How to hide toolbar after collapsing while recyclerView scrolling down

collapsingtoolbarlayout.xml

<android.support.design.widget.CoordinatorLayout 
    android:id="@+id/careers_coordinator_layout"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:fitsSystemWindows="true"
    xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    tools:context=".activity.CareersActivity"
    xmlns:tools="http://schemas.android.com/tools">

    <android.support.design.widget.AppBarLayout
        android:id="@+id/appBar"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:fitsSystemWindows="true"
        android:theme="@style/ThemeOverlay.AppCompat.Dark.ActionBar">

        <android.support.design.widget.CollapsingToolbarLayout
            android:id="@+id/collapsing_toolbar"
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:fitsSystemWindows="true"
            app:contentScrim="?attr/colorPrimary"
            app:layout_scrollFlags="scroll|enterAlways|enterAlwaysCollapsed">

            <ImageView
                android:id="@+id/background"
                android:layout_width="match_parent"
                android:layout_height="256dp"
                android:scaleType="centerCrop"
                android:fitsSystemWindows="true"
                app:layout_collapseMode="parallax"
                android:src="@drawable/placeholder"/>

            <android.support.v7.widget.Toolbar
                android:id="@+id/toolbar"
                android:layout_width="match_parent"
                android:layout_height="?attr/actionBarSize"
                app:contentScrim="?attr/colorPrimary"
                android:fitsSystemWindows="true"
                app:titleTextColor="@color/main_color_white"
                app:popupTheme="@style/ThemeOverlay.AppCompat.Light"
                app:layout_collapseMode="pin"/>

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

        <android.support.design.widget.TabLayout
            android:id="@+id/tabs"
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:background="?attr/colorPrimary"
            app:tabIndicatorColor="@color/colorAccent"
            app:tabSelectedTextColor="@color/colorAccent"
            app:tabTextColor="@android:color/white"
            app:tabIndicatorHeight="4dp"
            app:tabMode="fixed"/>

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

    <android.support.v4.view.ViewPager
        android:id="@+id/viewpager"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        app:layout_behavior="@string/appbar_scrolling_view_behavior" />

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

For CollapsingToolbarLayout use scroll flags:

`app:layout_scrollFlags="scroll|enterAllwaysCollapsed"`

this flag combination will disappear toolbar while scrolling down. And CollapsingToolbarLayout will expand fully when you scroll to top of the list.

And no need to remove app:layout_collapseMode="pin" from Toolbar, because collapseMode flags are to define behavior and placement of views inside CollapsingToolbarLayout and will not effect actual collapsing and expansion of CollapsingToolbarLayout.