[webview_flutter_android] Added the functionality to fullscreen html5 video (#3879)

At this moment on android the fullscreen html5 video does not work. This PR solves that issues, adding the functionality that the video is played fullscreen when you click on the fullscreen-button in the video player.

Fixes flutter/flutter#27101

- [ x I read and followed the [relevant style guides] and ran the auto-formatter. (Unlike the flutter/flutter repo, the flutter/packages repo does use `dart format`.)

Author: paulppn

packages/webview_flutter/webview_flutter_android/CHANGELOG.md

@@ -1,3 +1,8 @@
+## 3.10.0
+
+* Adds support for playing video in fullscreen. See
+  `AndroidWebViewController.setCustomWidgetCallbacks`.
+
 ## 3.9.5
 
 * Updates pigeon to 11 and removes unneeded enum wrappers.

packages/webview_flutter/webview_flutter_android/README.md

@@ -36,7 +36,7 @@ This can be configured for versions >=23 with
 `AndroidWebViewWidgetCreationParams.displayWithHybridComposition`. See https://pub.dev/packages/webview_flutter#platform-specific-features
 for more details on setting platform-specific features in the main plugin.
 
-### External Native API
+## External Native API
 
 The plugin also provides a native API accessible by the native code of Android applications or
 packages. This API follows the convention of breaking changes of the Dart API, which means that any
@@ -52,6 +52,27 @@ Java:
 import io.flutter.plugins.webviewflutter.WebViewFlutterAndroidExternalApi;
 ```
 
+## Fullscreen Video
+
+To display a video as fullscreen, an app must manually handle the notification that the current page
+has entered fullscreen mode. This can be done by calling
+`AndroidWebViewController.setCustomWidgetCallbacks`. Below is an example implementation.
+
+<?code-excerpt "example/lib/main.dart (fullscreen_example)"?>
+```dart
+androidController.setCustomWidgetCallbacks(
+  onShowCustomWidget: (Widget widget, OnHideCustomWidgetCallback callback) {
+    Navigator.of(context).push(MaterialPageRoute<void>(
+      builder: (BuildContext context) => widget,
+      fullscreenDialog: true,
+    ));
+  },
+  onHideCustomWidget: () {
+    Navigator.of(context).pop();
+  },
+);
+```
+
 ## Contributing
 
 This package uses [pigeon][3] to generate the communication layer between Flutter and the host

packages/webview_flutter/webview_flutter_android/android/src/main/java/io/flutter/plugins/webviewflutter/CustomViewCallbackFlutterApiImpl.java

@@ -0,0 +1,62 @@
+// Copyright 2013 The Flutter Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+package io.flutter.plugins.webviewflutter;
+
+import android.webkit.WebChromeClient.CustomViewCallback;
+import androidx.annotation.NonNull;
+import androidx.annotation.VisibleForTesting;
+import io.flutter.plugin.common.BinaryMessenger;
+import io.flutter.plugins.webviewflutter.GeneratedAndroidWebView.CustomViewCallbackFlutterApi;
+
+/**
+ * Flutter API implementation for `CustomViewCallback`.
+ *
+ * <p>This class may handle adding native instances that are attached to a Dart instance or passing
+ * arguments of callbacks methods to a Dart instance.
+ */
+public class CustomViewCallbackFlutterApiImpl {
+  // To ease adding additional methods, this value is added prematurely.
+  @SuppressWarnings({"unused", "FieldCanBeLocal"})
+  private final BinaryMessenger binaryMessenger;
+
+  private final InstanceManager instanceManager;
+  private CustomViewCallbackFlutterApi api;
+
+  /**
+   * Constructs a {@link CustomViewCallbackFlutterApiImpl}.
+   *
+   * @param binaryMessenger used to communicate with Dart over asynchronous messages
+   * @param instanceManager maintains instances stored to communicate with attached Dart objects
+   */
+  public CustomViewCallbackFlutterApiImpl(
+      @NonNull BinaryMessenger binaryMessenger, @NonNull InstanceManager instanceManager) {
+    this.binaryMessenger = binaryMessenger;
+    this.instanceManager = instanceManager;
+    api = new CustomViewCallbackFlutterApi(binaryMessenger);
+  }
+
+  /**
