title: How to Change Margin of TextView
body: <p>I have TextView added Programmatically in to LinearLayout and on some external events I want to decrease bottom margin of that TextView to -10, for that I tried following. </p>
  
  <pre><code>LinearLayout.LayoutParams lastTxtParams = new LinearLayout.LayoutParams(LinearLayout.LayoutParams.WRAP_CONTENT, LinearLayout.LayoutParams.WRAP_CONTENT);
  lastTxtParams.setMargins(0, 0, 0, -10);
  mOldTextView.setLayoutParams(lastTxtParams);
  mOldTextView.invalidate();
  </code></pre>
  
  <p>Is the right way of modifying Margin of widget that has been added to View?<br>
  Some how it is not working.</p>