title: Robust way to implement "bottom navigation tab bar"
body: <p>The effect is like this:</p>
  
  <p><img src="https://i.stack.imgur.com/yaeh0.png" alt="enter image description here"></p>
  
  <p>I have investigated some methods. </p>
  
  <p>Somebody use <code>radiogroup</code>, somebody use <code>tabhost</code>.</p>
  
  <p>What is the simplest way?</p>
  
  <p>Is there any other way?</p>