wendux · guofeng007 · Apr 3, 2020
diff --git a/github_client_app/ios/Runner/Info.plist b/github_client_app/ios/Runner/Info.plist
@@ -41,5 +41,7 @@
 	</array>
 	<key>UIViewControllerBasedStatusBarAppearance</key>
 	<false/>
+	 <key>io.flutter.embedded_views_preview</key>
+  <true/>
 </dict>
 </plist>
diff --git a/github_client_app/lib/main.dart b/github_client_app/lib/main.dart
@@ -60,6 +60,7 @@ class MyApp extends StatelessWidget {
               "login": (context) => LoginRoute(),
               "themes": (context) => ThemeChangeRoute(),
               "language": (context) => LanguageRoute(),
+              "webview": (context)=> WebViewRoute(),
             },
           );
         },

diff --git a/github_client_app/lib/routes/index.dart b/github_client_app/lib/routes/index.dart
@@ -1,4 +1,5 @@
 export 'home_page.dart';
 export 'login.dart';
 export 'theme_change.dart';
-export 'language.dart';
+export 'language.dart';
+export 'webview.dart';
diff --git a/github_client_app/lib/routes/webview.dart b/github_client_app/lib/routes/webview.dart
@@ -0,0 +1,333 @@
+import 'dart:async';
+import 'dart:convert';
+import 'package:flutter/material.dart';
+import 'package:webview_flutter/webview_flutter.dart';
+
+const String kNavigationExamplePage = '''
+<!DOCTYPE html><html>
+<head><title>Navigation Delegate Example</title></head>
+<body>
+<p>
+The navigation delegate is set to block navigation to the youtube website.
+</p>
+<ul>
+<ul><a href="https://www.youtube.com/">https://www.youtube.com/</a></ul>
+<ul><a href="https://www.google.com/">https://www.google.com/</a></ul>
+</ul>
+</body>
+</html>
+''';
+
+class WebViewRoute extends StatefulWidget {
+
+
+  @override
+  _WebViewRouteState createState() => _WebViewRouteState();
+}
+
+class _WebViewRouteState extends State<WebViewRoute> {
+
+  final Completer<WebViewController> _controller =
+      Completer<WebViewController>();
+
+  @override
+  Widget build(BuildContext context) {
+    return Scaffold(
+      appBar: AppBar(
+        title: const Text('Flutter WebView example'),
+        // This drop down menu demonstrates that Flutter widgets can be shown over the web view.
+        actions: <Widget>[
+          NavigationControls(_controller.future),
+          SampleMenu(_controller.future),
+        ],
+      ),
+      // We're using a Builder here so we have a context that is below the Scaffold
+      // to allow calling Scaffold.of(context) so we can show a snackbar.
+      body: Builder(builder: (BuildContext context) {
+        return WebView(
+          initialUrl: ModalRoute.of(context).settings.arguments,
+          javascriptMode: JavascriptMode.unrestricted,
+          onWebViewCreated: (WebViewController webViewController) {
+            _controller.complete(webViewController);
+          },
+          // TODO(iskakaushik): Remove this when collection literals makes it to stable.
