title: Change an Int value on button click databinding
body: <p>I can do this programatically, but i want to know best approach using <code>android databinding</code>.</p>
  
  <p>Here is my xml layout. I want to increase or decrease int value <code>onClick</code> of some button. I don't want handle click in activity class. Is this possible, if yes.</p>
  
  <p>In below layout you can see an Integer value count. Value count should be changed on click of Button.</p>
  
  <pre><code>&lt;?xml version="1.0" encoding="utf-8"?&gt;
  &lt;layout
      xmlns:android="http://schemas.android.com/apk/res/android"&gt;
  
      &lt;data&gt;
  
          &lt;import type="android.view.View"/&gt;
  
          &lt;variable
              name="activity"
              type="com.amelio.ui.activities.ActivityProductDetail"/&gt;
  
          &lt;variable
              name="count"
              type="Integer"/&gt;
      &lt;/data&gt;
  
      &lt;LinearLayout
          android:layout_height="wrap_content"
          android:layout_width="wrap_content"
          &gt;
  
          &lt;Button
              android:layout_height="wrap_content"
              android:layout_width="wrap_content"
              android:onClick="@{() -&gt; count++}"
              android:text="Less"
              /&gt;
  
          &lt;TextView
              android:layout_height="wrap_content"
              android:layout_width="wrap_content"
              android:text="@{`` + count}"
              /&gt;
  
          &lt;Button
              android:layout_height="wrap_content"
              android:layout_width="wrap_content"
              android:id="@+id/ivBtnPlus"
              android:onClick="@{() -&gt; count--}"
              android:text="Add"
              /&gt;
      &lt;/LinearLayout&gt;
  &lt;/layout&gt;
  </code></pre>