android - 如何在 android studio (Camera2) 中获得相机分辨率

Question

我只需要设备的相机分辨率(以像素为单位)。我已经尝试过这个，但它在我的应用程序上没有显示任何内容。我想我错过了一些东西

   @RequiresApi(api = Build.VERSION_CODES.LOLLIPOP)
@Override
protected void onCreate(@Nullable  Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);
    ActivityCompat.requestPermissions(MainActivity.this,
            new String[]{Manifest.permission.CAMERA, Manifest.permission.WRITE_EXTERNAL_STORAGE},
            1);
    textView = (TextView) findViewById(R.id.textView);

    }
    @NonNull
    public Size getResolution(@NonNull final CameraManager cameraManager, @NonNull final String cameraId) throws CameraAccessException
    {
        CameraManager cameraManager1 = (CameraManager) getSystemService(CAMERA_SERVICE);

        final CameraCharacteristics  characteristics = cameraManager.getCameraCharacteristics(cameraId);
        final StreamConfigurationMap map             = characteristics.get(CameraCharacteristics.SCALER_STREAM_CONFIGURATION_MAP);

        if (map == null)
        {
            throw new IllegalStateException("Failed to get configuration map.");

        }

        final Size[] choices = map.getOutputSizes(ImageFormat.JPEG);
        final Size size = getResolution(cameraManager, cameraId);
        final float megapixels = (((size.getWidth() * size.getHeight()) / 1000.0f) / 1000.0f);
        final String caption = String.format(Locale.getDefault(), "%.1f", megapixels);
        textView.setText(caption);

        return size;
    }

}

Answer 1

尝试下一个方法。您需要传递 CameraManager 的初始化实例，然后是您想要获取其分辨率的相机镜头标识符。

@NonNull
public Size getResolution(@NonNull final CameraManager cameraManager, @NonNull final String cameraId) throws CameraAccessException
{
    final CameraCharacteristics  characteristics = cameraManager.getCameraCharacteristics(cameraId);
    final StreamConfigurationMap map             = characteristics.get(CameraCharacteristics.SCALER_STREAM_CONFIGURATION_MAP);

    if (map == null)
    {
        throw new IllegalStateException("Failed to get configuration map.");
    }

    final Size[] choices = map.getOutputSizes(ImageFormat.JPEG);

    Arrays.sort(choices, Collections.reverseOrder(new Comparator<Size>()
    {
        @Override
        public int compare(@NonNull final Size lhs, @NonNull final Size rhs)
        {
            // Cast to ensure the multiplications won't overflow
            return Long.signum((lhs.getWidth() * (long)lhs.getHeight()) - (rhs.getWidth() * (long)rhs.getHeight()));
        }
    }));

    return choices[0];
}

该方法将返回分辨率大小。如果您需要显示它，您有很多选择。例如，如果您需要在 TextView 中以 1280x720 等格式显示宽度和高度，那么您可以执行以下操作:

final Size size = getResolution(cameraManager, stringId);
yourTextView.setText(size.toString());

如果您需要以百万像素显示，那么您可以执行以下操作:

final Size size = getResolution(cameraManager, stringId);
final float megapixels = (((size.getWidth() * size.getHeight()) / 1000.0f) / 1000.0f);
final String caption = String.format(Locale.getDefault(), "%.1f", megapixels);
yourTextView.setText(caption);