android - 为什么我的 Android 应用程序中的图像选择器会自动将纵向图像旋转为横向图像？

Question

我在我的 android 应用程序中使用此代码来启动相机/画廊以获取图像，并将其显示到 ImageView 中。

当用户选择横向图像时，一切正常，但当用户选择纵向图像时，图像会旋转 90 度显示。我不明白为什么..我正在 Android 4.3 的 Galaxy S3 上测试我的应用程序

我注意到只有用手机拍照时才会出现问题..也许这是 S3 的问题？

这是我的代码:

    private void openImageIntent() {
        // Camera.
        System.gc();

        final List<Intent> cameraIntents = new ArrayList<Intent>();
        final Intent captureIntent = new Intent(android.provider.MediaStore.ACTION_IMAGE_CAPTURE);
        final PackageManager packageManager = getPackageManager();
        final List<ResolveInfo> listCam = packageManager.queryIntentActivities(captureIntent, 0);
        for(ResolveInfo res : listCam) {
            final String packageName = res.activityInfo.packageName;
            final Intent intent = new Intent(captureIntent);
            intent.setComponent(new ComponentName(res.activityInfo.packageName, res.activityInfo.name));
            intent.setPackage(packageName);
            cameraIntents.add(intent);
        }

        // Filesystem.
        final Intent galleryIntent = new Intent();
        galleryIntent.setType("image/*");
        galleryIntent.setAction(Intent.ACTION_GET_CONTENT);

        // Chooser of filesystem options.
        Intent chooserIntent = Intent.createChooser(galleryIntent, "Scegli dove prelevare l'immagine");

        // Add the camera options.
        chooserIntent.putExtra(Intent.EXTRA_INITIAL_INTENTS, cameraIntents.toArray(new Parcelable[]{}));
        //Log.i("sto lanciando il chooser","vado eh");
        startActivityForResult(chooserIntent, 4982);
    }


    private String selectedImagePath;
    @Override
    protected void onActivityResult(int requestCode, int resultCode, Intent data){
        super.onActivityResult(requestCode, resultCode, data);



        if (resultCode == RESULT_OK) {
            if (requestCode == 4982) {


                Uri selectedImageUri = data.getData();
                selectedImagePath = getPath(selectedImageUri);
                //Log.i("immagine",selectedImagePath);

                myImageView.setImageBitmap(decodeSampledBitmapFromFile(new File(selectedImagePath)));

            }
        }

    } 
    public String getPath(Uri uri) {
        String[] projection = { MediaStore.Images.Media.DATA };
        Cursor cursor = managedQuery(uri, projection, null, null, null);
        int column_index = cursor
                .getColumnIndexOrThrow(MediaStore.Images.Media.DATA);
        cursor.moveToFirst();
        return cursor.getString(column_index);
    }


    public static Bitmap decodeSampledBitmapFromFile(File file) {

        // First decode with inJustDecodeBounds=true to check dimensions
         BitmapFactory.Options o = new BitmapFactory.Options();
            o.inJustDecodeBounds = true;
        BitmapFactory.decodeFile(file.getAbsolutePath(), o);

        //The new size we want to scale to
        final int REQUIRED_SIZE=430;

        //Find the correct scale value. It should be the power of 2.
        int scale=1;
        while(o.outWidth/scale/2>=REQUIRED_SIZE && o.outHeight/scale/2>=REQUIRED_SIZE)
            scale*=2;

        //Decode with inSampleSize
        BitmapFactory.Options o2 = new BitmapFactory.Options();
        o2.inSampleSize=scale;

        return BitmapFactory.decodeFile(file.getAbsolutePath(), o2);
       }

Answer 1

许多 Android 设备，如果在拍照时设备是纵向的，请不要将图像旋转为纵向。相反，他们以横向方式存储图像，并在图像中放置一个 EXIF header 以告诉任何图像查看者“嘿!请将其旋转 270 度!”。这很可能就是您遇到的情况，因为我知道三星设备经常出现此问题。