title: Make part of image transparent on Touch
body: <p>I have a layout with the follwoing:</p>
  
  <p><code>Framelayout</code> with two <code>ImageView</code>s. Each <code>ImageView</code> has one image.</p>
  
  <p>What I am trying to acheive is: on touch on the <code>ImageView</code>, the touch area should become <strong>transparent</strong> and show the image below.</p>
  
  <p>Layout XML:</p>
  
  <pre><code>&lt;?xml version="1.0" encoding="utf-8"?&gt;
  &lt;LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
      android:layout_width="match_parent"
      android:layout_height="match_parent" &gt;
  
      &lt;FrameLayout
          android:layout_width="wrap_content"
          android:layout_height="wrap_content" &gt;
  
          &lt;ImageView
              android:id="@+id/imageView1"
              android:layout_width="wrap_content"
              android:layout_height="wrap_content"
              android:src="@drawable/rect" /&gt;
  
          &lt;ImageView
              android:id="@+id/imageView2"
              android:layout_width="wrap_content"
              android:layout_height="wrap_content"
              android:src="@drawable/i2" /&gt;
      &lt;/FrameLayout&gt;
  
  &lt;/LinearLayout&gt;
  </code></pre>
  
  <p>So basically on touch on <code>imageView2</code> the touch area should show the image from <code>imageView1</code>.</p>
  
  <p>I just need some pointers or references.</p>