Fix lifecycle, focus loss, crossfade and tab race review findings

- MainActivity: remove rotate callbacks in onDestroy, ignore connect
  results once destroyed, rotate the background only while resumed,
  guard the fade end action.
- HomeRows: each row owns one TileAdapter over a mutable list; rebinds
  refill it and notifyDataSetChanged instead of setAdapter, so focus and
  scroll survive a sample arriving (change payload keeps the holder).
- Crossfade: flip front only on onResourceReady, cancel the animation
  before resetting alpha.
- Tab loads ignore errors from a tab that is no longer shown; Home does
  not fire a second /folders request while one is in flight.
- Load the instance logo after login in connect().
- FolderActivity: request grid focus after layout.

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

3 files changed, 54 insertions, 17 deletions

diff --git a/app/src/main/java/mygram/droid/FolderActivity.java b/app/src/main/java/mygram/droid/FolderActivity.java
index 8da2533..10a9940 100644
--- a/app/src/main/java/mygram/droid/FolderActivity.java
+++ b/app/src/main/java/mygram/droid/FolderActivity.java
@@ -53,7 +53,7 @@ public final class FolderActivity extends Activity {
 			Collections.shuffle(posts);
 			grid = Ui.grid(this, Ui.postTiles(this, posts), Ui.POST_W, Ui.POST_H, 6);
 			show(grid);
-			grid.requestFocus();
+			grid.post(grid::requestFocus); // after layout
 		}, e -> show(Ui.text(this, "Cannot load folder: " + e.getMessage(), 18)));
 	}
 
diff --git a/app/src/main/java/mygram/droid/HomeRows.java b/app/src/main/java/mygram/droid/HomeRows.java
index ed638b6..e4abeb5 100644
--- a/app/src/main/java/mygram/droid/HomeRows.java
+++ b/app/src/main/java/mygram/droid/HomeRows.java
@@ -37,11 +37,14 @@ final class HomeRows extends RecyclerView.Adapter<HomeRows.Row> {
 	static final class Row extends RecyclerView.ViewHolder {
 		final TextView title;
 		final RecyclerView tiles;
+		/** Backing list of the row's one adapter: rebinds refill it instead of replacing the adapter. */
+		final List<TileAdapter.Tile> list = new ArrayList<>();
 
 		Row(LinearLayout v, TextView title, RecyclerView tiles) {
 			super(v);
 			this.title = title;
 			this.tiles = tiles;
+			tiles.setAdapter(new TileAdapter(list, Ui.POST_W, Ui.POST_H));
 		}
 	}
 
@@ -80,17 +83,18 @@ final class HomeRows extends RecyclerView.Adapter<HomeRows.Row> {
 			samples.put(f.slug, posts); // marks it loading, so it is fetched once
 			Api.async(() -> Api.folderSample(f, SAMPLE), p -> {
 				samples.put(f.slug, p);
-				notifyItemChanged(folders.indexOf(f));
+				notifyItemChanged(folders.indexOf(f), Boolean.TRUE); // payload: keep the holder, so focus stays
 			}, e -> {
 				// the row keeps only its Continue tile
 			});
 		}
-		List<TileAdapter.Tile> tiles = new ArrayList<>();
+		List<TileAdapter.Tile> tiles = row.list;
+		tiles.clear();
 		for (Post p : posts)
 			tiles.add(TileAdapter.post(p, () -> open(f, p)));
 		tiles.add(new TileAdapter.Tile(null, "Continue", R.drawable.ic_arrow_forward, -1,
 				() -> FolderActivity.open(activity, f)));
-		row.tiles.setAdapter(new TileAdapter(tiles, Ui.POST_W, Ui.POST_H));
+		row.tiles.getAdapter().notifyDataSetChanged();
 	}
 
 	@Override
diff --git a/app/src/main/java/mygram/droid/MainActivity.java b/app/src/main/java/mygram/droid/MainActivity.java
index 6f8d76d..7578f05 100644
--- a/app/src/main/java/mygram/droid/MainActivity.java
+++ b/app/src/main/java/mygram/droid/MainActivity.java
@@ -59,7 +59,8 @@ public final class MainActivity extends Activity {
 	private RecyclerView homeList;
 	private HomeRows homeRows;
 	private int tab = HOME;
-	private boolean ready;
+	private boolean ready, resumed, homeLoading;
+	private ImageView logo;
 
