如何在UIImagePicker上禁用自动对焦并与前置摄像头一样工作？

Question

我想使用UIImagePicker禁用相机应用程序的自动对焦，并且与没有聚焦的前置相机相同。可以帮助我吗？

我使用过这段代码，但只隐藏了方框，但仍在关注......

-(void)disableAutoFocus
     {
         NSArray *devices = [AVCaptureDevice devices];
         NSError *error;
         for (AVCaptureDevice *device in devices) {
             if (([device hasMediaType:AVMediaTypeVideo]) &&
                ([device position] == AVCaptureDevicePositionBack) ) {
                 [device lockForConfiguration:&error];
                      if ([device isFocusModeSupported:AVCaptureFocusModeLocked]) {
                          device.focusMode = AVCaptureFocusModeLocked;
                          NSLog(@"Focus locked");
        }

        [device unlockForConfiguration];
    }
}

}