[webview_flutter_android] Expose the Java InstanceManager (#6421)

packages/webview_flutter/webview_flutter_android/CHANGELOG.md

@@ -1,3 +1,7 @@
+## 2.10.2
+
+* Adds a getter to expose the Java InstanceManager.
+
 ## 2.10.1
 
 * Adds a method to the `WebView` wrapper to retrieve the X and Y positions simultaneously.

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

@@ -15,6 +15,9 @@
 /**
  * Maintains instances used to communicate with the corresponding objects in Dart.
  *
+ * <p>Objects stored in this container are represented by an object in Dart that is also stored in
+ * an InstanceManager with the same identifier.
+ *
  * <p>When an instance is added with an identifier, either can be used to retrieve the other.
  *
  * <p>Added instances are added as a weak reference and a strong reference. When the strong

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

@@ -8,6 +8,7 @@
 import android.os.Handler;
 import android.view.View;
 import androidx.annotation.NonNull;
+import androidx.annotation.Nullable;
 import io.flutter.embedding.engine.plugins.FlutterPlugin;
 import io.flutter.embedding.engine.plugins.activity.ActivityAware;
 import io.flutter.embedding.engine.plugins.activity.ActivityPluginBinding;
@@ -166,4 +167,10 @@ private void updateContext(Context context) {
     webViewHostApi.setContext(context);
     javaScriptChannelHostApi.setPlatformThreadHandler(new Handler(context.getMainLooper()));
   }
+
+  /** Maintains instances used to communicate with the corresponding objects in Dart. */
+  @Nullable
+  public InstanceManager getInstanceManager() {
+    return instanceManager;
+  }
 }

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

@@ -511,4 +511,9 @@ public void setBackgroundColor(Long instanceId, Long color) {
     final WebView webView = (WebView) instanceManager.getInstance(instanceId);
     webView.setBackgroundColor(color.intValue());
   }
+
+  /** Maintains instances used to communicate with the corresponding WebView Dart object. */
+  public InstanceManager getInstanceManager() {
+    return instanceManager;
+  }
 }

packages/webview_flutter/webview_flutter_android/android/src/test/java/io/flutter/plugins/webviewflutter/WebViewFlutterPluginTest.java

@@ -0,0 +1,45 @@
+// 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 static org.junit.Assert.assertNotNull;
+import static org.mockito.Mockito.when;
+
+import android.content.Context;
+import io.flutter.embedding.engine.plugins.FlutterPlugin;
+import io.flutter.plugin.common.BinaryMessenger;
+import io.flutter.plugin.platform.PlatformViewRegistry;
+import org.junit.Rule;
+import org.junit.Test;
+import org.mockito.Mock;
+import org.mockito.junit.MockitoJUnit;
+import org.mockito.junit.MockitoRule;
+
+public class WebViewFlutterPluginTest {
+  @Rule public MockitoRule mockitoRule = MockitoJUnit.rule();
+
+  @Mock Context mockContext;
+
+  @Mock BinaryMessenger mockBinaryMessenger;
+
+  @Mock PlatformViewRegistry mockViewRegistry;
+
+  @Mock FlutterPlugin.FlutterPluginBinding mockPluginBinding;
+
+  @Test
+  public void getInstanceManagerAfterOnAttachedToEngine() {
+    final WebViewFlutterPlugin webViewFlutterPlugin = new WebViewFlutterPlugin();
+
+    when(mockPluginBinding.getApplicationContext()).thenReturn(mockContext);
+    when(mockPluginBinding.getPlatformViewRegistry()).thenReturn(mockViewRegistry);
+    when(mockPluginBinding.getBinaryMessenger()).thenReturn(mockBinaryMessenger);
+
+    webViewFlutterPlugin.onAttachedToEngine(mockPluginBinding);
+
+    assertNotNull(webViewFlutterPlugin.getInstanceManager());
+
+    webViewFlutterPlugin.onDetachedFromEngine(mockPluginBinding);
+  }
+}

packages/webview_flutter/webview_flutter_android/pubspec.yaml

@@ -2,7 +2,7 @@ name: webview_flutter_android
 description: A Flutter plugin that provides a WebView widget on Android.
 repository: https://github.com/flutter/plugins/tree/main/packages/webview_flutter/webview_flutter_android
 issue_tracker: https://github.com/flutter/flutter/issues?q=is%3Aissue+is%3Aopen+label%3A%22p%3A+webview%22
-version: 2.10.1
+version: 2.10.2
 
 environment:
   sdk: ">=2.14.0 <3.0.0"