[webview_flutter] Add a backgroundColor option to the webview (#4584)

e-adrien · web-flow · commit 0c5357fb258e · 2021-12-07T01:04:04.000-08:00
diff --git a/packages/webview_flutter/webview_flutter/CHANGELOG.md b/packages/webview_flutter/webview_flutter/CHANGELOG.md
@@ -1,3 +1,7 @@
+## 2.5.0
+
+* Adds an option to set the background color of the webview.
+
 ## 2.4.0
 
 * Adds support for the `loadFile` and `loadHtmlString` methods.
diff --git a/packages/webview_flutter/webview_flutter/example/lib/main.dart b/packages/webview_flutter/webview_flutter/example/lib/main.dart
@@ -48,6 +48,27 @@ const String kLocalExamplePage = '''
 </html>
 ''';
 
+const String kTransparentBackgroundPage = '''
+  <!DOCTYPE html>
+  <html>
+  <head>
+    <title>Transparent background test</title>
+  </head>
+  <style type="text/css">
+    body { background: transparent; margin: 0; padding: 0; }
+    #container { position: relative; margin: 0; padding: 0; width: 100vw; height: 100vh; }
+    #shape { background: red; width: 200px; height: 200px; margin: 0; padding: 0; position: absolute; top: calc(50% - 100px); left: calc(50% - 100px); }
+    p { text-align: center; }
+  </style>
+  <body>
+    <div id="container">
+      <p>Transparent background test</p>
+      <div id="shape"></div>
+    </div>
+  </body>
+  </html>
+''';
+
 class WebViewExample extends StatefulWidget {
   @override
   _WebViewExampleState createState() => _WebViewExampleState();
@@ -68,6 +89,7 @@ class _WebViewExampleState extends State<WebViewExample> {
   @override
   Widget build(BuildContext context) {
     return Scaffold(
+      backgroundColor: Colors.green,
       appBar: AppBar(
         title: const Text('Flutter WebView example'),
         // This drop down menu demonstrates that Flutter widgets can be shown over the web view.
@@ -106,6 +128,7 @@ class _WebViewExampleState extends State<WebViewExample> {
             print('Page finished loading: $url');
           },
           gestureNavigationEnabled: true,
+          backgroundColor: const Color(0x00000000),
         );
       }),
       floatingActionButton: favoriteButton(),
@@ -155,6 +178,7 @@ enum MenuOptions {
   navigationDelegate,
   loadLocalFile,
   loadHtmlString,
+  transparentBackground,
 }
 
 class SampleMenu extends StatelessWidget {
@@ -170,6 +194,7 @@ class SampleMenu extends StatelessWidget {
       builder:
           (BuildContext context, AsyncSnapshot<WebViewController> controller) {
         return PopupMenuButton<MenuOptions>(
+          key: const ValueKey<String>('ShowPopupMenu'),
           onSelected: (MenuOptions value) {
             switch (value) {
               case MenuOptions.showUserAgent:
@@ -199,6 +224,9 @@ class SampleMenu extends StatelessWidget {
               case MenuOptions.loadHtmlString:
                 _onLoadHtmlStringExample(controller.data!, context);
                 break;
+              case MenuOptions.transparentBackground:
+                _onTransparentBackground(controller.data!, context);
+                break;
             }
           },
           itemBuilder: (BuildContext context) => <PopupMenuItem<MenuOptions>>[
@@ -239,6 +267,11 @@ class SampleMenu extends StatelessWidget {
               value: MenuOptions.loadLocalFile,
               child: Text('Load local file'),
             ),
+            const PopupMenuItem<MenuOptions>(
+              key: ValueKey<String>('ShowTransparentBackgroundExample'),
+              value: MenuOptions.transparentBackground,
+              child: Text('Transparent background example'),
+            ),
           ],
         );
       },
@@ -327,6 +360,11 @@ class SampleMenu extends StatelessWidget {
     await controller.loadHtmlString(kLocalExamplePage);
   }
 
