[webview_flutter] Add support for payment requests on Android (flutter#9679)

Expose android native [WebViewFeature#isFeatureSupported](https://developer.android.com/reference/androidx/webkit/WebViewFeature#isFeatureSupported(java.lang.String)), [WebSettingsCompat#setPaymentRequestEnabled](https://developer.android.com/reference/kotlin/androidx/webkit/WebSettingsCompat#setPaymentRequestEnabled(android.webkit.WebSettings,boolean)) and [WebViewFeature#PAYMENT_REQUEST](https://developer.android.com/reference/androidx/webkit/WebViewFeature#PAYMENT_REQUEST()) to allow developers to check if payment request feature is supported in WebView.

This change is for Google Pay integration in Android WebView.
Fixes flutter/flutter#172150

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Author: mataku

packages/webview_flutter/webview_flutter_android/CHANGELOG.md

@@ -1,3 +1,7 @@
+## 4.10.0
+
+* Adds support for the Payment Request API with `AndroidWebViewController.isWebViewFeatureSupported` and `AndroidWebViewController.setPaymentRequestEnabled`.
+
 ## 4.9.1
 
 * Updates kotlin version to 2.2.0 to enable gradle 8.11 support.

packages/webview_flutter/webview_flutter_android/README.md

@@ -52,6 +52,37 @@ Java:
 import io.flutter.plugins.webviewflutter.WebViewFlutterAndroidExternalApi;
 ```
 
+## Enable Payment Request in WebView
+
+The Payment Request API can be enabled by calling `AndroidWebViewController.setPaymentRequestEnabled` after
+checking `AndroidWebViewController.isWebViewFeatureSupported`.
+
+<?code-excerpt "example/lib/readme_excerpts.dart (payment_request_example)"?>
+```dart
+final bool paymentRequestEnabled = await androidController
+    .isWebViewFeatureSupported(WebViewFeatureType.paymentRequest);
+
+if (paymentRequestEnabled) {
+  await androidController.setPaymentRequestEnabled(true);
+}
+```
+
+Add intent filters to your AndroidManifest.xml to discover and invoke Android payment apps using system intents:
+
+```xml
+<queries>
+  <intent>
+    <action android:name="org.chromium.intent.action.PAY"/>
+  </intent>
+  <intent>
+    <action android:name="org.chromium.intent.action.IS_READY_TO_PAY"/>
+  </intent>
+  <intent>
+    <action android:name="org.chromium.intent.action.UPDATE_PAYMENT_DETAILS"/>
+  </intent>
+</queries>
+```
+
 ## Fullscreen Video
 
 To display a video as fullscreen, an app must manually handle the notification that the current page

packages/webview_flutter/webview_flutter_android/android/src/main/java/io/flutter/plugins/webviewflutter/AndroidWebkitLibrary.g.kt

@@ -567,6 +567,18 @@ abstract class AndroidWebkitLibraryPigeonProxyApiRegistrar(val binaryMessenger:
    */
   abstract fun getPigeonApiCertificate(): PigeonApiCertificate
 
+  /**
+   * An implementation of [PigeonApiWebSettingsCompat] used to add a new Dart instance of
+   * `WebSettingsCompat` to the Dart `InstanceManager`.
+   */
+  abstract fun getPigeonApiWebSettingsCompat(): PigeonApiWebSettingsCompat
+
+  /**
+   * An implementation of [PigeonApiWebViewFeature] used to add a new Dart instance of
+   * `WebViewFeature` to the Dart `InstanceManager`.
+   */
+  abstract fun getPigeonApiWebViewFeature(): PigeonApiWebViewFeature
+
   fun setUp() {
     AndroidWebkitLibraryPigeonInstanceManagerApi.setUpMessageHandlers(
         binaryMessenger, instanceManager)
@@ -598,6 +610,9 @@ abstract class AndroidWebkitLibraryPigeonProxyApiRegistrar(val binaryMessenger:
         binaryMessenger, getPigeonApiSslCertificateDName())
     PigeonApiSslCertificate.setUpMessageHandlers(binaryMessenger, getPigeonApiSslCertificate())
     PigeonApiCertificate.setUpMessageHandlers(binaryMessenger, getPigeonApiCertificate())
