使用Flutter WebRTC切换流似乎失败了

Question

我正在尝试使用Flutter WebRTC从前摄像头切换到后摄像头，但无法使其工作。

我有以下

// Stop the current stream and remove the tracks
await Future.forEach(videoStream!.getVideoTracks(), (MediaStreamTrack? track) async {
if (track != null) {
try {
await track.stop();
await videoStream!.removeTrack(track);
} catch (e) {
if (kDebugMode) {
print(e);
}
}
}
});
videoStream!.getVideoTracks().forEach((track) {
track.stop();
videoStream!.removeTrack(track, removeFromNative: true);
});
final mediaConstraints = {
'audio': false, // NO need to capture audio again
'video': {
'deviceId': videoInputDeviceId,
}
};
MediaStream newStream = await navigator.mediaDevices.getUserMedia(mediaConstraints);
final newTrack = newStream.getVideoTracks()[0];
await videoStream!.addTrack(newTrack, addToNative: true);

如果我在它们周围放置try catch，得到以下错误

flutter: PlatformException(mediaStreamRemoveTrack: Track is nil, null, null, null)
flutter: !--- Event: Failed to enable webcam
flutter: Concurrent modification during iteration: Instance(length:0) of '_GrowableList'.

Answer 1

我是这样做的:

MediaStream localStream;
if (localStream != null) {
await localStream!.getVideoTracks()[0].switchCamera();
}