+  Future<void> _onTransparentBackground(
+      WebViewController controller, BuildContext context) async {
+    await controller.loadHtmlString(kTransparentBackgroundPage);
+  }
+
   Widget _getCookieList(String cookies) {
     if (cookies == null || cookies == '""') {
       return Container();
diff --git a/packages/webview_flutter/webview_flutter/lib/src/webview.dart b/packages/webview_flutter/webview_flutter/lib/src/webview.dart
@@ -94,6 +94,7 @@ class WebView extends StatefulWidget {
     this.initialMediaPlaybackPolicy =
         AutoMediaPlaybackPolicy.require_user_action_for_all_media_types,
     this.allowsInlineMediaPlayback = false,
+    this.backgroundColor,
   })  : assert(javascriptMode != null),
         assert(initialMediaPlaybackPolicy != null),
         assert(allowsInlineMediaPlayback != null),
@@ -286,6 +287,12 @@ class WebView extends StatefulWidget {
   /// The default policy is [AutoMediaPlaybackPolicy.require_user_action_for_all_media_types].
   final AutoMediaPlaybackPolicy initialMediaPlaybackPolicy;
 
+  /// The background color of the [WebView].
+  ///
+  /// When `null` the platform's webview default background color is used. By
+  /// default [backgroundColor] is `null`.
+  final Color? backgroundColor;
+
   @override
   State<StatefulWidget> createState() => _WebViewState();
 }
@@ -357,6 +364,7 @@ CreationParams _creationParamsfromWidget(WebView widget) {
     javascriptChannelNames: _extractChannelNames(widget.javascriptChannels),
     userAgent: widget.userAgent,
     autoMediaPlaybackPolicy: widget.initialMediaPlaybackPolicy,
+    backgroundColor: widget.backgroundColor,
   );
 }
 
diff --git a/packages/webview_flutter/webview_flutter/pubspec.yaml b/packages/webview_flutter/webview_flutter/pubspec.yaml
@@ -2,7 +2,7 @@ name: webview_flutter
 description: A Flutter plugin that provides a WebView widget on Android and iOS.
 repository: https://github.com/flutter/plugins/tree/master/packages/webview_flutter/webview_flutter
 issue_tracker: https://github.com/flutter/flutter/issues?q=is%3Aissue+is%3Aopen+label%3A%22p%3A+webview%22
-version: 2.4.0
+version: 2.5.0
 
 environment:
   sdk: ">=2.14.0 <3.0.0"
@@ -19,9 +19,9 @@ flutter:
 dependencies:
   flutter:
     sdk: flutter
-  webview_flutter_android: ^2.4.0
-  webview_flutter_platform_interface: ^1.5.2
-  webview_flutter_wkwebview: ^2.4.0
+  webview_flutter_android: ^2.5.0
+  webview_flutter_platform_interface: ^1.7.0
+  webview_flutter_wkwebview: ^2.5.0
 
 dev_dependencies:
   build_runner: ^2.1.5
diff --git a/packages/webview_flutter/webview_flutter/test/webview_flutter_test.dart b/packages/webview_flutter/webview_flutter/test/webview_flutter_test.dart
@@ -1020,6 +1020,34 @@ void main() {
     });
   });
 
+  group('Background color', () {
+    testWidgets('Defaults to null', (WidgetTester tester) async {
+      await tester.pumpWidget(const WebView());
+
+      final CreationParams params = captureBuildArgs(
+        mockWebViewPlatform,
+        creationParams: true,
+      ).single as CreationParams;
+
+      expect(params.backgroundColor, null);
+    });
+
+    testWidgets('Can be transparent', (WidgetTester tester) async {
+      const Color transparentColor = Color(0x00000000);
+
+      await tester.pumpWidget(const WebView(
+        backgroundColor: transparentColor,
+      ));
+
+      final CreationParams params = captureBuildArgs(
+        mockWebViewPlatform,
+        creationParams: true,
+      ).single as CreationParams;
+
+      expect(params.backgroundColor, transparentColor);
+    });
+  });
+
   group('Custom platform implementation', () {
     setUp(() {
       WebView.platform = MyWebViewPlatform();
