Android编程中调用Camera时预览画面有旋转问题的解决方法

public static int getDisplayRotation(Activity activity) {
  int rotation = activity.getWindowManager().getDefaultDisplay()
    .getRotation();
  switch (rotation) {
    case Surface.ROTATION_0: return 0;
    case Surface.ROTATION_90: return 90;
    case Surface.ROTATION_180: return 180;
    case Surface.ROTATION_270: return 270;
  }
  return 0;
}
public static void setCameraDisplayOrientation(Activity activity,
    int cameraId, Camera camera) {
  // See android.hardware.Camera.setCameraDisplayOrientation for
  // documentation.
  Camera.CameraInfo info = new Camera.CameraInfo();
  Camera.getCameraInfo(cameraId, info);
  int degrees = getDisplayRotation(activity);
  int result;
  if (info.facing == Camera.CameraInfo.CAMERA_FACING_FRONT) {
    result = (info.orientation + degrees) % 360;
    result = (360 - result) % 360; // compensate the mirror
  } else { // back-facing
    result = (info.orientation - degrees + 360) % 360;
  }
  camera.setDisplayOrientation(result);
}