[webview_flutter] add gesture navigation for iOS

This introduces a boolean for the allowsBackForwardNavigationGestures
setting of the WKWebView in iOS. It has no effect on Android.

Author: wwwdata

packages/webview_flutter/CHANGELOG.md

@@ -1,6 +1,7 @@
 ## 0.3.18
 
 * Add support for onPageStarted event.
+* Add setting for iOS to allow gesture based navigation.
 
 ## 0.3.17
 

packages/webview_flutter/example/lib/main.dart

@@ -74,6 +74,7 @@ class _WebViewExampleState extends State<WebViewExample> {
           onPageFinished: (String url) {
             print('Page finished loading: $url');
           },
+          allowsBackForwardNavigationGestures: true,
         );
       }),
       floatingActionButton: favoriteButton(),

packages/webview_flutter/example/test_driver/webview_flutter_e2e.dart

@@ -4,6 +4,7 @@
 
 import 'dart:async';
 import 'dart:convert';
+import 'dart:io';
 import 'dart:typed_data';
 
 import 'package:flutter/foundation.dart';
@@ -652,6 +653,36 @@ void main() {
       expect(currentUrl, 'https://www.google.com/');
     });
   });
+
+  testWidgets('launches with allowsBackForwardNavigationGestures on iOS',
+      (WidgetTester tester) async {
+    if (Platform.isIOS != true) {
+      return;
+    }
+
+    final Completer<WebViewController> controllerCompleter =
+        Completer<WebViewController>();
+    await tester.pumpWidget(
+      Directionality(
+        textDirection: TextDirection.ltr,
+        child: SizedBox(
+          width: 400,
+          height: 300,
+          child: WebView(
+            key: GlobalKey(),
+            initialUrl: 'https://flutter.dev/',
+            allowsBackForwardNavigationGestures: true,
+            onWebViewCreated: (WebViewController controller) {
+              controllerCompleter.complete(controller);
+            },
+          ),
+        ),
+      ),
+    );
+    final WebViewController controller = await controllerCompleter.future;
+    final String currentUrl = await controller.currentUrl();
+    expect(currentUrl, 'https://flutter.dev/');
+  });
 }
 
 // JavaScript booleans evaluate to different string values on Android and iOS.

packages/webview_flutter/ios/Classes/FlutterWebView.m

@@ -260,6 +260,10 @@ - (NSString*)applySettings:(NSDictionary<NSString*, id>*)settings {
     } else if ([key isEqualToString:@"userAgent"]) {
       NSString* userAgent = settings[key];
       [self updateUserAgent:[userAgent isEqual:[NSNull null]] ? nil : userAgent];
+    } else if ([key isEqualToString:@"allowsBackForwardNavigationGestures"]) {
+      NSNumber* allowsBackForwardNavigationGestures = settings[key];
+      _webView.allowsBackForwardNavigationGestures =
+          [allowsBackForwardNavigationGestures boolValue];
     } else {
       [unknownKeys addObject:key];
     }

packages/webview_flutter/lib/platform_interface.dart

@@ -232,6 +232,7 @@ class WebSettings {
     this.hasNavigationDelegate,
     this.debuggingEnabled,
     @required this.userAgent,
+    this.allowsBackForwardNavigationGestures,
   }) : assert(userAgent != null);
 
   /// The JavaScript execution mode to be used by the webview.
@@ -255,9 +256,14 @@ class WebSettings {
   /// See also [WebView.userAgent].
   final WebSetting<String> userAgent;
 
