Android中 检查网络连接状态的变化，无网络时跳转到设置界面

在AndroidManifest.xml中加一个声明

<receiver android:name="NetCheckReceiver">
    <intent-filter>
           <action android:name="android.net.conn.CONNECTIVITY_CHANGE" />
    </intent-filter>
</receiver>

import android.content.BroadcastReceiver;
import android.content.Context;
import android.content.Intent;
import android.net.ConnectivityManager;

public class NetCheckReceiver extends BroadcastReceiver{

    //android 中网络变化时所发的Intent的名字
    private static final String netACTION="android.net.conn.CONNECTIVITY_CHANGE";
    @Override
    public void onReceive(Context context, Intent intent) {

        if(intent.getAction().equals(netACTION)){
    //Intent中ConnectivityManager.EXTRA_NO_CONNECTIVITY这个关键字表示着当前是否连接上了网络
    //true 代表网络断开   false 代表网络没有断开
            if(intent.getBooleanExtra(ConnectivityManager.EXTRA_NO_CONNECTIVITY, false)){
                aActivity.stopFlag = true;
            }else{
                aActivity.stopFlag = false;
            }
        }
    }
}

private boolean checkNetwork() {
        ConnectivityManager conn = (ConnectivityManager) getSystemService(Context.CONNECTIVITY_SERVICE);
        NetworkInfo net = conn.getActiveNetworkInfo();
        if (net != null && net.isConnected()) {
            return true;
        }
        return false;
    }

 if (!checkNetwork()) {
            Toast.makeText(this, R.string.lose_network, Toast.LENGTH_LONG).show();
            Intent intent = new Intent("android.settings.WIRELESS_SETTINGS");
            startActivity(intent);
            return;
        }