title: Android set outline corner radius for custom radio buttons group
body: <p>this screen shot is custom radio button group as an simple switch buttons</p>
  
  <p><a href="https://i.stack.imgur.com/SmG6e.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/SmG6e.png" alt="enter image description here"></a></p>
  
  <p>when i click on Search or Offers as end of buttons, buttons don't have corner radius size, for example:</p>
  
  <p><a href="https://i.stack.imgur.com/2NoYD.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/2NoYD.png" alt="enter image description here"></a></p>
  
  <p><a href="https://i.stack.imgur.com/CQ2Qg.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/CQ2Qg.png" alt="enter image description here"></a></p>
  
  <p>my <code>toggle_widget_background</code> xml laout is:</p>
  
  <pre><code>&lt;?xml version="1.0" encoding="UTF-8" standalone="no"?&gt;
  &lt;selector xmlns:android="http://schemas.android.com/apk/res/android"&gt;
      &lt;item android:drawable="@color/md_pink_A700" android:state_checked="true" /&gt;
      &lt;item android:drawable="@color/md_pink_500" android:state_pressed="true" /&gt;
      &lt;item android:drawable="@android:color/transparent" /&gt;
  &lt;/selector&gt;
  </code></pre>
  
  <p>now how can i set corner radius for left and right buttons?</p>
  
  <p>this xml layout not working:</p>
  
  <pre><code>&lt;?xml version="1.0" encoding="UTF-8" standalone="no"?&gt;
  &lt;selector xmlns:android="http://schemas.android.com/apk/res/android"&gt;
      &lt;item  android:drawable="@color/md_pink_A700" android:state_checked="true"&gt;
          &lt;shape  &gt;
              &lt;corners
                  android:bottomLeftRadius="7dp"
                  android:bottomRightRadius="7dp"
                  android:topLeftRadius="7dp"
                  android:topRightRadius="7dp"
                  /&gt;
          &lt;/shape&gt;
      &lt;/item&gt;
  
      &lt;item  android:drawable="@color/md_pink_500" android:state_checked="true"&gt;
          &lt;shape  &gt;
              &lt;corners
                  android:bottomLeftRadius="7dp"
                  android:bottomRightRadius="7dp"
                  android:topLeftRadius="7dp"
                  android:topRightRadius="7dp"
                  /&gt;
          &lt;/shape&gt;
      &lt;/item&gt;
  
      &lt;item  android:drawable="@android:color/transparent" android:state_checked="true"&gt;
          &lt;shape  &gt;
              &lt;corners
                  android:bottomLeftRadius="7dp"
                  android:bottomRightRadius="7dp"
                  android:topLeftRadius="7dp"
                  android:topRightRadius="7dp"
                  /&gt;
          &lt;/shape&gt;
      &lt;/item&gt;
  
  &lt;/selector&gt;
  </code></pre>