title: Warning shows when i use Hash Map In android(Use new SparseArray<String>)
body: <p>I am new to developing in android. In my android app I'm using <code>HashMap</code>, but I'm getting a warning: </p>
  
  <pre><code>**"Use new SparseArray&lt;String&gt;(...) instead for better performance"**
  </code></pre>
  
  <p>What does this mean, and how can I use <code>SparseArray&lt;String&gt;</code> instead?</p>