公共代码参考（ConnectivityManager）

package com.fredric.util;



import android.content.Context;

import android.net.ConnectivityManager;

import android.net.NetworkInfo;

import android.net.NetworkInfo.State;



/*-

 * 网络工具类

 */



public class NetUtils {



    //判断网络是否连接

    public static boolean isConnected(Context context){

        

        ConnectivityManager connectivity = (ConnectivityManager) context  

                .getSystemService(Context.CONNECTIVITY_SERVICE);

        //WLAN五种状态

        //1，显示连接已保存，但标题栏没有，即没有实质连接上，输出为：not connect， available

        //2，显示连接已保存，标题栏也有已连接上的图标，            输出为：connect， available

        //3，选择不保存后                                                                     输出为：not connect， available

        //4，选择连接，在正在获取IP地址时                                     输出为：not connect， not available

        //5，连接上后                                                                           输出为：connect， available

        if(null != connectivity){

            NetworkInfo info = connectivity.getActiveNetworkInfo();

            if(null != info && info.isConnected()){

                return true;

            }

        }

        

        return false;

    }

    

    //判断是否wifi连接

    public static boolean isWifiConnect(Context context){

        ConnectivityManager connectivity = (ConnectivityManager) context  

                .getSystemService(Context.CONNECTIVITY_SERVICE);

        if(null != connectivity){

            State state = connectivity

                    .getNetworkInfo(ConnectivityManager.TYPE_WIFI).getState();

            if(state == State.CONNECTED){

                return true;

            }

        }

        

        return false;        

    }

    

    //判断GPRS是否连接

    public static boolean isGPRSConnect(Context context){

        ConnectivityManager connectivity = (ConnectivityManager) context  

                .getSystemService(Context.CONNECTIVITY_SERVICE);

        if(null != connectivity){

            State state = connectivity

                    .getNetworkInfo(ConnectivityManager.TYPE_MOBILE).getState();

            if(state == State.CONNECTED){

                return true;

            }

        }

        

        return false;        

    }

}