ios - 我正在尝试切换此代码以使用前置摄像头

Question

我是编程新手，正在尝试修复此代码以使用前置摄像头而不是默认设置为后置摄像头。我不确定我需要更改什么才能使其正常工作。

这是我的示例代码:

-(void)viewWillAppear:(BOOL)animated{
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 = self.frameForCapture.frame;

[previewLayer setFrame:frame];

[rootLayer insertSublayer:previewLayer atIndex:0];


stillImageOutput = [[AVCaptureStillImageOutput alloc] init];
NSDictionary *outputSettings = [[NSDictionary alloc] initWithObjectsAndKeys:AVVideoCodecJPEG, AVVideoCodecKey, nil];
[stillImageOutput setOutputSettings:outputSettings];

[session addOutput:stillImageOutput];

[session startRunning];

Answer 1

替换这个:

AVCaptureDevice *inputDevice = [AVCaptureDevice       defaultDeviceWithMediaType:AVMediaTypeVideo];
NSError *error;
AVCaptureDeviceInput *deviceInput = [AVCaptureDeviceInput deviceInputWithDevice:inputDevice error:&error];

有了这个:

NSArray *devices = [AVCaptureDevice devicesWithMediaType:AVMediaTypeVideo];
AVCaptureDevice *frontCamera;
for (AVCaptureDevice *dev in devices) {
    if (dev.position == AVCaptureDevicePositionFront) {
        frontCamera = dev;
        break;
    }
}
if (!frontCamera) {
    NSLog(@"No front camera found!");
    // Handle no front camera error
}
NSError *error;
AVCaptureDeviceInput *input = [AVCaptureDeviceInput deviceInputWithDevice:frontCamera error:&error];