Android ImageView显示旋转的图像，尽管源未旋转

问题描述

我正在尝试在gridview中显示画廊图像，并在单击图像时打开图像的全屏视图.奇怪的是，当图像显示在图库中时，它们遵循正确的旋转方向.但是，当我只是在自定义图库中查询照片时，它们始终会逆时针旋转90度.

I am trying to display gallery images in a gridview, and on image click, open a fullscreen view for the image. The weird thing is, that when the images are displaying in the gallery, they follow the correct rotation. But When I simply query the photos in my custom gallery, they are always rotated by 90 degrees counter clockwise.

我已经看到一些使用exif接口旋转的解决方案，由于加载原始位图和新旋转的位图，因此需要旋转内存.

I have seen some solutions to rotate using exif interface which will require memory to rotate since it loads the original bitmap and the newly rotated one.

我的问题是:为什么简单地在ImageView中显示图库中的图像会导致图像旋转?

谢谢.

推荐答案

public static int calculateInSampleSize(BitmapFactory.Options options,
                int reqWidth, int reqHeight) {
            // Raw height and width of image
            final int height = options.outHeight;
            final int width = options.outWidth;
            int inSampleSize = 1;

            if (height > reqHeight || width > reqWidth) {

                final int halfHeight = height / 2;
                final int halfWidth = width / 2;

                // Calculate the largest inSampleSize value that is a power of 2 and
                // keeps both
                // height and width larger than the requested height and width.
                while ((halfHeight / inSampleSize) > reqHeight
                        && (halfWidth / inSampleSize) > reqWidth) {
                    inSampleSize *= 2;
                }
            }
            return inSampleSize;
        }


    public static Bitmap decodeSampledBitmapFromResource(Resources res,
                int resId, int reqWidth, int reqHeight) {
            // First decode with inJustDecodeBounds=true to check dimensions
            final BitmapFactory.Options options = new BitmapFactory.Options();
            options.inJustDecodeBounds = true;
            BitmapFactory.decodeResource(res, resId, options);
            // Calculate inSampleSize
            options.inSampleSize = calculateInSampleSize(options, reqWidth,
                    reqHeight);
            // Decode bitmap with inSampleSize set
            options.inJustDecodeBounds = false;
            return BitmapFactory.decodeResource(res, resId, options);
        }

检查图像的旋转并正确显示...为

Check the rotation of the Image and display it properly...as

    scaledBitmap=decodeSampledBitmapFromResource(.....);
    ExifInterface exif=null;
            try {
                exif = new ExifInterface(filePath);
                int orientation = exif.getAttributeInt(
                        ExifInterface.TAG_ORIENTATION, 0);
                Log.d("EXIF", "Exif: " + orientation);
                Matrix matrix = new Matrix();
                if (orientation == 6) {
                    matrix.postRotate(90);
                    Log.d("EXIF", "Exif: " + orientation);
                } else if (orientation == 3) {
                    matrix.postRotate(180);
                    Log.d("EXIF", "Exif: " + orientation);
                } else if (orientation == 8) {
                    matrix.postRotate(270);
                    Log.d("EXIF", "Exif: " + orientation);
                }
                scaledBitmap = Bitmap.createBitmap(scaledBitmap, 0, 0,
                        scaledBitmap.getWidth(), scaledBitmap.getHeight(), matrix,
                        true);
            } catch (IOException e) {
                e.printStackTrace();
            }

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