title: Simulate button press
body: <p>I have this resource for a <code>Button</code></p>
  
  <pre><code>&lt;?xml version="1.0" encoding="utf-8"?&gt;
  &lt;selector xmlns:android="http://schemas.android.com/apk/res/android"&gt;
  
      &lt;item android:state_pressed="true"&gt;
          &lt;shape&gt;
              &lt;solid android:color="@color/CLR_GREEN" /&gt;
              &lt;corners android:radius="5dp" /&gt;
              &lt;padding android:left="10dp" android:top="10dp"
                  android:right="10dp" android:bottom="10dp" /&gt;
          &lt;/shape&gt;
      &lt;/item&gt;
  
      &lt;item&gt;
          &lt;shape&gt;
              &lt;solid android:color="@color/CLR_GREEN_DARK" /&gt;
              &lt;corners android:radius="5dp" /&gt;
              &lt;padding android:left="10dp" android:top="10dp"
                  android:right="10dp" android:bottom="10dp" /&gt;
          &lt;/shape&gt;
      &lt;/item&gt;
  &lt;/selector&gt;
  </code></pre>
  
  <p>And I refer to this button in code as <code>greenBtn</code></p>
  
  <p>How do I simulate its pressure without firing its <code>onClick</code> event? i.e. how do I make it change its background color as if it was pressed, stay in this state for half a second and then be back in its original state?</p>