我们经常需要判断网络状态的变化，如有无网络，所以需要监听网络状态的变化，比如网络断开，网络连接给予友好提示。如何监听网络状态的变化呢，最近工作中需要用到这个，于是就用广播机制来实现了网络状态的监听。
使用广播机制来监听网络状态主要涉及到以下几点：
1.需要自己编写个网络广播接收器，该接收器继承BroadcastReceiver类，用来接收系统发出的广播。比如我自己写了个NetStatusReceiver广播接收器。代码如下：
package com.log.system; import android.content.BroadcastReceiver;
import android.content.Context;
import android.content.Intent;
import android.net.ConnectivityManager;
import android.net.NetworkInfo;
import android.widget.Toast; public class NetStatusReceiver extends BroadcastReceiver{ public static final int NETSTATUS_INAVAILABLE = 0;
public static final int NETSTATUS_WIFI = 1;
public static final int NETSTATUS_MOBILE = 2;
public static int netStatus = 0;
public static boolean updateSuccess = false;
private INetStatusListener mINetStatusListener; public void onReceive(Context context, Intent intent) {
ConnectivityManager cm = (ConnectivityManager) context.getSystemService(Context.CONNECTIVITY_SERVICE);
NetworkInfo mobileNetInfo = cm.getNetworkInfo(ConnectivityManager.TYPE_MOBILE);
NetworkInfo wifiNetInfo = cm.getNetworkInfo(ConnectivityManager.TYPE_WIFI);
NetworkInfo allNetInfo = cm.getActiveNetworkInfo(); if (allNetInfo == null) {
if (mobileNetInfo != null && (mobileNetInfo.isConnected() || mobileNetInfo.isConnectedOrConnecting())) {
netStatus = NETSTATUS_MOBILE;
} else if (wifiNetInfo != null && wifiNetInfo.isConnected() || wifiNetInfo.isConnectedOrConnecting()) {
netStatus = NETSTATUS_WIFI;
} else {
netStatus = NETSTATUS_INAVAILABLE;
}
} else {
if (allNetInfo.isConnected() || allNetInfo.isConnectedOrConnecting()) {
if (mobileNetInfo.isConnected() || mobileNetInfo.isConnectedOrConnecting()) {
netStatus = NETSTATUS_MOBILE;
} else {
netStatus = NETSTATUS_WIFI;
}
} else {
netStatus = NETSTATUS_INAVAILABLE;
}
}
if(mINetStatusListener != null){
mINetStatusListener.getNetState(netStatus);
}
// if (netStatus == NETSTATUS_INAVAILABLE) {
// Toast.makeText(context, "网络未连接",Toast.LENGTH_SHORT).show();
// } else if (netStatus == NETSTATUS_MOBILE) {
// Toast.makeText(context, "网络处于移动网络",Toast.LENGTH_SHORT).show();
// } else {
// Toast.makeText(context, "网络处于Wifi网络",Toast.LENGTH_SHORT).show();
// }
} public void setNetStateListener(INetStatusListener listener){
mINetStatusListener = listener;
} public interface INetStatusListener{
public void getNetState(int state);
}
}
2.注册广播接收器
首先new一个广播接收器，然后对该接收器进行注册，也就是注册广播，然后并设置监听器。注册广播和设置监听的实现如下：
netReceiver = new NetStatusReceiver();
setRegisterReceiver(netReceiver);
setNetListener();
对应的具体方法实现代码如下：
public void setRegisterReceiver(NetStatusReceiver netReceiver){
IntentFilter filter = new IntentFilter();
filter.addAction(ConnectivityManager.CONNECTIVITY_ACTION);
registerReceiver(netReceiver, filter);
}
public void setNetListener(){
netReceiver.setNetStateListener(new INetStatusListener() {
@Override
public void getNetState(int state) {
// TODO Auto-generated method stub
if (state == NetStatusReceiver.NETSTATUS_INAVAILABLE) {
Toast.makeText(getBaseContext(), "网络未连接",
Toast.LENGTH_SHORT).show();
} else {
Toast.makeText(getBaseContext(), "网络已经连接",
Toast.LENGTH_SHORT).show();
}
}
});
}
3.为了要获取网络的状态，需要在manifest文件中设置相关权限，即配置：
<uses-permission android:name="android.permission.ACCESS_NETWORK_STATE" />