Android CollapsingToolbarLayout不可滚动

Question

我在CoordinatorLayout家长内使用AppBarLayout，CollapsingToolbarLayout，ViewPager，RelativeLayout。

在滚动列表ViewPager (include recyclerview inside fragment)之前，滚动CollapsingToolbarLayout正常工作。但是，当我第一次滚动ViewPager时，再次滚动CollapsingToolbarLayout无效。!!为什么呢？

我想在viewpager上滚动并在CollapsingToolbarLayout上滚动。 CollapsingToolbarLayout不可滚动：|

我的XML布局：

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
android:id="@+id/mainLayout"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:clickable="true">

<ImageView
    android:id="@+id/BgPhoto"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:layout_gravity="top"
    android:scaleType="centerCrop" />

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

    <android.support.design.widget.AppBarLayout
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:background="@android:color/transparent">

        <android.support.design.widget.CollapsingToolbarLayout
            android:layout_width="match_parent"
            android:layout_height="match_parent"
            android:minHeight="60dp"
            android:background="@color/trans10"
            app:layout_scrollFlags="scroll|exitUntilCollapsed"
            app:contentScrim="@android:color/transparent"
            app:titleEnabled="false">

            <LinearLayout
                android:layout_width="match_parent"
                android:layout_height="wrap_content"
                android:layout_gravity="top"
                android:orientation="vertical"
                app:layout_collapseMode="none">

                <!-- date and rate -->
                <LinearLayout
                    android:id="@+id/linearLayout"
                    android:layout_width="match_parent"
                    android:layout_height="wrap_content"
                    android:orientation="horizontal"
                    android:paddingTop="5dp"
                    android:paddingBottom="20dp"
                    android:paddingLeft="15dp"
                    android:paddingRight="15dp"
                    android:weightSum="3">

                    <TextView
                        android:layout_width="wrap_content"
                        android:layout_height="wrap_content"
                        android:layout_weight="1"
                        android:textSize="12sp"
                        android:gravity="left"/>

                    <TextView
                        android:layout_width="wrap_content"
                        android:layout_height="wrap_content"
                        android:layout_weight="1"
                        android:textSize="12sp"
                        android:gravity="center"/>

                    <TextView
                        android:layout_width="wrap_content"
                        android:layout_height="wrap_content"
                        android:layout_weight="1"
                        android:textSize="12sp"
                        android:gravity="right"/>

                </LinearLayout>

                <com.facebook.drawee.view.SimpleDraweeView
                    xmlns:fresco="http://schemas.android.com/apk/res-auto"
                    android:id="@+id/circlePhoto"
                    android:layout_width="150dp"
                    android:layout_height="150dp"
                    android:layout_gravity="center"
                    fresco:fadeDuration="200"
                    fresco:actualImageScaleType="centerCrop"
                    fresco:roundingBorderWidth="1dp"
                    fresco:roundAsCircle="true"/>

            </LinearLayout>

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

        <android.support.design.widget.TabLayout
            android:id="@+id/tabLayout"
            android:layout_width="match_parent"
            android:layout_height="50dp"
            app:tabTextAppearance="?android:attr/textAppearanceSmall"
            app:tabTextColor="@color/trans11"
            app:tabSelectedTextColor="@color/white"
            app:tabMode="fixed"
            app:tabIndicatorHeight="2dp"
            app:tabIndicatorColor="@color/white" />

    </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> </RelativeLayout>