Update for Flutter 3.10 beta (#1746)

## Pre-launch Checklist

- [x] I read the [Flutter Style Guide] _recently_, and have followed its
advice.
- [x] I signed the [CLA].
- [x] I read the [Contributors Guide].
- [x] I updated/added relevant documentation (doc comments with `///`).
- [ ] All existing and new tests are passing.

---------

Co-authored-by: David Iglesias <ditman@gmail.com>
Co-authored-by: Mark Thompson <2554588+MarkTechson@users.noreply.github.com>
Co-authored-by: John Ryan <ryjohn@google.com>

platform_design/lib/main.dart

@@ -103,26 +103,22 @@ class _PlatformAdaptingHomePageState extends State<PlatformAdaptingHomePage> {
         ],
       ),
       tabBuilder: (context, index) {
-        switch (index) {
-          case 0:
-            return CupertinoTabView(
+        assert(index <= 2 && index >= 0, 'Unexpected tab index: $index');
+        return switch (index) {
+          0 => CupertinoTabView(
               defaultTitle: SongsTab.title,
               builder: (context) => SongsTab(key: songsTabKey),
-            );
-          case 1:
-            return CupertinoTabView(
+            ),
+          1 => CupertinoTabView(
               defaultTitle: NewsTab.title,
               builder: (context) => const NewsTab(),
-            );
-          case 2:
-            return CupertinoTabView(
+            ),
+          2 => CupertinoTabView(
               defaultTitle: ProfileTab.title,
               builder: (context) => const ProfileTab(),
-            );
-          default:
-            assert(false, 'Unexpected tab');
-            return const SizedBox.shrink();
-        }
+            ),
+          _ => const SizedBox.shrink(),
+        };
       },
     );
   }

platform_design/lib/song_detail_tab.dart

@@ -58,9 +58,8 @@ class SongDetailTab extends StatelessWidget {
           Expanded(
             child: ListView.builder(
               itemCount: 10,
-              itemBuilder: (context, index) {
-                if (index == 0) {
-                  return const Padding(
+              itemBuilder: (context, index) => switch (index) {
+                0 => const Padding(
                     padding: EdgeInsets.only(left: 15, top: 16, bottom: 8),
                     child: Text(
                       'You might also like:',
@@ -69,10 +68,8 @@ class SongDetailTab extends StatelessWidget {
                         fontWeight: FontWeight.w500,
                       ),
                     ),
-                  );
-                }
-                // Just a bunch of boxes that simulates loading song choices.
-                return const SongPlaceholderTile();
+                  ),
+                _ => const SongPlaceholderTile(),
               },
             ),
           ),

platform_design/lib/utils.dart

@@ -33,31 +33,23 @@ final wordPairIterator = generateWordPairs();
 String generateRandomHeadline() {
   final artist = capitalizePair(wordPairIterator.first);
 
-  switch (_random.nextInt(10)) {
-    case 0:
-      return '$artist says ${nouns[_random.nextInt(nouns.length)]}';
-    case 1:
-      return '$artist arrested due to ${wordPairIterator.first.join(' ')}';
-    case 2:
-      return '$artist releases ${capitalizePair(wordPairIterator.first)}';
-    case 3:
-      return '$artist talks about his ${nouns[_random.nextInt(nouns.length)]}';
-    case 4:
-      return '$artist talks about her ${nouns[_random.nextInt(nouns.length)]}';
-    case 5:
-      return '$artist talks about their ${nouns[_random.nextInt(nouns.length)]}';
-    case 6:
-      return '$artist says their music is inspired by ${wordPairIterator.first.join(' ')}';
-    case 7:
-      return '$artist says the world needs more ${nouns[_random.nextInt(nouns.length)]}';
-    case 8:
-      return '$artist calls their band ${adjectives[_random.nextInt(adjectives.length)]}';
-    case 9:
-      return '$artist finally ready to talk about ${nouns[_random.nextInt(nouns.length)]}';
-  }
-
-  assert(false, 'Failed to generate news headline');
-  return 'Failed to generate news headline';
+  return switch (_random.nextInt(10)) {
+    0 => '$artist says ${nouns[_random.nextInt(nouns.length)]}',
+    1 => '$artist arrested due to ${wordPairIterator.first.join(' ')}',
+    2 => '$artist releases ${capitalizePair(wordPairIterator.first)}',
+    3 => '$artist talks about his ${nouns[_random.nextInt(nouns.length)]}',
+    4 => '$artist talks about her ${nouns[_random.nextInt(nouns.length)]}',
+    5 => '$artist talks about their ${nouns[_random.nextInt(nouns.length)]}',
+    6 =>
+      '$artist says their music is inspired by ${wordPairIterator.first.join(' ')}',
+    7 =>
+      '$artist says the world needs more ${nouns[_random.nextInt(nouns.length)]}',
+    8 =>
+      '$artist calls their band ${adjectives[_random.nextInt(adjectives.length)]}',
+    9 =>
+      '$artist finally ready to talk about ${nouns[_random.nextInt(nouns.length)]}',
+    _ => 'Failed to generate news headline',
+  };
 }
 
 List<MaterialColor> getRandomColors(int amount) {

platform_design/lib/widgets.dart

@@ -19,15 +19,15 @@ class PlatformWidget extends StatelessWidget {
 
   @override
   Widget build(context) {
-    switch (defaultTargetPlatform) {
-      case TargetPlatform.android:
-        return androidBuilder(context);
-      case TargetPlatform.iOS:
-        return iosBuilder(context);
-      default:
-        assert(false, 'Unexpected platform $defaultTargetPlatform');
-        return const SizedBox.shrink();
-    }
+    assert(
+        defaultTargetPlatform == TargetPlatform.android ||
+            defaultTargetPlatform == TargetPlatform.iOS,
+        'Unexpected platform $defaultTargetPlatform');
+    return switch (defaultTargetPlatform) {
+      TargetPlatform.android => androidBuilder(context),
+      TargetPlatform.iOS => iosBuilder(context),
+      _ => const SizedBox.shrink()
+    };
   }
 }
 

platform_design/pubspec.yaml

@@ -3,7 +3,7 @@ description: A project showcasing a Flutter app following different platform IA
 version: 1.0.0+1
 
 environment:
-  sdk: '>=2.19.5 <4.0.0'
+  sdk: ^3.0.0-0
 
 dependencies:
   english_words: ^4.0.0