 	@Override
 	protected void onCreate(Bundle state) {
@@ -98,11 +99,9 @@ public final class MainActivity extends Activity {
 		bar.setGravity(Gravity.CENTER_VERTICAL);
 		int p = Ui.dp(this, 16);
 		bar.setPadding(p * 2, p, p * 2, 0);
-		LinearLayout logo = Ui.iconButton(this, R.drawable.ic_home, "Home", v -> show(HOME));
-		// Foldergram's logo is AGPLv3: loaded from the instance, never bundled.
-		Glide.with(this).load(Api.resolve(Prefs.server(), "/icon-192.png")).error(R.drawable.ic_home)
-				.into((ImageView) logo.getChildAt(0));
-		bar.addView(logo);
+		LinearLayout home = Ui.iconButton(this, R.drawable.ic_home, "Home", v -> show(HOME));
+		logo = (ImageView) home.getChildAt(0);
+		bar.addView(home);
 		bar.addView(new Space(this), new LinearLayout.LayoutParams(0, 1, 1));
 		bar.addView(Ui.iconButton(this, R.drawable.ic_reels, "Reels", v -> Playlist.openReels(this)));
 		bar.addView(Ui.iconButton(this, R.drawable.ic_favorite, "Liked", v -> show(LIKED)));
@@ -121,12 +120,19 @@ public final class MainActivity extends Activity {
 			Likes.load();
 			return Api.randomFeed();
 		}, posts -> {
+			if (isDestroyed())
+				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);
 			backgrounds = posts;
 			handler.removeCallbacks(rotate);
 			rotateBackground();
 			show(tab);
-		}, this::failed);
+		}, e -> {
+			if (!isDestroyed())
+				failed(e);
+		});
 	}
 
 	private void failed(Exception e) {
@@ -151,20 +157,31 @@ public final class MainActivity extends Activity {
 				return;
 			}
 			message("Loading…");
+			if (homeLoading)
+				return; // the request in flight shows the list when it lands
+			homeLoading = true;
 			Api.async(Api::folders, folders -> {
+				homeLoading = false;
 				homeRows = new HomeRows(this, folders);
 				homeList = Ui.list(this, RecyclerView.VERTICAL);
 				homeList.setAdapter(homeRows);
 				if (tab == HOME)
 					setContent(homeList);
-			}, this::failed);
+			}, e -> {
+				homeLoading = false;
+				if (tab == t)
+					failed(e);
+			});
 		} else if (t == LIKED) {
 			message("Loading…");
 			Api.async(Api::likes, posts -> {
 				if (tab == LIKED)
 					setContent(posts.isEmpty() ? centered("No liked posts yet")
 							: Ui.grid(this, Ui.postTiles(this, posts), Ui.POST_W, Ui.POST_H, 6));
-			}, this::failed);
+			}, e -> {
+				if (tab == t)
+					failed(e);
+			});
 		} else {
 			message("Loading…");
 			Api.async(Api::folders, folders -> {
@@ -175,13 +192,17 @@ public final class MainActivity extends Activity {
 					tiles.add(new TileAdapter.Tile(f.avatarUrl, f.name, R.drawable.ic_folder, -1,
 							() -> FolderActivity.open(this, f)));
 				setContent(Ui.grid(this, tiles, 160, 160, 5));
-			}, this::failed);
+			}, e -> {
+				if (tab == t)
+					failed(e);
+			});
 		}
 	}
 
 	@Override
 	protected void onResume() {
 		super.onResume();
+		resumed = true;
 		if (!ready)
 			return;
 		handler.removeCallbacks(rotate);
@@ -195,7 +216,14 @@ public final class MainActivity extends Activity {
 	@Override
 	protected void onPause() {
 		super.onPause();
+		resumed = false;
+		handler.removeCallbacks(rotate);
+	}
+
+	@Override
+	protected void onDestroy() {
 		handler.removeCallbacks(rotate);
+		super.onDestroy();
 	}
 
 	private void rotateBackground() {
@@ -204,6 +232,7 @@ public final class MainActivity extends Activity {
 		Post p = backgrounds.get(ThreadLocalRandom.current().nextInt(backgrounds.size()));
 		// Never pass the old drawable as a Glide placeholder: Glide may recycle its bitmap.
 		ImageView back = layers[1 - front], top = layers[front];
+		back.animate().cancel();
 		back.setAlpha(0f);
 		back.bringToFront();
 		Glide.with(this).load(p.media.get(0).thumbnailUrl).listener(new RequestListener<Drawable>() {
@@ -215,12 +244,16 @@ public final class MainActivity extends Activity {
 			@Override
 			public boolean onResourceReady(Drawable d, Object model, Target<Drawable> target, DataSource source,
 					boolean first) {
-				back.animate().alpha(1f).setDuration(1500).withEndAction(() -> Glide.with(top).clear(top)).start();
+				front = 1 - front; // only now, so a failed load leaves the old layer on top
+				back.animate().alpha(1f).setDuration(1500).withEndAction(() -> {
+					if (!isDestroyed())
+						Glide.with(top).clear(top);
+				}).start();
 				return false;
 			}
 		}).into(back);
-		front = 1 - front;
-		handler.postDelayed(rotate, Prefs.backgroundSeconds() * 1000L);
+		if (resumed)
+			handler.postDelayed(rotate, Prefs.backgroundSeconds() * 1000L);
 	}
 
 	private void message(String s) {