title: How to decrease radio button drawable size?
body: <p>I have four radio button.</p>
  
  <h1>xml source</h1>
  
  <pre><code>&lt;RadioButton
      android:id="@+id/fragBtn1"
      android:layout_width="0dp"
      android:layout_height="fill_parent"
      android:layout_weight="1"
      android:background="@drawable/btn_bg_selector"
      android:button="@null"
      android:drawableTop="@drawable/btn_img_selector" /&gt;
  </code></pre>
  
  <h1>btn_img_selector</h1>
  
  <pre><code>&lt;selector xmlns:android="http://schemas.android.com/apk/res/android"&gt;
      &lt;item android:drawable="@drawable/selected_btn" android:gravity="center" android:state_checked="true"/&gt;
      &lt;item android:drawable="@drawable/nonselected_btn" android:gravity="center"/&gt;
  &lt;/selector&gt;
  </code></pre>
  
  <h1>btn_bg_selector</h1>
  
  <pre><code>&lt;selector xmlns:android="http://schemas.android.com/apk/res/android"&gt;
      &lt;item android:drawable="@color/btnPressed" android:state_pressed="true"/&gt;
      &lt;item android:drawable="@color/btnNonPressed"/&gt;
  &lt;/selector&gt;
  </code></pre>
  
  <p>But button image is too big.<br>
  I want to decrease a button image size only..(not decrease button size)<br>
  For example, I want to scale a button image size 30px * 30px.<br>
  Is it possible? </p>