Pepper android app never started function onRobotFocusGained() on a real pepper

I have a problem with some simple kotlin code on a pepper robot. I followed the "get started" tutorial from softbanks (https://qisdk.softbankrobotics.com/sdk/doc/pepper-sdk/ch1_gettingstarted/hello_human_tutorial.html) and it works fine, except to start the function onRobotFocusGained. I have implemented some logs to see, that the program starts the functions "onCreate", "onStart" and "onResume" but never the "onRobotFocusGained". If I start the code from the tutorial on GitHub (https://github.com/aldebaran/qisdk-tutorials), it works fine. But this program is too heavy for any complete beginners. My goal is to implement a minimal example for my colleagues to start with programming on pepper.

So, how pepper starts the function "onRobotFocusGained" (https://qisdk.softbankrobotics.com/sdk/doc/pepper-sdk/ch2_principles/focus_lifecycle.html#focus-lifecycle)?

Here is my short program for pepper to say once "hello humans" if i start the program but pepper never says it.

package com.example.hello_pepper_2

import android.os.Bundle
import android.util.Log
import android.com.aldebaran.qi.sdk.QiContext
import android.com.aldebaran.qi.sdk.QiSDK
import android.com.aldebaran.qi.sdk.RobotLifecycleCallbacks
import android.com.aldebaran.qi.sdk.`object`.conversation.Say
import android.com.aldebaran.qi.sdk.builder.SayBuilder
import android.com.aldebaran.qi.sdk.design.activity.RobotActivity

class MainActivity : RobotActivity(), RobotLifecycleCallbacks {

    var robotContext: QiContext? = null

    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        // Register the RobotLifecycleCallbacks to this Activity.
        QiSDK.register(this, this)
        setContentView(R.layout.activity_main)

        Log.e("MSG", "onCreate")
        Log.e("Context", "robot.Context.toString()")
    }

    override fun onStart() {
        super.onStart()

        Log.e("MSG", "onStart")
        Log.e("Context", "robot.Context.toString()")
    }

    override fun onResume() {
        super.onResume()

        Log.e("MSG", "onResume")
        Log.e("Context", "robot.Context.toString()")
    }

    override fun onRestart() {
        super.onRestart()

        Log.e("MSG", "onRestart")
        Log.e("Context", "robot.Context.toString()")
    }

    override fun onPause() {
        super.onPause()

        Log.e("MSG", "onPause")
        Log.e("Context", "robot.Context.toString()")
    }

    override fun onStop() {
        super.onStop()

        Log.e("MSG", "onStop")
        Log.e("Context", "robot.Context.toString()")
    }

    override fun onDestroy() {
        // Unregister the RobotLifecycleCallbacks for this Activity.
        QiSDK.unregister(this, this)
        super.onDestroy()

        robotContext = null

        Log.e("MSG", "onDestroy")
        Log.e("Context", "robot.Context.toString()")
    }

    override fun onRobotFocusGained(qiContext: QiContext) {
        // The robot focus is gained.

        robotContext = qiContext

        saySomething("Hello Humans")

        Log.e("MSG", "onRobotFocusGained")
        Log.e("Context", "robot.Context.toString()")
    }

    override fun onRobotFocusLost() {
        // The robot focus is lost.

        Log.e("MSG", "onRobotFocusLost")
        Log.e("Context", "robot.Context.toString()")
    }

    override fun onRobotFocusRefused(reason: String) {
        // The robot focus is refused.

        Log.e("MSG", "onRobotFocusRefused")
        Log.e("Context", "robot.Context.toString()")
    }

    fun saySomething(phrase: String) {
        Log.e("MSG", "saySomething")
        Log.e("Context", "robot.Context.toString()")

        val say: Say = SayBuilder
            .with(robotContext)
            .withText(phrase)
            .build()

        say.run()
    }
}