Crop and resize an image in Android

Question

I am reading an image from disk and displaying it inside of a row in a ListView. The image files are larger than what needs to be displayed inside the ImageView of the rows. Since I need to cache the bitmaps in RAM for faster access I would like them to only be as large as the ImageViews (85x85 dip)

Right now I am reading in the file with

bitmap = BitmapFactory.decodeFile(file);

and the ImageView is responsible for scaling and cropping it

android:scaleType="centerCrop"

AFAIK this is keeping the entire bitmap in memory (because I cached it XD) and that is bad

How can I remove this responsibility from the ImageView and do the crop + scale while loading the file? All the bitmaps will be displayed at 85x85 dip and need to be 'centerCrop'

Solution

You can find out the dimensions of your pictures before loading, cropping and scaling:

BitmapFactory.Options options = new BitmapFactory.Options();
    options.inJustDecodeBounds = true;

    Bitmap bmo = BitmapFactory.decodeFile(file.getAbsolutePath(), options);

Then load it in sample size:

...
options.inSampleSize = 1/2;
bmo = BitmapFactory.decodeFile(file.getAbsolutePath(), options);

...
 = Bitmap.createScaledBitmap(bmo, dW, dH, false);

don't forget to recycle temporary bitmaps or you'll get OOME.

bmo.recycle();