Develop Reference

Duplicate and overlapping text in TextView when using LiveData or StateFlow

To be as clear as possible, I'm going to show the problem with a gif.
As you can see, the text is overlapping in my emulator and I don't know how to solve it, I don't know what I'm doing wrong.
It should be displayed correctly without overlapping. What I'm doing is subscribing to changes in both LiveData and StateFlow. When I press the button, I make it change the value, but instead of changing, it seems to return both values at once (Default and Hello). Could it be that the view is not refreshing? Or could it be a problem with my emulator?
Anyway, I'll leave all the code here in case you can figure it out.
FlowsFragment.kt
import android.os.Bundle
import androidx.fragment.app.Fragment
import android.view.View
import androidx.fragment.app.viewModels
import androidx.lifecycle.lifecycleScope
import com.rr.stateflow_livedata_flow_sharedflow.databinding.FragmentFlowsBinding
import kotlinx.coroutines.flow.collectLatest
class FlowsFragment : Fragment(R.layout.fragment_flows) {
private lateinit var binding: FragmentFlowsBinding
private val viewModel: FlowsViewModel by viewModels()
override fun onViewCreated(view: View, savedInstanceState: Bundle?) {
super.onViewCreated(view, savedInstanceState)
binding = FragmentFlowsBinding.bind(view)
binding.btnLiveData.setOnClickListener {
viewModel.triggerLiveData()
}
binding.btnStateFlow.setOnClickListener {
viewModel.triggerStateFlow()
}
subscribeToObservables()
}
private fun subscribeToObservables() {
viewModel.liveData.observe(viewLifecycleOwner) {
binding.tvLiveData.text = it
}
lifecycleScope.launchWhenStarted {
viewModel.stateFlow.collectLatest {
binding.tvStateFlow.text = it
}
}
}
}
FlowsViewModel.kt
import androidx.lifecycle.LiveData
import androidx.lifecycle.MutableLiveData
import androidx.lifecycle.ViewModel
import kotlinx.coroutines.flow.*
class FlowsViewModel : ViewModel() {
private val _liveData = MutableLiveData("Default LiveData")
val liveData: LiveData<String> = _liveData
private val _stateFlow = MutableStateFlow("Default StateFlow")
val stateFlow: StateFlow<String> = _stateFlow.asStateFlow()
fun triggerLiveData() {
_liveData.value = "Hello LiveData!"
}
fun triggerStateFlow() {
_stateFlow.value = "Hello StateFlow!"
}
}
fragment_flows.xml
<?xml version="1.0" encoding="utf-8"?>
<androidx.constraintlayout.widget.ConstraintLayout 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"
android:layout_width="match_parent"
android:layout_height="match_parent"
tools:context=".FlowsFragment">
<TextView
android:id="#+id/tvLiveData"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_marginTop="32dp"
android:fontFamily="sans-serif-condensed"
android:text="Hello World!"
android:textColor="#color/black"
android:textSize="34sp"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toTopOf="parent" />
<Button
android:id="#+id/btnLiveData"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_marginTop="8dp"
android:text="LIVEDATA"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toBottomOf="#+id/tvLiveData" />
<TextView
android:id="#+id/tvStateFlow"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_marginTop="32dp"
android:fontFamily="sans-serif-condensed"
android:text="Hello World!"
android:textColor="#color/black"
android:textSize="34sp"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toBottomOf="#+id/btnLiveData" />
<Button
android:id="#+id/btnStateFlow"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_marginTop="8dp"
android:text="STATEFLOW"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toBottomOf="#+id/tvStateFlow" />
<TextView
android:id="#+id/tvFlow"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_marginTop="32dp"
android:fontFamily="sans-serif-condensed"
android:text="Hello World!"
android:textColor="#color/black"
android:textSize="34sp"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintHorizontal_bias="0.504"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toBottomOf="#+id/btnStateFlow" />
<Button
android:id="#+id/btnFlow"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_marginTop="8dp"
android:text="FLOW"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toBottomOf="#+id/tvFlow" />
<TextView
android:id="#+id/tvSharedFlow"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_marginTop="32dp"
android:fontFamily="sans-serif-condensed"
android:text="Hello World!"
android:textColor="#color/black"
android:textSize="34sp"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toBottomOf="#+id/btnFlow" />
<Button
android:id="#+id/btnSharedFlow"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_marginTop="8dp"
android:text="SHAREDFLOW"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toBottomOf="#+id/tvSharedFlow" />
</androidx.constraintlayout.widget.ConstraintLayout>
I hope that the text doesn't overlap and returns the latest value of LiveData and StateFlow.
Edit with more info: The application displays the view directly from the fragment, MainActivity only has a fragment container that I show below.
MainActivity.kt
import androidx.appcompat.app.AppCompatActivity
import android.os.Bundle
import androidx.fragment.app.add
import androidx.fragment.app.commit
class MainActivity : AppCompatActivity() {
override fun onCreate(savedInstanceState: Bundle?) {
super.onCreate(savedInstanceState)
setContentView(R.layout.activity_main)
supportFragmentManager.commit {
setReorderingAllowed(true)
add<FlowsFragment>(R.id.mainActivityFragmentContainer)
}
}
}
activity_main.xml
<?xml version="1.0" encoding="utf-8"?>
<androidx.constraintlayout.widget.ConstraintLayout 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"
android:layout_width="match_parent"
android:layout_height="match_parent"
tools:context=".MainActivity">
<androidx.fragment.app.FragmentContainerView
android:id="#+id/mainActivityFragmentContainer"
android:name="com.rr.stateflow_livedata_flow_sharedflow.FlowsFragment"
android:layout_width="match_parent"
android:layout_height="match_parent"
tools:layout="#layout/fragment_flows" />
</androidx.constraintlayout.widget.ConstraintLayout>

