Fix bar height changes when toggle keyboard (#106542)

packages/flutter/lib/src/cupertino/bottom_tab_bar.dart

@@ -156,7 +156,7 @@ class CupertinoTabBar extends StatelessWidget implements PreferredSizeWidget {
   @override
   Widget build(BuildContext context) {
     assert(debugCheckHasMediaQuery(context));
-    final double bottomPadding = MediaQuery.of(context).padding.bottom;
+    final double bottomPadding = MediaQuery.of(context).viewPadding.bottom;
 
     final Color backgroundColor = CupertinoDynamicColor.resolve(
       this.backgroundColor ?? CupertinoTheme.of(context).barBackgroundColor,

packages/flutter/lib/src/material/bottom_navigation_bar.dart

@@ -1114,7 +1114,7 @@ class _BottomNavigationBarState extends State<BottomNavigationBar> with TickerPr
     final BottomNavigationBarLandscapeLayout layout = widget.landscapeLayout
       ?? bottomTheme.landscapeLayout
       ?? BottomNavigationBarLandscapeLayout.spread;
-    final double additionalBottomPadding = MediaQuery.of(context).padding.bottom;
+    final double additionalBottomPadding = MediaQuery.of(context).viewPadding.bottom;
 
     Color? backgroundColor;
     switch (_effectiveType) {

packages/flutter/test/cupertino/bottom_tab_bar_test.dart

@@ -316,7 +316,7 @@ Future<void> main() async {
 
     // Verify height with bottom padding.
     await pumpWidgetWithBoilerplate(tester, MediaQuery(
-      data: const MediaQueryData(padding: EdgeInsets.only(bottom: 40.0)),
+      data: const MediaQueryData(viewPadding: EdgeInsets.only(bottom: 40.0)),
       child: CupertinoTabScaffold(
         tabBar: tabBar,
         tabBuilder: (BuildContext context, int index) {
@@ -359,7 +359,7 @@ Future<void> main() async {
     // Verify height with bottom padding.
     const double bottomPadding = 40.0;
     await pumpWidgetWithBoilerplate(tester, MediaQuery(
-      data: const MediaQueryData(padding: EdgeInsets.only(bottom: bottomPadding)),
+      data: const MediaQueryData(viewPadding: EdgeInsets.only(bottom: bottomPadding)),
       child: CupertinoTabScaffold(
         tabBar: tabBar,
         tabBuilder: (BuildContext context, int index) {
@@ -370,6 +370,60 @@ Future<void> main() async {
     expect(tester.getSize(find.byType(CupertinoTabBar)).height, tabBarHeight + bottomPadding);
   });
 
+  testWidgets('Ensure bar height will not change when toggle keyboard', (WidgetTester tester) async {
+    const double tabBarHeight = 56.0;
+    final CupertinoTabBar tabBar = CupertinoTabBar(
+      height: tabBarHeight,
+      items: <BottomNavigationBarItem>[
+        BottomNavigationBarItem(
+          icon: ImageIcon(MemoryImage(Uint8List.fromList(kTransparentImage))),
+          label: 'Aka',
+        ),
+        BottomNavigationBarItem(
+          icon: ImageIcon(MemoryImage(Uint8List.fromList(kTransparentImage))),
+          label: 'Shiro',
+        ),
+      ],
+    );
+
+    const double bottomPadding = 34.0;
+
+    // Test the height is correct when keyboard not showing.
+    // So viewInset should be 0.0.
+    await pumpWidgetWithBoilerplate(tester, MediaQuery(
+      data: const MediaQueryData(
+        padding: EdgeInsets.only(bottom: bottomPadding),
+        viewPadding: EdgeInsets.only(bottom: bottomPadding),
+      ),
+      child: CupertinoTabScaffold(
+        tabBar: tabBar,
+        tabBuilder: (BuildContext context, int index) {
+          return const Placeholder();
+        },
+      ),
+    ));
+    expect(tester.getSize(find.byType(CupertinoTabBar)).height, tabBarHeight + bottomPadding);
+
+    // Now show keyboard, and test the bar height will not change.
+    await pumpWidgetWithBoilerplate(tester,
+      MediaQuery(
+        data: const MediaQueryData(
+          viewPadding: EdgeInsets.only(bottom: bottomPadding),
+          viewInsets: EdgeInsets.only(bottom: 336.0),
+        ),
+        child:  CupertinoTabScaffold(
+          tabBar: tabBar,
+          tabBuilder: (BuildContext context, int index) {
+            return const Placeholder();
+          },
+        ),
+      ),
+    );
+
+    // Expect the bar height should not change.
+    expect(tester.getSize(find.byType(CupertinoTabBar)).height, tabBarHeight + bottomPadding);
+  });
+
   testWidgets('Opaque background does not add blur effects', (WidgetTester tester) async {
     await pumpWidgetWithBoilerplate(tester, MediaQuery(
       data: const MediaQueryData(),

