iOS闪关灯的打开与关闭

//点击的按钮时要执行的方法
-（void)ClickButton {  
    AVCaptureDevice *device = [AVCaptureDevice defaultDeviceWithMediaType:AVMediaTypeVideo];
    if ([device hasTorch] && [device hasFlash]) {
        [device lockForConfiguration:nil];
        } 
    if (device.torchMode == AVCaptureTorchModeOn) {
        [device setTorchMode:AVCaptureTorchModeOff];     
    }else{
        [device setTorchMode:AVCaptureTorchModeOn]; 
    }
    [device unlockForConfiguration];
}