android - 从图库应用程序中选择图像

Question

我使用此代码允许用户从图库应用中选择一张图片，然后再获取该图片。

@Override
public void onActivityResult(int requestCode, int resultCode, Intent data) {
        super.onActivityResult(requestCode, resultCode, data);
        if (resultCode == getActivity().RESULT_OK) {
            if (requestCode == REQUEST_CAMERA) {
                Bitmap photo = (Bitmap) data.getExtras().get("data");
                mImg.setImageBitmap(photo);
            } else if (requestCode == SELECT_FILE) {
                Uri selectedImageUri = data.getData();
                String[] projection = {MediaStore.MediaColumns.DATA};
                CursorLoader cursorLoader = new CursorLoader(getActivity(), selectedImageUri, projection, null, null,
                        null);
                Cursor cursor = cursorLoader.loadInBackground();
                int column_index = cursor.getColumnIndexOrThrow(MediaStore.MediaColumns.DATA);
                cursor.moveToFirst();

                String selectedImagePath = cursor.getString(column_index);

                Bitmap bm;
                BitmapFactory.Options options = new BitmapFactory.Options();
                options.inJustDecodeBounds = true;
                BitmapFactory.decodeFile(selectedImagePath, options);
                final int REQUIRED_SIZE = 200;
                int scale = 1;
                while (options.outWidth / scale / 2 >= REQUIRED_SIZE
                        && options.outHeight / scale / 2 >= REQUIRED_SIZE)
                    scale *= 2;
                options.inSampleSize = scale;
                options.inJustDecodeBounds = false;
                bm = BitmapFactory.decodeFile(selectedImagePath, options);

                mImg.setImageBitmap(bm);
                mImg.setAlpha(1);

            }
    }
}

但在这个答案中 here有人告诉我这段代码在大多数 Android 设备上都不起作用。我能知道为什么吗？获取用户选择的图像的最佳方式是什么。

我将其发布在一个单独的问题中，因为它可能很有趣。

Answer 1

通过使用位图，您的图像可能看起来很模糊。如果图片太大，当你想上传或检索它们到(从)服务器时会出现问题。所以 uri 比 bitmap 好。

你可以尝试下面的代码，你会看到 bitmap 和 uri 之间的区别

 @Override
    protected void onActivityResult(int requestCode, int resultCode, Intent data) {
        super.onActivityResult(requestCode, resultCode, data);
        switch (requestCode) {
            case RESULT_LOAD_IMAGE:
                if (requestCode == RESULT_LOAD_IMAGE && resultCode == RESULT_OK & null != data) {
                    selectedImage = data.getData();
                    imageView.setImageURI(selectedImage);
                }
                else
                {
                    imageView.setImageResource(R.mipmap.no_image);
                }

                break;

            case REQUEST_IMAGE_CAPTURE:
                if (requestCode == REQUEST_IMAGE_CAPTURE && resultCode == RESULT_OK) {
                    try {
                        selectedImage = imageUri;
                        getContentResolver().notifyChange(selectedImage, null);
                        imageView.setImageURI(null);
                        imageView.setImageURI(imageUri);
                    } catch (Exception e) {
                        Toast.makeText(this, "Failed to load", Toast.LENGTH_SHORT)
                                .show();
                        Log.e("Camera", e.toString());
                    }
                    Log.e("A", "AAA");
                }
        }
    }