android 监听网络状态

1.注册intentfilter

IntentFilter filter = new IntentFilter();
filter.addAction(WifiManager.NETWORK_STATE_CHANGED_ACTION);
registerReceiver(receiver, filter);

2.设置receiver

        if (WifiManager.NETWORK_STATE_CHANGED_ACTION.equals(action)) {
            NetworkInfo info = (NetworkInfo) intent
                    .getParcelableExtra(WifiManager.EXTRA_NETWORK_INFO);
            if (info.getState().equals(NetworkInfo.State.CONNECTED)) {
                //do whatever you want when wifi is active and connected to a hotspot
            }

        }