[camerax] Add LifecycleOwner Proxy

packages/camera/camera_android_camerax/android/src/main/java/io/flutter/plugins/camerax/CameraAndroidCameraxPlugin.java

@@ -4,6 +4,7 @@
 
 package io.flutter.plugins.camerax;
 
+import android.app.Activity;
 import android.content.Context;
 import androidx.annotation.NonNull;
 import androidx.lifecycle.LifecycleOwner;
@@ -79,9 +80,17 @@ public void onAttachedToActivity(@NonNull ActivityPluginBinding activityPluginBi
         pluginBinding.getApplicationContext(),
         pluginBinding.getTextureRegistry());
     updateContext(pluginBinding.getApplicationContext());
-    processCameraProviderHostApi.setLifecycleOwner(
-        (LifecycleOwner) activityPluginBinding.getActivity());
-    systemServicesHostApi.setActivity(activityPluginBinding.getActivity());
+
+    Activity activity = activityPluginBinding.getActivity();
+
+    if (activity instanceof LifecycleOwner) {
+      processCameraProviderHostApi.setLifecycleOwner((LifecycleOwner) activity);
+    } else {
+      ProxyLifecycleProvider proxyLifecycleProvider = new ProxyLifecycleProvider(activity);
+      processCameraProviderHostApi.setLifecycleOwner(proxyLifecycleProvider);
+    }
+
+    systemServicesHostApi.setActivity(activity);
     systemServicesHostApi.setPermissionsRegistry(
         activityPluginBinding::addRequestPermissionsResultListener);
   }

packages/camera/camera_android_camerax/android/src/main/java/io/flutter/plugins/camerax/ProxyLifecycleProvider.java

@@ -0,0 +1,90 @@
+// 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.camerax;
+
+import android.app.Activity;
+import android.app.Application.ActivityLifecycleCallbacks;
+import android.os.Bundle;
+import androidx.annotation.NonNull;
+import androidx.annotation.VisibleForTesting;
+import androidx.lifecycle.Lifecycle;
+import androidx.lifecycle.Lifecycle.Event;
+import androidx.lifecycle.LifecycleOwner;
+import androidx.lifecycle.LifecycleRegistry;
+
+/**
+ * This class provides a custom {@link LifecycleOwner} for the activity driven by {@link
+ * ActivityLifecycleCallbacks}.
+ *
+ * <p>This is used in the case where a direct {@link LifecycleOwner} is not available.
+ */
+public class ProxyLifecycleProvider implements ActivityLifecycleCallbacks, LifecycleOwner {
+
+  @VisibleForTesting @NonNull public LifecycleRegistry lifecycle = new LifecycleRegistry(this);
+  private final int registrarActivityHashCode;
+
+  ProxyLifecycleProvider(@NonNull Activity activity) {
+    this.registrarActivityHashCode = activity.hashCode();
+    activity.getApplication().registerActivityLifecycleCallbacks(this);
+  }
+
+  @Override
+  public void onActivityCreated(@NonNull Activity activity, @NonNull Bundle savedInstanceState) {
+    if (activity.hashCode() != registrarActivityHashCode) {
+      return;
+    }
+    lifecycle.handleLifecycleEvent(Event.ON_CREATE);
+  }
+
+  @Override
+  public void onActivityStarted(@NonNull Activity activity) {
+    if (activity.hashCode() != registrarActivityHashCode) {
+      return;
+    }
+    lifecycle.handleLifecycleEvent(Event.ON_START);
+  }
+
+  @Override
+  public void onActivityResumed(@NonNull Activity activity) {
+    if (activity.hashCode() != registrarActivityHashCode) {
+      return;
+    }
+    lifecycle.handleLifecycleEvent(Event.ON_RESUME);
+  }
+
+  @Override
+  public void onActivityPaused(@NonNull Activity activity) {
+    if (activity.hashCode() != registrarActivityHashCode) {
+      return;
+    }
+    lifecycle.handleLifecycleEvent(Event.ON_PAUSE);
+  }
+
+  @Override
+  public void onActivityStopped(@NonNull Activity activity) {
+    if (activity.hashCode() != registrarActivityHashCode) {
+      return;
+    }
+    lifecycle.handleLifecycleEvent(Event.ON_STOP);
+  }
+
+  @Override
+  public void onActivitySaveInstanceState(@NonNull Activity activity, @NonNull Bundle outState) {}
+
+  @Override
+  public void onActivityDestroyed(@NonNull Activity activity) {
+    if (activity.hashCode() != registrarActivityHashCode) {
+      return;
+    }
+    activity.getApplication().unregisterActivityLifecycleCallbacks(this);
+    lifecycle.handleLifecycleEvent(Event.ON_DESTROY);
+  }
+
+  @NonNull
+  @Override
+  public Lifecycle getLifecycle() {
+    return lifecycle;
+  }
+}

