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>

1 files changed, 7 insertions, 3 deletions

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