我不希望我的用户尝试下载任何东西,除非他们连接了Wi-Fi。然而,我似乎只能判断是否启用了Wi-Fi,但他们仍然可能有3G连接。

android.net.wifi.WifiManager m = (WifiManager) getSystemService(WIFI_SERVICE);
android.net.wifi.SupplicantState s = m.getConnectionInfo().getSupplicantState();
NetworkInfo.DetailedState state = WifiInfo.getDetailedStateOf(s);
if (state != NetworkInfo.DetailedState.CONNECTED) {
    return false;
}

然而,这种状态并不是我所期望的。即使Wi-Fi是连接的,我得到OBTAINING_IPADDR作为状态。


当前回答

val wifi = context!!.applicationContext.getSystemService(Context.WIFI_SERVICE) as WifiManager?        
         if (wifi!!.isWifiEnabled) 
              //do action here
    
         else 
             //do action here
    
        
                    

其他回答

虽然Jason的回答是正确的,但现在getNetWorkInfo (int)是一个不推荐使用的方法。所以,下一个函数将是一个很好的选择:

public static boolean isWifiAvailable (Context context)
{
    boolean br = false;
    ConnectivityManager cm = null;
    NetworkInfo ni = null;

    cm = (ConnectivityManager) context.getSystemService(Context.CONNECTIVITY_SERVICE);
    ni = cm.getActiveNetworkInfo();
    br = ((null != ni) && (ni.isConnected()) && (ni.getType() == ConnectivityManager.TYPE_WIFI));

    return br;
}

类似于@Jason Knight的回答,但以Kotlin的方式:

val connManager = getSystemService(Context.CONNECTIVITY_SERVICE) as ConnectivityManager
val mWifi = connManager.getNetworkInfo(ConnectivityManager.TYPE_WIFI)

if (mWifi.isConnected) {
     // Do whatever
}

许多答案使用了废弃的代码,或者在更高API版本上可用的代码。现在我用这样的东西

ConnectivityManager connectivityManager = (ConnectivityManager) context.getSystemService(Context.CONNECTIVITY_SERVICE);
        if(connectivityManager != null) {
            for (Network net : connectivityManager.getAllNetworks()) {
                NetworkCapabilities nc = connectivityManager.getNetworkCapabilities(net);
                if (nc != null && nc.hasTransport(NetworkCapabilities.TRANSPORT_WIFI)
                        && nc.hasCapability(NetworkCapabilities.NET_CAPABILITY_INTERNET))
                    return true;
            }
        }
        return false;

使用WifiManager你可以做到:

WifiManager wifi = (WifiManager) getSystemService (Context.WIFI_SERVICE);
if (wifi.getConnectionInfo().getNetworkId() != -1) {/* connected */}

方法getNeworkId只有在没有连接到网络时才返回-1;

我在我的应用程序中使用这个来检查活动网络是否为Wi-Fi:

ConnectivityManager cm = (ConnectivityManager) getSystemService(Context.CONNECTIVITY_SERVICE);
NetworkInfo ni = cm.getActiveNetworkInfo();
if (ni != null && ni.getType() == ConnectivityManager.TYPE_WIFI)
{

    // Do your work here

}