[camera] Fix exception in registerWith (#6009)
Fixes a regression from an unintented change in behavior during the
conversion to an in-app method channel for Android and iOS. Although the
Dart code for their implementations is almost identical to the shared
method channel version, the differences in initialization paths caused
the platform versions to try to use the widget bindings before they had
been set up: The constructor for a `dartPluginClass` is called during
`registerWith`, which is before `main`, but the constructor for the
default implementation isn't called until `CameraPlatform.instance` is
called, since Dart automatically does lazy static class initializtion.
To avoid the issue without forcing bindings to be initialized early,
this makes setting up the platform channel listener lazily.
Fixes https://github.com/flutter/flutter/issues/106236
diff --git a/packages/camera/camera_android/CHANGELOG.md b/packages/camera/camera_android/CHANGELOG.md
index eab03e8..e9972ae 100644
--- a/packages/camera/camera_android/CHANGELOG.md
+++ b/packages/camera/camera_android/CHANGELOG.md
@@ -1,3 +1,7 @@
+## 0.9.8+2
+
+* Fixes exception in registerWith caused by the switch to an in-package method channel.
+
## 0.9.8+1
* Ignores deprecation warnings for upcoming styleFrom button API changes.
diff --git a/packages/camera/camera_android/lib/src/android_camera.dart b/packages/camera/camera_android/lib/src/android_camera.dart
index 5fb3443..db6264c 100644
--- a/packages/camera/camera_android/lib/src/android_camera.dart
+++ b/packages/camera/camera_android/lib/src/android_camera.dart
@@ -19,14 +19,6 @@
/// The Android implementation of [CameraPlatform] that uses method channels.
class AndroidCamera extends CameraPlatform {
- /// Construct a new method channel camera instance.
- AndroidCamera() {
- const MethodChannel channel =
- MethodChannel('plugins.flutter.io/camera_android/fromPlatform');
- channel.setMethodCallHandler(
- (MethodCall call) => handleDeviceMethodCall(call));
- }
-
/// Registers this class as the default instance of [CameraPlatform].
static void registerWith() {
CameraPlatform.instance = AndroidCamera();
@@ -34,6 +26,12 @@
final Map<int, MethodChannel> _channels = <int, MethodChannel>{};
+ /// The name of the channel that device events from the platform side are
+ /// sent on.
+ @visibleForTesting
+ static const String deviceEventChannelName =
+ 'plugins.flutter.io/camera_android/fromPlatform';
+
/// The controller we need to broadcast the different events coming
/// from handleMethodCall, specific to camera events.
///
@@ -50,11 +48,15 @@
///
/// It is a `broadcast` because multiple controllers will connect to
/// different stream views of this Controller.
- /// This is only exposed for test purposes. It shouldn't be used by clients of
- /// the plugin as it may break or change at any time.
- @visibleForTesting
- final StreamController<DeviceEvent> deviceEventStreamController =
- StreamController<DeviceEvent>.broadcast();
+ late final StreamController<DeviceEvent> _deviceEventStreamController =
+ _createDeviceEventStreamController();
+
+ StreamController<DeviceEvent> _createDeviceEventStreamController() {
+ // Set up the method handler lazily.
+ const MethodChannel channel = MethodChannel(deviceEventChannelName);
+ channel.setMethodCallHandler(_handleDeviceMethodCall);
+ return StreamController<DeviceEvent>.broadcast();
+ }
// The stream to receive frames from the native code.
StreamSubscription<dynamic>? _platformImageStreamSubscription;
@@ -192,7 +194,7 @@
@override
Stream<DeviceOrientationChangedEvent> onDeviceOrientationChanged() {
- return deviceEventStreamController.stream
+ return _deviceEventStreamController.stream
.whereType<DeviceOrientationChangedEvent>();
}
@@ -518,14 +520,10 @@
}
/// Converts messages received from the native platform into device events.
- ///
- /// This is only exposed for test purposes. It shouldn't be used by clients of
- /// the plugin as it may break or change at any time.
- @visibleForTesting
- Future<dynamic> handleDeviceMethodCall(MethodCall call) async {
+ Future<dynamic> _handleDeviceMethodCall(MethodCall call) async {
switch (call.method) {
case 'orientation_changed':
- deviceEventStreamController.add(DeviceOrientationChangedEvent(
+ _deviceEventStreamController.add(DeviceOrientationChangedEvent(
deserializeDeviceOrientation(
call.arguments['orientation']! as String)));
break;
diff --git a/packages/camera/camera_android/pubspec.yaml b/packages/camera/camera_android/pubspec.yaml
index eca2b53..7d93ecb 100644
--- a/packages/camera/camera_android/pubspec.yaml
+++ b/packages/camera/camera_android/pubspec.yaml
@@ -2,7 +2,7 @@
description: Android implementation of the camera plugin.