+   * Stores the `CustomViewCallback` instance and notifies Dart to create and store a new
+   * `CustomViewCallback` instance that is attached to this one. If `instance` has already been
+   * added, this method does nothing.
+   */
+  public void create(
+      @NonNull CustomViewCallback instance,
+      @NonNull CustomViewCallbackFlutterApi.Reply<Void> callback) {
+    if (!instanceManager.containsInstance(instance)) {
+      api.create(instanceManager.addHostCreatedInstance(instance), callback);
+    }
+  }
+
+  /**
+   * Sets the Flutter API used to send messages to Dart.
+   *
+   * <p>This is only visible for testing.
+   */
+  @VisibleForTesting
+  void setApi(@NonNull CustomViewCallbackFlutterApi api) {
+    this.api = api;
+  }
+}

packages/webview_flutter/webview_flutter_android/android/src/main/java/io/flutter/plugins/webviewflutter/CustomViewCallbackHostApiImpl.java

@@ -0,0 +1,46 @@
+// Copyright 2013 The Flutter Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+package io.flutter.plugins.webviewflutter;
+
+import android.webkit.WebChromeClient.CustomViewCallback;
+import androidx.annotation.NonNull;
+import io.flutter.plugin.common.BinaryMessenger;
+import io.flutter.plugins.webviewflutter.GeneratedAndroidWebView.CustomViewCallbackHostApi;
+import java.util.Objects;
+
+/**
+ * Host API implementation for `CustomViewCallback`.
+ *
+ * <p>This class may handle instantiating and adding native object instances that are attached to a
+ * Dart instance or handle method calls on the associated native class or an instance of the class.
+ */
+public class CustomViewCallbackHostApiImpl implements CustomViewCallbackHostApi {
+  // To ease adding additional methods, this value is added prematurely.
+  @SuppressWarnings({"unused", "FieldCanBeLocal"})
+  private final BinaryMessenger binaryMessenger;
+
+  private final InstanceManager instanceManager;
+
+  /**
+   * Constructs a {@link CustomViewCallbackHostApiImpl}.
+   *
+   * @param binaryMessenger used to communicate with Dart over asynchronous messages
+   * @param instanceManager maintains instances stored to communicate with attached Dart objects
+   */
+  public CustomViewCallbackHostApiImpl(
+      @NonNull BinaryMessenger binaryMessenger, @NonNull InstanceManager instanceManager) {
+    this.binaryMessenger = binaryMessenger;
+    this.instanceManager = instanceManager;
+  }
+
+  @Override
+  public void onCustomViewHidden(@NonNull Long identifier) {
+    getCustomViewCallbackInstance(identifier).onCustomViewHidden();
+  }
+
+  private CustomViewCallback getCustomViewCallbackInstance(@NonNull Long identifier) {
+    return Objects.requireNonNull(instanceManager.getInstance(identifier));
+  }
+}

packages/webview_flutter/webview_flutter_android/android/src/main/java/io/flutter/plugins/webviewflutter/FlutterWebViewFactory.java renamed to packages/webview_flutter/webview_flutter_android/android/src/main/java/io/flutter/plugins/webviewflutter/FlutterViewFactory.java

@@ -5,16 +5,17 @@
 package io.flutter.plugins.webviewflutter;
 
 import android.content.Context;
+import android.view.View;
 import androidx.annotation.NonNull;
 import androidx.annotation.Nullable;
 import io.flutter.plugin.common.StandardMessageCodec;
 import io.flutter.plugin.platform.PlatformView;
 import io.flutter.plugin.platform.PlatformViewFactory;
 
-class FlutterWebViewFactory extends PlatformViewFactory {
+class FlutterViewFactory extends PlatformViewFactory {
   private final InstanceManager instanceManager;
 
-  FlutterWebViewFactory(InstanceManager instanceManager) {
+  FlutterViewFactory(InstanceManager instanceManager) {
     super(StandardMessageCodec.INSTANCE);
     this.instanceManager = instanceManager;
   }
@@ -24,13 +25,26 @@ class FlutterWebViewFactory extends PlatformViewFactory {
   public PlatformView create(Context context, int viewId, @Nullable Object args) {
     final Integer identifier = (Integer) args;
     if (identifier == null) {
-      throw new IllegalStateException("An identifier is required to retrieve WebView instance.");
