public static void setCameraDisplayOrientation(Activity activity,int cameraIo, Camera camera){

Camera.CameraInfo info=new Camera.CameraInfo();
Camera.getCameraInfo(cameraIo,info);
int rotation=activity.getWindowManager().getDefaultDisplay().getRotation();
int degress=0;
switch(rotation){
case Surface.ROTATION_0:
  degress=0;
  break;
case Surface.ROTATION_90:
  degress=90;
  break;
 case Surface.ROTATION_180:
  degress=180;
  break;
case Surface.ROTATION_270:
  degress=270;
  break;
}
int result;
if(info.facing=Camera.CameraInfo.CAMERA_FACING_FRONT){
 result = (info.orientation + degrees) % 360;
 > 就是摄像头需要顺时针转过多少度才能恢复自然方向
 result = (360 - result) % 360;
 } else { // back-facing
 result = (info.orientation - degrees + 360) % 360;
 }
 camera.setDisplayOrientation(result);
switch (result) {
  case 0:
  case 180:
  setCameraSize(camera.getParameters(),      getScreenWidth(), getScreenHeight());
  break;
  case 90:
  case 270:
  setCameraSize(camera.getParameters(),      getScreenHeight(), getScreenWidth());
   break;
}
}

public static void setCameraSize(Camera.Parameters parameters, int width, int height) {
  Map<String, List<Size>> allSizes = new HashMap<>();
  String typePreview = "typePreview";
  String typePicture = "typePicture";
  allSizes.put(typePreview, parameters.getSupportedPreviewSizes());
  allSizes.put(typePicture, parameters.getSupportedPictureSizes());
  Iterator iterator = allSizes.entrySet().iterator();
  while (iterator.hasNext()) {
   Map.Entry<String, List<Size>> entry = (Map.Entry<String, List<Size>>) iterator.next();
   List<Size> sizes = entry.getValue();
   if (sizes == null || sizes.isEmpty()) continue;
   ArrayList<WrapCameraSize> wrapCameraSizes = new ArrayList<>(sizes.size());
   for (Size size : sizes) {
    WrapCameraSize wrapCameraSize = new WrapCameraSize();
    wrapCameraSize.setWidth(size.width);
    wrapCameraSize.setHeight(size.height);
    wrapCameraSize.setD(Math.abs((size.width - width)) + Math.abs((size.height - height)));
    if (size.width == width && size.height == height) {
     if (typePreview.equals(entry.getKey())) {
      parameters.setPreviewSize(size.width, size.height);
     } else if (typePicture.equals(entry.getKey())) {
      parameters.setPictureSize(size.width, size.height);
     }
     Log.d(TAG, "best size: width=" + size.width + ";height=" + size.height);
     break;
    }
    wrapCameraSizes.add(wrapCameraSize);
   }
   Log.d(TAG, "wrapCameraSizes.size()=" + wrapCameraSizes.size());
   Size resultSize = null;
   if (typePreview.equals(entry.getKey())) {
    resultSize = parameters.getPreviewSize();
   } else if (typePicture.equals(entry.getKey())) {
    resultSize = parameters.getPictureSize();
   }
   if (resultSize == null || (resultSize.width != width && resultSize.height != height)) {
    //找到相机Preview Size 和 Picture Size中最适合的大小
    if(wrapCameraSizes.isEmpty()) continue;
    WrapCameraSize minCameraSize = Collections.min(wrapCameraSizes);
    while (!(minCameraSize.getWidth() >= width && minCameraSize.getHeight() >= height)) {
     wrapCameraSizes.remove(minCameraSize);
     if(wrapCameraSizes.isEmpty()) break;
     minCameraSize = null;
     minCameraSize = Collections.min(wrapCameraSizes);
    }
    Log.d(TAG, "best min size: width=" + minCameraSize.getWidth() + ";height=" + minCameraSize.getHeight());
    if (typePreview.equals(entry.getKey())) {
     parameters.setPreviewSize(minCameraSize.getWidth(), minCameraSize.getHeight());
    } else if (typePicture.equals(entry.getKey())) {
     parameters.setPictureSize(minCameraSize.getWidth(), minCameraSize.getHeight());
    }
   }
   iterator.remove();
  }
 }