iOS - 开启手电筒

//点击手电筒

- (void)clickFlashLight:(UIButton*)btn{

btn.selected=!btn.selected;

AVCaptureDevice *device =[AVCaptureDevicedefaultDeviceWithMediaType:AVMediaTypeVideo]; 

//修改前必须先锁定

[self.devicelockForConfiguration:nil];

//必须判定是否有闪光灯，否则如果没有闪光灯会崩溃

if([self.devicehasFlash]) {

if(device.torchMode==AVCaptureFlashModeOff) {

device.torchMode=AVCaptureTorchModeOn;

}else if(device.torchMode==AVCaptureFlashModeOn) {

device.torchMode=AVCaptureTorchModeOff;

}

}

[self.deviceunlockForConfiguration];

}