如何在android的camera2中通过代码改变焦点？

Question

我想在 android 的相机应用中实现一个功能，我可以单击一个按钮而不是获取 2 张具有不同焦点的照片（不是手动对焦功能）。

我已经全部完成了，除了我的焦点变化部分无法运行，我找不到原因，并尝试分析：

尝试1：我使用this和this中的焦点控制代码来改变焦点，但是没有用。

1. 相机制造商设置部分：

   private CaptureRequest.Builder initDngBuilder() {
       CaptureRequest.Builder captureBuilder = null;
       try {
           captureBuilder = mCameraSession.getDevice().createCaptureRequest(CameraDevice.TEMPLATE_PREVIEW);
   
           captureBuilder.addTarget(mImageReader.getSurface());
           captureBuilder.addTarget(surface);
           // Required for RAW capture
           captureBuilder.set(CaptureRequest.STATISTICS_LENS_SHADING_MAP_MODE, CaptureRequest.STATISTICS_LENS_SHADING_MAP_MODE_ON);
           captureBuilder.set(CaptureRequest.CONTROL_AE_MODE, CaptureRequest.CONTROL_AE_MODE_OFF);
           captureBuilder.set(CaptureRequest.CONTROL_AF_MODE, CameraMetadata.CONTROL_AF_MODE_OFF);
           captureBuilder.set(CaptureRequest.LENS_FOCUS_DISTANCE, 0.1f);
           captureBuilder.set(CaptureRequest.SENSOR_EXPOSURE_TIME, (long) ((214735991 - 13231) / 2));
           captureBuilder.set(CaptureRequest.CONTROL_AE_EXPOSURE_COMPENSATION, 0);
           captureBuilder.set(CaptureRequest.SENSOR_SENSITIVITY, (10000 - 100) / 2);
           captureBuilder.set(CaptureRequest.JPEG_ORIENTATION, 90);
           CameraManager cameraManager = (CameraManager) getActivity().getSystemService(Context.CAMERA_SERVICE);
           String cameraid = CameraCharacteristics.LENS_FACING_FRONT + "";
           CameraCharacteristics cameraCharacteristics = cameraManager.getCameraCharacteristics(cameraid);
           Range<Integer> fps[] = cameraCharacteristics.get(CameraCharacteristics.CONTROL_AE_AVAILABLE_TARGET_FPS_RANGES);
           captureBuilder.set(CaptureRequest.CONTROL_AE_TARGET_FPS_RANGE, fps[fps.length - 1]);
       } catch (CameraAccessException e) {
           Toast.makeText(getActivity(), "reject", Toast.LENGTH_SHORT).show();
       } catch (NullPointerException e) {
           Toast.makeText(getActivity(), "fail", Toast.LENGTH_SHORT).show();
       }
       return captureBuilder;}
   private CaptureRequest.Builder initDngBuilder2() {
   CaptureRequest.Builder captureBuilder = null;
   try {
       captureBuilder = mCameraSession.getDevice().createCaptureRequest(CameraDevice.TEMPLATE_PREVIEW);
       captureBuilder.addTarget(mImageReader.getSurface());
       captureBuilder.addTarget(surface);
       // Required for RAW capture
       captureBuilder.set(CaptureRequest.STATISTICS_LENS_SHADING_MAP_MODE, CaptureRequest.STATISTICS_LENS_SHADING_MAP_MODE_ON);
       captureBuilder.set(CaptureRequest.CONTROL_AE_MODE, CaptureRequest.CONTROL_AE_MODE_OFF);
       captureBuilder.set(CaptureRequest.CONTROL_AF_MODE, CameraMetadata.CONTROL_AF_MODE_OFF);
       captureBuilder.set(CaptureRequest.LENS_FOCUS_DISTANCE, 100.0f);
       captureBuilder.set(CaptureRequest.SENSOR_EXPOSURE_TIME, (long) ((214735991 - 13231) / 2));
       captureBuilder.set(CaptureRequest.CONTROL_AE_EXPOSURE_COMPENSATION, 0);
       captureBuilder.set(CaptureRequest.SENSOR_SENSITIVITY, (10000 - 100) / 2);
       captureBuilder.set(CaptureRequest.JPEG_ORIENTATION, 90);
       CameraManager cameraManager = (CameraManager) getActivity().getSystemService(Context.CAMERA_SERVICE);
       String cameraid = CameraCharacteristics.LENS_FACING_FRONT + "";
       CameraCharacteristics cameraCharacteristics = cameraManager.getCameraCharacteristics(cameraid);
       Range<Integer> fps[] = cameraCharacteristics.get(CameraCharacteristics.CONTROL_AE_AVAILABLE_TARGET_FPS_RANGES);
       captureBuilder.set(CaptureRequest.CONTROL_AE_TARGET_FPS_RANGE, fps[fps.length - 1]);
   } catch (CameraAccessException e) {
       Toast.makeText(getActivity(), "reject", Toast.LENGTH_SHORT).show();
   } catch (NullPointerException e) {
       Toast.makeText(getActivity(), "fail", Toast.LENGTH_SHORT).show();
   }
   return captureBuilder;
   

   }

2. 点击监听部分：

   private View.OnClickListener picOnClickListener = new View.OnClickListener() {
   @Override
   public void onClick(View view) {
       try {
           mCameraSession.capture(initDngBuilder().build(), null, mHandler);
           mCameraSession.capture(initDngBuilder2().build(), null, mHandler);
       } catch (CameraAccessException e) {
           e.printStackTrace();
       }
   }};
   

尝试2：我想弄清楚我的android设备是否没有这个能力（我认为这一点是因为：https://stackoverflow.com/a/42912408/9521891），所以我使用：

int[] ints = mCameraCharacteristics.get(CameraCharacteristics.REQUEST_AVAILABLE_CAPABILITIES);

for (int i = 0; i < ints.length; i++){
    Log.d(TAG, ints[i] + ",");
}

而我只得到：“0,”。 这是否意味着设备没有'MANUAL_SENSOR'功能？

Answer 1

是的，如果REQUEST_AVAILABLE_CAPABILITIES的内容只包含BACKWARD_COMPATIBLE(0)，那么设备不支持MANUAL_SENSOR。

因此，不支持将 LENS_FOCUS_DISTANCE 设置为 0.0f（无限远对焦）以外的任何值。