+          // ignore: prefer_collection_literals
+          javascriptChannels: <JavascriptChannel>[
+            _toasterJavascriptChannel(context),
+          ].toSet(),
+          navigationDelegate: (NavigationRequest request) {
+            if (request.url.startsWith('https://www.youtube.com/')) {
+              print('blocking navigation to $request}');
+              return NavigationDecision.prevent;
+            }
+            print('allowing navigation to $request');
+            return NavigationDecision.navigate;
+          },
+          onPageStarted: (String url) {
+            print('Page started loading: $url');
+          },
+          onPageFinished: (String url) {
+            print('Page finished loading: $url');
+          },
+          gestureNavigationEnabled: true,
+        );
+      }),
+      floatingActionButton: favoriteButton(),
+    );
+  }
+
+  JavascriptChannel _toasterJavascriptChannel(BuildContext context) {
+    return JavascriptChannel(
+        name: 'Toaster',
+        onMessageReceived: (JavascriptMessage message) {
+          Scaffold.of(context).showSnackBar(
+            SnackBar(content: Text(message.message)),
+          );
+        });
+  }
+
+  Widget favoriteButton() {
+    return FutureBuilder<WebViewController>(
+        future: _controller.future,
+        builder: (BuildContext context,
+            AsyncSnapshot<WebViewController> controller) {
+          if (controller.hasData) {
+            return FloatingActionButton(
+              onPressed: () async {
+                final String url = await controller.data.currentUrl();
+                Scaffold.of(context).showSnackBar(
+                  SnackBar(content: Text('Favorited $url')),
+                );
+              },
+              child: const Icon(Icons.favorite),
+            );
+          }
+          return Container();
+        });
+  }
+}
+
+enum MenuOptions {
+  showUserAgent,
+  listCookies,
+  clearCookies,
+  addToCache,
+  listCache,
+  clearCache,
+  navigationDelegate,
+}
+
+class SampleMenu extends StatelessWidget {
+  SampleMenu(this.controller);
+
+  final Future<WebViewController> controller;
+  final CookieManager cookieManager = CookieManager();
+
+  @override
+  Widget build(BuildContext context) {
+    return FutureBuilder<WebViewController>(
+      future: controller,
+      builder:
+          (BuildContext context, AsyncSnapshot<WebViewController> controller) {
+        return PopupMenuButton<MenuOptions>(
+          onSelected: (MenuOptions value) {
+            switch (value) {
+              case MenuOptions.showUserAgent:
+                _onShowUserAgent(controller.data, context);
+                break;
+              case MenuOptions.listCookies:
+                _onListCookies(controller.data, context);
+                break;
+              case MenuOptions.clearCookies:
+                _onClearCookies(context);
+                break;
+              case MenuOptions.addToCache:
+                _onAddToCache(controller.data, context);
+                break;
+              case MenuOptions.listCache:
+                _onListCache(controller.data, context);
+                break;
+              case MenuOptions.clearCache:
+                _onClearCache(controller.data, context);
+                break;
+              case MenuOptions.navigationDelegate:
+                _onNavigationDelegateExample(controller.data, context);
+                break;
+            }
+          },
+          itemBuilder: (BuildContext context) => <PopupMenuItem<MenuOptions>>[
+            PopupMenuItem<MenuOptions>(
+              value: MenuOptions.showUserAgent,
+              child: const Text('Show user agent'),
+              enabled: controller.hasData,
+            ),
+            const PopupMenuItem<MenuOptions>(
+              value: MenuOptions.listCookies,
+              child: Text('List cookies'),
+            ),
+            const PopupMenuItem<MenuOptions>(
+              value: MenuOptions.clearCookies,
+              child: Text('Clear cookies'),
+            ),
+            const PopupMenuItem<MenuOptions>(
+              value: MenuOptions.addToCache,
+              child: Text('Add to cache'),
+            ),
+            const PopupMenuItem<MenuOptions>(
+              value: MenuOptions.listCache,
+              child: Text('List cache'),
+            ),
+            const PopupMenuItem<MenuOptions>(
+              value: MenuOptions.clearCache,
+              child: Text('Clear cache'),
+            ),
+            const PopupMenuItem<MenuOptions>(
+              value: MenuOptions.navigationDelegate,
+              child: Text('Navigation Delegate example'),
+            ),
+          ],
+        );
+      },
+    );
+  }
+
+  void _onShowUserAgent(
+      WebViewController controller, BuildContext context) async {
+    // Send a message with the user agent string to the Toaster JavaScript channel we registered
+    // with the WebView.
