android camera2 分辨率代码如何写

下面是一个简单的 Android Camera2 API 分辨率设置示例代码：

private static final int REQUEST_CAMERA_PERMISSION = 200;
private CameraDevice cameraDevice;
private CameraCaptureSession cameraCaptureSessions;
private CaptureRequest.Builder captureRequestBuilder;
private Size imageDimension;
private ImageReader imageReader;

// 在 onCreate 方法中调用此方法
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);
        imageDimension = chooseOptimalSize(map.getOutputSizes(SurfaceTexture.class), width, height);
        // Add permission for camera and let user grant the permission
        if (ActivityCompat.checkSelfPermission(this, Manifest.permission.CAMERA) != PackageManager.PERMISSION_GRANTED
                && ActivityCompat.checkSelfPermission(this, Manifest.permission.WRITE_EXTERNAL_STORAGE) != PackageManager.PERMISSION_GRANTED) {
            ActivityCompat.requestPermissions(MainActivity.this, new String[]{Manifest.permission.CAMERA, Manifest.permission.WRITE_EXTERNAL_STORAGE}, REQUEST_CAMERA_PERMISSION);
            return;
        }
        manager.openCamera(cameraId, stateCallback, null);
    } catch (CameraAccessException e) {
        e.printStackTrace();
    }
}

// 在 CameraDevice.StateCallback 的 onOpened 方法中调用此方法
private void createCameraPreview() {
    try {
        SurfaceTexture texture = textureView.getSurfaceTexture();
        texture.setDefaultBufferSize(imageDimension.getWidth(), imageDimension.getHeight());
        Surface surface = new Surface(texture);
        captureRequestBuilder = cameraDevice.createCaptureRequest(CameraDevice.TEMPLATE_PREVIEW);
        captureRequestBuilder.addTarget(surface);
        cameraDevice.createCaptureSession(Arrays.asList(surface), new CameraCaptureSession.StateCallback() {
            @Override
            public void onConfigured(@NonNull CameraCaptureSession cameraCaptureSession) {
                // 相机已经关闭
                if (null == cameraDevice) {
                    return;
                }
                // 会话准备就绪，开始显示预览
                cameraCaptureSessions = cameraCaptureSession;
                updatePreview();
            }

            @Override
            public void onConfigureFailed(@NonNull CameraCaptureSession cameraCaptureSession) {
                Toast.makeText(MainActivity.this, "Configuration change", Toast.LENGTH_SHORT).show();
            }
        }, null);
    } catch (CameraAccessException e) {
        e.printStackTrace();
    }
}

// 在 CameraCaptureSession.StateCallback 的 onConfigured 方法中调用此方法
private void updatePreview() {
    if (null == cameraDevice) {
        Log.e(TAG, "updatePreview error, return");
    }
    captureRequestBuilder.set(CaptureRequest.CONTROL_MODE, CameraMetadata.CONTROL_MODE_AUTO);
    try {
        cameraCaptureSessions.setRepeatingRequest(captureRequestBuilder.build(), null, mBackgroundHandler);
    } catch (CameraAccessException e) {
        e.printStackTrace();
    }
}

// 在 chooseOptimalSize 方法中选择最佳尺寸
private static 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];
    }
}

// 在 CompareSizesByArea 类中实现比较器
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());
    }
}

在上面的示例代码中，`imageDimension` 可以设置为您需要的分辨率。在 `createCameraPreview` 方法中，我们将 `texture` 的默认缓冲区大小设置为 `imageDimension` 的大小。在 `chooseOptimalSize` 方法中，我们选择最佳尺寸，使它与屏幕宽高比相等，同时大于或等于指定的宽高。