Eu tenho usado a biblioteca de suporte ao design do Android para reduzir o layout da barra de ferramentas. Tudo funciona bem, exceto que eu quero rolar a exibição inteira no conteúdo de rolagem em collapsingBarlayout

Aqui está o layout xml:

<?xml version="1.0" encoding="utf-8"?>
<android.support.v4.widget.DrawerLayout
    xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    android:id="@+id/drawer_layout"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:fitsSystemWindows="true">


    <android.support.design.widget.CoordinatorLayout
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:fitsSystemWindows="true">

        <android.support.design.widget.AppBarLayout
            android:id="@+id/appbar"
            android:layout_width="match_parent"
            android:layout_height="420dp"
            android:theme="@style/ThemeOverlay.AppCompat.Dark.ActionBar"
            android:fitsSystemWindows="true">

            <android.support.design.widget.CollapsingToolbarLayout
                android:id="@+id/collapsing_toolbar"
                android:layout_width="match_parent"
                android:layout_height="match_parent"
                app:layout_scrollFlags="scroll|exitUntilCollapsed"
                app:contentScrim="?attr/colorPrimary"
                app:expandedTitleMarginStart="48dp"
                app:expandedTitleMarginEnd="64dp"
                android:fitsSystemWindows="true">

                <android.support.v4.view.ViewPager
                    xmlns:android="http://schemas.android.com/apk/res/android"
                    android:id="@+id/pager"
                    android:layout_width="match_parent"
                    android:layout_height="match_parent"
                    android:scaleType="centerCrop"
                    app:layout_collapseMode="parallax"
                    app:layout_collapseParallaxMultiplier="0.8"
                    android:fitsSystemWindows="true"
                    app:layout_behavior="@string/appbar_scrolling_view_behavior"
                    />

                <android.support.v7.widget.Toolbar
                    android:id="@+id/toolbar"
                    android:layout_width="match_parent"
                    android:layout_height="?attr/,actionBarSize"
                    app:popupTheme="@style/ThemeOverlay.AppCompat.Light"
                    app:layout_collapseMode="pin" />

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

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

        <android.support.v4.widget.NestedScrollView
            android:id="@+id/scroll_view"
            android:layout_width="match_parent"
            android:layout_height="match_parent"
            android:clipToPadding="false"
            app:layout_behavior="@string/appbar_scrolling_view_behavior">

            <include layout="@layout/activity_item_detail"
                />

        </android.support.v4.widget.NestedScrollView>

        <android.support.design.widget.FloatingActionButton
            android:id="@+id/fab_button"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_margin="@dimen/activity_vertical_margin"
            android:clickable="true"
            android:src="@android:drawable/ic_menu_call"
            app:layout_anchor="@+id/appbar"
            app:layout_anchorGravity="bottom|right|end"
            style="@style/floating_action_button"
            />

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

    <android.support.design.widget.NavigationView
        android:id="@+id/navigation_view"
        android:layout_width="wrap_content"
        android:layout_height="match_parent"
        android:layout_gravity="start"
        app:headerLayout="@layout/drawer_header"
        app:menu="@menu/drawer"/>
</android.support.v4.widget.DrawerLayout>

A rolagem do conteúdo funciona se tocar em algo, exceto o viewpager / barra de ferramentas. Eu preciso da mesma experiência de rolagem ao tocar e rolar verticalmente no pager de exibição também. Tentara substituir o pager onTouchEvent do view para passar o evento de movimento ACTION_UP para scroll_view.

nestedScrollView.post(new Runnable() {
    @Override
    public void run() {
        mPager.setOnTouchListener(new View.OnTouchListener() {
            @Override
            public boolean onTouch(View v, MotionEvent event) {
                if (event.getAction() == MotionEvent.ACTION_UP) {
                    return nestedScrollView.onTouchEvent(event);
                } else {
                    return v.onTouchEvent(event);
                }
            }
        });
    }
});

Mas isso não funciona. Por favor, ajude com uma solução alternativa / qualquer invasão que possa resolver rapidamente isso.