+    await controller.evaluateJavascript(
+        'Toaster.postMessage("User Agent: " + navigator.userAgent);');
+  }
+
+  void _onListCookies(
+      WebViewController controller, BuildContext context) async {
+    final String cookies =
+        await controller.evaluateJavascript('document.cookie');
+    Scaffold.of(context).showSnackBar(SnackBar(
+      content: Column(
+        mainAxisAlignment: MainAxisAlignment.end,
+        mainAxisSize: MainAxisSize.min,
+        children: <Widget>[
+          const Text('Cookies:'),
+          _getCookieList(cookies),
+        ],
+      ),
+    ));
+  }
+
+  void _onAddToCache(WebViewController controller, BuildContext context) async {
+    await controller.evaluateJavascript(
+        'caches.open("test_caches_entry"); localStorage["test_localStorage"] = "dummy_entry";');
+    Scaffold.of(context).showSnackBar(const SnackBar(
+      content: Text('Added a test entry to cache.'),
+    ));
+  }
+
+  void _onListCache(WebViewController controller, BuildContext context) async {
+    await controller.evaluateJavascript('caches.keys()'
+        '.then((cacheKeys) => JSON.stringify({"cacheKeys" : cacheKeys, "localStorage" : localStorage}))'
+        '.then((caches) => Toaster.postMessage(caches))');
+  }
+
+  void _onClearCache(WebViewController controller, BuildContext context) async {
+    await controller.clearCache();
+    Scaffold.of(context).showSnackBar(const SnackBar(
+      content: Text("Cache cleared."),
+    ));
+  }
+
+  void _onClearCookies(BuildContext context) async {
+    final bool hadCookies = await cookieManager.clearCookies();
+    String message = 'There were cookies. Now, they are gone!';
+    if (!hadCookies) {
+      message = 'There are no cookies.';
+    }
+    Scaffold.of(context).showSnackBar(SnackBar(
+      content: Text(message),
+    ));
+  }
+
+  void _onNavigationDelegateExample(
+      WebViewController controller, BuildContext context) async {
+    final String contentBase64 =
+        base64Encode(const Utf8Encoder().convert(kNavigationExamplePage));
+    await controller.loadUrl('data:text/html;base64,$contentBase64');
+  }
+
+  Widget _getCookieList(String cookies) {
+    if (cookies == null || cookies == '""') {
+      return Container();
+    }
+    final List<String> cookieList = cookies.split(';');
+    final Iterable<Text> cookieWidgets =
+        cookieList.map((String cookie) => Text(cookie));
+    return Column(
+      mainAxisAlignment: MainAxisAlignment.end,
+      mainAxisSize: MainAxisSize.min,
+      children: cookieWidgets.toList(),
+    );
+  }
+}
+
+class NavigationControls extends StatelessWidget {
+  const NavigationControls(this._webViewControllerFuture)
+      : assert(_webViewControllerFuture != null);
+
+  final Future<WebViewController> _webViewControllerFuture;
+
+  @override
+  Widget build(BuildContext context) {
+    return FutureBuilder<WebViewController>(
+      future: _webViewControllerFuture,
+      builder:
+          (BuildContext context, AsyncSnapshot<WebViewController> snapshot) {
+        final bool webViewReady =
+            snapshot.connectionState == ConnectionState.done;
+        final WebViewController controller = snapshot.data;
+        return Row(
+          children: <Widget>[
+            IconButton(
+              icon: const Icon(Icons.arrow_back_ios),
+              onPressed: !webViewReady
+                  ? null
+                  : () async {
+                      if (await controller.canGoBack()) {
+                        await controller.goBack();
+                      } else {
+                        Scaffold.of(context).showSnackBar(
+                          const SnackBar(content: Text("No back history item")),
+                        );
+                        return;
+                      }
+                    },
+            ),
+            IconButton(
+              icon: const Icon(Icons.arrow_forward_ios),
+              onPressed: !webViewReady
+                  ? null
+                  : () async {
+                      if (await controller.canGoForward()) {
+                        await controller.goForward();
+                      } else {
+                        Scaffold.of(context).showSnackBar(
+                          const SnackBar(
+                              content: Text("No forward history item")),
+                        );
+                        return;
+                      }
+                    },
+            ),
+            IconButton(
+              icon: const Icon(Icons.replay),
+              onPressed: !webViewReady
+                  ? null
+                  : () {
+                      controller.reload();
+                    },
+            ),
+          ],
+        );
+      },
+    );
+  }
+}