Toast Menu Activity ListView AlertDialog

package ke.we.sd; import java.util.ArrayList; import java.util.List; import android.app.Activity; import android.app.AlertDialog; import android.content.DialogInterface; import android.os.Bundle; import android.view.Menu; import android.view.MenuInflater; import android.view.MenuItem; import android.widget.Adapter; import android.widget.AdapterView; import android.widget.ArrayAdapter; import android.widget.ListView; import android.widget.TextView; import android.widget.Toast; public class Ac02 extends Activity{ @Override protected void onCreate(Bundle savedInstanceState) { // TODO Auto-generated method stub super.onCreate(savedInstanceState); setContentView(R.layout.ac02); ListViewTest(); } @Override public boolean onCreateOptionsMenu(Menu menu) { // TODO Auto-generated method stub MenuInflater mi=getMenuInflater(); mi.inflate(R.menu.menustyle, menu); return super.onCreateOptionsMenu(menu); } @Override public boolean onOptionsItemSelected(MenuItem item) { // TODO Auto-generated method stub switch(item.getItemId()){ case R.id.about_menu: Toast.makeText(this, "网络中断,请设置你的网络",Toast.LENGTH_SHORT).show(); return true; case R.id.exit_menu: AlertDialogTest(); } return true; } public void ListViewTest(){ ListView lisv=(ListView)findViewById(R.id.listview1); List<String>data=new ArrayList<String>(); data.add("新闻综合"); data.add("财经频道"); data.add("军事频道"); data.add("读书频道"); data.add("体育频道"); data.add("农业频道"); data.add("历史记录"); ArrayAdapter <String>adapter=new ArrayAdapter<String>(this,android.R.layout.simple_list_item_1,data); lisv.setAdapter(adapter); } public void AlertDialogTest(){ new AlertDialog.Builder(this) .setTitle("提示") .setMessage("确认退出程序？") .setIcon(R.drawable.qq_dialog_err_icon) .setPositiveButton("确定",new DialogInterface.OnClickListener(){ public void onClick(DialogInterface dialoginterface, int i){ Ac02.this.finish(); } }).show(); } }