Spinner

 

package  com.test.android;

import  android.app.Activity;
import  android.os.Bundle;
import  android.view.View;
import  android.widget.AdapterView;
import  android.widget.ArrayAdapter;
import  android.widget.Spinner;
import  android.widget.Toast;

public   class  HelloAndroid  extends  Activity {
     private   static   final  String[] m_arr  =  { " 第一组 " , " 第二组 " , " 第三组 " };
     /**  Called when the activity is first created.  */
    @Override
     public   void  onCreate(Bundle savedInstanceState) {
         super .onCreate(savedInstanceState);
        setContentView(R.layout.main);

        Spinner _spin  =  (Spinner)findViewById(R.id.Spinner01);
        ArrayAdapter < String >  ada  =   new  ArrayAdapter < String > ( this , android.R.layout.simple_spinner_item, m_arr);
        ada.setDropDownViewResource(android.R.layout.simple_spinner_dropdown_item);
        _spin.setAdapter(ada);
        _spin.setOnItemSelectedListener( new  Spinner.OnItemSelectedListener(){
             public   void  onItemSelected(AdapterView <?>  arg0, View arg1,  int  arg2,  long  arg3){
                dispToast( " 选择的是 " + m_arr[arg2]);
                arg0.setVisibility(View.VISIBLE);
            }
             public   void  onNothingSelected(AdapterView <?>  arg0){
                 //
            }
        });
   }
     public   void  dispToast(String str){
        Toast.makeText( this , str, Toast.LENGTH_SHORT).show();
    }
}