[camera] availableCameras() implementation for CameraX re-write

packages/camera/camera_android_camerax/CHANGELOG.md

@@ -9,3 +9,4 @@
 * Bump CameraX version to 1.3.0-alpha03 and Kotlin version to 1.8.0.
 * Changes instance manager to allow the separate creation of identical objects.
 * Adds Preview and Surface classes, along with other methods needed to implement camera preview.
+* Adds implementation of availableCameras()

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

@@ -55,14 +55,9 @@ public List<Long> filter(@NonNull Long identifier, @NonNull List<Long> cameraInf
     }
 
     List<CameraInfo> filteredCameraInfos = cameraSelector.filter(cameraInfosForFilter);
-    final CameraInfoFlutterApiImpl cameraInfoFlutterApiImpl =
-        new CameraInfoFlutterApiImpl(binaryMessenger, instanceManager);
     List<Long> filteredCameraInfosIds = new ArrayList<Long>();
 
     for (CameraInfo cameraInfo : filteredCameraInfos) {
-      if (!instanceManager.containsInstance(cameraInfo)) {
-        cameraInfoFlutterApiImpl.create(cameraInfo, result -> {});
-      }
       Long filteredCameraInfoId = instanceManager.getIdentifierForStrongReference(cameraInfo);
       filteredCameraInfosIds.add(filteredCameraInfoId);
     }

packages/camera/camera_android_camerax/lib/src/android_camera_camerax.dart

@@ -5,6 +5,11 @@
 import 'dart:async';
 
 import 'package:camera_platform_interface/camera_platform_interface.dart';
+import 'package:flutter/foundation.dart';
+
+import 'camera_info.dart';
+import 'camera_selector.dart';
+import 'process_camera_provider.dart';
 
 /// The Android implementation of [CameraPlatform] that uses the CameraX library.
 class AndroidCameraCameraX extends CameraPlatform {
@@ -13,9 +18,56 @@ class AndroidCameraCameraX extends CameraPlatform {
     CameraPlatform.instance = AndroidCameraCameraX();
   }
 
+  /// ProcessCameraProvider used to get list of cameras. Visible only for testing.
+  @visibleForTesting
+  ProcessCameraProvider? processCameraProvider;
+
+  /// Camera selector used to determine which CameraInfos are back cameras.
+  @visibleForTesting
+  CameraSelector? backCameraSelector = CameraSelector.getDefaultBackCamera();
+
+  /// Camera selector used to determine which CameraInfos are back cameras.
+  @visibleForTesting
+  CameraSelector? frontCameraSelector = CameraSelector.getDefaultFrontCamera();
+
   /// Returns list of all available cameras and their descriptions.
   @override
   Future<List<CameraDescription>> availableCameras() async {
-    throw UnimplementedError('availableCameras() is not implemented.');
+    final List<CameraDescription> cameraDescriptions = <CameraDescription>[];
+
+    processCameraProvider ??= await ProcessCameraProvider.getInstance();
+    final List<CameraInfo> cameraInfos =
+        await processCameraProvider!.getAvailableCameraInfos();
+
+    CameraLensDirection? cameraLensDirection;
+    int cameraCount = 0;
+    int? cameraSensorOrientation;
+    String? cameraName;
+
+    for (final CameraInfo cameraInfo in cameraInfos) {
+      // Determine the lens direction by filtering the CameraInfo
+      // TODO(gmackall): replace this with call to CameraInfo.getLensFacing when changes containing that method are available
+      if ((await backCameraSelector!.filter(<CameraInfo>[cameraInfo]))
+          .isNotEmpty) {
+        cameraLensDirection = CameraLensDirection.back;
+      } else if ((await frontCameraSelector!.filter(<CameraInfo>[cameraInfo]))
+          .isNotEmpty) {
+        cameraLensDirection = CameraLensDirection.front;
+      } else {
+        //Skip this CameraInfo as its lens direction is unknown
+        continue;
+      }
+
+      cameraSensorOrientation = await cameraInfo.getSensorRotationDegrees();
+      cameraName = 'Camera $cameraCount';
+      cameraCount++;
+
+      cameraDescriptions.add(CameraDescription(
+          name: cameraName,
+          lensDirection: cameraLensDirection,
+          sensorOrientation: cameraSensorOrientation));
+    }
+
+    return cameraDescriptions;
   }
 }

