Theme.AppCompat.Light.DarkActionBar results in no ActionBar showing

Question

I created a project with a blank activity (and then wrote code to put in a basic fragment - empty linear layout) in Android Studio but there is no ActionBar showing. Why?

Device: Emulator (Nexus 5 size), API 19

The main activity extends FragmentActivity.

The Android Studio generated styles.xml:

<resources>

    <!-- Base application theme. -->
    <style name="AppTheme" parent="Theme.AppCompat.Light.DarkActionBar">
        <!-- Customize your theme here. -->
    </style>

</resources>

The activity layout:

<?xml version="1.0" encoding="utf-8"?>
<FrameLayout xmlns:android="http://schemas.android.com/apk/res/android"
              android:id="@+id/fragmentContainer"
              android:layout_width="match_parent"
              android:layout_height="match_parent" />

The fragment:

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
              android:orientation="vertical"
              android:layout_width="match_parent"
              android:layout_height="match_parent" />

Manifest:

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
    package="com.mycompany.test" >

    <application
        android:allowBackup="true"
        android:icon="@drawable/ic_launcher"
        android:label="@string/app_name"
        android:theme="@style/AppTheme" >
        <activity
            android:name=".TestActivity"
            android:label="@string/app_name" >
            <intent-filter>
                <action android:name="android.intent.action.MAIN" />

                <category android:name="android.intent.category.LAUNCHER" />
            </intent-filter>
        </activity>
    </application>

</manifest>

Answer 1

Instead of extending FragmentActivity, I need the main class to extend AppCompatActivity.

As explained here:

http://developer.android.com/training/basics/fragments/creating.html

If you're using the v7 appcompat library, your activity should instead extend ActionBarActivity, which is a subclass of FragmentActivity (for more information, read Adding the Action Bar).

EDIT

ActionBarActivity is now deprecated. Use AppCompatActivity instead.