跟网络相关的Android工具类

    import android.app.Activity;  
    import android.content.ComponentName;  
    import android.content.Context;  
    import android.content.Intent;  
    import android.net.ConnectivityManager;  
    import android.net.NetworkInfo;  
      
    //跟网络相关的工具类  
    public class NetUtils  
    {  
        private NetUtils()  
        {  
            /* cannot be instantiated */  
            throw new UnsupportedOperationException("cannot be instantiated");  
        }  
      
        /** 
         * 判断网络是否连接 
         *  
         * @param context 
         * @return 
         */  
        public static boolean isConnected(Context context)  
        {  
      
            ConnectivityManager connectivity = (ConnectivityManager) context  
                    .getSystemService(Context.CONNECTIVITY_SERVICE);  
      
            if (null != connectivity)  
            {  
      
                NetworkInfo info = connectivity.getActiveNetworkInfo();  
                if (null != info && info.isConnected())  
                {  
                    if (info.getState() == NetworkInfo.State.CONNECTED)  
                    {  
                        return true;  
                    }  
                }  
            }  
            return false;  
        }  
      
        /** 
         * 判断是否是wifi连接 
         */  
        public static boolean isWifi(Context context)  
        {  
            ConnectivityManager cm = (ConnectivityManager) context  
                    .getSystemService(Context.CONNECTIVITY_SERVICE);  
      
            if (cm == null)  
                return false;  
            return cm.getActiveNetworkInfo().getType() == ConnectivityManager.TYPE_WIFI;  
      
        }  
      
        /** 
         * 打开网络设置界面 
         */  
        public static void openSetting(Activity activity)  
        {  
            Intent intent = new Intent("/");  
            ComponentName cm = new ComponentName("com.android.settings","com.android.settings.WirelessSettings");  
            intent.setComponent(cm);  
            intent.setAction("android.intent.action.VIEW");  
            activity.startActivityForResult(intent,0);  
        }  
      
    }