shape

1、画虚线，实线：

android:shape="line" 可以修改你想要的形状

<?xml version="1.0" encoding="utf-8"?>
<shape xmlns:android="http://schemas.android.com/apk/res/android" 
     android:shape="line">
     <!-- 显示一条虚线，破折线的宽度为dashWith，破折线之间的空隙的宽度为dashGap，当dashGap=0dp时，为实线 -->
   <stroke android:width="1dp" android:color="#D5D5D5"    
             android:dashWidth="2dp" android:dashGap="3dp" />   
             <!-- 虚线的高度 --> 
     <size android:height="2dp" />    
</shape>

2、画圆角矩形

<?xml version="1.0" encoding="utf-8"?>
<shape xmlns:android="http://schemas.android.com/apk/res/android" 
    android:shape="rectangle">
            <!-- 填充颜色 -->
    <solid android:color="#FFFFFF"></solid>
   
    <!-- 线的宽度，颜色灰色 -->
    <stroke android:width="1dp" android:color="#D5D5D5"></stroke>        
   
    <!-- 矩形的圆角半径 -->
    <corners android:radius="0dp" />       
            
</shape>

3、一半圆角：

<shape xmlns:android="http://schemas.android.com/apk/res/android" 
    android:shape="rectangle">
        <corners  android:topLeftRadius="16dp" <!--上面左圆角的半径-->
              android:topRightRadius="16dp"          <!--上面右圆角的半径-->
              android:bottomLeftRadius="0dp"         <!--下面左圆角的半径-->
              android:bottomRightRadius="0dp"/>   <!--下面右圆角的半径-->

        <gradient android:startColor="#ffffff" 
              android:endColor="#ffffff"
              android:angle="270"/>

        <stroke   android:width="1dp" 
              android:color="#80000000" /> 
        </shape>