Android Theme.AppCompat.Light with Dark Toolbar (for light text)

In order to change the color of the title in your Toolbar you simply have to add the attribute android:textColorPrimary to your Toolbar style.

Please see the following example for even more attributes of the Toolbar.

Example

<style name="MyToolbarStyle" parent="ThemeOverlay.AppCompat.ActionBar">
    <!-- Used to for the title of the Toolbar -->
    <item name="android:textColorPrimary">#fff</item>
    <!-- Used to for the title of the Toolbar when parent is Theme.AppCompat.Light -->
    <item name="android:textColorPrimaryInverse">#fff</item>
    <!-- Used to color the text of the action menu icons -->
    <item name="android:textColorSecondary">#fff</item>
    <!-- Used to color the overflow menu icon -->
    <item name="actionMenuTextColor">#fff</item>
    <!-- Color of the Toolbar -->
    <item name="android:background">#455a64</item>
</style>

Result

You can customize toolbar yourself no need to set default text, use your own textview :

<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="?attr/colorPrimary"
   android:minHeight="@dimen/abc_action_bar_default_height_material">

   <!-- Below will add your text in the center of toolbar -->
   <TextView
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_gravity="center"
        android:text="Your Text"
        android:textColor=#ff0000
        android:textStyle="bold"/>

</android.support.v7.widget.Toolbar>