Android中如何判断是否联网

首先在AndroidManifest.xml中添加与连接网络相关的权限：

 

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

import android.net.ConnectivityManager;

import android.net.NetworkInfo;

判断联网的代码如下：

 

 ConnectivityManager connectivityManager = (ConnectivityManager)getSystemService(CONNECTIVITY_SERVICE);
         NetworkInfo networkInfo = connectivityManager.getActiveNetworkInfo();
         if(networkInfo == null || !networkInfo.isAvailable())
         {
             //当前有可用网络
         }
         else
         {
             //当前无可用网络
         }