Add missing import

Author: adasiewiczr

samplekotlin/src/main/java/com/example/chattutorial/ChannelActivity.kt

@@ -3,6 +3,7 @@ package com.example.chattutorial
 import android.content.Context
 import android.content.Intent
 import android.os.Bundle
+import androidx.activity.addCallback
 import androidx.activity.viewModels
 import androidx.appcompat.app.AppCompatActivity
 import com.example.chattutorial.databinding.ActivityChannelBinding

samplekotlin/src/main/java/com/example/chattutorial/ChannelActivity2.kt

@@ -3,6 +3,7 @@ package com.example.chattutorial
 import android.content.Context
 import android.content.Intent
 import android.os.Bundle
+import androidx.activity.addCallback
 import androidx.activity.viewModels
 import androidx.appcompat.app.AppCompatActivity
 import com.example.chattutorial.databinding.ActivityChannel2Binding

samplekotlin/src/main/java/com/example/chattutorial/ChannelActivity3.kt

@@ -3,6 +3,7 @@ package com.example.chattutorial
 import android.content.Context
 import android.content.Intent
 import android.os.Bundle
+import androidx.activity.addCallback
 import androidx.activity.viewModels
 import androidx.appcompat.app.AppCompatActivity
 import com.example.chattutorial.databinding.ActivityChannel3Binding

samplekotlin/src/main/java/com/example/chattutorial/ChannelActivity4.kt

@@ -3,6 +3,7 @@ package com.example.chattutorial
 import android.content.Context
 import android.content.Intent
 import android.os.Bundle
+import androidx.activity.addCallback
 import androidx.activity.viewModels
 import androidx.appcompat.app.AppCompatActivity
 import com.example.chattutorial.databinding.ActivityChannel4Binding