packages/camera/camera_android_camerax/test/android_camera_camerax_test.dart

@@ -0,0 +1,88 @@
+// 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.
+
+import 'package:camera_android_camerax/camera_android_camerax.dart';
+import 'package:camera_android_camerax/src/camera_info.dart';
+import 'package:camera_android_camerax/src/camera_selector.dart';
+import 'package:camera_android_camerax/src/process_camera_provider.dart';
+import 'package:camera_platform_interface/camera_platform_interface.dart';
+import 'package:flutter_test/flutter_test.dart';
+import 'package:mockito/annotations.dart';
+import 'package:mockito/mockito.dart';
+
+import 'android_camera_camerax_test.mocks.dart';
+
+@GenerateMocks(<Type>[
+  ProcessCameraProvider,
+  CameraSelector,
+  CameraInfo,
+])
+void main() {
+  TestWidgetsFlutterBinding.ensureInitialized();
+
+  test('Should fetch CameraDescription instances for available cameras',
+      () async {
+    // Arrange
+    final List<dynamic> returnData = <dynamic>[
+      <String, dynamic>{
+        'name': 'Camera 0',
+        'lensFacing': 'back',
+        'sensorOrientation': 0
+      },
+      <String, dynamic>{
+        'name': 'Camera 1',
+        'lensFacing': 'front',
+        'sensorOrientation': 90
+      }
+    ];
+
+    //Create mocks to use
+    final MockProcessCameraProvider mockProcessCameraProvider =
+        MockProcessCameraProvider();
+    final MockCameraSelector mockBackCameraSelector = MockCameraSelector();
+    final MockCameraSelector mockFrontCameraSelector = MockCameraSelector();
+    final MockCameraInfo mockFrontCameraInfo = MockCameraInfo();
+    final MockCameraInfo mockBackCameraInfo = MockCameraInfo();
+    AndroidCameraCameraX.registerWith();
+
+    //Set class level ProcessCameraProvider and camera selectors to created mocks
+    final AndroidCameraCameraX androidCameraCamerax = AndroidCameraCameraX();
+    androidCameraCamerax.backCameraSelector = mockBackCameraSelector;
+    androidCameraCamerax.frontCameraSelector = mockFrontCameraSelector;
+    androidCameraCamerax.processCameraProvider = mockProcessCameraProvider;
+
+    //Mock calls to native platform
+    when(mockProcessCameraProvider.getAvailableCameraInfos()).thenAnswer(
+        (_) async => <MockCameraInfo>[mockBackCameraInfo, mockFrontCameraInfo]);
+    when(mockBackCameraSelector.filter(<MockCameraInfo>[mockFrontCameraInfo]))
+        .thenAnswer((_) async => <MockCameraInfo>[]);
+    when(mockBackCameraSelector.filter(<MockCameraInfo>[mockBackCameraInfo]))
+        .thenAnswer((_) async => <MockCameraInfo>[mockBackCameraInfo]);
+    when(mockFrontCameraSelector.filter(<MockCameraInfo>[mockBackCameraInfo]))
+        .thenAnswer((_) async => <MockCameraInfo>[]);
+    when(mockFrontCameraSelector.filter(<MockCameraInfo>[mockFrontCameraInfo]))
+        .thenAnswer((_) async => <MockCameraInfo>[mockFrontCameraInfo]);
+    when(mockBackCameraInfo.getSensorRotationDegrees())
+        .thenAnswer((_) async => 0);
+    when(mockFrontCameraInfo.getSensorRotationDegrees())
+        .thenAnswer((_) async => 90);
+
+    final List<CameraDescription> cameraDescriptions =
+        await androidCameraCamerax.availableCameras();
+
+    expect(cameraDescriptions.length, returnData.length);
+    for (int i = 0; i < returnData.length; i++) {
+      final Map<String, Object?> typedData =
+          (returnData[i] as Map<dynamic, dynamic>).cast<String, Object?>();
+      final CameraDescription cameraDescription = CameraDescription(
+        name: typedData['name']! as String,
+        lensDirection: (typedData['lensFacing']! as String) == 'front'
+            ? CameraLensDirection.front
+            : CameraLensDirection.back,
+        sensorOrientation: typedData['sensorOrientation']! as int,
+      );
+      expect(cameraDescriptions[i], cameraDescription);
+    }
+  });
+}

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

@@ -0,0 +1,79 @@
+// Mocks generated by Mockito 5.3.2 from annotations
+// in camera_android_camerax/test/android_camera_camerax_test.dart.
+// Do not manually edit this file.
+
+// ignore_for_file: no_leading_underscores_for_library_prefixes
+import 'dart:async' as _i3;
+
+import 'package:camera_android_camerax/src/camera_info.dart' as _i4;
+import 'package:camera_android_camerax/src/camera_selector.dart' as _i5;
+import 'package:camera_android_camerax/src/process_camera_provider.dart' as _i2;
+import 'package:mockito/mockito.dart' as _i1;
+
+// 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 [ProcessCameraProvider].
+///
+/// See the documentation for Mockito's code generation for more information.
+class MockProcessCameraProvider extends _i1.Mock
+    implements _i2.ProcessCameraProvider {
+  MockProcessCameraProvider() {
+    _i1.throwOnMissingStub(this);
+  }
+
+  @override
+  _i3.Future<List<_i4.CameraInfo>> getAvailableCameraInfos() =>
+      (super.noSuchMethod(
+        Invocation.method(
+          #getAvailableCameraInfos,
+          [],
+        ),
+        returnValue: _i3.Future<List<_i4.CameraInfo>>.value(<_i4.CameraInfo>[]),
+      ) as _i3.Future<List<_i4.CameraInfo>>);
+}
+
+/// A class which mocks [CameraSelector].
+///
+/// See the documentation for Mockito's code generation for more information.
+class MockCameraSelector extends _i1.Mock implements _i5.CameraSelector {
+  MockCameraSelector() {
+    _i1.throwOnMissingStub(this);
+  }
+
+  @override
+  _i3.Future<List<_i4.CameraInfo>> filter(List<_i4.CameraInfo>? cameraInfos) =>
+      (super.noSuchMethod(
+        Invocation.method(
+          #filter,
+          [cameraInfos],
+        ),
+        returnValue: _i3.Future<List<_i4.CameraInfo>>.value(<_i4.CameraInfo>[]),
+      ) as _i3.Future<List<_i4.CameraInfo>>);
+}
+
+/// A class which mocks [CameraInfo].
+///
+/// See the documentation for Mockito's code generation for more information.
+class MockCameraInfo extends _i1.Mock implements _i4.CameraInfo {
+  MockCameraInfo() {
+    _i1.throwOnMissingStub(this);
+  }
+
+  @override
+  _i3.Future<int> getSensorRotationDegrees() => (super.noSuchMethod(
+        Invocation.method(
+          #getSensorRotationDegrees,
+          [],
+        ),
+        returnValue: _i3.Future<int>.value(0),
+      ) as _i3.Future<int>);
+}