EDIT This is not the solution, it's a bad way to solve the problem.
I just have to add this line of code in fragment_flows.xml.
android:background="#color/white"
Just by setting the background of the fragment to white, the text is no longer duplicated and overlapping.
Does anyone know why this happens? Why does what is drawn on the screen stick to the background if there is no background in the fragment layout?

how to get data from dynamically created views

I am pretty much a beginner in app development. I am creating a GPA calculator. I was able to create a button that would create a new EditText view for each time it was tapped. but I don't know how can get the values from those EditTexts separately so I can use them to calculate GPA. I looked up every similar question here and on the internet in general, but none of them helped me. Here is my code:
activity_main.xml
<?xml version="1.0" encoding="utf-8"?>
<androidx.constraintlayout.widget.ConstraintLayout 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"
android:layout_width="match_parent"
android:layout_height="match_parent"
tools:context=".MainActivity">
<LinearLayout
android:id="#+id/layout_list"
android:layout_width="match_parent"
android:layout_height="500dp"
android:orientation="vertical"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toTopOf="parent">
<Button
android:id="#+id/add_button"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_marginLeft="20dp"
android:layout_marginTop="20dp"
android:drawableRight="#drawable/ic_baseline_add_24"
android:text="Add"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toBottomOf="#+id/textView" />
</LinearLayout>
<Button
android:id="#+id/calculate_button"
android:layout_width="180dp"
android:layout_height="wrap_content"
android:layout_marginLeft="20dp"
android:text="Calculate"
app:layout_constraintLeft_toLeftOf="#id/layout_list"
app:layout_constraintTop_toBottomOf="#id/layout_list" />
<TextView
android:id="#+id/result"
android:layout_width="100dp"
android:layout_height="wrap_content"
android:layout_marginLeft="20dp"
android:layout_marginTop="13dp"
android:hint="GPA:0.0"
android:textSize="20dp"
app:layout_constraintStart_toEndOf="#id/calculate_button"
app:layout_constraintTop_toBottomOf="#id/layout_list"
tools:text="GPA:0.0" />
</androidx.constraintlayout.widget.ConstraintLayout>
new_layout.xml
<?xml version="1.0" encoding="utf-8"?>
<androidx.constraintlayout.widget.ConstraintLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
android:layout_width="match_parent"
android:layout_height="match_parent">
<EditText
android:id="#+id/gpa_points"
android:layout_width="150dp"
android:layout_height="wrap_content"
android:layout_margin="20dp"
android:background="#drawable/custom_input"
android:hint=" GPA point"
android:inputType="number"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toTopOf="parent" />
<EditText
android:id="#+id/credit_points"
android:layout_width="100dp"
android:layout_height="wrap_content"
android:layout_margin="20dp"
android:background="#drawable/custom_input"
android:hint=" ETCS"
android:inputType="number"
app:layout_constraintStart_toEndOf="#+id/gpa_points"
app:layout_constraintTop_toTopOf="parent" />
