android 实时检测网络状态

xml添加权限:

 <uses-permission android:name="android.permission.ACCESS_WIFI_STATE" />
<uses-permission android:name="android.permission.ACCESS_NETWORK_STATE" />

onCreate:注册帧听
NetState receiver = new NetState();
IntentFilter filter = new IntentFilter();

filter.addAction(ConnectivityManager.CONNECTIVITY_ACTION);
this.registerReceiver(receiver, filter);
receiver.onReceive(this, null);

添加类:

class NetState extends BroadcastReceiver{

    @Override
public void onReceive(Context context, Intent arg1) {
        ConnectivityManager manager = (ConnectivityManager)context.getSystemService(Context.CONNECTIVITY_SERVICE);
        NetworkInfo gprs = manager.getNetworkInfo(ConnectivityManager.TYPE_MOBILE);
        NetworkInfo wifi = manager.getNetworkInfo(ConnectivityManager.TYPE_WIFI);
if(!gprs.isConnected() && !wifi.isConnected())
        {
            AlertDialog.Builder ab = new AlertDialog.Builder(context);
            ab.setMessage("网络连接断开，请检查网络");
            ab.setPositiveButton("确定", new DialogInterface.OnClickListener() {
                @Override
public void onClick(DialogInterface dialog, int which) {
// TODO Auto-generated method stub
                    dialog.dismiss();
                }
            }).show();

        }
else{
            AlertDialog.Builder ab = new AlertDialog.Builder(context);
            ab.setMessage("网络连接成功");
            ab.setPositiveButton("确定", new DialogInterface.OnClickListener() {
                @Override
public void onClick(DialogInterface dialog, int which) {
// TODO Auto-generated method stub
                    dialog.dismiss();
                }
            }).show();               

        }
    }
}