android 判断 当前网络状态 无网络弹出提示框 2秒后消失

package com.example.nonetworkshowdialog;

import android.net.ConnectivityManager;
import android.net.NetworkInfo;
import android.os.Bundle;
import android.app.Activity;
import android.app.AlertDialog;
import android.app.Dialog;
import android.content.Context;
import android.view.Menu;

public class MainActivity extends Activity {
 private Dialog m_noNetWorkDialog = null;// 无网络提示框

 @Override
 protected void onCreate(Bundle savedInstanceState) {
  super.onCreate(savedInstanceState);
  setContentView(R.layout.activity_main);

  m_noNetWorkDialog = new AlertDialog.Builder(MainActivity.this).setView(
    m_noNetWorkView).create();

 }

 /**
  * 检查网络是否连接,未连接弹出对话框,几秒后消失
  *
  * @throws InterruptedException
  * */
 public boolean checkNetwork0(Context context) {
  ConnectivityManager manager = (ConnectivityManager) context
    .getSystemService(Context.CONNECTIVITY_SERVICE);
  NetworkInfo info = manager.getActiveNetworkInfo();
  if (info == null || !info.isConnected()) {
   m_noNetWorkDialog.show();
   new Thread(new Runnable() {
    @Override
    public void run() {
     // TODO Auto-generated method stub
     try {
      Thread.sleep(2000);
      m_noNetWorkDialog.dismiss();
     } catch (InterruptedException e) {
      // TODO Auto-generated catch block
      e.printStackTrace();
     }
    }
   }).start();
   return false;
  }
  if (info.isRoaming()) {
   return true;
  }
  return true;
 }