title: Android button select and press drawable
body: <p>I'm trying to make a button with state press and select,
  I already did the same with tabs and it works but I don't know why here does not work.
   I have done it like this:</p>
  
  <p>button_sel.xml</p>
  
  <pre><code>&lt;shape xmlns:android="http://schemas.android.com/apk/res/android" 
         android:shape="rectangle"&gt;
      &lt;gradient android:startColor="@color/azulado" 
                android:endColor="@color/azulBrillante"
                android:angle="270" /&gt;
       &lt;corners android:radius="@dimen/corner_radius" /&gt;
       &lt;stroke android:width="2px" 
               android:color="@color/blanco" /&gt;
   &lt;/shape&gt;
  </code></pre>
  
  <p>button_unsel.xml</p>
  
  <pre><code>&lt;shape xmlns:android="http://schemas.android.com/apk/res/android" 
         android:shape="rectangle"&gt;
      &lt;gradient android:startColor="@color/botonesD" 
                android:endColor="@color/botones"
                android:angle="270" /&gt;
      &lt;corners android:radius="@dimen/corner_radius" /&gt;
      &lt;stroke android:width="2px" 
              android:color="@color/blanco" /&gt;
  &lt;/shape&gt;
  </code></pre>
  
  <p>And the selector, button.xml:</p>
  
  <pre><code>&lt;selector xmlns:android="http://schemas.android.com/apk/res/android"&gt;
      &lt;item android:drawable="@drawable/button_sel"  
            android:state_selected="true" 
            android:state_pressed="true"/&gt;
  &lt;item android:drawable="@drawable/button_unsel" 
        android:state_selected="false" 
        android:state_pressed="false"/&gt;
  &lt;/selector&gt;
  </code></pre>
  
  <p>And here I call the drawable as a background:</p>
  
  <pre><code> &lt;style name="button"&gt;
      &lt;item name="android:background"&gt;@drawable/button&lt;/item&gt;
      &lt;item name="android:textSize"&gt;@dimen/text_size&lt;/item&gt;
      &lt;item name="android:padding"&gt;@dimen/padding_button&lt;/item&gt;
      &lt;item name="android:textColor"&gt;@color/blanco&lt;/item&gt;
   &lt;/style&gt;
  </code></pre>
  
  <p>Thank you!!!!</p>