如何从用户库中显示尺寸合适的图像？

Question

我正在努力在我的两个活动中展示适当大小的图像。 CatalogActivity中的图像看起来像是正确缩小然后裁剪，而EditorActivity中的图像是完整的并且要小得多。 唯一的区别是目录中的图像来自图像资源，而编辑器图像来自画廊，所以来自Uri。

你能告诉我为什么这个差异以及如何使EditorActivity的图像与另一个图像相同？

来自CatalogActivity：

MiningField#setUsageType(MiningField$UsageType)

来自EditorActivity：

// Make the sample image smaller so it doesn't take too much space in the     memory
Bitmap sourdoughBitmap = ProductsEntry.decodeSampledBitmapFromResource(getResources(), R.drawable.sourdough_picture, 72, 72);

来自ProductsEntry：

@Override
    protected void onActivityResult(int requestCode, int resultCode, Intent intent) {
       super.onActivityResult(requestCode, resultCode, intent);

        if (requestCode == RESULT_LOAD_PICTURE && resultCode == RESULT_OK && null != intent) {
            Uri selectedPictureUri = intent.getData();
            // Show the selected picture in an ImageView in the editor
            try {
                // Scale the bitmap received from the uri so it fits in the small ImageView
                scaledPictureBitmap = ProductsEntry.decodeSampledBitmapFromUri(this, selectedPictureUri, 72, 72);
                // Hide the gray picture placeholder
                mImageView.setBackgroundResource(0);
                // Show the scaled bitmap in the ImageView
                mImageView.setImageBitmap(scaledPictureBitmap);
                // The user has chosen a picture and we can change
                // the text of the button to say "Change picture"
                mAddPictureButton.setText(R.string.edit_product_change_photo);
            } catch (FileNotFoundException e) {
                e.printStackTrace();
            }
        }
    }

来自activity_editor.xml：

/**
         * Helps create a smaller bitmap image from resource
         * @param resources - a resources object
         * @param resourceId - the id of the image in the drawable folder
         * @param requiredWidth - the width that we want for the final image
         * @param requiredHeight - the height that we want for the final image
         * @return the decoded Bitmap
         */
        public static Bitmap decodeSampledBitmapFromResource(Resources resources, int resourceId,
                                                             int requiredWidth, int requiredHeight){
            // First decode with inJustDecodeBounds = true to check dimensions
            final BitmapFactory.Options options = new BitmapFactory.Options();
            options.inJustDecodeBounds = true;
            BitmapFactory.decodeResource(resources, resourceId, options);

            // Calculate inSampleSize
            options.inSampleSize = calculateInSampleSize(options, requiredWidth, requiredHeight);

            // Decode bitmap with inJustDecodeBounds = false
            options.inJustDecodeBounds = false;
            return BitmapFactory.decodeResource(resources, resourceId, options);
        }

        /**
         * Helps create a smaller bitmap image from a uri
         * @param context - a context object
         * @param uri - the uri of the image
         * @param requiredWidth - the width that we want for the final image
         * @param requiredHeight - the height that we want for the final image
         * @return the decoded Bitmap
         */
        public static Bitmap decodeSampledBitmapFromUri(Context context, Uri uri, int requiredWidth, int requiredHeight)
        throws FileNotFoundException {
            // First decode with inJustDecodeBounds = true, only to check dimensions
            final BitmapFactory.Options options = new BitmapFactory.Options();
            options.inJustDecodeBounds = true;
            BitmapFactory.decodeStream(context.getContentResolver().openInputStream(uri), null, options);

            // Calculate inSampleSize
            options.inSampleSize = calculateInSampleSize(options, requiredWidth, requiredHeight);

            // Decode bitmap with inJustDecodeBounds = false
            options.inJustDecodeBounds = false;
            return BitmapFactory.decodeStream(context.getContentResolver().openInputStream(uri), null, options);
        }

        /**
         * Calculate a sample size value that is a power of 2 based on a target width and height
         * @param options is used to pass options to the BitmapFactory
         * @param requiredWidth is the width that we want for the final image
         * @param requiredHeight is the height that we want for the final image
         * @return by how much to scale down the image
         */
        private static int calculateInSampleSize(BitmapFactory.Options options, int requiredWidth, int requiredHeight) {
            // Raw height and width of the image
            final int height = options.outHeight;
            final int width = options.outWidth;
            int inSampleSize = 1;

            if (height > requiredHeight || width > requiredWidth) {

                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 required height and width
                while ((halfHeight / inSampleSize) >= requiredHeight
                        && (halfWidth / inSampleSize) >= requiredWidth){
                    inSampleSize *= 2;
                }
            }

            return inSampleSize;
        }

链接到存储库here。