How to make Toolbar transparent?

Question

It is self Q&A post I have transparent ActionBar which overlays layout. After migration to the latest support library I have been forced to get rid off the ActionBar in favor of the Toolbar. The old ways to make it transparent and overlay that layout doesn't work anymore.

<style name="CustomActionBarTheme" parent="@android:style/Theme.AppCompat">
    <item name="android:windowActionBarOverlay">true</item>
    <item name="windowActionBarOverlay">true</item>
    <item name="android:actionBarStyle">@style/TransparentActionBar</item>
</style>

<style name="TransparentActionBar" parent="@android:style/Widget.Holo.Light.ActionBar">
    <item name="android:background">@android:color/transparent</item>
</style>

Answer 1

Create your toolbar.xml file with background of AppBarLayout is @null

<?xml version="1.0" encoding="utf-8"?>
<android.support.design.widget.AppBarLayout
    android:id="@+id/general_appbar"
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:background="@null"
    xmlns:android="http://schemas.android.com/apk/res/android">
    <android.support.v7.widget.Toolbar
        android:layout_width="match_parent"
        android:layout_height="?attr/actionBarSize">
        <TextView
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:gravity="center_horizontal"
            android:text="Login"
            android:textSize="20sp"/>
    </android.support.v7.widget.Toolbar>

</android.support.design.widget.AppBarLayout>

and here is result: