Revert "ScaffoldMessenger (#64101)"

This reverts commit 48f1a0a.
flutter · Sep 4, 2020 · 9476f29 · 9476f29
1 parent 9248fda
commit 9476f29
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Showing 11 changed files with 302 additions and 818 deletions.
diff --git a/packages/flutter/lib/src/material/app.dart b/packages/flutter/lib/src/material/app.dart
@@ -17,7 +17,6 @@ import 'floating_action_button.dart';
 import 'icons.dart';
 import 'material_localizations.dart';
 import 'page.dart';
-import 'scaffold.dart';
 import 'theme.dart';
 
 /// [MaterialApp] uses this [TextStyle] as its [DefaultTextStyle] to encourage
@@ -169,7 +168,6 @@ class MaterialApp extends StatefulWidget {
   const MaterialApp({
     Key key,
     this.navigatorKey,
-    this.scaffoldMessengerKey,
     this.home,
     this.routes = const <String, WidgetBuilder>{},
     this.initialRoute,
@@ -217,7 +215,6 @@ class MaterialApp extends StatefulWidget {
   /// Creates a [MaterialApp] that uses the [Router] instead of a [Navigator].
   const MaterialApp.router({
     Key key,
-    this.scaffoldMessengerKey,
     this.routeInformationProvider,
     @required this.routeInformationParser,
     @required this.routerDelegate,
@@ -266,14 +263,6 @@ class MaterialApp extends StatefulWidget {
   /// {@macro flutter.widgets.widgetsApp.navigatorKey}
   final GlobalKey<NavigatorState> navigatorKey;
 
-  /// A key to use when building the [ScaffoldMessenger].
-  ///
-  /// If a [scaffoldMessengerKey] is specified, the [ScaffoldMessenger] can be
-  /// directly manipulated without first obtaining it from a [BuildContext] via
-  /// [ScaffoldMessenger.of]: from the [scaffoldMessengerKey], use the
-  /// [GlobalKey.currentState] getter.
-  final GlobalKey<ScaffoldMessengerState> scaffoldMessengerKey;
-
   /// {@macro flutter.widgets.widgetsApp.home}
   final Widget home;
 
@@ -733,30 +722,27 @@ class _MaterialAppState extends State<MaterialApp> {
     }
     theme ??= widget.theme ?? ThemeData.light();
 
-    return ScaffoldMessenger(
-      key: widget.scaffoldMessengerKey,
-      child: AnimatedTheme(
-        data: theme,
-        isMaterialAppTheme: true,
-        child: widget.builder != null
-          ? Builder(
-              builder: (BuildContext context) {
-                // Why are we surrounding a builder with a builder?
-                //
-                // The widget.builder may contain code that invokes
-                // Theme.of(), which should return the theme we selected
-                // above in AnimatedTheme. However, if we invoke
-                // widget.builder() directly as the child of AnimatedTheme
-                // then there is no Context separating them, and the
-                // widget.builder() will not find the theme. Therefore, we
-                // surround widget.builder with yet another builder so that
-                // a context separates them and Theme.of() correctly
-                // resolves to the theme we passed to AnimatedTheme.
-                return widget.builder(context, child);
-              },
-            )
-          : child,
-      )
+    return AnimatedTheme(
+      data: theme,
+      isMaterialAppTheme: true,
+      child: widget.builder != null
+        ? Builder(
+            builder: (BuildContext context) {
+              // Why are we surrounding a builder with a builder?
+              //
+              // The widget.builder may contain code that invokes
+              // Theme.of(), which should return the theme we selected
+              // above in AnimatedTheme. However, if we invoke
+              // widget.builder() directly as the child of AnimatedTheme
+              // then there is no Context separating them, and the
+              // widget.builder() will not find the theme. Therefore, we
+              // surround widget.builder with yet another builder so that
+              // a context separates them and Theme.of() correctly
+              // resolves to the theme we passed to AnimatedTheme.
+              return widget.builder(context, child);
+            },
+          )
+        : child,
     );
   }
 

diff --git a/packages/flutter/lib/src/material/app_bar.dart b/packages/flutter/lib/src/material/app_bar.dart
@@ -137,7 +137,7 @@ class _ToolbarContainerLayout extends SingleChildLayoutDelegate {
 ///           icon: const Icon(Icons.add_alert),
 ///           tooltip: 'Show Snackbar',
 ///           onPressed: () {
-///             ScaffoldMessenger.of(context).showSnackBar(snackBar);
+///             scaffoldKey.currentState.showSnackBar(snackBar);
 ///           },
 ///         ),
 ///         IconButton(

diff --git a/packages/flutter/lib/src/material/debug.dart b/packages/flutter/lib/src/material/debug.dart
@@ -9,7 +9,7 @@ import 'package:flutter/widgets.dart';
 
 import 'material.dart';
 import 'material_localizations.dart';
-import 'scaffold.dart' show Scaffold, ScaffoldMessenger;
+import 'scaffold.dart' show Scaffold;
 
 /// Asserts that the given context has a [Material] ancestor.
 ///
@@ -125,34 +125,3 @@ bool debugCheckHasScaffold(BuildContext context) {
   }());
   return true;
 }
-
-/// Asserts that the given context has a [ScaffoldMessenger] ancestor.
-///
-/// Used by various widgets to make sure that they are only used in an
-/// appropriate context.
-///
-/// To invoke this function, use the following pattern, typically in the
-/// relevant Widget's build method:
-///
-/// ```dart
-/// assert(debugCheckHasScaffoldMessenger(context));
-/// ```
-///
-/// Does nothing if asserts are disabled. Always returns true.
-bool debugCheckHasScaffoldMessenger(BuildContext context) {
-  assert(() {
-    if (context.widget is! ScaffoldMessenger && context.findAncestorWidgetOfExactType<ScaffoldMessenger>() == null) {
-      throw FlutterError.fromParts(<DiagnosticsNode>[
-        ErrorSummary('No ScaffoldMessenger widget found.'),
-        ErrorDescription('${context.widget.runtimeType} widgets require a ScaffoldMessenger widget ancestor.'),
-        ...context.describeMissingAncestor(expectedAncestorType: ScaffoldMessenger),
-        ErrorHint(
-          'Typically, the ScaffoldMessenger widget is introduced by the MaterialApp '
-          'at the top of your application widget tree.'
-        )
-      ]);
-    }
-    return true;
-  }());
-  return true;
-}