android之网络状态的判断

第一步：接收状态信息

             （1、写setActivity方法是为了获得界面的控件设定是否隐藏

                 2、此类继承BroadcastReceiver，作用是重新广播接收者）

import android.app.Activity;
import android.content.BroadcastReceiver;
import android.content.Context;
import android.content.Intent;
import android.net.ConnectivityManager;
import android.net.NetworkInfo;
import android.util.Log;
import android.view.View;
import android.widget.TextView;
import android.widget.Toast;


/**
 * Created by Administrator on 2014/9/2.
 */
public class ConnectionChangeReceiver extends BroadcastReceiver {
    public Activity activity;

    @Override
    public void onReceive(Context context, Intent intent) {
        boolean success = false;
        ConnectivityManager connectivityManager = (ConnectivityManager) context.getSystemService(
                Context.CONNECTIVITY_SERVICE);//获取状态对象
        NetworkInfo.State state = connectivityManager.getNetworkInfo(ConnectivityManager.TYPE_WIFI).getState();
        // 判断是否正在使用WIFI网络
        if (NetworkInfo.State.CONNECTED == state) {
            TextView view = (TextView) activity.findViewById(R.id.network);
            view.setVisibility(View.GONE);
            Log.e("-------wifi-----", "连接");
            success = true;
        }
        // 获取GPRS网络连接状态
        state = connectivityManager.getNetworkInfo(ConnectivityManager.TYPE_MOBILE).getState();
        // 判断是否正在使用GPRS网络
        if (NetworkInfo.State.CONNECTED == state) {
            TextView view = (TextView) activity.findViewById(R.id.network);
            view.setVisibility(View.GONE);
            Log.e("-------GPRS-----", "连接");
            success = true;
        }
        if (!success) {
            Log.e("-------net-----", "无连接");
            TextView view = (TextView) activity.findViewById(R.id.network);
            view.setVisibility(View.VISIBLE);
            Toast.makeText(context, "网络状态改变", Toast.LENGTH_LONG).show();
        }
    }

    public void setActivity(Activity activity) {
        this.activity = activity;
    }
}

第二步：创建对象，启动广播接收者：

ConnectionChangeReceiver receiver = new ConnectionChangeReceiver(this);

this.registerReceiver(receiver,new IntentFilter(ConnectivityManager.CONNECTIVITY_ACTION));

第三步：在manifest中加上权限：

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

        作用是为了重新类ConnectionChangeReceiver中

ConnectivityManager connectivityManager = (ConnectivityManager) context.getSystemService( Context.CONNECTIVITY_SERVICE);

        能够获取对象。

第四步：布局文件 

         初始化显示无网络连接提醒时，默认为不可见状态，即Visibility为gone

第五步：方法的重用：

         在广播接收者中加上一个改变activity的方法即可，而且不要带有构造函数，否者报错，见

第一步源码。