╔══════════════════════════════════════════════╗ ^ ║ ImageView ╔══════════════╗ ║ | ║ ║ ║ ║ | ║
I think you can let the Android OS take care of this for you. Set the scale type on the ImageView to fitXY and the image it displays will be sized to fit the current size of the view.
fitXY