title: android gallery view change alpha value
body: <p>I am making an android gallery. I want to be able to extend it's basic behavior so the view that its centered to be most visible (it's alpha value to be 1.0) and the views that are from the left and to the right to have some minimum visibility which will increase if the user scrolls and positions a particular view in the center. 
  I am wondering if someone has done this before, or has an idea how I should try and do this. </p>