Camera2动态调整预览分辨率、拍照分辨率

对于Camera2 API，可以使用以下步骤动态地调整预览分辨率和拍照分辨率：

1. 获取CameraManager实例，并使用getCameraIdList()方法获取可用摄像头的ID列表。
2. 通过CameraManager.openCamera()方法打开所需的摄像头。
3. 获取CameraCharacteristics对象，以获取可用的预览分辨率和拍照分辨率列表。
4. 使用CameraDevice.createCaptureSession()方法创建一个CameraCaptureSession对象，以便在其中设置预览和拍照请求。
5. 在CameraCaptureSession.setRepeatingRequest()方法中设置预览请求，并在需要拍照时使用CameraCaptureSession.capture()方法设置拍照请求。
6. 在设置预览和拍照请求时，使用CaptureRequest.Builder对象设置所需的分辨率。

以下是参考代码：

// 获取CameraManager实例
CameraManager cameraManager = (CameraManager) getSystemService(Context.CAMERA_SERVICE);
// 获取可用摄像头ID列表
String[] cameraIds = cameraManager.getCameraIdList();
// 打开所需的摄像头
cameraManager.openCamera(cameraId, stateCallback, null);

// 获取CameraCharacteristics对象
CameraCharacteristics characteristics = cameraManager.getCameraCharacteristics(cameraId);
// 获取可用的预览分辨率列表
StreamConfigurationMap map = characteristics.get(CameraCharacteristics.SCALER_STREAM_CONFIGURATION_MAP);
Size[] previewSizes = map.getOutputSizes(SurfaceTexture.class);
// 获取可用的拍照分辨率列表
Size[] pictureSizes = map.getOutputSizes(ImageFormat.JPEG);

// 创建CameraCaptureSession对象
cameraDevice.createCaptureSession(Arrays.asList(surface), new CameraCaptureSession.StateCallback() {
    @Override
    public void onConfigured(@NonNull CameraCaptureSession session) {
        try {
            // 创建预览请求
            CaptureRequest.Builder previewRequestBuilder = cameraDevice.createCaptureRequest(CameraDevice.TEMPLATE_PREVIEW);
            previewRequestBuilder.addTarget(surface);
            previewRequestBuilder.set(CaptureRequest.CONTROL_MODE, CameraMetadata.CONTROL_MODE_AUTO);
            previewRequestBuilder.set(CaptureRequest.CONTROL_AF_MODE, CameraMetadata.CONTROL_AF_MODE_CONTINUOUS_PICTURE);
            previewRequestBuilder.set(CaptureRequest.CONTROL_AE_MODE, CameraMetadata.CONTROL_AE_MODE_ON_AUTO_FLASH);
            // 设置预览分辨率
            previewRequestBuilder.set(CaptureRequest.SCALER_CROP_REGION, previewSize);
            CaptureRequest previewRequest = previewRequestBuilder.build();
            // 设置持续的预览请求
            session.setRepeatingRequest(previewRequest, null, null);
        } catch (CameraAccessException e) {
            e.printStackTrace();
        }
    }

    @Override
    public void onConfigureFailed(@NonNull CameraCaptureSession session) {
        Toast.makeText(MainActivity.this, "配置失败", Toast.LENGTH_SHORT).show();
    }
}, null);

// 创建拍照请求
CaptureRequest.Builder captureRequestBuilder = cameraDevice.createCaptureRequest(CameraDevice.TEMPLATE_STILL_CAPTURE);
captureRequestBuilder.addTarget(imageReader.getSurface());
captureRequestBuilder.set(CaptureRequest.CONTROL_MODE, CameraMetadata.CONTROL_MODE_AUTO);
captureRequestBuilder.set(CaptureRequest.CONTROL_AF_MODE, CameraMetadata.CONTROL_AF_MODE_CONTINUOUS_PICTURE);
captureRequestBuilder.set(CaptureRequest.CONTROL_AE_MODE, CameraMetadata.CONTROL_AE_MODE_ON_AUTO_FLASH);
// 设置拍照分辨率
captureRequestBuilder.set(CaptureRequest.SCALER_CROP_REGION, pictureSize);
CaptureRequest captureRequest = captureRequestBuilder.build();
// 设置单次拍照请求
session.capture(captureRequest, null, null);