Android elevation shadows not showing at runtime

Question

I'm trying to utilize elevation attributes to display drop shadows. As you can see from the images, it displays fine in Android Studio but when run on the device, one of the drop shadows disappears. Why would one show but not the other? Image from Android Studio Screenshot from Marshmallow device <ScrollView xmlns:android="http://schemas.android.com/apk/res/android" xmlns:tools="http://schemas.android.com/tools" android:orientation="vertical" android:layout_width="match_parent" android:layout_height="match_parent" android:background="@color/white_80" > <LinearLayout android:layout_width="match_parent" android:layout_height="wrap_content" android:orientation="vertical"> <LinearLayout android:id="@+id/booking_details_top_block" android:layout_width="match_parent" android:layout_height="wrap_content" android:orientation="vertical" android:elevation="4dp" > <LinearLayout android:id="@+id/image_block" android:layout_width="match_parent" android:layout_height="wrap_content" android:orientation="horizontal" android:gravity="center_horizontal" > <ImageView android:layout_width="50dp" android:layout_height="50dp" android:layout_margin="8dp" android:background="@color/black" /> <ImageView android:layout_width="50dp" android:layout_height="50dp" android:layout_margin="8dp" android:background="@color/black" /> </LinearLayout> <LinearLayout android:layout_width="match_parent" android:layout_height="wrap_content" android:orientation="vertical" android:gravity="center_horizontal" android:layout_margin="16dp" android:padding="16dp" android:background="@drawable/booking_detail_date_background" > <TextView android:layout_width="wrap_content" android:layout_height="wrap_content" android:layout_margin="4dp" tools:text ="Tuesday, September 1" /> <TextView android:layout_width="wrap_content" android:layout_height="wrap_content" android:layout_margin="4dp" tools:text ="4:00 PM - 6:00 PM" /> </LinearLayout> <TextView android:id="@+id/bookings_status" android:layout_width="wrap_content" android:layout_height="wrap_content" android:paddingTop="4dp" android:paddingBottom="4dp" android:paddingRight="16dp" android:paddingLeft="16dp" android:gravity="center_horizontal" android:layout_gravity="center_horizontal" android:background="@drawable/status_background" android:textColor="@color/white" tools:text="CONFIRMED" /> <LinearLayout android:layout_width="match_parent" android:layout_height="wrap_content" android:orientation="vertical" android:gravity="center_horizontal" android:layout_marginTop="8dp" android:padding="8dp" > <TextView android:layout_width="wrap_content" android:layout_height="wrap_content" android:layout_margin="4dp" android:text ="@string/booking_details_brig" /> <TextView android:layout_width="wrap_content" android:layout_height="wrap_content" android:layout_margin="4dp" tools:text ="Lorena M." /> </LinearLayout> <RatingBar android:id="@+id/rate_bar" android:layout_width="wrap_content" android:layout_height="wrap_content" android:stepSize="1" style="@style/Widget.CustomRatingBar" android:layout_gravity="center_horizontal" android:layout_marginTop="8dp" android:layout_marginBottom="24dp" android:layout_marginRight="@dimen/dialog_horizontal_margin" android:layout_marginLeft="@dimen/dialog_horizontal_margin" /> <View android:layout_width="match_parent" android:layout_height="1dp" /> </LinearLayout> <include layout="@layout/widget_booking_details" /> </LinearLayout> widget_booking_details > <LinearLayout android:layout_width="match_parent" android:layout_height="wrap_content" android:background="@color/white" android:elevation="2dp" android:orientation="vertical"> <LinearLayout android:layout_width="match_parent" android:layout_height="wrap_content" android:orientation="horizontal" android:paddingTop="8dp" android:paddingBottom="8dp" > <TextView android:layout_width="0dp" android:layout_height="wrap_content" android:layout_weight="1" android:layout_marginLeft="@dimen/booking_details_margin" android:paddingTop="@dimen/booking_details_padding" android:paddingBottom="@dimen/booking_details_padding" android:layout_gravity="center_vertical" android:text="@string/booking_details_address"/> <LinearLayout android:layout_width="0dp" android:layout_height="wrap_content" android:layout_weight="1" android:orientation="vertical" android:layout_gravity="center_vertical" > <TextView android:layout_width="wrap_content" android:layout_height="wrap_content" tools:text="22 Phitsanulok Rd, apt. 3"/> <TextView android:layout_width="wrap_content" android:layout_height="wrap_content" tools:text="Khwaeng Dusit, Dusit"/> </LinearLayout> </LinearLayout> <View android:layout_width="match_parent" android:layout_height="1dp" android:background="@color/white" android:layout_marginStart="@dimen/booking_details_margin" android:layout_marginEnd="@dimen/booking_details_margin" /> <RelativeLayout android:layout_width="match_parent" android:layout_height="wrap_content"> <LinearLayout