feat: add D-pad navigation for phones

test/note_editor_shortcuts_test.dart

@@ -172,6 +172,115 @@ void main() {
     expect(find.byType(NoteEditorScreen), findsNothing);
   });
 
+  testWidgets('holding the D-pad center goes back to the list',
+      (tester) async {
+    await tester.runAsync(() async {
+      await tester.pumpWidget(MaterialApp(
+        home: Builder(
+          builder: (context) => TextButton(
+            onPressed: () => Navigator.push(
+              context,
+              MaterialPageRoute(
+                builder: (_) => NoteEditorScreen(
+                    note: note, notesDirectoryPath: note.parent.path),
+              ),
+            ),
+            child: const Text('list'),
+          ),
+        ),
+      ));
+      await tester.tap(find.text('list'));
+      await tester.pump();
+      await Future<void>.delayed(const Duration(milliseconds: 100));
+    });
+    await tester.pumpAndSettle();
+
+    await tester.sendKeyDownEvent(LogicalKeyboardKey.select);
+    await tester.pump(const Duration(milliseconds: 200));
+    await tester.sendKeyUpEvent(LogicalKeyboardKey.select);
+    await tester.pumpAndSettle();
+    expect(find.byType(NoteEditorScreen), findsOneWidget,
+        reason: 'a short press stays in the note');
+
+    await tester.sendKeyDownEvent(LogicalKeyboardKey.select);
+    await tester.pump(const Duration(milliseconds: 600));
+    await tester.sendKeyUpEvent(LogicalKeyboardKey.select);
+    await tester.pumpAndSettle();
+    expect(find.byType(NoteEditorScreen), findsNothing);
+  });
+
+  testWidgets('D-pad Right opens the menu and Left goes back to the list',
+      (tester) async {
+    await tester.runAsync(() async {
+      await tester.pumpWidget(MaterialApp(
+        home: Builder(
+          builder: (context) => TextButton(
+            onPressed: () => Navigator.push(
+              context,
+              MaterialPageRoute(
+                builder: (_) => NoteEditorScreen(
+                    note: note, notesDirectoryPath: note.parent.path),
+              ),
+            ),
+            child: const Text('list'),
+          ),
+        ),
+      ));
+      await tester.tap(find.text('list'));
+      await tester.pump();
+      await Future<void>.delayed(const Duration(milliseconds: 100));
+    });
+    await tester.pumpAndSettle();
+
+    await _press(tester, LogicalKeyboardKey.arrowRight);
+    expect(find.text('Save'), findsOneWidget);
+    // Share has focus first; Down moves to Save, which closes the menu.
+    await _press(tester, LogicalKeyboardKey.arrowDown);
+    await _press(tester, LogicalKeyboardKey.select);
+    expect(find.text('Save'), findsNothing);
+
+    await _press(tester, LogicalKeyboardKey.keyE, control: true);
+    await _press(tester, LogicalKeyboardKey.arrowRight);
+    expect(find.text('Save'), findsNothing,
+        reason: 'arrows move the caret in edit mode');
+    await _press(tester, LogicalKeyboardKey.arrowLeft);
+    expect(find.byType(NoteEditorScreen), findsOneWidget);
+
+    await _press(tester, LogicalKeyboardKey.keyE, control: true);
+    await _press(tester, LogicalKeyboardKey.arrowLeft);
+    expect(find.byType(NoteEditorScreen), findsNothing);
+  });
+
+  testWidgets('the D-pad moves past the font size slider in the menu',
+      (tester) async {
+    await pumpEditor(tester);
+    await _press(tester, LogicalKeyboardKey.arrowRight);
+
+    String focusedLabel() {
+      final context = FocusManager.instance.primaryFocus!.context!;
+      if (context.findAncestorWidgetOfExactType<Slider>() != null ||
+          context.widget is Slider) {
+        return 'slider';
+      }
+      final texts = find.descendant(
+          of: find.byWidget(context.widget), matching: find.byType(Text));
+      return tester.widgetList<Text>(texts).map((t) => t.data).join();
+    }
+
+    // Share, Save, Autosave, slider, Preview.
+    for (var i = 0; i < 3; i++) {
+      await _press(tester, LogicalKeyboardKey.arrowDown);
+    }
+    expect(focusedLabel(), 'slider');
+
+    await _press(tester, LogicalKeyboardKey.arrowRight);
+    expect(tester.widget<MarkdownView>(find.byType(MarkdownView)).fontSize, 18,
+        reason: 'Right adjusts the slider');
+
+    await _press(tester, LogicalKeyboardKey.arrowDown);
+    expect(focusedLabel(), 'Preview Mode');
+  });
+
   testWidgets('the open note follows theme switches', (tester) async {
     final mode = ValueNotifier(ThemeMode.light);
     await tester.runAsync(() async {

