Question

I’ve encountered totally bizarre behavior in the way Android loads bitmaps into ImageView. For example, I have a 500×313 image file called urimg_01.jpg. With this code:

        img.setImageResource(R.drawable.urimg_01);
        Bitmap bitmap = ((BitmapDrawable) img.getDrawable()).getBitmap();
        Log.v(TAG,"---------------------> bitmap width = "+bitmap.getWidth());
        Log.v(TAG,"---------------------> bitmap height = "+bitmap.getHeight());

the ImageView bitmap is 750×470. (I have a Nexus S with 480×800 display.)

With this code, which reads a copy of the same file located in getFilesDir():

            Log.v(TAG,"image file is "+filelist[0].getAbsolutePath());
            FileInputStream fis = new FileInputStream(filelist[0]);
            FileDescriptor fd = fis.getFD();
            Bitmap bitmap = BitmapFactory.decodeFileDescriptor(fd);
            if (bitmap != null) {
                Log.v(TAG,"---------------------> bitmap width = "+bitmap.getWidth());
                Log.v(TAG,"---------------------> bitmap height = "+bitmap.getHeight());
                img.setImageBitmap(bitmap);
                fis.close();
            }

the ImageView bitmap is 500×313, as expected.

In the case of setImageResource(), where the devil is it getting 750×470 from?? And how do I get it to use the correct dimensions for resources in drawable?

Answer 1

Your resource is being scaled up because it’s probably stored in a medium density folder and you’re using a high density device. See Bitmap getWidth returns wrong value for details.