AVCapture不会填满整个视图

Question

我试图在视图中显示实时摄像头视频，但当我运行以下代码时，它不会填满整个屏幕。它只有3.5英寸的屏幕大小(运行在5.5英寸的屏幕上)。我已经将视图的autolayout设置为两边的0。

    session = [[AVCaptureSession alloc] init];
    [session setSessionPreset:AVCaptureSessionPresetPhoto];
    AVCaptureDevice *inputDevice = [AVCaptureDevice defaultDeviceWithMediaType:AVMediaTypeVideo];
    NSError *error;
    AVCaptureDeviceInput *deviceInput = [AVCaptureDeviceInput deviceInputWithDevice:inputDevice error:&error];
    if ([session canAddInput:deviceInput]) {
        [session addInput:deviceInput];
    }
    AVCaptureVideoPreviewLayer *previewLayer = [[AVCaptureVideoPreviewLayer alloc] initWithSession:session];
    [previewLayer setVideoGravity:AVLayerVideoGravityResizeAspectFill];
    CALayer *rootLayer = [[self view] layer];
    [rootLayer setMasksToBounds:YES];
    CGRect frame = frameForCapture.frame;
    [previewLayer setFrame:frame];
    [rootLayer insertSublayer:previewLayer atIndex:0];
    stillImage = [[AVCaptureStillImageOutput alloc] init];
    NSDictionary *outputSettings = [[NSDictionary alloc] initWithObjectsAndKeys:AVVideoCodecJPEG, AVVideoCodecKey, nil];
    [stillImage setOutputSettings:outputSettings];
    [session addOutput:stillImage];
    [session startRunning];

当我将视图控制器的大小从3.5英寸设置为5.5英寸并运行时，它会填满整个屏幕。autolayout在大小改变时工作，但在运行时不工作。

Answer 1

层不像视图那样遵循自动调整大小/自动布局的方式，你需要在调整大小时手动设置层的框架。一种很好的方法是引入一个包含预览层的视图子类，并在-layoutSubviews中将其框架设置为视图的边界