title: How to add elements to the current open activity Android
body: <p>I am new with android and i am trying to understand how to add element to open activity layout and to display the changes immediately.
  is it possible by adding with <code>addView</code>? i tried with no succeed.</p>
  
  <pre><code>    TextView sv = new TextView(this);
      TextView b = new TextView(this);
      sv.setGravity(Gravity.CENTER_VERTICAL);
      b.setText("ggg");
      sv.setText("asdsadasdasdasdasdas");
  
      RelativeLayout ll = new RelativeLayout(this);
      ll.addView(sv);
      ll.addView(b);
      this.setContentView(ll);
  </code></pre>
  
  <p>in this way its delete everything was before</p>