Convert URI to real path format

In the exercises "Select Image using Android build-in Gallery" ad "Display Gallery selected image using BitmapFactory", the uri returned from build-in Gallery app is in the format of "content://media/external/images/...". To convert it to the real path format (eg. /mnt/sdcard/dropbox/Eric/....png), the following function can be used.

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