title: Android Manifest- intent filter and activity
body: <p>Could someone explain the following lines in the manifest - </p>
  
  <pre><code>    &lt;activity
          android:name=".AboutUs"
          android:label="@string/app_name"&gt;
          &lt;intent-filter &gt;
              &lt;action android:name="com.example.app1.ABOUT" /&gt;
              &lt;category android:name="android.intent.category.DEFAULT"/&gt;
          &lt;/intent-filter&gt;
  
      &lt;/activity&gt;    
  </code></pre>
  
  <p>How are the fields in activity and intent filter important and when are they used/referred ?
  Sorry, i tried to read the documentation but still couldnt figure much out.</p>
  
  <p>Thank you</p>