[flutter_adaptive_scaffold] use MediaQuery.sizeOf instead of `Media…

…Query.of` to prevent unnecessary rebuilds (#6544)

the `isActive` method uses `MediaQuery.of(context).size.width`, which triggers widget rebuilds whenever a property of `MediaQuery` changes, even when the size.width doesn't change.

instead, we should be using `MediaQuery.sizeOf(context).width`.  

fixes: flutter/flutter#146801

packages/flutter_adaptive_scaffold/CHANGELOG.md

@@ -1,3 +1,7 @@
+## 0.1.10+2
+
+* Reduce rebuilds when invoking `isActive` method.
+
 ## 0.1.10+1
 
 * Removes a broken design document link from the README.

packages/flutter_adaptive_scaffold/lib/src/breakpoints.dart

@@ -95,7 +95,7 @@ class WidthPlatformBreakpoint extends Breakpoint {
 
     // Null boundaries are unbounded, assign the max/min of their associated
     // direction on a number line.
-    final double width = MediaQuery.of(context).size.width;
+    final double width = MediaQuery.sizeOf(context).width;
     final double lowerBound = begin ?? double.negativeInfinity;
     final double upperBound = end ?? double.infinity;
 
@@ -126,6 +126,6 @@ abstract class Breakpoint {
   const Breakpoint();
 
   /// A method that returns true based on conditions related to the context of
-  /// the screen such as MediaQuery.of(context).size.width.
+  /// the screen such as MediaQuery.sizeOf(context).width.
   bool isActive(BuildContext context);
 }

packages/flutter_adaptive_scaffold/pubspec.yaml

@@ -1,6 +1,6 @@
 name: flutter_adaptive_scaffold
 description: Widgets to easily build adaptive layouts, including navigation elements.
-version: 0.1.10+1
+version: 0.1.10+2
 issue_tracker: https://github.com/flutter/flutter/issues?q=is%3Aissue+is%3Aopen+label%3A%22p%3A+flutter_adaptive_scaffold%22
 repository: https://github.com/flutter/packages/tree/main/packages/flutter_adaptive_scaffold
 

packages/flutter_adaptive_scaffold/test/breakpoint_test.dart

@@ -2,8 +2,8 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-import 'package:flutter/foundation.dart';
-import 'package:flutter/widgets.dart';
+import 'package:flutter/material.dart';
+import 'package:flutter_adaptive_scaffold/src/breakpoints.dart';
 import 'package:flutter_test/flutter_test.dart';
 import 'simulated_layout.dart';
 
@@ -51,4 +51,42 @@ void main() {
     expect(find.byKey(const Key('Breakpoints.largeDesktop')), findsOneWidget);
     expect(find.byKey(const Key('Breakpoints.largeMobile')), findsNothing);
   }, variant: TargetPlatformVariant.desktop());
+
+  testWidgets('Breakpoint.isActive should not trigger unnecessary rebuilds',
+      (WidgetTester tester) async {
+    await tester.pumpWidget(const DymmyWidget());
+    expect(find.byKey(const Key('button')), findsOneWidget);
+
+    // First build.
+    expect(DymmyWidget.built, isTrue);
+
+    // Invoke `isActive` method.
+    await tester.tap(find.byKey(const Key('button')));
+    DymmyWidget.built = false;
+
+    // Should not rebuild after modifying any property in `MediaQuery`.
+    tester.platformDispatcher.textScaleFactorTestValue = 2;
+    await tester.pumpAndSettle();
+    expect(DymmyWidget.built, isFalse);
+  });
+}
+
+class DymmyWidget extends StatelessWidget {
+  const DymmyWidget({super.key});
+
+  static bool built = false;
+  @override
+  Widget build(BuildContext context) {
+    built = true;
+    return Directionality(
+      textDirection: TextDirection.ltr,
+      child: ElevatedButton(
+        key: const Key('button'),
+        onPressed: () {
+          Breakpoints.small.isActive(context);
+        },
+        child: const SizedBox(),
+      ),
+    );
+  }
 }