为什么我的Android边框无法显示？

Question

border.xml:

 <shape xmlns:android="http://schemas.android.com/apk/res/android"
        android:shape="rectangle" >    
        <solid android:color="#ffffff" />
            <stroke
            android:width="1dip"
            android:color="#cbcbcb" />    
        <corners android:radius="7dp" />    
    </shape>

Set Background of LinearLayout:

      <?xml version="1.0" encoding="utf-8"?>
      <LinearLayout
                    android:layout_width="match_parent"
                    android:layout_height="wrap_content"
                    android:background="@drawable/border"
                    android:orientation="vertical" >
       //Child control
    </LinearLayout>

If LinearLayout has some child control: border display ok. But If LinearLayout have very much child controls, border can't display. Why border not display? how set border in this case?

Answer 1

because of this line :

android:layout_height="wrap_content"

when the LinearLayout doesn't have a child so wrap_content in android:layout_height cause that LinearLayout height to 0dp and nothing gonna show.set some size to your Layout and border will show up.