关于NetworkInfo对象的isConnected()与isAvailable()

public class MainActivity extends Activity
{
   /** Called when the activity is first created. */
   @Override
   public void onCreate(Bundle savedInstanceState)
   {
       super.onCreate(savedInstanceState);
       setContentView(R.layout.main);

       this.registerReceiver(mBroadcastReceiver, new IntentFilter(
               ConnectivityManager.CONNECTIVITY_ACTION));
   }

   private BroadcastReceiver mBroadcastReceiver = new BroadcastReceiver()
   {
       @Override
       public void onReceive(Context context, Intent intent)
       {
           Bundle bundle = intent.getExtras();
           NetworkInfo aNetworkInfo = (NetworkInfo) bundle
                   .get(ConnectivityManager.EXTRA_NETWORK_INFO);

           if (aNetworkInfo.isConnected())
           {
               System.out.println("connecte");
           } else
           {
               System.out.println("not connect");
           }

           if (aNetworkInfo.isAvailable())
           {
               System.out.println("available");
           } else
           {
               System.out.println("not available");
           }
           System.out.println("--------------------");
       }
   };
}

总结有以下5种状态：

在WLAN设置界面

1，显示连接已保存，但标题栏没有，即没有实质连接上，输出为：not connect， available

2，显示连接已保存，标题栏也有已连接上的图标，输出为：connect， available

3，选择不保存后输出为：not connect， available

4，选择连接，在正在获取IP地址时输出为：not connect， not available

5，连接上后输出为：connect， available

文章出处：http://blog.csdn.net/santicom/article/details/6932421