网络工具,通过该类可以直接监听网络状态改变

package com.bearbaby.erp.staff.util;

import android.content.BroadcastReceiver;
import android.content.Context;
import android.content.Intent;
import android.content.IntentFilter;
import android.net.ConnectivityManager;
import android.net.NetworkInfo;
import android.widget.Toast;

import com.bearbaby.erp.staff.MyApplication;

import java.util.ArrayList;
import java.util.List;
/**
* Created by Administrator on 2017/4/19.
*/

public class NetUtils {
private static boolean netStateLink = true;
private static boolean registered = false;//防止重复注册
private static boolean showToasted = false;  //防止application和启动页面重复初始化后,没网络提示语的重复
private static Context context;
private static NetUtils instance;
private static ConnectionChangeReceiver myNetReceiver;
private static final String TAG = "NetUtils";
private NetUtils() {
}
public static synchronized NetUtils getInstance() {    //对获取实例的方法进行同步
if (instance == null)
instance = new NetUtils();
return instance;
}
//获得是否有网络连接
public static boolean isnetStateLink() {
LogUtil.i(TAG, "isnetStateLink:是否有网络?"+netStateLink);
return netStateLink;
}
/**
* 这个一定要调用一次
* 否则应用无法联网一定要在网络请求之前调用
*启动页面初始化就好 为了安全起见,application一定要调用,startup也要调用,
* 因为用户返回键退出后,不会再走application的创建,(应用退出,但是不杀死进程不会走application的)
* @param contexts 一定要是Context,不能是Activity的this
*/
public static void init(Context contexts) {
if (contexts != null) {
context = contexts;
ConnectivityManager connectivityManager = (ConnectivityManager) context.getSystemService(Context.CONNECTIVITY_SERVICE);
NetworkInfo mobNetInfo = connectivityManager.getNetworkInfo(ConnectivityManager.TYPE_MOBILE);
NetworkInfo wifiNetInfo = connectivityManager.getNetworkInfo(ConnectivityManager.TYPE_WIFI);
if (!mobNetInfo.isConnected() && !wifiNetInfo.isConnected()) {
netStateLink = false;
if (!showToasted){
Toast.makeText(context,"联网失败,请检查网络设置",Toast.LENGTH_SHORT) .show();
showToasted=true;
}
LogUtil.i(TAG, "isnetStateLink:  初始化网络状态没有网络连接.........");
} else {
LogUtil.i(TAG, "isnetStateLink:  初始化网络状态有网络连接.........");
netStateLink = true;
}
if (!registered){
registerReceiver();//注册.......
}
}
}
/**
* 注册网络监听
*/
private static void registerReceiver() {
LogUtil.i(TAG, " 注册网络监听registerReceiver.........");
IntentFilter filter = new IntentFilter(ConnectivityManager.CONNECTIVITY_ACTION);
myNetReceiver = new ConnectionChangeReceiver();
context.registerReceiver(myNetReceiver, filter);
registered=true;
}
/**
* 取消网络注册监听
* 需要在应用最后一个页面销毁后注销(MainActivity退出后一定要调用),
* 不然提示第一次进入后的联网失败,请检查网络设置,会重复
*/
public static void unregisterReceiver() {
LogUtil.i(TAG, " 反注册网络监听unregisterReceiver.........");
if (registered){
try {
if (context!=null){
context.unregisterReceiver(myNetReceiver);
LogUtil.i(TAG, " 成功反注册网络监听.........");
registered=false;
}
} catch (Exception e) {
e.printStackTrace();
LogUtil.e(TAG, "异常反注册网络监听........."+e.getMessage());
registered=false;
}
registered=false;
}
showToasted=false;
}
static List<NetworkState> ln = new ArrayList();
//网络状态监听
static class ConnectionChangeReceiver extends BroadcastReceiver {
@Override
public void onReceive(Context context, Intent intent) {
ConnectivityManager connectivityManager = (ConnectivityManager) context.getSystemService(Context.CONNECTIVITY_SERVICE);
NetworkInfo mobNetInfo = connectivityManager.getNetworkInfo(ConnectivityManager.TYPE_MOBILE);
NetworkInfo wifiNetInfo = connectivityManager.getNetworkInfo(ConnectivityManager.TYPE_WIFI);
if (!mobNetInfo.isConnected() && !wifiNetInfo.isConnected()) {
if (netStateLink) {
if ( MyApplication.getContext().isAppVisible()) {
ToastUtil.show("网络已断开!");
for (NetworkState ns : ln) {
if (ns != null) {
ns.disconnectNetwork();
}
}
}
}
netStateLink = false;
} else {
if (!netStateLink){
if ( MyApplication.getContext().isAppVisible()) {
ToastUtil.show("网络已恢复!");
//通知监听,如果不在前台不通知,防止有网络后,做其他网络操作退出回到登录页面
netStateLink = true;//这个必须要在回调前修改为true 因为接口后面可能会有网络操作,到时候任然无法请求
for (NetworkState ns : ln) {
if (ns != null) {
ns.connectedNetwork();
}
}
}
}
netStateLink = true;
}
}
}
//添加网络监听和removeNetworkListen搭配
public void addNetworkListen(NetworkState ns) {
if (ns != null) {
ln.add(ns);
}
}
//网络状态监听回调接口
public interface NetworkState {
//连接上网络
void connectedNetwork();
//断开网络
void disconnectNetwork();
}
//移除网络监听,和addNetworkListen搭配使用
public synchronized void　　en(NetworkState ns) {
if (ns != null) {
for (int i = 0; i < ln.size(); i++) {
if (ln.get(i) == ns) {
ln.remove(i);
}
}
}
}
}