title: How to make Play Store like ToolBar?
body: <p>I am trying to make a toolbar that behaves like the toolbar of PlayStore app.</p>
  
  <p>I am not interested in the "search" feature. I am interested in the transparency which reveals the layout behind it. And after scrolling up the background becomes solid.</p>
  
  <p>This is the first state displaying transparent background revealing the layout underneath it.</p>
  
  <p><a href="https://i.stack.imgur.com/dKHVd.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/dKHVd.png" alt="transparent_background_revealing_layout_underneath"></a></p>
  
  <p>This is the toolbar with solid background displaying the title.</p>
  
  <p><a href="https://i.stack.imgur.com/g9xj5.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/g9xj5.png" alt="solid_background_hiding_layout"></a></p>
  
  <p>I am not interested in the third state where the complete toolbar is completely hidden.</p>
  
  <p><a href="https://i.stack.imgur.com/DYUq5.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/DYUq5.png" alt="toolbar_completely_hidden"></a></p>
  
  <p>Although it won't harm to have this in my app; but my primary goal is to get the first two effects.</p>