android:layout_width="match_parent" android:layout_height="wrap_content" android:orientation="horizontal" android:paddingTop="@dimen/booking_details_padding" android:paddingBottom="@dimen/booking_details_padding" > <TextView android:layout_width="0dp" android:layout_height="wrap_content" android:layout_weight="1" android:layout_marginLeft="@dimen/booking_details_margin" android:paddingTop="4dp" android:paddingBottom="4dp" android:layout_gravity="center_vertical" android:text="@string/booking_details_services"/> <LinearLayout android:layout_width="0dp" android:layout_height="wrap_content" android:layout_weight="1" android:orientation="vertical" android:layout_gravity="center_vertical" > <TextView android:layout_width="wrap_content" android:layout_height="wrap_content" tools:text="Waves after waves,"/> <TextView android:layout_width="wrap_content" android:layout_height="wrap_content" tools:text="Evening glam"/> </LinearLayout> </LinearLayout> <ImageButton android:layout_width="wrap_content" android:layout_height="wrap_content" android:layout_marginRight="@dimen/booking_details_margin" android:layout_alignParentRight="true" android:layout_centerVertical="true" android:src="@drawable/up_arrow" android:background="@color/cream" /> </RelativeLayout> <View android:layout_width="match_parent" android:layout_height="1dp" android:background="@color/white" android:layout_marginStart="@dimen/booking_details_margin" android:layout_marginEnd="@dimen/booking_details_margin" /> <LinearLayout android:layout_width="match_parent" android:layout_height="wrap_content" android:orientation="horizontal" android:paddingTop="@dimen/booking_details_padding" android:paddingBottom="@dimen/booking_details_padding" > <TextView android:layout_width="0dp" android:layout_height="wrap_content" android:layout_weight="1" android:layout_marginLeft="@dimen/booking_details_margin" android:paddingTop="4dp" android:paddingBottom="4dp" android:layout_gravity="center_vertical" android:text="@string/booking_details_cost"/> <TextView android:layout_width="0dp" android:layout_height="wrap_content" android:layout_weight="1" android:layout_gravity="center_vertical" tools:text="24,600B"/> </LinearLayout> <View android:layout_width="match_parent" android:layout_height="1dp" android:background="@color/white" android:layout_marginStart="@dimen/booking_details_margin" android:layout_marginEnd="@dimen/booking_details_margin" /> <LinearLayout android:layout_width="match_parent" android:layout_height="wrap_content" android:orientation="horizontal" android:paddingTop="@dimen/booking_details_padding" android:paddingBottom="@dimen/booking_details_padding" > <TextView android:layout_width="0dp" android:layout_height="wrap_content" android:layout_weight="1" android:layout_marginLeft="@dimen/booking_details_margin" android:paddingTop="4dp" android:paddingBottom="4dp" android:layout_gravity="center_vertical" android:text="@string/booking_details_payment"/> <TextView android:layout_width="0dp" android:layout_height="wrap_content" android:layout_weight="1" android:layout_gravity="center_vertical" tools:text="Mastercard ending 1234"/> </LinearLayout> <View android:layout_width="match_parent" android:layout_height="1dp" android:background="@color/white" android:layout_marginStart="@dimen/booking_details_margin" android:layout_marginEnd="@dimen/booking_details_margin" /> <LinearLayout android:layout_width="match_parent" android:layout_height="wrap_content" android:orientation="horizontal" android:paddingTop="@dimen/booking_details_padding" android:paddingBottom="@dimen/booking_details_padding" > <TextView android:layout_width="0dp" android:layout_height="wrap_content" android:layout_weight="1" android:layout_marginLeft="@dimen/booking_details_margin" android:paddingTop="4dp" android:paddingBottom="4dp" android:layout_gravity="center_vertical" android:text="@string/booking_details_booking_ref"/> <TextView android:layout_width="0dp" android:layout_height="wrap_content" android:layout_weight="1" android:layout_gravity="center_vertical" tools:text="1639460503"/> </LinearLayout> </LinearLayout> <LinearLayout android:layout_width="match_parent" android:layout_height="wrap_content" android:orientation="horizontal" android:paddingTop="@dimen/booking_details_padding" android:paddingBottom="@dimen/booking_details_padding" android:background="@color/white" > <TextView android:layout_width="0dp" android:layout_height="wrap_content" android:layout_weight="1" android:layout_marginLeft="@dimen/booking_details_margin" android:paddingTop="4dp" android:paddingBottom="4dp" android:layout_gravity="center_vertical" android:text="@string/booking_details_booking_help"/> <TextView android:layout_width="0dp" android:layout_height="wrap_content" android:layout_weight="1" android:layout_gravity="center_vertical" android:text="@string/booking_details_booking_help_email"/> <!--TODO make email an actual link--> </LinearLayout>

Answer 1

奇怪的解决方案，但我只需要在背景颜色：

    <LinearLayout
        android:id="@+id/booking_details_top_block"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:orientation="vertical"
        android:background="@color/white"
        android:elevation="4dp"
        >