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();
    }
}