iOS 如何打开后灯（闪光灯）

- (void)torchOnOrOff

{

    AVCaptureDevice *device = [AVCaptureDevice defaultDeviceWithMediaType:AVMediaTypeVideo];

    [device lockForConfiguration:nil];

    if (device.torchMode == AVCaptureTorchModeOff) {

        [device setTorchMode: AVCaptureTorchModeOn];

    }else{

        [device setTorchMode: AVCaptureTorchModeOff];

    }

    [device unlockForConfiguration];

}

来判断该摄像头是否有提供闪光灯

我是要持续开启所以使用Torch Mode

lockForConfiguration跟unlockForConfiguration是配对的API

呼叫lockForConfiguration就可以控制硬件了

控制完毕后要呼叫unlockForConfiguration