packages/flutter/test/material/bottom_navigation_bar_test.dart

@@ -991,7 +991,7 @@ void main() {
     await tester.pumpWidget(
       MaterialApp(
         home: MediaQuery(
-          data: const MediaQueryData(padding: EdgeInsets.only(bottom: 40.0)),
+          data: const MediaQueryData(viewPadding: EdgeInsets.only(bottom: 40.0)),
           child: Scaffold(
             bottomNavigationBar: BottomNavigationBar(
               items: const <BottomNavigationBarItem>[
@@ -1018,7 +1018,7 @@ void main() {
     await tester.pumpWidget(
       MaterialApp(
         home: MediaQuery(
-          data: const MediaQueryData(padding: EdgeInsets.only(bottom: 40.0)),
+          data: const MediaQueryData(viewPadding: EdgeInsets.only(bottom: 40.0)),
           child: Scaffold(
             bottomNavigationBar: BottomNavigationBar(
               selectedFontSize: 8,
@@ -1042,6 +1042,58 @@ void main() {
     expect(tester.getSize(find.byType(BottomNavigationBar)).height, expectedHeight);
   });
 
+  testWidgets('BottomNavigationBar height will not change when toggle keyboard', (WidgetTester tester) async {
+
+    final Widget child = Scaffold(
+      bottomNavigationBar: BottomNavigationBar(
+        selectedFontSize: 8,
+        items: const <BottomNavigationBarItem>[
+          BottomNavigationBarItem(
+            icon: Icon(Icons.ac_unit),
+            label: 'AC',
+          ),
+          BottomNavigationBarItem(
+            icon: Icon(Icons.access_alarm),
+            label: 'Alarm',
+          ),
+        ],
+      ),
+    );
+
+    // Test the bar height is correct when not showing the keyboard.
+    await tester.pumpWidget(
+      MaterialApp(
+        home: MediaQuery(
+          data: const MediaQueryData(
+            viewPadding: EdgeInsets.only(bottom: 40.0),
+            padding: EdgeInsets.only(bottom: 40.0),
+          ),
+          child: child,
+        ),
+      ),
+    );
+
+    // Expect the height is the correct.
+    const double expectedHeight = kBottomNavigationBarHeight + 40.0;
+    expect(tester.getSize(find.byType(BottomNavigationBar)).height, expectedHeight);
+
+    // Now we show the keyboard.
+    await tester.pumpWidget(
+      MaterialApp(
+        home: MediaQuery(
+          data: const MediaQueryData(
+            viewPadding: EdgeInsets.only(bottom: 40.0),
+            viewInsets: EdgeInsets.only(bottom: 336.0),
+          ),
+          child: child,
+        ),
+      ),
+    );
+
+    // Expect the height is the same.
+    expect(tester.getSize(find.byType(BottomNavigationBar)).height, expectedHeight);
+  });
+
   testWidgets('BottomNavigationBar action size test', (WidgetTester tester) async {
     await tester.pumpWidget(
       MaterialApp(

packages/flutter/test/material/scaffold_test.dart

@@ -672,7 +672,7 @@ void main() {
         home: MediaQuery(
           data: const MediaQueryData(
             // Representing a navigational notch at the bottom of the screen
-            padding: EdgeInsets.fromLTRB(0.0, 0.0, 0.0, 40.0),
+            viewPadding: EdgeInsets.fromLTRB(0.0, 0.0, 0.0, 40.0),
           ),
           child: Scaffold(
             body: SingleChildScrollView(