<Button
android:id="#+id/close"
android:layout_width="30dp"
android:layout_height="30dp"
android:layout_marginLeft="20dp"
android:layout_marginTop="18dp"
android:background="#drawable/ic_baseline_close_24"
app:layout_constraintLeft_toRightOf="#id/credit_points"
app:layout_constraintTop_toTopOf="parent" />
</androidx.constraintlayout.widget.ConstraintLayout>
MainActivity.kt
package com.example.gpacalculator
import androidx.appcompat.app.AppCompatActivity
import android.os.Bundle
import android.view.View
import android.widget.Button
import android.widget.LinearLayout
class MainActivity : AppCompatActivity() {
private var layout: LinearLayout? = null
override fun onCreate(savedInstanceState: Bundle?) {
super.onCreate(savedInstanceState)
setContentView(R.layout.activity_main)
layout = findViewById(R.id.layout_list)
val addButton: Button = findViewById(R.id.add_button)
addButton.setOnClickListener { addView() }
val calculateButton: Button = findViewById(R.id.calculate_button)
calculateButton.setOnClickListener { calculate() }
}
private fun addView() {
val gpaView: View = layoutInflater.inflate(R.layout.new_layout, null, false)
layout?.addView(gpaView)
}
i added this function to my code
fun calculate(){
var total = 0.0
var etcs = 0.0
layout.children.forEach { newLayout ->
// Find the gpa_points EditText in the child layout
val gpaPointsEditText = newLayout.findViewById<EditText>(R.id.gpa_points) as? EditText
val creditsEditText = newLayout.findViewById<EditText>(R.id.credit_points) as? EditText
// Parse the text to be able to perform calculations
val gpaPoints = gpaPointsEditText?.text.toString().toDouble()
val credits = creditsEditText?.text.toString().toDouble()
total+=gpaPoints*credits
etcs+=credits
}
var gpa = total/etcs
val result:TextView = findViewById(R.id.result)
result.text=gpa.toString()
}
but it gives me an error like this
java.lang.NumberFormatException: For input string: "null"
atsun.misc.FloatingDecimal.readJavaFormatString(FloatingDecimal.java:2043)
at sun.misc.FloatingDecimal.parseDouble(FloatingDecimal.java:110)
at java.lang.Double.parseDouble(Double.java:538)
at com.example.gpacalculator.MainActivity.calculate(MainActivity.kt:46)
at com.example.gpacalculator.MainActivity.onCreate$lambda1(MainActivity.kt:27)
at com.example.gpacalculator.MainActivity.$r8$lambda$1xRU0rpJNKxzUpdKrPz49s5lowk(Unknown Source:0)
at com.example.gpacalculator.MainActivity$$ExternalSyntheticLambda0.onClick(Unknown Source:2)

You can iterate on the child views of layout, and retrieve the GPA.
// Get a decimal format for the current locale
private val decimalFormat = DecimalFormat.getInstance()
// Iterate on the children of layout
layout.children.forEach { newLayout ->
// Find the gpa_points EditText in the child layout
val gpaPointsEditText = newLayout.findViewById<EditText>(R.id.gpa_points) as EditText
// Parse the text to be able to perform calculations
val gpaPointsStr = gpaPointsEditText.text.toString()
val gpaPoints = decimalFormat.parse(str)
}
To learn more about layouts :
https://developer.android.com/guide/topics/ui/declaring-layout

How to implement a SearchView to search specific buttons in a LinearLayout?

