class ImageViewZoom
public methods:
 setImage(Bitmap) - Bitmap which you want to show in view(layout)
 setImage(Bitmap bitmap, int widthOfParent) - you can set maximum width(in pixels) of parent  if you want. But in most cases above will be enough.
 
Extend class and override method
protected void onImageClick(float posX, float posY)
to add custom ontouchhandler

Look at example for more.