+  /// Whether to allow swipe based navigation in iOS.
+  ///
+  /// See also: [WebView.allowsBackForwardNavigationGestures]
+  final bool allowsBackForwardNavigationGestures;
+
   @override
   String toString() {
-    return 'WebSettings(javascriptMode: $javascriptMode, hasNavigationDelegate: $hasNavigationDelegate, debuggingEnabled: $debuggingEnabled, userAgent: $userAgent,)';
+    return 'WebSettings(javascriptMode: $javascriptMode, hasNavigationDelegate: $hasNavigationDelegate, debuggingEnabled: $debuggingEnabled, userAgent: $userAgent, allowsBackForwardNavigationGestures: $allowsBackForwardNavigationGestures)';
   }
 }
 

packages/webview_flutter/lib/src/webview_method_channel.dart

@@ -137,6 +137,8 @@ class MethodChannelWebViewPlatform implements WebViewPlatformController {
     _addIfNonNull('jsMode', settings.javascriptMode?.index);
     _addIfNonNull('hasNavigationDelegate', settings.hasNavigationDelegate);
     _addIfNonNull('debuggingEnabled', settings.debuggingEnabled);
+    _addIfNonNull('allowsBackForwardNavigationGestures',
+        settings.allowsBackForwardNavigationGestures);
     _addSettingIfPresent('userAgent', settings.userAgent);
     return map;
   }

packages/webview_flutter/lib/webview_flutter.dart

@@ -151,6 +151,7 @@ class WebView extends StatefulWidget {
     this.userAgent,
     this.initialMediaPlaybackPolicy =
         AutoMediaPlaybackPolicy.require_user_action_for_all_media_types,
+    this.allowsBackForwardNavigationGestures,
   })  : assert(javascriptMode != null),
         assert(initialMediaPlaybackPolicy != null),
         super(key: key);
@@ -311,6 +312,13 @@ class WebView extends StatefulWidget {
   /// The default policy is [AutoMediaPlaybackPolicy.require_user_action_for_all_media_types].
   final AutoMediaPlaybackPolicy initialMediaPlaybackPolicy;
 
+  /// A Boolean value indicating whether horizontal swipe gestures will trigger back-forward list navigations.
+  ///
+  /// This only works on iOS.
+  ///
+  /// By default `allowsBackForwardNavigationGestures` is false.
+  final bool allowsBackForwardNavigationGestures;
+
   @override
   State<StatefulWidget> createState() => _WebViewState();
 }
@@ -384,6 +392,8 @@ WebSettings _webSettingsFromWidget(WebView widget) {
     hasNavigationDelegate: widget.navigationDelegate != null,
     debuggingEnabled: widget.debuggingEnabled,
     userAgent: WebSetting<String>.of(widget.userAgent),
+    allowsBackForwardNavigationGestures:
+        widget.allowsBackForwardNavigationGestures,
   );
 }
 

packages/webview_flutter/pubspec.yaml

@@ -1,6 +1,6 @@
 name: webview_flutter
 description: A Flutter plugin that provides a WebView widget on Android and iOS.
-version: 0.3.17
+version: 0.3.18
 author: Flutter Team <flutter-dev@googlegroups.com>
 homepage: https://github.com/flutter/plugins/tree/master/packages/webview_flutter
 

packages/webview_flutter/test/webview_flutter_test.dart

@@ -822,6 +822,7 @@ void main() {
       await tester.pumpWidget(
         const WebView(
           initialUrl: 'https://youtube.com',
+          allowsBackForwardNavigationGestures: true,
         ),
       );
 
@@ -837,6 +838,7 @@ void main() {
               hasNavigationDelegate: false,
               debuggingEnabled: false,
               userAgent: WebSetting<String>.of(null),
+              allowsBackForwardNavigationGestures: true,
             ),
             // TODO(iskakaushik): Remove this when collection literals makes it to stable.
             // ignore: prefer_collection_literals
@@ -1193,7 +1195,9 @@ class MatchesWebSettings extends Matcher {
         _webSettings.hasNavigationDelegate ==
             webSettings.hasNavigationDelegate &&
         _webSettings.debuggingEnabled == webSettings.debuggingEnabled &&
-        _webSettings.userAgent == webSettings.userAgent;
+        _webSettings.userAgent == webSettings.userAgent &&
+        _webSettings.allowsBackForwardNavigationGestures ==
+            webSettings.allowsBackForwardNavigationGestures;
   }
 }