android中如何判斷是否聯網

首先在androidManifest.XML中添加與連接網絡相關的權限：

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 <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> 

 <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>

判斷聯網的代碼如下：

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 ConnectivityManager connectivityManager = (ConnectivityManager)getSystemService(CONNECTIVITY_SERVICE);  
       NetworkInfo networkInfo = connectivityManager.getActiveNetworkInfo();  
       if(networkInfo == null || !networkInfo.isAvailable())  
        {  
           //當前有可用網絡  
        }  
       else   
        {  
            //當前無可用網絡  
        }