我有如下所示的xml，它应该在嵌套滚动视图上显示背景图像。但它只显示Android 5.0上升但不适用于棒棒糖以下的版本。对于低于5.0的版本，它仅显示没有背景的圆形图像按钮。任何建议或想法都非常感谢和欢迎
<android.support.design.widget.CoordinatorLayout
xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_height="match_parent"
android:layout_width="match_parent"
xmlns:app="http://schemas.android.com/apk/res-auto"
android:id="@+id/coordinator"
android:fitsSystemWindows="true">
<android.support.design.widget.AppBarLayout
android:id="@+id/appbar"
android:layout_height="192dp"
android:layout_width="match_parent"
android:fitsSystemWindows="true"
android:theme="@style/ThemeOverlay.AppCompat.Light">
<android.support.design.widget.CollapsingToolbarLayout
android:id="@+id/collapsing_toolbar"
android:layout_height="match_parent"
android:layout_width="match_parent"
android:fitsSystemWindows="true"
android:background="#000000"
app:contentScrim="?attr/colorPrimary"
app:expandedTitleMarginBottom="32dp"
app:expandedTitleMarginEnd="64dp"
app:expandedTitleMarginStart="48dp"
app:layout_scrollFlags="scroll|exitUntilCollapsed">
<ImageView
android:id="@+id/header"
android:layout_height="match_parent"
android:layout_width="match_parent"
android:background="@drawable/ndwlogo"
android:fitsSystemWindows="true"
android:scaleType="centerCrop"
app:layout_collapseMode="parallax"/>
<android.support.v7.widget.Toolbar
android:id="@+id/anim_toolbar"
android:layout_width="match_parent"
android:layout_height="?attr/actionBarSize"
app:layout_collapseMode="pin"
app:popupTheme="@style/ThemeOverlay.AppCompat.Light"/>
</android.support.design.widget.CollapsingToolbarLayout>
</android.support.design.widget.AppBarLayout>
<android.support.v4.widget.NestedScrollView
android:layout_width="match_parent"
android:layout_height="match_parent"
android:fillViewport="true"
app:layout_behavior="@string/appbar_scrolling_view_behavior">
<!-- Scrollable content goes inside-->
<!--this is the parent linear layout-->
<LinearLayout
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical"
android:weightSum="9">
<LinearLayout
android:layout_width="fill_parent"
android:layout_marginTop="16dp"
android:layout_height="0dp"
android:orientation="horizontal"
android:layout_weight="2"
android:weightSum="2">
<com.pkmmte.view.CircularImageView
android:layout_width="0dp"
android:id="@+id/agenda_btn"
android:layout_marginLeft="56dp"
android:layout_height="match_parent"
android:layout_weight="1"
android:src="@drawable/agenda"/>
<com.pkmmte.view.CircularImageView
android:layout_width="0dp"
android:id="@+id/info_btn"
android:layout_height="match_parent"
android:layout_weight="1"
android:src="@drawable/info" />
</LinearLayout>
<LinearLayout
android:layout_width="fill_parent"
android:layout_marginTop="?attr/actionBarSize"
android:layout_height="0dp"
android:orientation="horizontal"
android:layout_gravity="center_horizontal"
android:layout_weight="2"
android:weightSum="2">
<com.pkmmte.view.CircularImageView
android:layout_width="0dp"
android:layout_marginLeft="56dp"
android:id="@+id/maps_btn"
android:layout_height="match_parent"
android:layout_weight="1"
android:src="@drawable/maps"/>
<com.pkmmte.view.CircularImageView
android:layout_width="0dp"
android:id="@+id/news_btn"
android:layout_height="match_parent"
android:layout_weight="1"
android:src="@drawable/news" />
</LinearLayout>
<LinearLayout
android:layout_width="fill_parent"
android:layout_marginTop="?attr/actionBarSize"
android:layout_height="0dp"
android:orientation="horizontal"
android:layout_gravity="center_horizontal"
android:layout_weight="2"
android:weightSum="2">
<com.pkmmte.view.CircularImageView
android:layout_width="0dp"
android:layout_marginLeft="56dp"
android:layout_height="match_parent"
android:layout_weight="1"
android:id="@+id/guide_btn"
android:src="@drawable/ndw_guide"/>
<com.pkmmte.view.CircularImageView
android:layout_width="0dp"
android:layout_height="match_parent"
android:layout_weight="1"
android:id="@+id/directory_btn"
android:src="@drawable/directory" />
</LinearLayout>
<LinearLayout
android:layout_width="fill_parent"
android:layout_marginTop="?attr/actionBarSize"
android:layout_height="0dp"
android:orientation="horizontal"
android:layout_gravity="center_horizontal"
android:layout_weight="2"
android:weightSum="2">
<com.pkmmte.view.CircularImageView
android:layout_width="0dp"
android:layout_marginLeft="56dp"
android:layout_height="match_parent"
android:layout_weight="1"
android:id="@+id/social_btn"
android:src="@drawable/socialmedia"/>
<com.pkmmte.view.CircularImageView
android:layout_width="0dp"
android:layout_height="match_parent"
android:layout_weight="1"
android:id="@+id/partners_btn"
android:src="@drawable/partners" />
</LinearLayout>
<LinearLayout
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:paddingLeft="32dp"
android:layout_weight="1">
<TextView
android:id="@+id/showtimer"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:text="@string/showtimer" />
</LinearLayout>
<LinearLayout
android:layout_width="fill_parent"
android:layout_marginTop="20dp"
android:layout_height="0dp"
android:orientation="horizontal"
android:layout_gravity="center_horizontal"
android:layout_weight="2"
android:weightSum="4">
<TextView
android:layout_height="match_parent"
android:layout_marginLeft="32dp"
android:id="@+id/timerday"
android:text="@string/countdowndefault"
android:layout_width="0dp"
android:textSize="30dp"
android:layout_weight="1"/>
<TextView
android:layout_width="0dp"
android:layout_height="match_parent"
android:layout_weight="1"
android:textSize="30dp"
android:text="@string/countdowndefault"
android:id="@+id/timerhour" />
<TextView
android:layout_width="0dp"
android:layout_height="match_parent"
android:layout_weight="1"
android:textSize="30dp"
android:text="@string/countdowndefault"
android:id="@+id/timermins"/>
<TextView
android:layout_width="0dp"
android:layout_height="match_parent"
android:layout_weight="1"
android:textSize="30dp"
android:text="@string/countdowndefault"
android:id="@+id/timersec" />
</LinearLayout>
</LinearLayout>
</android.support.v4.widget.NestedScrollView>
</android.support.design.widget.CoordinatorLayout>