repository: https://github.com/flutter/plugins/tree/main/packages/camera/camera_android
issue_tracker: https://github.com/flutter/flutter/issues?q=is%3Aissue+is%3Aopen+label%3A%22p%3A+camera%22
-version: 0.9.8+1
+version: 0.9.8+2
environment:
sdk: ">=2.14.0 <3.0.0"
diff --git a/packages/camera/camera_android/test/android_camera_test.dart b/packages/camera/camera_android/test/android_camera_test.dart
index 9674b0c..ca1f245 100644
--- a/packages/camera/camera_android/test/android_camera_test.dart
+++ b/packages/camera/camera_android/test/android_camera_test.dart
@@ -25,6 +25,24 @@
expect(CameraPlatform.instance, isA<AndroidCamera>());
});
+ test('registration does not set message handlers', () async {
+ AndroidCamera.registerWith();
+
+ // Setting up a handler requires bindings to be initialized, and since
+ // registerWith is called very early in initialization the bindings won't
+ // have been initialized. While registerWith could intialize them, that
+ // could slow down startup, so instead the handler should be set up lazily.
+ final ByteData? response = await TestDefaultBinaryMessengerBinding
+ .instance!.defaultBinaryMessenger
+ .handlePlatformMessage(
+ AndroidCamera.deviceEventChannelName,
+ const StandardMethodCodec().encodeMethodCall(const MethodCall(
+ 'orientation_changed',
+ <String, Object>{'orientation': 'portraitDown'})),
+ (ByteData? data) {});
+ expect(response, null);
+ });
+
group('Creation, Initialization & Disposal Tests', () {
test('Should send creation data and receive back a camera id', () async {
// Arrange
@@ -402,12 +420,14 @@
// Emit test events
const DeviceOrientationChangedEvent event =
DeviceOrientationChangedEvent(DeviceOrientation.portraitUp);
- await camera.handleDeviceMethodCall(
- MethodCall('orientation_changed', event.toJson()));
- await camera.handleDeviceMethodCall(
- MethodCall('orientation_changed', event.toJson()));
- await camera.handleDeviceMethodCall(
- MethodCall('orientation_changed', event.toJson()));
+ for (int i = 0; i < 3; i++) {
+ await TestDefaultBinaryMessengerBinding.instance!.defaultBinaryMessenger
+ .handlePlatformMessage(
+ AndroidCamera.deviceEventChannelName,
+ const StandardMethodCodec().encodeMethodCall(
+ MethodCall('orientation_changed', event.toJson())),
+ null);
+ }
// Assert
expect(await streamQueue.next, event);
diff --git a/packages/camera/camera_avfoundation/CHANGELOG.md b/packages/camera/camera_avfoundation/CHANGELOG.md
index eab03e8..e9972ae 100644
--- a/packages/camera/camera_avfoundation/CHANGELOG.md
+++ b/packages/camera/camera_avfoundation/CHANGELOG.md
@@ -1,3 +1,7 @@
+## 0.9.8+2
+
+* Fixes exception in registerWith caused by the switch to an in-package method channel.
+
## 0.9.8+1
* Ignores deprecation warnings for upcoming styleFrom button API changes.
diff --git a/packages/camera/camera_avfoundation/lib/src/avfoundation_camera.dart b/packages/camera/camera_avfoundation/lib/src/avfoundation_camera.dart
index 1bff901..c75d41f 100644
--- a/packages/camera/camera_avfoundation/lib/src/avfoundation_camera.dart
+++ b/packages/camera/camera_avfoundation/lib/src/avfoundation_camera.dart
@@ -19,14 +19,6 @@
/// An iOS implementation of [CameraPlatform] based on AVFoundation.
class AVFoundationCamera extends CameraPlatform {
- /// Construct a new method channel camera instance.
- AVFoundationCamera() {
- const MethodChannel channel =
- MethodChannel('plugins.flutter.io/camera_avfoundation/fromPlatform');
- channel.setMethodCallHandler(
- (MethodCall call) => handleDeviceMethodCall(call));
- }
-
/// Registers this class as the default instance of [CameraPlatform].
static void registerWith() {
CameraPlatform.instance = AVFoundationCamera();
@@ -34,6 +26,12 @@
final Map<int, MethodChannel> _channels = <int, MethodChannel>{};
+ /// The name of the channel that device events from the platform side are
+ /// sent on.
+ @visibleForTesting
+ static const String deviceEventChannelName =
+ 'plugins.flutter.io/camera_avfoundation/fromPlatform';
+
/// The controller we need to broadcast the different events coming
/// from handleMethodCall, specific to camera events.
///
@@ -50,11 +48,15 @@
///
/// It is a `broadcast` because multiple controllers will connect to
/// different stream views of this Controller.
- /// This is only exposed for test purposes. It shouldn't be used by clients of
- /// the plugin as it may break or change at any time.
