使用AVFoundation，我被困在从后到前和前到后的更改相机上
为此，我使用以下代码。
- (IBAction)CameraToggleButtonPressed:(id)sender
{
if ([[AVCaptureDevice devicesWithMediaType:AVMediaTypeVideo] count] > 1)
{
NSError *error;
AVCaptureDeviceInput *NewVideoInput;
AVCaptureDevicePosition position = [[VideoInputDevice device] position];
if (position == AVCaptureDevicePositionBack)
{
NewVideoInput = [[AVCaptureDeviceInput alloc] initWithDevice:[self CameraWithPosition:AVCaptureDevicePositionFront] error:&error];
}
else if (position == AVCaptureDevicePositionFront)
{
NewVideoInput = [[AVCaptureDeviceInput alloc] initWithDevice:[self CameraWithPosition:AVCaptureDevicePositionBack] error:&error];
}
if (NewVideoInput != nil)
{
[CaptureSession beginConfiguration]; [CaptureSession removeInput:VideoInputDevice];
if ([CaptureSession canAddInput:NewVideoInput])
{
[CaptureSession addInput:NewVideoInput];
VideoInputDevice = NewVideoInput;
}
else
{
[CaptureSession addInput:VideoInputDevice];
}
[self CameraSetOutputProperties];
[CaptureSession commitConfiguration];
}
}
}
[CaptureSession canAddInput:NewVideoInput]总是返回false，所以相机不会改变。我不明白为什么会话不能添加新的输入设备
请帮我解决这个问题
提前感谢。
AVCaptureVideoPreviewLayer *captureVideoPreviewLayer;
bool isUsingFrontFacingCamera;
方法：
- (void) switchCam{
if (![self cameraIsRunning])
return;
AVCaptureDevicePosition desiredPosition;
if (isUsingFrontFacingCamera)
desiredPosition = AVCaptureDevicePositionBack;
else
desiredPosition = AVCaptureDevicePositionFront;
for (AVCaptureDevice *d in [AVCaptureDevice devicesWithMediaType:AVMediaTypeVideo]) {
if ([d position] == desiredPosition) {
[[captureVideoPreviewLayer session] beginConfiguration];
AVCaptureDeviceInput *input = [AVCaptureDeviceInput deviceInputWithDevice:d error:nil];
for (AVCaptureInput *oldInput in [[captureVideoPreviewLayer session] inputs]) {
[[captureVideoPreviewLayer session] removeInput:oldInput];
}
[[captureVideoPreviewLayer session] addInput:input];
[[captureVideoPreviewLayer session] commitConfiguration];
break;
}
}
isUsingFrontFacingCamera = !isUsingFrontFacingCamera;
}
- (bool) cameraIsRunning{
return [session isRunning];
}