title: Android make a view transparent, or at least semi transparent
body: <p>I'm using the <a href="https://github.com/umano/AndroidSlidingUpPanel" rel="nofollow">AndroidSlidingUpPanel</a>. I'm trying to make one of the views semi-transparent. So that you can see what's under it. So its basically a LinearLayout which moves, but I can't see whats underneath.</p>
  
  <p>I've tried setting the <code>alpha</code>, the background color (with alpha)</p>
  
  <p>xml settings:</p>
  
  <pre><code>android:background="@android:color/transparent"
  </code></pre>
  
  <p>as well as:</p>
  
  <pre><code>android:background="#22000000"
  </code></pre>
  
  <p>I've also tried programmatically:</p>
  
  <pre><code>view.setAlpha((float) 0.45));
  </code></pre>
  
  <p>The thing is everything I do doesn't make it transparent. I can see the colours change but its still fully opaque.</p>
  
  <p>Perhaps i've missed something? How can I make it transparent so I can see whats underneath</p>