下拉列表问题

Question

我现在要实现一个二级联动的下拉列表，就是选定省份后，城市的下拉列表出现相应变化，但一直报错，请大家帮我看看
package zye.client.Client;import android.app.Activity;
import android.content.Context;
import android.os.Bundle;
import android.view.View;
import android.widget.AdapterView;
import android.widget.ArrayAdapter;
import android.widget.Spinner;
import android.widget.AdapterView.OnItemSelectedListener;public class cityset extends Activity{
private String[] province = new String[] {"直辖市", "特别行政区","黑龙江"};
private String[] city = new String[]{"北京","上海","天津","重庆"};
private String[][] pandc = new String[][]{{"北京","上海","天津","重庆"},{"香港","澳门"},{"哈尔滨","齐齐哈尔","牡丹江","大庆","伊春","双鸭山","鹤岗","鸡西","佳木斯","七台河","黑河","绥化","大兴安岭"}};
private Spinner sp;
private Spinner sp2;
private Context context;

 public void onCreate(Bundle savedInstanceState) {
     super.onCreate(savedInstanceState);
     setContentView(R.layout.cityset);
     
     context = this;
     
     ArrayAdapter<String> adapter = new ArrayAdapter<String>(this,android.R.layout.simple_spinner_item, province);  
        adapter.setDropDownViewResource(android.R.layout.simple_spinner_dropdown_item);  
        sp = (Spinner) findViewById(R.id.province);  
        sp.setAdapter(adapter);
        sp.setOnItemSelectedListener(selectListener);
        
        
        ArrayAdapter<String> adapter2 = new ArrayAdapter<String>(this,android.R.layout.simple_spinner_item, city);  
        adapter2.setDropDownViewResource(android.R.layout.simple_spinner_dropdown_item);  
        sp2 = (Spinner) findViewById(R.id.city);
        sp2.setAdapter(adapter2);
        
    }
 
 private OnItemSelectedListener selectListener = new OnItemSelectedListener(){
 public void onItemSelected(AdapterView parent, View v, int position,long id){
 int pos = sp.getSelectedItemPosition();
 adapter2 = new ArrayAdapter<String>(context,android.R.layout.simple_spinner_item, pandc[pos]);
 sp2.setAdapter(adapter2);
 }
   
 public void onNothingSelected(AdapterView arg0){  }  };}<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="fill_parent"
    android:layout_height="fill_parent"
    android:background="#FFFFFF"
    >
<Spinner android:id="@+id/province"  
     android:layout_width="fill_parent"  
       android:layout_height="45px"
       android:layout_marginLeft="75px"
       android:layout_marginRight="20px"
android:layout_marginTop="7px"  
      android:drawSelectorOnTop="true"
      android:layout_alignParentRight="true"  
    />
    <Spinner android:id="@+id/city"  
     android:layout_width="fill_parent"  
       android:layout_height="45px"
       android:layout_marginLeft="75px"
       android:layout_marginRight="20px"
android:layout_marginTop="3px"  
      android:drawSelectorOnTop="true"
      android:layout_alignParentRight="true" 
      android:layout_below="@id/province" 
         />
      
</RelativeLayout>

Answer 1

报错是adapter2 cannot be resolved，不明白为什么会报这个错

Answer 2

我自己解决了 private OnItemSelectedListener selectListener = new OnItemSelectedListener(){
 public void onItemSelected(AdapterView parent, View v, int position,long id){
 int pos = sp.getSelectedItemPosition();
 ArrayAdapter<String> adapter3 = new ArrayAdapter<String>(context,android.R.layout.simple_spinner_item, pandc[pos]);
 sp2.setAdapter(adapter3);
 }
   
 public void onNothingSelected(AdapterView arg0){  }  };又重新声明了一个ArrayAdapter，不过还是不明白为什么不能重用adapter2，另外怎么省份和城市的下拉列表的表现形式不一样，那个城市的下拉列表打开颜色非常地暗，省份的下拉列表就很好

Answer 3

看了你的代码，应该在IDE里面就会报错啊：adapter2是在onCreate()函数里面声明的局部变量，怎么能在其他函数里面用呢？你再仔细看看。。

Answer 4

private OnItemSelectedListener selectListener = new OnItemSelectedListener(){
         public void onItemSelected(AdapterView parent, View v, int position,long id){
             int pos = sp.getSelectedItemPosition();
             adapter2 = new ArrayAdapter<String>(context,android.R.layout.simple_spinner_item, pandc[pos]);
             sp2.setAdapter(adapter2);
         }
这里有错！

Answer 5

重新设置颜色值或者样式，总觉得sdk有bug

Answer 6

adapter2是局部变量吧？应该重新定义才能用

Answer 7

我知道怎么回事
//         ArrayAdapter<String> adapter2 = new ArrayAdapter<String>(this,android.R.layout.simple_spinner_item, city);  
//         adapter2.setDropDownViewResource(android.R.layout.simple_spinner_dropdown_item);  
         sp2 = (Spinner) findViewById(R.id.city);
//         sp2.setAdapter(adapter2);
只要第三句，就行了，剩下的adapter2在private OnItemSelectedListener selectListener = new OnItemSelectedListener(){}里面赋值就行了