appcompat-v7 v21 Could not find class

Question

I got this issue on setContentView(R.layout.themed_titles);

E/dalvikvm﹕ Could not find class 'android.support.v7.app.ActionBarActivityDelegateBase$2', referenced from method android.support.v7.app.ActionBarActivityDelegateBase.ensureSubDecor
E/dalvikvm﹕ Could not find class 'android.support.v7.internal.widget.ActionBarContextView', referenced from method android.support.v7.app.ActionBarActivityDelegateBase.startSupportActionModeFromWindow
E/dalvikvm﹕ Could not find class 'android.support.v7.internal.widget.ActionBarContextView', referenced from method android.support.v7.app.ActionBarActivityDelegateBase.startSupportActionModeFromWindow
E/dalvikvm﹕ Could not find class 'android.support.v7.internal.widget.ActionBarOverlayLayout$1', referenced from method android.support.v7.internal.widget.ActionBarOverlayLayout.<init>
E/dalvikvm﹕ Could not find class 'android.support.v7.internal.widget.ActionBarOverlayLayout$1', referenced from method android.support.v7.internal.widget.ActionBarOverlayLayout.<init>
E/AndroidRuntime﹕ FATAL EXCEPTION: main
        java.lang.RuntimeException: Unable to start activity ComponentInfo{br.com.math.semhora.viewpager/viewpager.BaseActivity}: android.view.InflateException: Binary XML file line #17: Error inflating class android.support.v7.internal.widget.ActionBarOverlayLayout

My xml:

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
 **Line17**   xmlns:app="http://schemas.android.com/apk/res-auto"
    android:layout_width="fill_parent"
    android:layout_height="fill_parent"
    android:orientation="vertical" >

    <com.viewpagerindicator.TitlePageIndicator
        android:id="@+id/indicator"
        android:padding="10dip"
        android:layout_height="wrap_content"
        android:layout_width="fill_parent"
        android:background="#18FF0000"
        android:textColor="#AA000000"
        app:footerColor="#FFAA2222"
        app:footerLineHeight="1dp"
        app:footerIndicatorHeight="3dp"
        app:footerIndicatorStyle="underline"
        app:selectedColor="#FF000000"
        app:selectedBold="true"
        />

    <ViewStub
        android:id="@+id/vstubMain"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:inflatedId="@id/no_connect"
        android:layout="@layout/no_connection" />

    <android.support.v4.view.ViewPager
        android:id="@+id/pager"
        android:layout_width="fill_parent"
        android:layout_height="0dp"
        android:layout_weight="1"
        android:background="#F6F6F0" />

</LinearLayout>

Before this issue, I got an error on Log asking me to change all 'app' tags on xml to change to 'android' saying that if you are using appcompat you should use android instead.

It was working with appcompact v20

Answer 1

After I update to appcompact v21.0.2 and buildToolsVersion '21.1.1', it works at moment.