android camera2 分辨率代码如何写

使用Android Camera2 API设置相机分辨率有以下几个步骤：

1. 获取CameraManager实例

CameraManager manager = (CameraManager) getSystemService(Context.CAMERA_SERVICE);

2. 获取可用的相机列表

String cameraId = manager.getCameraIdList()[0]; //获取第一个相机id

3. 获取相机的特性

CameraCharacteristics characteristics = manager.getCameraCharacteristics(cameraId);

4. 获取相机支持的分辨率列表

StreamConfigurationMap map = characteristics.get(CameraCharacteristics.SCALER_STREAM_CONFIGURATION_MAP);
Size[] sizes = map.getOutputSizes(SurfaceTexture.class); //获取支持的SurfaceTexture分辨率列表

5. 设置相机分辨率

mPreviewSize = chooseOptimalSize(sizes, width, height); //自定义方法选择最佳分辨率
mPreviewRequestBuilder.set(CaptureRequest.SCALER_CROP_REGION, mZoomRect); //设置裁剪区域
mPreviewRequestBuilder.set(CaptureRequest.CONTROL_AE_TARGET_FPS_RANGE, new Range<>(30, 30)); //设置帧率
mPreviewRequestBuilder.set(CaptureRequest.CONTROL_MODE, CameraMetadata.CONTROL_MODE_AUTO); //设置自动对焦等参数

完整代码示例：

private Size chooseOptimalSize(Size[] choices, int width, int height) {
    List<Size> bigEnough = new ArrayList<>();
    for (Size option : choices) {
        if (option.getHeight() == option.getWidth() * height / width && option.getWidth() >= width && option.getHeight() >= height) {
            bigEnough.add(option);
        }
    }
    if (bigEnough.size() > 0) {
        return Collections.min(bigEnough, new CompareSizesByArea());
    } else {
        return choices[0];
    }
}

private static class CompareSizesByArea implements Comparator<Size> {
    @Override
    public int compare(Size lhs, Size rhs) {
        return Long.signum((long) lhs.getWidth() * lhs.getHeight() - (long) rhs.getWidth() * rhs.getHeight());
    }
}

private void setUpCameraOutputs(int width, int height) {
    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);
        mPreviewSize = chooseOptimalSize(sizes, width, height);
        mZoomRect = new Rect(0, 0, mPreviewSize.getWidth(), mPreviewSize.getHeight());
        mImageReader = ImageReader.newInstance(mPreviewSize.getWidth(), mPreviewSize.getHeight(), ImageFormat.YUV_420_888, 2);
        mImageReader.setOnImageAvailableListener(mOnImageAvailableListener, mBackgroundHandler);
        mSensorOrientation = characteristics.get(CameraCharacteristics.SENSOR_ORIENTATION);
        if (ActivityCompat.checkSelfPermission(this, Manifest.permission.CAMERA) != PackageManager.PERMISSION_GRANTED) {
            return;
        }
        manager.openCamera(cameraId, mStateCallback, null);
    } catch (CameraAccessException e) {
        e.printStackTrace();
    }
}

private void createCameraPreviewSession() {
    try {
        SurfaceTexture texture = mTextureView.getSurfaceTexture();
        texture.setDefaultBufferSize(mPreviewSize.getWidth(), mPreviewSize.getHeight());
        Surface surface = new Surface(texture);
        mPreviewRequestBuilder = mCameraDevice.createCaptureRequest(CameraDevice.TEMPLATE_PREVIEW);
        mPreviewRequestBuilder.addTarget(surface);
        mPreviewRequestBuilder.addTarget(mImageReader.getSurface());
        mCameraDevice.createCaptureSession(Arrays.asList(surface, mImageReader.getSurface()), new CameraCaptureSession.StateCallback() {
            @Override
            public void onConfigured(@NonNull CameraCaptureSession cameraCaptureSession) {
                if (mCameraDevice == null) {
                    return;
                }
                try {
                    mPreviewSession = cameraCaptureSession;
                    mPreviewRequestBuilder.set(CaptureRequest.CONTROL_MODE, CameraMetadata.CONTROL_MODE_AUTO);
                    mPreviewRequest = mPreviewRequestBuilder.build();
                    mPreviewSession.setRepeatingRequest(mPreviewRequest, mCaptureCallback, mBackgroundHandler);
                } catch (CameraAccessException e) {
                    e.printStackTrace();
                }
            }

            @Override
            public void onConfigureFailed(@NonNull CameraCaptureSession cameraCaptureSession) {

            }
        }, null);
    } catch (CameraAccessException e) {
        e.printStackTrace();
    }
}