Android Toolbar for API 19? (for API 21 works ok)

If you use Toolbar then you should be able to view the exact same Toolbar in any API.

For doing that you should have a XML in res/layout:

<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="?attr/actionBarSize"/>

And in your main layout you should include it:

<include
    android:id="@+id/app_bar"
    layout="@layout/app_bar" />

Also you should set your style as No Action Bar on your styles.xml

<style name="AppTheme.Base" parent="Theme.AppCompat.NoActionBar">
    <item name="colorPrimary">@color/primary</item>
    <item name="colorPrimaryDark">@color/primaryDark</item>
    <item name="colorAccent">@color/accent</item>
</style>

But for API 21 you should have another styles.xml:

<style name="AppTheme" parent="AppTheme.Base">
    <item name="android:colorPrimary">@color/primary</item>
    <item name="android:colorPrimaryDark">@color/primaryDark</item>
    <item name="android:colorAccent">@color/accent</item>
</style>

And finally in your Main Activity

toolbar = (Toolbar) findViewById(R.id.app_bar);
setSupportActionBar(toolbar);

And finally to any thing you want to do to the toolbar, obtain it and treat it like the old Action Bar:

getSupportActionBar().setHomeAsUpEnabled(true);

Material Design for Pre-Lollipop Devices :

All of your themes (that want an Action Bar/Toolbar) must inherit from Theme.AppCompat. There are variants available, including Light and NoActionBar.

When inflating anything to be displayed on the action bar (such as a SpinnerAdapter for list navigation in the toolbar), make sure you use the action bar’s themed context, retrieved via getSupportActionBar().getThemedContext().

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Android Support Library 22.1 :

AppCompat allows you to use android:theme for Toolbars (deprecating the app:theme used previously) and, even better, brings android:theme support to all views on API 11+ devices.