打开ios设备的闪光灯代码

- (void) turnTorchOn: (bool) on {Class captureDeviceClass = NSClassFromString(@"AVCaptureDevice");if (captureDeviceClass != nil) {    AVCaptureDevice *device = [AVCaptureDevice defaultDeviceWithMediaType:AVMediaTypeVideo];    if ([device hasTorch] && [device hasFlash]){        [device lockForConfiguration:nil];        if (on) {            [device setTorchMode:AVCaptureTorchModeOn];            [device setFlashMode:AVCaptureFlashModeOn];            torchIsOn = YES;        } else {            [device setTorchMode:AVCaptureTorchModeOff];            [device setFlashMode:AVCaptureFlashModeOff];            torchIsOn = NO;                    }        [device unlockForConfiguration];    }}}