layout设置background图片遮挡问题

Question

layout图片

Answer 1

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="vertical" >    <RelativeLayout
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:background="@drawable/back" >        <LinearLayout
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_alignParentBottom="true"
            android:layout_centerHorizontal="true"
            android:layout_marginBottom="200dp"
            android:background="@drawable/front"
            android:orientation="vertical" >
        </LinearLayout>    </RelativeLayout></LinearLayout>
layout代码如上，RelativeLayout里的LinearLayout的背景图片front完全显示不出来，全屏都是RelativeLayout的背景图片back

Answer 2

如果把<RelativeLayout
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:background="@drawable/back" >  这里该成颜色值得话就没问题