How to setOnSeekBarChangeListener in a Kotlin Fragment - kotlin

Question

I am currently working on a mobile application in my uni classes that utilizes a seekBar to let the user decide to use a timer for a quiz. This application uses main to host all of the fragments. currently I just want the textbox to display where the user scrolled the seek bar to but am struggling to find a solution. any advice would be greatly appreciated. this is the code I have within the
TitleFragment.kt:
package com.example.android.guesstheword.screens.title
import android.os.Bundle
import android.view.DragEvent
import android.view.LayoutInflater
import android.view.View
import android.view.ViewGroup
import android.widget.SeekBar
import android.widget.SeekBar.OnSeekBarChangeListener
import android.widget.Switch
import android.widget.TextView
import android.widget.Toast
import androidx.core.view.isVisible
import androidx.databinding.DataBindingUtil
import androidx.databinding.adapters.SeekBarBindingAdapter
import androidx.fragment.app.Fragment
import androidx.navigation.fragment.findNavController
import com.example.android.guesstheword.R
import com.example.android.guesstheword.databinding.TitleFragmentBinding
import kotlinx.android.synthetic.main.title_fragment.*
/**
* Fragment for the starting or title screen of the app
*/
class TitleFragment : Fragment() {
override fun onCreateView(inflater: LayoutInflater, container: ViewGroup?,
savedInstanceState: Bundle?): View {
// Inflate the layout for this fragment
val binding: TitleFragmentBinding = DataBindingUtil.inflate(
inflater, R.layout.title_fragment, container, false)
binding.timerSwitch.setOnClickListener {
if(binding.timerSwitch.isChecked){
binding.timerBar.visibility = View.VISIBLE
}
else{
binding.timerBar.visibility = View.INVISIBLE
}
}
val seekBar = binding.timerBar
seekBar.setOnSeekBarChangeListener(binding)
binding.playGameButton.setOnClickListener {
findNavController().navigate(TitleFragmentDirections.actionTitleToGame())
}
return binding.root
}
}
private fun SeekBar.setOnSeekBarChangeListener(binding: TitleFragmentBinding) {
val seconds = binding.timerSeconds
seconds.visibility = View.VISIBLE
seconds.text = binding.timerBar.progress.toString()
}
title_fragment.xml:
<?xml version="1.0" encoding="utf-8"?><!--
<layout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
xmlns:tools="http://schemas.android.com/tools">
<androidx.constraintlayout.widget.ConstraintLayout
android:id="#+id/title_layout"
android:layout_width="match_parent"
android:layout_height="match_parent"
tools:context=".screens.title.TitleFragment">
<TextView
android:id="#+id/get_ready_text"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_marginTop="8dp"
android:layout_marginBottom="8dp"
android:fontFamily="sans-serif"
android:text="#string/get_ready"
android:textColor="#color/black_text_color"
android:textSize="14sp"
android:textStyle="normal"
app:layout_constraintBottom_toTopOf="#+id/title_text"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintHorizontal_bias="0.5"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toTopOf="parent"
app:layout_constraintVertical_chainStyle="packed" />
<TextView
android:id="#+id/title_text"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_marginTop="16dp"
android:fontFamily="sans-serif"
android:text="#string/title_text"
android:textColor="#color/black_text_color"
android:textSize="34sp"
android:textStyle="normal"
app:layout_constraintBottom_toTopOf="#+id/play_game_button"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintHorizontal_bias="0.5"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toBottomOf="#+id/get_ready_text"
app:layout_constraintVertical_chainStyle="packed" />
<Button
android:id="#+id/play_game_button"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_marginBottom="32dp"
android:text="#string/play_button"
android:theme="#style/GoButton"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintStart_toStartOf="parent" />
<Switch
android:id="#+id/timer_switch"
android:layout_width="95dp"
android:layout_height="52dp"
android:text="Timer"
android:min="5"
android:max="360"
app:layout_constraintBottom_toTopOf="#+id/play_game_button"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toBottomOf="#+id/title_text"
app:layout_constraintVertical_bias="0.064"/>
<SeekBar
android:id="#+id/timerBar"
android:layout_width="132dp"
android:layout_height="85dp"
android:clickable="false"
android:visibility="gone"
app:layout_constraintBottom_toTopOf="#+id/play_game_button"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintHorizontal_bias="0.498"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toBottomOf="#+id/timer_switch"
app:layout_constraintVertical_bias="0.144" />
<TextView
android:id="#+id/timer_seconds"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:visibility="gone"
app:layout_constraintBottom_toTopOf="#+id/play_game_button"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toBottomOf="#+id/timerBar"
app:layout_constraintVertical_bias="0.17" />
</androidx.constraintlayout.widget.ConstraintLayout>
</layout>

Answer 1

You created an extension function called setOnSeekBarChangeListener which does not actually set it.
In order to set the listener, you need to do something like this:
binding.timerBar.setOnSeekBarChangeListener(object : SeekBar.OnSeekBarChangeListener{
override fun onProgressChanged(seekBar: SeekBar, progress: Int, fromUser: Boolean) {
// here, you react to the value being set in seekBar
}
override fun onStartTrackingTouch(seekBar: SeekBar) {
// you can probably leave this empty
}
override fun onStopTrackingTouch(seekBar: SeekBar) {
// you can probably leave this empty
}
})
But keep in mind that this is NOT the extension function you created.