Like failed" + (msg != null ? ": " + msg : ""), Toast.LENGTH_SHORT).show();
 		});
 	}
 
@@ -311,16 +328,26 @@ public final class ViewerActivity extends Activity {
 			return;
 		loadingMore = true;
 		int page = Playlist.reelsPage + 1;
+		List<Post> list = Playlist.posts;
 		Api.async(() -> Api.reels(Playlist.reelsSeed, page), o -> {
+			if (isDestroyed() || Playlist.posts != list)
+				return;
 			loadingMore = false;
 			Playlist.reelsPage = page;
-			boolean first = Playlist.posts.isEmpty();
-			Playlist.posts.addAll(Post.list(o, Prefs.server()));
+			boolean first = list.isEmpty();
+			int old = list.size();
+			list.addAll(Post.list(o, Prefs.server()));
 			if (!o.optBoolean("hasMore"))
 				Playlist.reelsSeed = 0;
-			if (first && !Playlist.posts.isEmpty())
+			if (first && !list.isEmpty())
 				show(0);
+			else if (parkedAtEnd && index == old - 1 && list.size() > old)
+				show(index + 1);
+			else if (list.isEmpty() && Playlist.reelsSeed == 0)
+				message.setText("No reels");
 		}, e -> {
+			if (isDestroyed())
+				return;
 			loadingMore = false;
 			if (Playlist.posts.isEmpty())
 				message.setText("Cannot load reels. Press Down to retry.");
@@ -368,6 +395,22 @@ public final class ViewerActivity extends Activity {
 	}
 
 	@Override
+	protected void onStart() {
+		super.onStart();
+		// The first show() already prepared (state is not IDLE), so this only revives a stopped decoder.
+		if (!Playlist.posts.isEmpty() && media().video && !failed && player.getPlaybackState() == Player.STATE_IDLE) {
+			player.setPlayWhenReady(!paused);
+			player.prepare();
+		}
+	}
+
+	@Override
+	protected void onStop() {
+		super.onStop();
+		player.stop(); // free the video decoder while in the background
+	}
+
+	@Override
 	protected void onPause() {
 		super.onPause();
 		if (!Playlist.posts.isEmpty() && !paused)
@@ -379,6 +422,8 @@ public final class ViewerActivity extends Activity {
 		super.onDestroy();
 		handler.removeCallbacksAndMessages(null);
 		generation++;
+		Glide.with(photo).clear(photo);
+		Glide.with(backdrop).clear(backdrop);
 		player.release();
 	}
 }