以下のようにWifiManagerからMACアドレスを取得
Sample.cs
string macAddr = "";
if (null == m_wifiManager) {
using (var activity = new AndroidJavaClass("com.unity3d.player.UnityPlayer").GetStatic<AndroidJavaObject>("currentActivity")) {
m_wifiManager = activity.Call<AndroidJavaObject>("getSystemService", "wifi");
}
}
macAddr = m_wifiManager.Call<AndroidJavaObject>("getConnectionInfo").Call<string>("getMacAddress");
return macAddr;