[webview_flutter_android] Updates plugin to use ProxyApiss (#7794)

Author: bparrishMines

packages/webview_flutter/webview_flutter_android/CHANGELOG.md

@@ -1,3 +1,7 @@
+## 4.1.0
+
+* Updates internal API wrapper to use `ProxyApi`s.
+
 ## 4.0.3
 
 * Bumps androidx.annotation:annotation from 1.8.2 to 1.9.1.

packages/webview_flutter/webview_flutter_android/CONTRIBUTING.md

@@ -0,0 +1,74 @@
+# Contributing to `webview_flutter_android`
+
+Please start by taking a look at the general guide to contributing to the `flutter/packages` repo:
+https://github.com/flutter/packages/blob/main/CONTRIBUTING.md
+
+## Package Structure
+
+This plugin serves as a platform implementation plugin as outlined in [federated plugins](https://docs.flutter.dev/packages-and-plugins/developing-packages#federated-plugins). 
+The sections below will provide an overview of how this plugin implements this portion with Android.
+
+For making changes to this package, please take a look at [changing federated plugins](https://github.com/flutter/flutter/blob/master/docs/ecosystem/contributing/README.md#changing-federated-plugins).
+
+### Quick Overview
+
+This plugin implements the platform interface provided by `webview_flutter_platform_interface` using
+the native WebKit APIs for Android.
+
+#### SDK Wrappers
+
+To access native APIS, this plugins uses Dart wrappers of the native library. The native library is
+wrapped using using the `ProxyApi` feature from the `pigeon` package.
+
+The wrappers for the native library can be updated and modified by changing `pigeons/android_webkit.dart`.
+
+The generated files are located:
+* `lib/src/android_webkit.g.dart`
+* `android/src/main/java/io/flutter/plugins/webviewflutter/AndroidWebkitLibrary.g.kt`
+
+To update the wrapper, follow the steps below:
+
+##### 1. Ensure the project has been built at least once
+
+Run `flutter build apk --debug` in `example/`.
+
+##### 2. Make changes to the respective pigeon file that matches the native SDK
+
+* Android Dependency: https://developer.android.com/reference/android/webkit/package-summary
+* Pigeon file to update: `pigeons/android_webkit.dart`
+
+##### 3. Run the code generator from the terminal
+
+Run: `dart run pigeon --input pigeons/android_webkit.dart`
+
+##### 4. Update the generated APIs in native code
+
+Running the `flutter build` command from step 1 again should provide build errors and indicate what
+needs to be done. Alternatively, it can be easier to update native code with the platform's specific
+IDE:
+
+Open `example/android/` in a separate Android Studio project.
+
+##### 5. Write API tests
+
+Assuming a non-static method or constructor was added to the native wrapper, a native test will need
+to be added.
+
+Tests location: `android/src/test/java/io/flutter/plugins/webviewflutter/`
+
+## Important Notes
+
+### Calling `WebView.destroy()` after Dart Instance is Garbage Collected
+
+To avoid a potentially breaking change, the code in `android/src/main/java/io/flutter/plugins/webviewflutter/AndroidWebkitLibrary.g.kt`
+needs to be updated after the pigeon generator is run. Please add
+
+```kotlin
+val instance: Any? = getInstance(identifier)
+if (instance is WebViewProxyApi.WebViewPlatformView) {
+  instance.destroy()
+}
+```
+
+to `AndroidWebkitLibraryPigeonInstanceManager.remove`. The current implementation of the native
+code doesn't currently support handling when the Dart instance is garbage collected.

packages/webview_flutter/webview_flutter_android/README.md

@@ -73,5 +73,9 @@ androidController.setCustomWidgetCallbacks(
 );
 ```
 
+## Contributing
+
+For information on contributing to this plugin, see [`CONTRIBUTING.md`](CONTRIBUTING.md).
+
 [1]: https://pub.dev/packages/webview_flutter
 [2]: https://flutter.dev/to/endorsed-federated-plugin

packages/webview_flutter/webview_flutter_android/android/build.gradle

@@ -2,13 +2,15 @@ group 'io.flutter.plugins.webviewflutter'
 version '1.0-SNAPSHOT'
 
 buildscript {
+    ext.kotlin_version = '1.9.10'
     repositories {
         google()
         mavenCentral()
     }
 
     dependencies {
         classpath 'com.android.tools.build:gradle:8.0.0'
+        classpath "org.jetbrains.kotlin:kotlin-gradle-plugin:$kotlin_version"
     }
 }
 
@@ -20,11 +22,21 @@ rootProject.allprojects {
 }
 
 apply plugin: 'com.android.library'
+apply plugin: 'kotlin-android'
 
 android {
     namespace 'io.flutter.plugins.webviewflutter'
     compileSdk 34
 
+    compileOptions {
+        sourceCompatibility JavaVersion.VERSION_11
+        targetCompatibility JavaVersion.VERSION_11
+    }
+
+    kotlinOptions {
+        jvmTarget = '11'
+    }
+
     defaultConfig {
         minSdkVersion 21
         testInstrumentationRunner "androidx.test.runner.AndroidJUnitRunner"
@@ -44,11 +56,6 @@ android {
         testImplementation 'androidx.test:core:1.3.0'
     }
 
-    compileOptions {
-        sourceCompatibility JavaVersion.VERSION_11
-        targetCompatibility JavaVersion.VERSION_11
-    }
-
     testOptions {
         unitTests.includeAndroidResources = true
         unitTests.returnDefaultValues = true