Enumeration.hasMoreElements() 会java.lang.NullPointerException

使用版本：implementation 'com.blankj:utilcodex:1.30.6'
测试机型：HUAWEI HWVKY (P10 Plus) Android 9 (SDK 28)
错误日志：
Exception java.lang.NullPointerException: Attempt to invoke interface method 'boolean java.util.Enumeration.hasMoreElements()' on a null object reference
at com.blankj.utilcode.util.NetworkUtils.getBroadcastIpAddress (NetworkUtils.java:562)
at com.it.inlumentech.ui.socket.UdpUtils$2.onTick (UdpUtils.java:271)
at android.os.CountDownTimer$1.handleMessage (CountDownTimer.java:130)
at android.os.Handler.dispatchMessage (Handler.java:112)
at android.os.Looper.loop (Looper.java:216)
at android.app.ActivityThread.main (ActivityThread.java:7625)
at java.lang.reflect.Method.invoke
at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run (RuntimeInit.java:524)
at com.android.internal.os.ZygoteInit.main (ZygoteInit.java:987)