ios - 具有多个方向问题的 AVCaptureSession

Question

我正在尝试实现条码扫描器。我有一个从 AVCaptureDevice 接收视频的 AVCaptureSession。我想支持所有方向。使用以下代码，当我运行该应用程序时，纵向方向一切正常。然而，在横向模式下， View 会旋转，但视频输入不会。所以我最终得到了一个 90 度旋转的视频。

当我实现 -(NSUInteger)supportedInterfaceOrientations 方法时，所有内容都被锁定到纵向位置。

谁能告诉我如何解决这个问题？

- (void)viewDidLoad
{
    [super viewDidLoad];
    // Do any additional setup after loading the view, typically from a nib.

    [self setupCaptureSession];

    _previewLayer.frame = _previewView.bounds;
    _previewView.center = self.view.center;
    _previewView.backgroundColor = [UIColor redColor];
    [_previewView.layer addSublayer:_previewLayer];

    [[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(applicationWillEnterForeground:) name:UIApplicationWillEnterForegroundNotification object:nil];

    [[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(applicationDidEnterBackground:) name:UIApplicationDidEnterBackgroundNotification object:nil];
}

- (void)didReceiveMemoryWarning
{
    [super didReceiveMemoryWarning];
    // Dispose of any resources that can be recreated.
}

-(void)viewDidAppear:(BOOL)animated
{
    [super viewDidAppear:animated];
    [self startRunning];
}

-(void)viewWillDisappear:(BOOL)animated
{
    [super viewWillDisappear:animated];
    [self stopRunning];
}

-(void) setupCaptureSession
{
    if (_captureSession)
        return;

    _videoDevice = [AVCaptureDevice defaultDeviceWithMediaType:AVMediaTypeVideo];

    if (!_videoDevice)
    {
        NSLog(@"No video camera on this device");
        return;
    }

    _captureSession = [[AVCaptureSession alloc]init];

    _videoInput = [[AVCaptureDeviceInput alloc]initWithDevice:_videoDevice error:nil];

    if ([_captureSession canAddInput:_videoInput])
    {
        [_captureSession addInput:_videoInput];
    }

    _previewLayer = [[AVCaptureVideoPreviewLayer alloc] initWithSession:_captureSession];

    _previewLayer.videoGravity = AVLayerVideoGravityResizeAspectFill;

}

-(void) startRunning
{
    if (_running)
        return;

    [_captureSession startRunning];
    _running = YES;
}

- (void) stopRunning
{
    if (!_running)
        return;

    [_captureSession stopRunning];
    _running = NO;
}

/*
-(NSUInteger)supportedInterfaceOrientations
{
    return UIInterfaceOrientationLandscapeLeft|UIInterfaceOrientationLandscapeRight|UIInterfaceOrientationPortrait|UIInterfaceOrientationPortraitUpsideDown;
}

*/

编辑:

我尝试了以下代码，但 previewLayer 方向仍然是倒置/横向。

    [[NSNotificationCenter defaultCenter] addObserver:self
                                             selector:@selector(orientationChanged)
                                                 name:UIDeviceOrientationDidChangeNotification
                                               object:nil];
-(void) orientationChanged
{
    if (self.interfaceOrientation == UIInterfaceOrientationPortraitUpsideDown)
        [_previewLayer.connection setVideoOrientation:AVCaptureVideoOrientationPortraitUpsideDown];

    if (self.interfaceOrientation == UIInterfaceOrientationPortrait)
        [_previewLayer.connection setVideoOrientation:AVCaptureVideoOrientationPortrait];

    if (self.interfaceOrientation == UIInterfaceOrientationLandscapeLeft)
        [_previewLayer.connection setVideoOrientation:AVCaptureVideoOrientationLandscapeLeft];

    if (self.interfaceOrientation == UIInterfaceOrientationLandscapeRight)
        [_previewLayer.connection setVideoOrientation:AVCaptureVideoOrientationLandscapeRight];
}

Answer 1

Ah 用以下方法修复了它

-(void) orientationChanged {
    UIDeviceOrientation deviceOrientation = [UIDevice currentDevice].orientation;
    if (deviceOrientation == UIInterfaceOrientationPortraitUpsideDown)
        [_previewLayer.connection setVideoOrientation:AVCaptureVideoOrientationPortraitUpsideDown];

    else if (deviceOrientation == UIInterfaceOrientationPortrait)
        [_previewLayer.connection setVideoOrientation:AVCaptureVideoOrientationPortrait];

    else if (deviceOrientation == UIInterfaceOrientationLandscapeLeft)
        [_previewLayer.connection setVideoOrientation:AVCaptureVideoOrientationLandscapeLeft];

    else
        [_previewLayer.connection setVideoOrientation:AVCaptureVideoOrientationLandscapeRight];
}