Why do I get "requesting permission to use WLAN. Allow?" prompt window in real mobile phone?

I use the Code A to set the enabled status of WiFi, it works well when I use Android Emulator with both API 26 and API 23 in Android Studio 3.1.3 , and none of prompt window display!

But I get a prompt window "An App is requesting permission to use WLAN. Allow?" in real mobile phone with Android 5.1 when I run the code A.

How can I make the prompt window not to display in real mobile phone? Thanks!

BTW,the real mobile phone is Samsung SM-J5008 with Android 5.1

Prompt Window

I have set the permissions

<uses-permission android:name="android.permission.ACCESS_WIFI_STATE" />
<uses-permission android:name="android.permission.CHANGE_WIFI_STATE" />

Code A

fun setWiFi(aWiFiDef: WiFiDef): Unit{
    val wifiManager =mContext.applicationContext.getSystemService(WIFI_SERVICE) as WifiManager
    wifiManager.isWifiEnabled=aWiFiDef.status        
}

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