+      throw new IllegalStateException("An identifier is required to retrieve a View instance.");
     }
 
-    final PlatformView view = instanceManager.getInstance(identifier);
-    if (view == null) {
-      throw new IllegalStateException("Unable to find WebView instance: " + args);
+    final Object instance = instanceManager.getInstance(identifier);
+
+    if (instance instanceof PlatformView) {
+      return (PlatformView) instance;
+    } else if (instance instanceof View) {
+      return new PlatformView() {
+        @Override
+        public View getView() {
+          return (View) instance;
+        }
+
+        @Override
+        public void dispose() {}
+      };
     }
-    return view;
+
+    throw new IllegalStateException(
+        "Unable to find a PlatformView or View instance: " + args + ", " + instance);
   }
 }

packages/webview_flutter/webview_flutter_android/android/src/main/java/io/flutter/plugins/webviewflutter/GeneratedAndroidWebView.java

@@ -2602,6 +2602,33 @@ public void onPermissionRequest(
           new ArrayList<Object>(Arrays.asList(instanceIdArg, requestInstanceIdArg)),
           channelReply -> callback.reply(null));
     }
+    /** Callback to Dart function `WebChromeClient.onShowCustomView`. */
+    public void onShowCustomView(
+        @NonNull Long instanceIdArg,
+        @NonNull Long viewIdentifierArg,
+        @NonNull Long callbackIdentifierArg,
+        @NonNull Reply<Void> callback) {
+      BasicMessageChannel<Object> channel =
+          new BasicMessageChannel<>(
+              binaryMessenger,
+              "dev.flutter.pigeon.webview_flutter_android.WebChromeClientFlutterApi.onShowCustomView",
+              getCodec());
+      channel.send(
+          new ArrayList<Object>(
+              Arrays.asList(instanceIdArg, viewIdentifierArg, callbackIdentifierArg)),
+          channelReply -> callback.reply(null));
+    }
+    /** Callback to Dart function `WebChromeClient.onHideCustomView`. */
+    public void onHideCustomView(@NonNull Long instanceIdArg, @NonNull Reply<Void> callback) {
+      BasicMessageChannel<Object> channel =
+          new BasicMessageChannel<>(
+              binaryMessenger,
+              "dev.flutter.pigeon.webview_flutter_android.WebChromeClientFlutterApi.onHideCustomView",
+              getCodec());
+      channel.send(
+          new ArrayList<Object>(Collections.singletonList(instanceIdArg)),
+          channelReply -> callback.reply(null));
+    }
     /** Callback to Dart function `WebChromeClient.onGeolocationPermissionsShowPrompt`. */
     public void onGeolocationPermissionsShowPrompt(
         @NonNull Long instanceIdArg,
@@ -2867,6 +2894,137 @@ public void create(
           channelReply -> callback.reply(null));
     }
   }
+  /**
+   * Host API for `CustomViewCallback`.
+   *
+   * <p>This class may handle instantiating and adding native object instances that are attached to
+   * a Dart instance or handle method calls on the associated native class or an instance of the
+   * class.
+   *
+   * <p>See
+   * https://developer.android.com/reference/android/webkit/WebChromeClient.CustomViewCallback.
+   *
+   * <p>Generated interface from Pigeon that represents a handler of messages from Flutter.
+   */
+  public interface CustomViewCallbackHostApi {
+    /** Handles Dart method `CustomViewCallback.onCustomViewHidden`. */
+    void onCustomViewHidden(@NonNull Long identifier);
+
+    /** The codec used by CustomViewCallbackHostApi. */
+    static @NonNull MessageCodec<Object> getCodec() {
+      return new StandardMessageCodec();
+    }
+    /**
+     * Sets up an instance of `CustomViewCallbackHostApi` to handle messages through the
+     * `binaryMessenger`.
+     */
+    static void setup(
+        @NonNull BinaryMessenger binaryMessenger, @Nullable CustomViewCallbackHostApi api) {
+      {
+        BasicMessageChannel<Object> channel =
+            new BasicMessageChannel<>(
+                binaryMessenger,
+                "dev.flutter.pigeon.webview_flutter_android.CustomViewCallbackHostApi.onCustomViewHidden",
