跟網絡相關的Android工具類

    import android.app.Activity;

    import android.content.ComponentName;

    import android.content.Context;

    import android.content.Intent;

    import android.net.ConnectivityManager;

    import android.net.NetworkInfo;


//跟網絡相關的工具類  
public class NetUtils  
{  
    private NetUtils()  
    {  
        /* cannot be instantiated */  
        throw new UnsupportedOperationException("cannot be instantiated");  
    }  

    /** 
     * 判斷網絡是否連接 
     *  
     * @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;  
    }  

    /** 
     * 判斷是否是wifi連接 
     */  
    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;  

    }  

    /** 
     * 打開網絡設置界面 
     */  
    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);  
    }  

}  </pre>