How to change the title color when using Theme.AppCompat.Light.NoActionBar

Question

I am creating my own action bar with menu items and therefore using Theme.AppCompat.Light.NoActionBar.

I want to have the action bar purple and the title color white, but at the moment it is black.

<style name="AppTheme" parent="Theme.AppCompat.Light.NoActionBar">
    <!-- Customize your theme here. -->
    <item name="colorPrimaryDark">@color/colorPrimaryDark</item>
    <item name="colorAccent">@color/colorAccent</item>
</style>

my action bar xml is:

<android.support.v7.widget.Toolbar  
   xmlns:android="http://schemas.android.com/apk/res/android"
   android:layout_width="match_parent"
   android:layout_height="wrap_content"
   android:background="@color/colorPrimary"
   android:id="@+id/app_bar"
>

Answer 1

As explained in this Google+ pro-tip, you can use a ThemeOverlay to customize only certain things. This is useful for when you need to make text light on a dark background, which can be achieved by adding android:theme="@style/ThemeOverlay.AppCompat.Dark.ActionBar" to your Toolbar:

<android.support.v7.widget.Toolbar  
  xmlns:android="http://schemas.android.com/apk/res/android"
  android:layout_width="match_parent"
  android:layout_height="wrap_content"
  android:background="@color/colorPrimary"
  android:id="@+id/app_bar"
  android:theme="@style/ThemeOverlay.AppCompat.Dark.ActionBar"
>

This technique was further discussed in the Theming with AppCompat blog+video.