+                getCodec());
+        if (api != null) {
+          channel.setMessageHandler(
+              (message, reply) -> {
+                ArrayList<Object> wrapped = new ArrayList<Object>();
+                ArrayList<Object> args = (ArrayList<Object>) message;
+                Number identifierArg = (Number) args.get(0);
+                try {
+                  api.onCustomViewHidden(
+                      (identifierArg == null) ? null : identifierArg.longValue());
+                  wrapped.add(0, null);
+                } catch (Throwable exception) {
+                  ArrayList<Object> wrappedError = wrapError(exception);
+                  wrapped = wrappedError;
+                }
+                reply.reply(wrapped);
+              });
+        } else {
+          channel.setMessageHandler(null);
+        }
+      }
+    }
+  }
+  /**
+   * Flutter API for `CustomViewCallback`.
+   *
+   * <p>This class may handle instantiating and adding Dart instances that are attached to a native
+   * instance or receiving callback methods from an overridden native class.
+   *
+   * <p>See
+   * https://developer.android.com/reference/android/webkit/WebChromeClient.CustomViewCallback.
+   *
+   * <p>Generated class from Pigeon that represents Flutter messages that can be called from Java.
+   */
+  public static class CustomViewCallbackFlutterApi {
+    private final @NonNull BinaryMessenger binaryMessenger;
+
+    public CustomViewCallbackFlutterApi(@NonNull BinaryMessenger argBinaryMessenger) {
+      this.binaryMessenger = argBinaryMessenger;
+    }
+
+    /** Public interface for sending reply. */
+    @SuppressWarnings("UnknownNullness")
+    public interface Reply<T> {
+      void reply(T reply);
+    }
+    /** The codec used by CustomViewCallbackFlutterApi. */
+    static @NonNull MessageCodec<Object> getCodec() {
+      return new StandardMessageCodec();
+    }
+    /** Create a new Dart instance and add it to the `InstanceManager`. */
+    public void create(@NonNull Long identifierArg, @NonNull Reply<Void> callback) {
+      BasicMessageChannel<Object> channel =
+          new BasicMessageChannel<>(
+              binaryMessenger,
+              "dev.flutter.pigeon.webview_flutter_android.CustomViewCallbackFlutterApi.create",
+              getCodec());
+      channel.send(
+          new ArrayList<Object>(Collections.singletonList(identifierArg)),
+          channelReply -> callback.reply(null));
+    }
+  }
+  /**
+   * Flutter API for `View`.
+   *
+   * <p>This class may handle instantiating and adding Dart instances that are attached to a native
+   * instance or receiving callback methods from an overridden native class.
+   *
+   * <p>See https://developer.android.com/reference/android/view/View.
+   *
+   * <p>Generated class from Pigeon that represents Flutter messages that can be called from Java.
+   */
+  public static class ViewFlutterApi {
+    private final @NonNull BinaryMessenger binaryMessenger;
+
+    public ViewFlutterApi(@NonNull BinaryMessenger argBinaryMessenger) {
+      this.binaryMessenger = argBinaryMessenger;
+    }
+
+    /** Public interface for sending reply. */
+    @SuppressWarnings("UnknownNullness")
+    public interface Reply<T> {
+      void reply(T reply);
+    }
+    /** The codec used by ViewFlutterApi. */
+    static @NonNull MessageCodec<Object> getCodec() {
+      return new StandardMessageCodec();
+    }
+    /** Create a new Dart instance and add it to the `InstanceManager`. */
+    public void create(@NonNull Long identifierArg, @NonNull Reply<Void> callback) {
+      BasicMessageChannel<Object> channel =
+          new BasicMessageChannel<>(
+              binaryMessenger,
+              "dev.flutter.pigeon.webview_flutter_android.ViewFlutterApi.create",
+              getCodec());
+      channel.send(
+          new ArrayList<Object>(Collections.singletonList(identifierArg)),
+          channelReply -> callback.reply(null));
+    }
+  }
   /**
    * Host API for `GeolocationPermissionsCallback`.
    *