在android开发中，如何实现两个spinner 关联

在android开发中，如何实现两个spinner 关联，即点击第一个spinner后可以在第二个spinner中动态添加数据？

main.xml

[code="xml"]<?xml version="1.0" encoding="utf-8"?>
android:orientation="vertical"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
>
android:layout_width="90px"
android:layout_height="42px"
android:layout_marginTop="3px"
android:layout_marginLeft="60px"/>

<Spinner android:id="@+id/list2"
    android:layout_width="90px" 
    android:layout_height="42px"
    android:layout_marginTop="3px"
    android:layout_marginLeft="60px"/>      

[/code]
Activity

[code="java"]public class AndroidTestActivity extends Activity {
private Spinner spinner1;
private Context context;
/** Called when the activity is first created. */
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
context = this;
spinner1 = (Spinner) findViewById(R.id.list1);
String[] m={"aaa","bbb"};
ArrayAdapter adapter = new ArrayAdapter(this,android.R.layout.simple_spinner_item,m);
spinner1.setAdapter(adapter);
spinner1.setOnItemSelectedListener(spinnerSelectedListener);
}

private Spinner.OnItemSelectedListener spinnerSelectedListener = new Spinner.OnItemSelectedListener()  
{  
    public void onItemSelected(AdapterView<?> arg0, View arg1, int arg2,  
            long arg3) {  
        String selectedValue = (String)spinner1.getSelectedItem();
        Spinner spinner2 = (Spinner) findViewById(R.id.list2);
        String[] m={selectedValue};
        ArrayAdapter<String> adapter = new ArrayAdapter<String>(context,
                android.R.layout.simple_spinner_item, m);
        spinner2.setAdapter(adapter);
    }  

    public void onNothingSelected(AdapterView<?> arg0) {  
        // TODO Auto-generated method stub  
    }         
};

}[/code]