<!-- styles.xml -->
<style name="AppTheme" parent="Theme.AppCompat.Light.NoActionBar">
<android.support.design.widget.AppBarLayout
android:gravity="center">
<android.support.v7.widget.Toolbar
android:id="@+id/toolbar"
app:contentInsetStart="0dp">
<TextView
android:id="@+id/toolbar_title"/>
</android.support.v7.widget.Toolbar>
</android.support.design.widget.AppBarLayout>
setSupportActionBar(findViewById(R.id.my_toolbar))