test/note_list_dpad_test.dart

@@ -0,0 +1,128 @@
+import 'dart:io';
+import 'package:flutter/material.dart';
+import 'package:flutter/services.dart';
+import 'package:flutter_test/flutter_test.dart';
+import 'package:muzzle_velocity/note_editor.dart';
+import 'package:muzzle_velocity/note_list.dart';
+import 'package:path_provider_platform_interface/path_provider_platform_interface.dart';
+import 'package:plugin_platform_interface/plugin_platform_interface.dart';
+import 'package:shared_preferences/shared_preferences.dart';
+
+class _FakePathProvider extends PathProviderPlatform
+    with MockPlatformInterfaceMixin {
+  _FakePathProvider(this.path);
+  final String path;
+
+  @override
+  Future<String?> getApplicationDocumentsPath() async => path;
+}
+
+Future<void> _press(WidgetTester tester, LogicalKeyboardKey key) async {
+  await tester.sendKeyEvent(key);
+  await tester.pumpAndSettle();
+}
+
+void main() {
+  late Directory notes;
+
+  setUp(() {
+    notes = Directory.systemTemp.createTempSync('mv-list');
+    for (final name in ['alpha', 'beta', 'gamma']) {
+      File('${notes.path}/$name.md').writeAsStringSync('# $name\n');
+    }
+    PathProviderPlatform.instance = _FakePathProvider(notes.path);
+    SharedPreferences.setMockInitialValues({'initialized': true});
+  });
+
+  Future<void> pumpList(WidgetTester tester) async {
+    await tester.runAsync(() async {
+      await tester.pumpWidget(MaterialApp(
+        home: NoteListScreen(
+          toggleTheme: (_) {},
+          toggleTags: () {},
+          isDarkMode: false,
+          showTags: true,
+        ),
+      ));
+      await Future<void>.delayed(const Duration(milliseconds: 200));
+    });
+    await tester.pumpAndSettle();
+  }
+
+  bool searchHasFocus(WidgetTester tester) =>
+      tester.widget<TextField>(find.byType(TextField)).focusNode!.hasFocus;
+
+  List<String> highlighted(WidgetTester tester) => [
+        for (final tile in tester.widgetList<ListTile>(find.byType(ListTile)))
+          if (tile.selected) (tile.title as Text).data!,
+      ];
+
+  testWidgets('Down enters the list, Up and Left return to the search field',
+      (tester) async {
+    await pumpList(tester);
+    expect(searchHasFocus(tester), isTrue);
+
+    await _press(tester, LogicalKeyboardKey.arrowDown);
+    expect(searchHasFocus(tester), isFalse);
+    expect(highlighted(tester), hasLength(1));
+    final first = highlighted(tester).single;
+
+    await _press(tester, LogicalKeyboardKey.arrowDown);
+    expect(highlighted(tester).single, isNot(first));
+
+    await _press(tester, LogicalKeyboardKey.arrowUp);
+    expect(highlighted(tester).single, first);
+
+    await _press(tester, LogicalKeyboardKey.arrowUp);
+    expect(searchHasFocus(tester), isTrue);
+    expect(highlighted(tester), isEmpty);
+
+    await _press(tester, LogicalKeyboardKey.arrowDown);
+    await _press(tester, LogicalKeyboardKey.arrowLeft);
+    expect(searchHasFocus(tester), isTrue);
+    expect(highlighted(tester), isEmpty);
+  });
+
+  testWidgets('Right clears the search text, then opens the menu',
+      (tester) async {
+    await pumpList(tester);
+    await tester.enterText(find.byType(TextField), 'alp');
+    await tester.pumpAndSettle();
+
+    await _press(tester, LogicalKeyboardKey.arrowRight);
+    expect(find.text('alp'), findsNothing);
+
+    await _press(tester, LogicalKeyboardKey.arrowRight);
+    expect(find.text('About'), findsOneWidget);
+  });
+
+  testWidgets('Right in the list opens the menu with D-pad navigation',
+      (tester) async {
+    await pumpList(tester);
+    await _press(tester, LogicalKeyboardKey.arrowDown);
+    await _press(tester, LogicalKeyboardKey.arrowRight);
+    expect(find.text('About'), findsOneWidget);
+
+    // The first item has focus, so moving down and selecting picks the second.
+    await _press(tester, LogicalKeyboardKey.arrowDown);
+    await _press(tester, LogicalKeyboardKey.select);
+    expect(find.text('About'), findsNothing);
+  });
+
+  testWidgets('center opens the highlighted note', (tester) async {
+    await pumpList(tester);
+    await _press(tester, LogicalKeyboardKey.arrowDown);
+    // The note reads its file with real I/O, so let it finish between frames.
+    await tester.runAsync(() async {
+      await tester.sendKeyEvent(LogicalKeyboardKey.select);
+      for (var i = 0; i < 10; i++) {
+        await tester.pump(const Duration(milliseconds: 50));
+        await Future<void>.delayed(const Duration(milliseconds: 20));
+      }
+    });
+    expect(find.byType(NoteEditorScreen), findsOneWidget);
+    final editor = tester.widget<TextField>(find.descendant(
+        of: find.byType(NoteEditorScreen), matching: find.byType(TextField)));
+    expect(editor.controller!.text, matches(r'^# (alpha|beta|gamma)\n$'));
+  });
+}