+    PigeonApiWebSettingsCompat.setUpMessageHandlers(
+        binaryMessenger, getPigeonApiWebSettingsCompat())
+    PigeonApiWebViewFeature.setUpMessageHandlers(binaryMessenger, getPigeonApiWebViewFeature())
   }
 
   fun tearDown() {
@@ -623,6 +638,8 @@ abstract class AndroidWebkitLibraryPigeonProxyApiRegistrar(val binaryMessenger:
     PigeonApiSslCertificateDName.setUpMessageHandlers(binaryMessenger, null)
     PigeonApiSslCertificate.setUpMessageHandlers(binaryMessenger, null)
     PigeonApiCertificate.setUpMessageHandlers(binaryMessenger, null)
+    PigeonApiWebSettingsCompat.setUpMessageHandlers(binaryMessenger, null)
+    PigeonApiWebViewFeature.setUpMessageHandlers(binaryMessenger, null)
   }
 }
 
@@ -727,6 +744,10 @@ private class AndroidWebkitLibraryPigeonProxyApiBaseCodec(
       registrar.getPigeonApiSslCertificate().pigeon_newInstance(value) {}
     } else if (value is java.security.cert.Certificate) {
       registrar.getPigeonApiCertificate().pigeon_newInstance(value) {}
+    } else if (value is androidx.webkit.WebSettingsCompat) {
+      registrar.getPigeonApiWebSettingsCompat().pigeon_newInstance(value) {}
+    } else if (value is androidx.webkit.WebViewFeature) {
+      registrar.getPigeonApiWebViewFeature().pigeon_newInstance(value) {}
     }
 
     when {
@@ -6310,3 +6331,159 @@ abstract class PigeonApiCertificate(
     }
   }
 }
+/**
+ * Compatibility version of `WebSettings`.
+ *
+ * See https://developer.android.com/reference/kotlin/androidx/webkit/WebSettingsCompat.
+ */
+@Suppress("UNCHECKED_CAST")
+abstract class PigeonApiWebSettingsCompat(
+    open val pigeonRegistrar: AndroidWebkitLibraryPigeonProxyApiRegistrar
+) {
+  abstract fun setPaymentRequestEnabled(webSettings: android.webkit.WebSettings, enabled: Boolean)
+
+  companion object {
+    @Suppress("LocalVariableName")
+    fun setUpMessageHandlers(binaryMessenger: BinaryMessenger, api: PigeonApiWebSettingsCompat?) {
+      val codec = api?.pigeonRegistrar?.codec ?: AndroidWebkitLibraryPigeonCodec()
+      run {
+        val channel =
+            BasicMessageChannel<Any?>(
+                binaryMessenger,
+                "dev.flutter.pigeon.webview_flutter_android.WebSettingsCompat.setPaymentRequestEnabled",
+                codec)
+        if (api != null) {
+          channel.setMessageHandler { message, reply ->
+            val args = message as List<Any?>
+            val webSettingsArg = args[0] as android.webkit.WebSettings
+            val enabledArg = args[1] as Boolean
+            val wrapped: List<Any?> =
+                try {
+                  api.setPaymentRequestEnabled(webSettingsArg, enabledArg)
+                  listOf(null)
+                } catch (exception: Throwable) {
+                  AndroidWebkitLibraryPigeonUtils.wrapError(exception)
+                }
+            reply.reply(wrapped)
+          }
+        } else {
+          channel.setMessageHandler(null)
+        }
+      }
+    }
+  }
+
+  @Suppress("LocalVariableName", "FunctionName")
+  /** Creates a Dart instance of WebSettingsCompat and attaches it to [pigeon_instanceArg]. */
+  fun pigeon_newInstance(
+      pigeon_instanceArg: androidx.webkit.WebSettingsCompat,
+      callback: (Result<Unit>) -> Unit
+  ) {
+    if (pigeonRegistrar.ignoreCallsToDart) {
+      callback(
+          Result.failure(
+              AndroidWebKitError("ignore-calls-error", "Calls to Dart are being ignored.", "")))
+    } else if (pigeonRegistrar.instanceManager.containsInstance(pigeon_instanceArg)) {
+      callback(Result.success(Unit))
+    } else {
+      val pigeon_identifierArg =