- @visibleForTesting
- final StreamController<DeviceEvent> deviceEventStreamController =
- StreamController<DeviceEvent>.broadcast();
+ late final StreamController<DeviceEvent> _deviceEventStreamController =
+ _createDeviceEventStreamController();
+
+ StreamController<DeviceEvent> _createDeviceEventStreamController() {
+ // Set up the method handler lazily.
+ const MethodChannel channel = MethodChannel(deviceEventChannelName);
+ channel.setMethodCallHandler(_handleDeviceMethodCall);
+ return StreamController<DeviceEvent>.broadcast();
+ }
// The stream to receive frames from the native code.
StreamSubscription<dynamic>? _platformImageStreamSubscription;
@@ -192,7 +194,7 @@
@override
Stream<DeviceOrientationChangedEvent> onDeviceOrientationChanged() {
- return deviceEventStreamController.stream
+ return _deviceEventStreamController.stream
.whereType<DeviceOrientationChangedEvent>();
}
@@ -523,14 +525,10 @@
}
/// Converts messages received from the native platform into device events.
- ///
- /// This is only exposed for test purposes. It shouldn't be used by clients of
- /// the plugin as it may break or change at any time.
- @visibleForTesting
- Future<dynamic> handleDeviceMethodCall(MethodCall call) async {
+ Future<dynamic> _handleDeviceMethodCall(MethodCall call) async {
switch (call.method) {
case 'orientation_changed':
- deviceEventStreamController.add(DeviceOrientationChangedEvent(
+ _deviceEventStreamController.add(DeviceOrientationChangedEvent(
deserializeDeviceOrientation(
call.arguments['orientation']! as String)));
break;
diff --git a/packages/camera/camera_avfoundation/pubspec.yaml b/packages/camera/camera_avfoundation/pubspec.yaml
index f1a5edf..adb0bf8 100644
--- a/packages/camera/camera_avfoundation/pubspec.yaml
+++ b/packages/camera/camera_avfoundation/pubspec.yaml
@@ -2,7 +2,7 @@
description: iOS implementation of the camera plugin.
repository: https://github.com/flutter/plugins/tree/main/packages/camera/camera_avfoundation
issue_tracker: https://github.com/flutter/flutter/issues?q=is%3Aissue+is%3Aopen+label%3A%22p%3A+camera%22
-version: 0.9.8+1
+version: 0.9.8+2
environment:
sdk: ">=2.14.0 <3.0.0"
diff --git a/packages/camera/camera_avfoundation/test/avfoundation_camera_test.dart b/packages/camera/camera_avfoundation/test/avfoundation_camera_test.dart
index 4b32d2e..67adcfa 100644
--- a/packages/camera/camera_avfoundation/test/avfoundation_camera_test.dart
+++ b/packages/camera/camera_avfoundation/test/avfoundation_camera_test.dart
@@ -25,6 +25,24 @@
expect(CameraPlatform.instance, isA<AVFoundationCamera>());
});
+ test('registration does not set message handlers', () async {
+ AVFoundationCamera.registerWith();
+
+ // Setting up a handler requires bindings to be initialized, and since
+ // registerWith is called very early in initialization the bindings won't
+ // have been initialized. While registerWith could intialize them, that
+ // could slow down startup, so instead the handler should be set up lazily.
+ final ByteData? response = await TestDefaultBinaryMessengerBinding
+ .instance!.defaultBinaryMessenger
+ .handlePlatformMessage(
+ AVFoundationCamera.deviceEventChannelName,
+ const StandardMethodCodec().encodeMethodCall(const MethodCall(
+ 'orientation_changed',
+ <String, Object>{'orientation': 'portraitDown'})),
+ (ByteData? data) {});
+ expect(response, null);
+ });
+
group('Creation, Initialization & Disposal Tests', () {
test('Should send creation data and receive back a camera id', () async {
// Arrange
@@ -402,12 +420,14 @@
// Emit test events
const DeviceOrientationChangedEvent event =
DeviceOrientationChangedEvent(DeviceOrientation.portraitUp);
- await camera.handleDeviceMethodCall(
- MethodCall('orientation_changed', event.toJson()));
- await camera.handleDeviceMethodCall(
- MethodCall('orientation_changed', event.toJson()));
- await camera.handleDeviceMethodCall(
- MethodCall('orientation_changed', event.toJson()));
+ for (int i = 0; i < 3; i++) {
+ await TestDefaultBinaryMessengerBinding.instance!.defaultBinaryMessenger
+ .handlePlatformMessage(
+ AVFoundationCamera.deviceEventChannelName,
+ const StandardMethodCodec().encodeMethodCall(
+ MethodCall('orientation_changed', event.toJson())),
+ null);
+ }
// Assert
expect(await streamQueue.next, event);
