自定义下拉菜单模式----Spinner与setDropDownViewResource的应用

Android提供的Spinner Widget的下拉菜单已经非常好用了,样式也还适用.但我们本节的Demo的重点在于自定义下拉菜单里的样式,其关键在于调用setDropDownViewResource方法,以XML的方式定义下拉菜单要显示的模样.

Step 1: 创建一个新的Android 工程, 我们命名为SpinnerDemo .

Step 2 :打开layout 文件夹,找到main.xml 将其内容改为:

<?xml version="1.0" encoding="utf-8"?>
 
<LinearLayout xmlns:android=http://schemas.android.com/apk/res/android 
android:orientation="vertical"
 android:padding="10dip" 
android:layout_width="fill_parent" 
android:layout_height="wrap_content">
 
<TextView 
android:layout_width="fill_parent" 
android:layout_height="wrap_content" 
 android:layout_marginTop="10dip" 
android:text="Please select a planet:" 

/>
 
 <Spinner  
android:id="@+id/spinner" 
android:layout_width="fill_parent" 
android:layout_height="wrap_content" 
android:drawSelectorOnTop="true" 
 android:prompt="@string/planet_prompt" 
 
/>  
 
</LinearLayout>
 
 注意:  
the Spinner's android:prompt   
is a string resource. In this case, Android does not allow it to be a string, it must 
be a reference to a resource. So... 
 Step 3 
:找到在res/values/string.xml, 
在里面加入如下(黑体 
)一行: 
 
 
<?xml version="1.0" encoding="utf-8"?>
 
<resources> 
<string name="hello">Hello World, SpinnerDemo!</string> 
<string name="app_name">SpinnerDemo</string> 
 <string name="planet_prompt">Choose a planet</string>  
</resources>
 
 
 
 Step 4 
:在res/values/ 
文件夹下创建一个xml 
文件,命名为arrays.xml:  
 
 
 <resources> 
 
 
 <string-array name="planets"> 

<item>Mercury</item> 
<item>Venus</item> 
<item>Earth</item> 
<item>Mars</item>
<item>Jupiter</item> 
<item>Saturn</item> 
<item>Uranus</item> 
<item>Neptune</item> 
 </string-array>  

  </resources>  
 
这是用户可以从Spinner Widget选择list 的选择项. 
 
 
 Step5 
:打开SpinnerDemo.java 
,编辑内容如下:
 
 
 
package com.android.test;
 
import android.app.Activity;
 
import android.os.Bundle;
 
 import android.widget.ArrayAdapter;
 
import android.widget.Spinner; 
 
 
public class SpinnerDemo  
extends Activity{
 
public void onCreate(Bundle savedInstanceState) {
 
super.onCreate(savedInstanceState);
 
setContentView(R.layout.main); 
 
 Spinner s = (Spinner) findViewById(R.id.spinner);
 
ArrayAdapter adapter = ArrayAdapter.createFromResource(
 
this, R.array.planets, android.R.layout.simple_spinner_item); 
 
adapter.setDropDownViewResource(android.R.layout.simple_spinner_dropdown_item);
 
s.setAdapter(adapter);  
 
}
 
}