+          pigeonRegistrar.instanceManager.addHostCreatedInstance(pigeon_instanceArg)
+      val binaryMessenger = pigeonRegistrar.binaryMessenger
+      val codec = pigeonRegistrar.codec
+      val channelName =
+          "dev.flutter.pigeon.webview_flutter_android.WebSettingsCompat.pigeon_newInstance"
+      val channel = BasicMessageChannel<Any?>(binaryMessenger, channelName, codec)
+      channel.send(listOf(pigeon_identifierArg)) {
+        if (it is List<*>) {
+          if (it.size > 1) {
+            callback(
+                Result.failure(
+                    AndroidWebKitError(it[0] as String, it[1] as String, it[2] as String?)))
+          } else {
+            callback(Result.success(Unit))
+          }
+        } else {
+          callback(
+              Result.failure(AndroidWebkitLibraryPigeonUtils.createConnectionError(channelName)))
+        }
+      }
+    }
+  }
+}
+/**
+ * Utility class for checking which WebView Support Library features are supported on the device.
+ *
+ * See https://developer.android.com/reference/kotlin/androidx/webkit/WebViewFeature.
+ */
+@Suppress("UNCHECKED_CAST")
+abstract class PigeonApiWebViewFeature(
+    open val pigeonRegistrar: AndroidWebkitLibraryPigeonProxyApiRegistrar
+) {
+  abstract fun isFeatureSupported(feature: String): Boolean
+
+  companion object {
+    @Suppress("LocalVariableName")
+    fun setUpMessageHandlers(binaryMessenger: BinaryMessenger, api: PigeonApiWebViewFeature?) {
+      val codec = api?.pigeonRegistrar?.codec ?: AndroidWebkitLibraryPigeonCodec()
+      run {
+        val channel =
+            BasicMessageChannel<Any?>(
+                binaryMessenger,
+                "dev.flutter.pigeon.webview_flutter_android.WebViewFeature.isFeatureSupported",
+                codec)
+        if (api != null) {
+          channel.setMessageHandler { message, reply ->
+            val args = message as List<Any?>
+            val featureArg = args[0] as String
+            val wrapped: List<Any?> =
+                try {
+                  listOf(api.isFeatureSupported(featureArg))
+                } catch (exception: Throwable) {
+                  AndroidWebkitLibraryPigeonUtils.wrapError(exception)
+                }
+            reply.reply(wrapped)
+          }
+        } else {
+          channel.setMessageHandler(null)
+        }
+      }
+    }
+  }
+
+  @Suppress("LocalVariableName", "FunctionName")
+  /** Creates a Dart instance of WebViewFeature and attaches it to [pigeon_instanceArg]. */
+  fun pigeon_newInstance(
+      pigeon_instanceArg: androidx.webkit.WebViewFeature,
+      callback: (Result<Unit>) -> Unit
+  ) {
+    if (pigeonRegistrar.ignoreCallsToDart) {
+      callback(
+          Result.failure(
+              AndroidWebKitError("ignore-calls-error", "Calls to Dart are being ignored.", "")))
+    } else if (pigeonRegistrar.instanceManager.containsInstance(pigeon_instanceArg)) {
+      callback(Result.success(Unit))
+    } else {
+      val pigeon_identifierArg =
+          pigeonRegistrar.instanceManager.addHostCreatedInstance(pigeon_instanceArg)
+      val binaryMessenger = pigeonRegistrar.binaryMessenger
+      val codec = pigeonRegistrar.codec
+      val channelName =
+          "dev.flutter.pigeon.webview_flutter_android.WebViewFeature.pigeon_newInstance"
+      val channel = BasicMessageChannel<Any?>(binaryMessenger, channelName, codec)
+      channel.send(listOf(pigeon_identifierArg)) {
+        if (it is List<*>) {
+          if (it.size > 1) {
+            callback(
+                Result.failure(
+                    AndroidWebKitError(it[0] as String, it[1] as String, it[2] as String?)))
+          } else {
