title: How to show grid for a custom x axis label: achartengine
body: <p>I want a functionality where if user clicks on the the graph and if the x co ordinate is close to our point on XY line graph then I want to show a vertical grid for that point.</p>
  
  <p>The only function that seems related is 
  mRenderer.setShowCustomTextGridY(boolean showGrid)</p>
  
  <p>But for which value should the grid be shown is not clear in the documentation.</p>
  
  <p>Please help. Which function should I use?</p>