title: Does Android need a default layout file called activity_main.xml
body: <p>I'm an Android noob and I'm having difficulty finding out something basic about Android.</p>
  
  <ul>
  <li>I currently have an activity_main.xml file.</li>
  <li>I want to use this layout when I first start the Android emulator, using Android Studio</li>
  <li>Does Android look for a file activity_main.xml and use it as the default layout?</li>
  </ul>
  
  <p>Here's my AndroidManifest.xml:</p>
  
  <p>
  </p>
  
  <pre><code>&lt;application
      android:allowBackup="true"
      android:icon="@mipmap/ic_launcher"
      android:label="@string/app_name"
      android:supportsRtl="true"
      android:theme="@style/AppTheme" &gt;
      &lt;activity android:name=".MainActivity" &gt;
          &lt;intent-filter&gt;
              &lt;action android:name="android.intent.action.MAIN" /&gt;
  
              &lt;category android:name="android.intent.category.LAUNCHER" /&gt;
          &lt;/intent-filter&gt;
      &lt;/activity&gt;
  &lt;/application&gt;
  </code></pre>
  
  <p></p>
  
  <p>So I understand that this specifies that my .MainActivity will respond to an action.MAIN intent call. What I don't know is what the action.MAIN intent call actually is, and how my activity_main.xml relates to this.</p>
  
  <pre><code>public class MainActivity extends AppCompatActivity {
  
      @Override
      protected void onCreate(Bundle savedInstanceState) {
          super.onCreate(savedInstanceState);
          setContentView(R.layout.activity_main);
      }
  }
  </code></pre>
  
  <p>Can anyone provide an explanation or a link to a good primer that explains these basic concepts?</p>