display huge Images in Android

I know it’s an old post but I spent a lot of time on this problem, so here’s my solution.

I wanted to display a 2000×3000 picture but I got out of memory or the image was too large to be displayed.

To begin, I get the dimensions of the picture:

o = new BitmapFactory.Options();
o.inJustDecodeBounds=true;
pictures = BitmapFactory.decodeStream(new FileInputStream(f), null, o);

Then I cut it up into four parts and displayed them with four ImageViews.
I tried to load the full picture and cut it into four (using BitmapFactory.create(bitmap,int,int,int,int)) but got out of memory again.

So I decided to use some BitMapRegionDecoder:

for (int i = 0; i < 2; i++) {
    for (int j = 0; j < 2; j++) {
        ImageView iv = new ImageView(this);         
        InputStream istream =   null;
        try {
         istream = this.getContentResolver().openInputStream(Uri.fromFile(f));
        } catch (FileNotFoundException e1) {
         e1.printStackTrace();
        }
        BitmapRegionDecoder decoder     =   null;
        try {
        decoder = BitmapRegionDecoder.newInstance(istream, false);
        } catch (IOException e) {
                    e.printStackTrace();
        }
    int nw = (j*width/k);
    int nh = (i*height/k);

    Bitmap bMap = decoder.decodeRegion(new Rect(nw,nh, (nw+width/k),(nh+height/k)), null);    
    iv.setImageBitmap(bMap);

    }
}

This worked.