Expandable Toolbar

activity_main_activity2.xml

<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    tools:context="zapbuild.kr.myexperimentwithview.MainActivity2">

    <zapbuild.kr.myexperimentwithview.fancytoolbar.NotifyingScrollView
        android:id="@+id/notifyScroll"
        android:layout_width="match_parent"
        android:layout_height="match_parent">

        <RelativeLayout
            android:id="@+id/parentCotainer"
            android:layout_width="match_parent"
            android:layout_height="match_parent"
            android:background="@color/material_blue_grey_800"
            android:orientation="vertical">

            <View
                android:id="@+id/dummy"
                android:layout_width="match_parent"
                android:layout_height="110dp" />

            <TextView
                android:id="@+id/tetxview2"
                android:layout_width="match_parent"
                android:layout_height="match_parent"
                android:layout_below="@+id/dummy"
                android:background="#fff"
                android:paddingTop="2dp"
                android:text="@string/long_text" />
        </RelativeLayout>
    </zapbuild.kr.myexperimentwithview.fancytoolbar.NotifyingScrollView>


    <LinearLayout
        android:id="@+id/fake_header"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:orientation="vertical">

        <View
            android:layout_width="match_parent"
            android:layout_height="56dp"
            android:background="@color/material_blue_grey_800" />

        <LinearLayout
            android:layout_width="match_parent"
            android:layout_height="56dp"
            android:background="@color/material_blue_grey_800"
            android:gravity="center_vertical"
            android:id="@+id/replaceable_toolbar"

            >

            <TextView
                android:layout_width="match_parent"
                android:layout_height="wrap_content"
                android:gravity="center_vertical"
                android:paddingLeft="48dp"
                android:text="Big data"
                android:textColor="@android:color/white"
                android:textSize="22sp"
                android:id="@+id/toolbar_title"
                />
        </LinearLayout>
    </LinearLayout>

    <android.support.v7.widget.Toolbar xmlns:android="http://schemas.android.com/apk/res/android"
        xmlns:app="http://schemas.android.com/apk/res-auto"
        android:id="@+id/toolbar"
        android:layout_width="match_parent"
        android:layout_height="@dimen/toolbar_height"
        android:background="@android:color/transparent"
        android:gravity="bottom"
        app:popupTheme="@style/ThemeOverlay.AppCompat.Light"
        app:theme="@style/ThemeOverlay.AppCompat.Dark.ActionBar" />

</RelativeLayout>