title: MPAndroidChart LineChart custom highlight drawable
body: <p>I'm using MPAndroid Chart library to draw Line Chart in my Android app. The status of graph is like: 
  <img src="https://i.stack.imgur.com/TLVMe.png" alt="MPAndroidChart -  Line Chart"></p>
  
  <p>I want to change it like this:</p>
  
  <p><img src="https://i.stack.imgur.com/mGzom.png" alt="Line Chart"></p>
  
  <p>So I want to change MPAnroid Line Chart's points, ts called "Circle Hole" in library. I want to switch this hole to drawable. There is a way I can do that? </p>
  
  <p>The circle hole change code is here: </p>
  
  <pre><code>LineDataSet set1 = new LineDataSet(yVals, "DataSet 1");
  set1.setDrawCircleHole( true );
  set1.setCircleColor( Color.BLACK );
  </code></pre>
  
  <p>Library reference is here: <a href="https://github.com/PhilJay/MPAndroidChart" rel="noreferrer">MPAndroidChart</a></p>