packages/camera/camera_android_camerax/android/src/test/java/io/flutter/plugins/camerax/ProxyLifecycleProviderTest.java

@@ -0,0 +1,121 @@
+// 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.camerax;
+
+import static org.junit.Assert.assertEquals;
+import static org.mockito.Mockito.mock;
+import static org.mockito.Mockito.verify;
+import static org.mockito.Mockito.verifyNoInteractions;
+import static org.mockito.Mockito.when;
+
+import android.app.Activity;
+import android.app.Application;
+import android.os.Bundle;
+import androidx.lifecycle.Lifecycle.Event;
+import androidx.lifecycle.LifecycleRegistry;
+import org.junit.Before;
+import org.junit.Rule;
+import org.junit.Test;
+import org.mockito.Mock;
+import org.mockito.junit.MockitoJUnit;
+import org.mockito.junit.MockitoRule;
+
+public class ProxyLifecycleProviderTest {
+  @Rule public MockitoRule mockitoRule = MockitoJUnit.rule();
+
+  @Mock Activity activity;
+  @Mock Application application;
+  @Mock LifecycleRegistry mockLifecycleRegistry;
+
+  private final int testHashCode = 27;
+
+  @Before
+  public void setUp() {
+    when(activity.getApplication()).thenReturn(application);
+  }
+
+  @Test
+  public void onActivityCreated_handlesOnCreateEvent() {
+    ProxyLifecycleProvider proxyLifecycleProvider = new ProxyLifecycleProvider(activity);
+    Bundle mockBundle = mock(Bundle.class);
+
+    proxyLifecycleProvider.lifecycle = mockLifecycleRegistry;
+
+    proxyLifecycleProvider.onActivityCreated(activity, mockBundle);
+
+    verify(mockLifecycleRegistry).handleLifecycleEvent(Event.ON_CREATE);
+  }
+
+  @Test
+  public void onActivityStarted_handlesOnActivityStartedEvent() {
+    ProxyLifecycleProvider proxyLifecycleProvider = new ProxyLifecycleProvider(activity);
+    proxyLifecycleProvider.lifecycle = mockLifecycleRegistry;
+
+    proxyLifecycleProvider.onActivityStarted(activity);
+
+    verify(mockLifecycleRegistry).handleLifecycleEvent(Event.ON_START);
+  }
+
+  @Test
+  public void onActivityResumed_handlesOnActivityResumedEvent() {
+    ProxyLifecycleProvider proxyLifecycleProvider = new ProxyLifecycleProvider(activity);
+    proxyLifecycleProvider.lifecycle = mockLifecycleRegistry;
+
+    proxyLifecycleProvider.onActivityResumed(activity);
+
+    verify(mockLifecycleRegistry).handleLifecycleEvent(Event.ON_RESUME);
+  }
+
+  @Test
+  public void onActivityPaused_handlesOnActivityPausedEvent() {
+    ProxyLifecycleProvider proxyLifecycleProvider = new ProxyLifecycleProvider(activity);
+    proxyLifecycleProvider.lifecycle = mockLifecycleRegistry;
+
+    proxyLifecycleProvider.onActivityPaused(activity);
+
+    verify(mockLifecycleRegistry).handleLifecycleEvent(Event.ON_PAUSE);
+  }
+
+  @Test
+  public void onActivityStopped_handlesOnActivityStoppedEvent() {
+    ProxyLifecycleProvider proxyLifecycleProvider = new ProxyLifecycleProvider(activity);
+    proxyLifecycleProvider.lifecycle = mockLifecycleRegistry;
+
+    proxyLifecycleProvider.onActivityStopped(activity);
+
+    verify(mockLifecycleRegistry).handleLifecycleEvent(Event.ON_STOP);
+  }
+
+  @Test
+  public void onActivityDestroyed_handlesOnActivityDestroyed() {
+    ProxyLifecycleProvider proxyLifecycleProvider = new ProxyLifecycleProvider(activity);
+    proxyLifecycleProvider.lifecycle = mockLifecycleRegistry;
+
+    proxyLifecycleProvider.onActivityDestroyed(activity);
+
+    verify(mockLifecycleRegistry).handleLifecycleEvent(Event.ON_DESTROY);
+  }
+
+  @Test
+  public void onActivitySaveInstanceState_doesNotHandleLifecycleEvvent() {
+    ProxyLifecycleProvider proxyLifecycleProvider = new ProxyLifecycleProvider(activity);
+    Bundle mockBundle = mock(Bundle.class);
+
+    proxyLifecycleProvider.lifecycle = mockLifecycleRegistry;
+
+    proxyLifecycleProvider.onActivitySaveInstanceState(activity, mockBundle);
+
+    verifyNoInteractions(mockLifecycleRegistry);
+  }
+
+  @Test
+  public void getLifecycle_returnsExpectedLifecycle() {
+    ProxyLifecycleProvider proxyLifecycleProvider = new ProxyLifecycleProvider(activity);
+
+    proxyLifecycleProvider.lifecycle = mockLifecycleRegistry;
+
+    assertEquals(proxyLifecycleProvider.getLifecycle(), mockLifecycleRegistry);
+  }
+}