+            callback(Result.success(Unit))
+          }
+        } else {
+          callback(
+              Result.failure(AndroidWebkitLibraryPigeonUtils.createConnectionError(channelName)))
+        }
+      }
+    }
+  }
+}

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

@@ -251,4 +251,16 @@ public void setContext(@NonNull Context context) {
   public FlutterAssetManager getFlutterAssetManager() {
     return flutterAssetManager;
   }
+
+  @NonNull
+  @Override
+  public PigeonApiWebViewFeature getPigeonApiWebViewFeature() {
+    return new WebViewFeatureProxyApi(this);
+  }
+
+  @NonNull
+  @Override
+  public PigeonApiWebSettingsCompat getPigeonApiWebSettingsCompat() {
+    return new WebSettingsCompatProxyApi(this);
+  }
 }

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

@@ -0,0 +1,32 @@
+// 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.annotation.SuppressLint;
+import android.webkit.WebSettings;
+import androidx.annotation.NonNull;
+import androidx.webkit.WebSettingsCompat;
+
+/**
+ * Proxy API implementation for {@link WebSettingsCompat}.
+ *
+ * <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 WebSettingsCompatProxyApi extends PigeonApiWebSettingsCompat {
+  public WebSettingsCompatProxyApi(@NonNull ProxyApiRegistrar pigeonRegistrar) {
+    super(pigeonRegistrar);
+  }
+
+  /**
+   * This method should only be called if {@link WebViewFeatureProxyApi#isFeatureSupported(String)}
+   * with PAYMENT_REQUEST returns true.
+   */
+  @SuppressLint("RequiresFeature")
+  @Override
+  public void setPaymentRequestEnabled(@NonNull WebSettings webSettings, boolean enabled) {
+    WebSettingsCompat.setPaymentRequestEnabled(webSettings, enabled);
+  }
+}

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

@@ -0,0 +1,25 @@
+// 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 androidx.annotation.NonNull;
+import androidx.webkit.WebViewFeature;
+
+/**
+ * Proxy API implementation for {@link WebViewFeature}.
+ *
+ * <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 WebViewFeatureProxyApi extends PigeonApiWebViewFeature {
+  public WebViewFeatureProxyApi(@NonNull ProxyApiRegistrar pigeonRegistrar) {
+    super(pigeonRegistrar);
+  }
+
+  @Override
+  public boolean isFeatureSupported(@NonNull String feature) {
+    return WebViewFeature.isFeatureSupported(feature);
+  }
+}

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

@@ -0,0 +1,39 @@
+// 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.fail;
+import static org.mockito.Mockito.mock;
+import static org.mockito.Mockito.mockStatic;
+
+import android.webkit.WebSettings;
+import androidx.webkit.WebSettingsCompat;
+import androidx.webkit.WebViewFeature;
+import org.junit.Test;
+import org.mockito.MockedStatic;
+
+public class WebSettingsCompatTest {
+  @Test
+  public void setPaymentRequestEnabled() {
+    final PigeonApiWebSettingsCompat api =
+        new TestProxyApiRegistrar().getPigeonApiWebSettingsCompat();
+
+    final WebSettings webSettings = mock(WebSettings.class);
+
+    try (MockedStatic<WebSettingsCompat> mockedStatic = mockStatic(WebSettingsCompat.class)) {
+      try (MockedStatic<WebViewFeature> mockedWebViewFeature = mockStatic(WebViewFeature.class)) {
+        mockedWebViewFeature
+            .when(() -> WebViewFeature.isFeatureSupported(WebViewFeature.PAYMENT_REQUEST))
+            .thenReturn(true);
+        api.setPaymentRequestEnabled(webSettings, true);
+        mockedStatic.verify(() -> WebSettingsCompat.setPaymentRequestEnabled(webSettings, true));
+      } catch (Exception e) {
+        fail(e.toString());
+      }
+    } catch (Exception e) {
+      fail(e.toString());
+    }
+  }
+}