title: Back arrow missing in my Activity
body: <p>I have created 2 activity in my android application. 2nd activity will launch from first activity button click. activity launches 
  but I can not see back arrow. I have to use hardware button to go back to main activity.</p>
  
  <p>This is my second activity xml</p>
  
  <pre><code>&lt;?xml version="1.0" encoding="utf-8"?&gt;
  &lt;LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
  android:layout_width="match_parent"
  android:layout_height="match_parent"
  android:orientation="vertical" &gt;
  
  &lt;com.xxxxxxx.widget.MonthView
      android:layout_width="300dp"
      android:layout_weight="1"
      android:paddingLeft="30dp"
      android:layout_height="fill_parent" /&gt;
    &lt;/LinearLayout&gt;
  </code></pre>
  
  <p>How to get the back arrow button on header of second activity?</p>
  
  <p>I am using java code to launch as follow</p>
  
  <pre><code> Intent intent = new Intent(getActivity(), CalendarActivity.class);
   getActivity().startActivity(intent);
  </code></pre>