Android相机如何自动对焦

Android相机如何自动对焦？

java
private CameraDevice mCameraDevice;
private CaptureRequest.Builder mPreviewRequestBuilder;
private CameraCaptureSession mCaptureSession;
private void openCamera() {
    CameraManager manager = (CameraManager) getSystemService(Context.CAMERA_SERVICE);
    try {
        String cameraId = manager.getCameraIdList()[0];
        CameraCharacteristics characteristics = manager.getCameraCharacteristics(cameraId);
        StreamConfigurationMap map = characteristics.get(CameraCharacteristics.SCALER_STREAM_CONFIGURATION_MAP);
        Size[] sizes = map.getOutputSizes(SurfaceTexture.class);
        Size previewSize = sizes[0]; // 选择合适的预览尺寸
        manager.openCamera(cameraId, new CameraDevice.StateCallback() {
            @Override
            public void onOpened(@NonNull CameraDevice camera) {
                mCameraDevice = camera;
                createCameraPreviewSession();
            }
            @Override
            public void onDisconnected(@NonNull CameraDevice camera) {
                mCameraDevice.close();
                mCameraDevice = null;
            }
            @Override
            public void onError(@NonNull CameraDevice camera, int error) {
                mCameraDevice.close();
                mCameraDevice = null;
            }
        }, null);
    } catch (CameraAccessException e) {
        e.printStackTrace();
    }
}
private void createCameraPreviewSession() {
    try {
        SurfaceTexture texture = mTextureView.getSurfaceTexture();
        texture.setDefaultBufferSize(previewSize.getWidth(), previewSize.getHeight());
        Surface surface = new Surface(texture);
        mPreviewRequestBuilder = mCameraDevice.createCaptureRequest(CameraDevice.TEMPLATE_PREVIEW);
        mPreviewRequestBuilder.addTarget(surface);
        mCameraDevice.createCaptureSession(Arrays.asList(surface), new CameraCaptureSession.StateCallback() {
            @Override
            public void onConfigured(@NonNull CameraCaptureSession session) {
                mCaptureSession = session;
                updatePreview();
            }
            @Override
            public void onConfigureFailed(@NonNull CameraCaptureSession session) {
                // 处理配置失败的情况
            }
        }, null);
    } catch (CameraAccessException e) {
        e.printStackTrace();
    }
}
private void updatePreview() {
    mPreviewRequestBuilder.set(CaptureRequest.CONTROL_MODE, CaptureRequest.CONTROL_MODE_AUTO);
    try {
        mCaptureSession.setRepeatingRequest(mPreviewRequestBuilder.build(), null, null);
    } catch (CameraAccessException e) {
        e.printStackTrace();
    }
}

java
private void updatePreview() {
    mPreviewRequestBuilder.set(CaptureRequest.CONTROL_MODE, CaptureRequest.CONTROL_MODE_AUTO);
    mPreviewRequestBuilder.set(CaptureRequest.CONTROL_AF_MODE, CaptureRequest.CONTROL_AF_MODE_CONTINUOUS_PICTURE);
    try {
        mCaptureSession.setRepeatingRequest(mPreviewRequestBuilder.build(), null, null);
    } catch (CameraAccessException e) {
        e.printStackTrace();
    }
}