I'm opening this discussion because I need help for a school project.
At the moment, I have a scrollable activity with some buttons, everything is built like this:
a constraint layout, with SearchView, ScrollView and a BottomNavigationBar, and inside the ScrollView there's a LinearLayout with all my buttons.
Here is the full xml file:
<?xml version="1.0" encoding="utf-8"?>
<androidx.constraintlayout.widget.ConstraintLayout xmlns:tools="http://schemas.android.com/tools"
android:layout_height="match_parent"
android:layout_width="match_parent"
xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto">
<SearchView
android:id="#+id/BarraRicerca"
android:layout_width="match_parent"
android:layout_height="50dp"
android:layout_marginTop="10dp"
android:gravity="top"
android:iconifiedByDefault="false"
android:imeOptions="actionDone"
android:queryHint="Cerca un tutorial"
android:labelFor="#id/BarraRicerca"
android:suggestionRowLayout="#color/white"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toTopOf="parent" />
<ScrollView
android:id="#+id/scrollView2"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:layout_alignParentTop="true"
android:layout_weight="1"
android:fillViewport="false"
android:orientation="vertical"
android:padding="10dp"
android:layout_marginTop="60dp"
app:layout_constraintBottom_toTopOf="#id/BottomBar"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toBottomOf="#id/BarraRicerca">
<LinearLayout
android:id="#+id/Linearlayout"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical"
tools:context="com.example.Flipper.FlipperList">
<Button
android:id="#+id/FlintstonesF"
android:layout_width="300dp"
android:layout_height="49dp"
android:layout_gravity="center_horizontal"
android:layout_margin="100dp"
android:text="Flintstones" />
<Button
android:id="#+id/tutorial2"
android:layout_width="300dp"
android:layout_height="49dp"
android:layout_gravity="center_horizontal"
android:layout_margin="200dp"
android:layout_weight="1"
android:text="ciao" />
<Button
android:id="#+id/tutorial3"
android:layout_width="300dp"
android:layout_height="49dp"
android:layout_gravity="center_horizontal"
android:layout_margin="100dp"
android:layout_weight="1"
android:text="hello" />
</LinearLayout>
</ScrollView>
<com.google.android.material.bottomnavigation.BottomNavigationView
android:id="#+id/BottomBar"
android:layout_width="0dp"
android:layout_height="60dp"
android:layout_marginStart="0dp"
android:layout_marginEnd="0dp"
android:layout_gravity="bottom"
android:background="?android:attr/windowBackground"
app:layout_constraintLeft_toLeftOf="parent"
app:layout_constraintRight_toRightOf="parent"
app:layout_constraintBottom_toBottomOf="parent"/>
</androidx.constraintlayout.widget.ConstraintLayout>
and the result is this, everything works
Now I need to implement the SearchView to actually search through my buttons, For example if I search Flintstones (or Flint, or Fli etc.) I want the Flintstones button to be the only one shown. The same goes for "ciao" and so on, I will obviously have more buttons than these.
I tried every possible solution I found on the internet but nothing seems to work. This is my code
package com.example.Flipper
import android.content.Intent
import android.os.Bundle
import android.view.View
import android.widget.*
import androidx.appcompat.app.AppCompatActivity
import androidx.core.view.isVisible
import com.example.pinballacademy.R
class FlipperList : AppCompatActivity() {
val passaFlintstones: Button get() = findViewById(R.id.FlintstonesF)
val bottone2: Button get() = findViewById(R.id.tutorial2)
val bottone3: Button get() = findViewById(R.id.tutorial3)
val searchbar: SearchView get() = findViewById(R.id.BarraRicerca)
val linLay: LinearLayout get() = findViewById(R.id.Linearlayout)
var listaFlipper: ArrayList<String> = ArrayList()
override fun onCreate(savedInstanceState: Bundle?) {
super.onCreate(savedInstanceState)
setContentView(R.layout.activity_flipper_list)
/* listaFlipper.clear();
listaFlipper.add(passaFlintstones.text.toString())
listaFlipper.add(bottone2.text.toString())
listaFlipper.add(bottone3.text.toString())*/
searchbar.isSubmitButtonEnabled=true
searchbar.setOnQueryTextListener() {
fun onQueryTextChange(newText: String?): Boolean {
filter(newText)
return true
}
fun onQueryTextSubmit(query: String?): Boolean {
filter(query)
return true
}
// Do your task here
}
passaFlintstones.setOnClickListener()
{
val intent = Intent(this, FlintstonesScheda::class.java)
//avvia registrazione
startActivity(intent)
// finish()
}
}
fun filter(searchText: String?) {
for (i in 0 until linLay.childCount) {
val button: Button = linLay.getChildAt(i) as Button
if (button.text.toString().contains(searchText!!)) {
button.isVisible=true
} else button.isVisible=false
}
}
private fun SearchView.setOnQueryTextListener(function: () -> Unit) {
}
}
As you can see I'm not even near to a solution, I hope you can help! Thank you!