packages/camera/camera_android_camerax/test/camera_test.dart

@@ -5,10 +5,18 @@
 import 'package:camera_android_camerax/src/camera.dart';
 import 'package:camera_android_camerax/src/instance_manager.dart';
 import 'package:flutter_test/flutter_test.dart';
+import 'package:mockito/annotations.dart';
 
+import 'camera_test.mocks.dart';
+import 'test_camerax_library.g.dart';
+
+@GenerateMocks(<Type>[TestInstanceManagerHostApi])
 void main() {
   TestWidgetsFlutterBinding.ensureInitialized();
 
+  // Mocks the call to clear the native InstanceManager.
+  TestInstanceManagerHostApi.setup(MockTestInstanceManagerHostApi());
+
   group('Camera', () {
     test('flutterApiCreateTest', () {
       final InstanceManager instanceManager = InstanceManager(

packages/camera/camera_android_camerax/test/camera_test.mocks.dart

@@ -0,0 +1,38 @@
+// Mocks generated by Mockito 5.4.0 from annotations
+// in camera_android_camerax/test/camera_test.dart.
+// Do not manually edit this file.
+
+// ignore_for_file: no_leading_underscores_for_library_prefixes
+import 'package:mockito/mockito.dart' as _i1;
+
+import 'test_camerax_library.g.dart' as _i2;
+
+// ignore_for_file: type=lint
+// ignore_for_file: avoid_redundant_argument_values
+// ignore_for_file: avoid_setters_without_getters
+// ignore_for_file: comment_references
+// ignore_for_file: implementation_imports
+// ignore_for_file: invalid_use_of_visible_for_testing_member
+// ignore_for_file: prefer_const_constructors
+// ignore_for_file: unnecessary_parenthesis
+// ignore_for_file: camel_case_types
+// ignore_for_file: subtype_of_sealed_class
+
+/// A class which mocks [TestInstanceManagerHostApi].
+///
+/// See the documentation for Mockito's code generation for more information.
+class MockTestInstanceManagerHostApi extends _i1.Mock
+    implements _i2.TestInstanceManagerHostApi {
+  MockTestInstanceManagerHostApi() {
+    _i1.throwOnMissingStub(this);
+  }
+
+  @override
+  void clear() => super.noSuchMethod(
+        Invocation.method(
+          #clear,
+          [],
+        ),
+        returnValueForMissingStub: null,
+      );
+}