Forum Thread: can you tell me, how do I get the apk that has been inserted undetectable backdoor AV ..?

What do you mean by "get" ? Do you want .apk file or what?

sorry, I mean how to avoid detection AV..?

You can use msfencode to avoid that. Or you can try with veil-evasion. Veil-evasion is tool which generate metasploit payloads that bypass AV . Those are your best options.

whether the veil-evasion could be used in the payload android apk ..?

Sorry, i miss that one. Currently there isnt payload in veil-evasion for android.