Squared non transparent background on custom input dialog

I have created a custom input dialog for my application, and in terms of funcionality it works, but every time it has a sort of square background which distones from the actual dialog content. I tried to set a background color to tranparent e to a custom background to remove it, but it did not work. I would like help to know how can I make it so only the actual dialog appears without this background. I'm also using Material components to create the dialog, with MaterialCardView for the base, MaterialTextView and MaterialButton.
This is my dialog xml
<?xml version="1.0" encoding="utf-8"?>
<com.google.android.material.card.MaterialCardView 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"
android:id="#+id/material_name_input_field"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:clickable="true"
android:focusable="true"
android:theme="#style/Theme.MaterialComponents.DayNight.Dialog.Alert"
app:cardCornerRadius="16dp"
app:cardElevation="1dp"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toTopOf="parent">
<!-- -->
<androidx.constraintlayout.widget.ConstraintLayout
android:id="#+id/input_field"
android:layout_width="wrap_content"
android:layout_height="match_parent">
<com.google.android.material.textview.MaterialTextView
android:id="#+id/input_name_title"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_marginStart="16dp"
android:text="#string/input_serie_name"
android:textSize="16pt"
app:layout_constraintEnd_toStartOf="#+id/name_input_field"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toTopOf="parent" />
<com.google.android.material.textfield.MaterialAutoCompleteTextView
android:id="#+id/name_input_field"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_marginStart="8dp"
android:layout_marginEnd="16dp"
android:text="#string/empty_text_input_field"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintStart_toEndOf="#+id/input_name_title"
app:layout_constraintTop_toTopOf="parent" />
<com.google.android.material.button.MaterialButton
android:id="#+id/negative"
style="#style/Widget.Material3.Button"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_marginStart="16dp"
android:text="#string/cancel"
android:textSize="8pt"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toBottomOf="#+id/name_input_field" />
<com.google.android.material.button.MaterialButton
android:id="#+id/positive"
style="#style/Widget.Material3.Button"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_marginEnd="16dp"
android:text="#string/done"
android:textSize="8pt"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintTop_toBottomOf="#+id/name_input_field" />
</androidx.constraintlayout.widget.ConstraintLayout>
</com.google.android.material.card.MaterialCardView>
Creating dialog here:
var inputDialog: InputDialog = InputDialog(parent)
inputDialog
.setCallbackFunction {
doSetSeriesName(series, it.toString(), onCardCreatedCallback)
inputDialog.dismiss()
}
.setTitle("Series Name:")
.show()
Dialog code
class InputDialog(
private var activity: Activity) : Dialog(activity), View.OnClickListener {
companion object {
private var TAG = "InputDialog"
}
private lateinit var textView: EditText
private lateinit var titleTextView: TextView
private lateinit var positive: MaterialButton
private lateinit var negative: MaterialButton
private lateinit var callbackFunction: (value: Any) -> Unit
fun setCallbackFunction(callbackFunction: (value: Any) -> Unit): InputDialog {
this.callbackFunction = callbackFunction
return this
}
fun setTitle(title: String): InputDialog {
titleTextView = findViewById(R.id.input_name_title)
titleTextView.text = title
return this
}
override fun onClick(view: View?) {
when (view?.id) {
R.id.positive -> {
callbackFunction(textView.text)
}
R.id.negative -> {
dismiss()
}
R.id.name_input_field -> {
SCLog.d(TAG, "Editing Name")
textView.text.clear()
}
else -> {
SCLog.d(TAG, "onClick: Unknown view.id")
}
}
}
override fun onCreate(savedInstanceState: Bundle?) {
SCLog.d(TAG, "onCreate: creating dialog")
super.onCreate(savedInstanceState)
requestWindowFeature(Window.FEATURE_NO_TITLE)
setContentView(R.layout.input_dialog)
textView = findViewById(R.id.name_input_field)
textView.text.clear()
textView.setHint(R.string.series_name_title)
positive = findViewById(R.id.positive)
negative = findViewById(R.id.negative)
positive.setOnClickListener(this)
negative.setOnClickListener(this)
}
}
And this is a image of how it currently is:

how do i save / use user input in android kotlin

i'm trying to write my very first android app. the only programing i have done in the past was some html 4 many years ago (before cms was a thing)
it is essentially a check list but i want to be able to have multiple lists seperated by a list name supplied by the user. i have an input text box called "island name" but i cant figure out how to capture that text from the user and save it for future use...
<?xml version="1.0" encoding="utf-8"?>
<androidx.constraintlayout.widget.ConstraintLayout 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"
android:layout_width="match_parent"
android:layout_height="match_parent">
<TextView
android:id="#+id/textView"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_marginTop="189dp"
android:text="temp call islander page"
android:textSize="30sp"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toTopOf="parent" />
<Button
android:id="#+id/button"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_marginEnd="125dp"
android:layout_marginBottom="271dp"
android:onClick="loadHome"
android:text="home"
android:textSize="30sp"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintEnd_toEndOf="parent" />
<EditText
android:id="#+id/editText"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_marginTop="41dp"
android:ems="10"
android:hint="island name"
android:inputType="textPersonName"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toBottomOf="#+id/button" />
<CheckBox
android:id="#+id/checkBox"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_marginEnd="7dp"
android:layout_marginBottom="8dp"
android:text="north"
app:layout_constraintBottom_toTopOf="#+id/checkBox2"
app:layout_constraintEnd_toEndOf="#+id/checkBox2" />
<CheckBox
android:id="#+id/checkBox2"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_marginStart="2dp"
android:layout_marginBottom="88dp"
android:text="south"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintStart_toStartOf="#+id/editText" />
println("your island name is $name")
<TextView
android:id="#+id/textView4"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_marginStart="5dp"
android:layout_marginTop="19dp"
android:text="you entered $name"
app:layout_constraintStart_toEndOf="#+id/checkBox2"
app:layout_constraintTop_toBottomOf="#+id/checkBox2" />
</androidx.constraintlayout.widget.ConstraintLayout>

To put it simply, in Android dev (Android Studio) you have your view, which is your .xml file and your program logic is written in your .kt or .java file then you refer to your respective view from the .kt oe ,java file.
e.g
activity_main.xml
<LinearLayout
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical">
<com.google.android.material.textfield.TextInputEditText
android:id="#+id/textView"
android:layout_height="wrap_content"
android:layout_width="200dp"/>
<Button
android:id="#+id/saveBtn"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="Save" />
</LinearLayout>
MainActivity.kt :
import kotlinx.android.synthetic.main.activity_main.* //this will reference all views in activity_main -
//Android studio usually auto imports this when you simply type control name
class MainActivity : AppCompatActivity() {
override fun onCreate(savedInstanceState: Bundle?) {
super.onCreate(savedInstanceState)
setContentView(R.layout.activity_main)
saveBtn.setOnClickListener {
saveDetails()
}
}
fun saveDetails(){
var userText = textView.text.toString()
textView4.setText(userText)
//do something with text
}
}

For those who is experiencing the same issue you can use sharedPreferences. As an example:
private lateinit var sp: SharedPreferences
private lateinit var editor: SharedPreferences.Editor
override fun onCreate(savedInstanceState: Bundle?) {
super.onCreate(savedInstanceState)
setContentView(R.layout.activity_main)
nameEditText = findViewById(R.id.etName)
ageEditText = findViewById(R.id.etAge)
sp = getSharedPreferences("my_sf", MODE_PRIVATE)
editor = sp.edit()
}
override fun onPause() {
super.onPause()
val name = nameEditText.text.toString()
val age = ageEditText.text.toString().toInt()
editor.apply {
putString("my_name", name)
putInt("my_age", age)
commit()
}
}
override fun onResume() {
super.onResume()
val name = sp.getString("my_name", null)
val age = sp.getInt("my_age", 0)
nameEditText.setText(name)
if (age!=0) ageEditText.setText(age.toString())
}