Issue with implementing View Binding in Android

Issue with implementing View Binding in Android - android

I am trying to implement view binding to one of my activity. The issue is I am not able to access the views and it shows unresolved reference.
Now when I am using tools:viewBindingIgnore="true"
then there are no issues with the views and I am able to access them but then I am getting unresolved symbol for the activity class.
activity_single_movie.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"
>
<LinearLayout
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical"
>
<ProgressBar
android:id="#+id/progress_bar"
android:layout_width="wrap_content"
android:layout_height="match_parent"
android:layout_gravity="center"
android:visibility="gone"/>
<TextView
android:id="#+id/text_error"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:gravity="center"
android:text="Connection gone!!"
android:textColor="#color/white"
android:visibility="gone" />
<ScrollView
app:layout_constraintTop_toTopOf= "parent"
android:layout_width="match_parent"
android:layout_height="match_parent"
>
<LinearLayout
android:id="#+id/linear_layout"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical">
<ImageView
android:id="#+id/movie_poster"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:adjustViewBounds="true"
android:layout_gravity="center"
android:scaleType="fitCenter"
android:src="#drawable/placeholder_image"/>
<LinearLayout
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical"
android:layout_margin="8dp" >
<TextView
android:id="#+id/movie_title"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="movie"
android:textStyle="bold"
android:textSize="18sp" />
<TextView
android:id="#+id/movie_tagline"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="sub title"
android:textStyle="bold"
android:textSize="14sp" />
<TextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="movie info"
android:textStyle="bold"
android:textSize="14sp" />
//Layout for Release Date
<LinearLayout
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="horizontal"
>
<TextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_marginTop="2dp"
android:text="Release Date: "
android:textSize="12sp"
style="bold" />
<TextView
android:id="#+id/movie_release_date"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_marginTop="2dp"
android:text="2019"
android:textSize="12sp"
style="bold" />
</LinearLayout>
//Layout for Rating
<LinearLayout
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="horizontal"
>
<TextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_marginTop="2dp"
android:text="Rating: "
android:textSize="12sp"
style="bold" />
<TextView
android:id="#+id/movie_rating"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_marginTop="2dp"
android:text="5/10"
android:textSize="12sp"
style="bold" />
</LinearLayout>
//Layout for Runtime
<LinearLayout
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="horizontal"
>
<TextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_marginTop="2dp"
android:text="Runtime: "
android:textSize="12sp"
style="bold" />
<TextView
android:id="#+id/movie_runtime"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_marginTop="2dp"
android:text="2hrs 13mins"
android:textSize="12sp"
style="bold" />
</LinearLayout>
//Layout for Budget
<LinearLayout
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="horizontal"
>
<TextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_marginTop="2dp"
android:text="Budget: "
android:textSize="12sp"
style="bold" />
<TextView
android:id="#+id/movie_budget"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_marginTop="2dp"
android:text="$550Million"
android:textSize="12sp"
style="bold" />
</LinearLayout>
//Layout for revenue
<LinearLayout
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="horizontal"
>
<TextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_marginTop="2dp"
android:text="Budget: "
android:textSize="12sp"
style="bold" />
<TextView
android:id="#+id/movie_revenue"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_marginTop="2dp"
android:text="$550Million"
android:textSize="12sp"
style="bold" />
</LinearLayout>
</LinearLayout>
</LinearLayout>
</ScrollView>
</LinearLayout>
</androidx.constraintlayout.widget.ConstraintLayout>
In SingleMovie.kt
package com.example.movieapp.ui.single_movie_details
import androidx.appcompat.app.AppCompatActivity
import android.os.Bundle
import android.view.View
import androidx.lifecycle.Observer
import androidx.lifecycle.ViewModel
import androidx.lifecycle.ViewModelProvider
import androidx.lifecycle.ViewModelProviders
import com.bumptech.glide.Glide
import com.example.movieapp.R
import com.example.movieapp.data.api.POSTER_BASE_URL
import com.example.movieapp.data.api.TheMovieDBClient
import com.example.movieapp.data.api.TheMovieDBInterface
import com.example.movieapp.data.repository.NetworkState
import com.example.movieapp.data.vo.MovieDetails
import com.example.movieapp.databinding.ActivitySingleMovieBinding
import java.text.NumberFormat
import java.util.*
class SingleMovie : AppCompatActivity() {
private lateinit var viewModel: SingleMovieViewModel
private lateinit var movieRepository: MovieDetailsRepository
private lateinit var binding: ActivitySingleMovieBinding
override fun onCreate(savedInstanceState: Bundle?) {
super.onCreate(savedInstanceState)
binding = ActivitySingleMovieBinding.inflate(layoutInflater)
val view = binding.root
setContentView(view)
val movieId: Int = intent.getIntExtra("id", 1)
val apiService: TheMovieDBInterface = TheMovieDBClient.getClient()
movieRepository = MovieDetailsRepository(apiService)
viewModel = getViewModel(movieId)
viewModel.movieDetails.observe(this, Observer {
bindUi(it)
})
viewModel.movieDetailsNetworkState.observe(this, Observer {
binding.progress_bar.setVisibility(if (it == NetworkState.LOADING) View.VISIBLE else View.GONE)
binding.text_error.setVisibility( if(it == NetworkState.ERROR) View.VISIBLE else View.GONE)
})
}
fun bindUi(it: MovieDetails){
binding.movie_title.setText(it.title)
binding.movie_tagline.setText(it.tagline)
binding.movie_release_date.setText(it.releaseDate)
binding.movie_rating.setText(it.voteAverage.toString())
binding.movie_runtime.setText(it.runtime.toString() + "minutes")
val formatCurrency: NumberFormat = NumberFormat.getCurrencyInstance(Locale.US)
binding.movie_budget.setText(formatCurrency.format(it.budget))
binding.movie_revenue.setText(formatCurrency.format(it.revenue))
//for poster of movie
val moviePosterURL: String = POSTER_BASE_URL + it.posterPath
Glide.with(this)
.load(moviePosterURL)
.into(binding.movie_poster)
}
private fun getViewModel(movieId: Int): SingleMovieViewModel {
return ViewModelProviders.of(this, object: ViewModelProvider.Factory {
override fun <T : ViewModel?> create(modelClass: Class<T>): T {
return SingleMovieViewModel(movieRepository, movieId) as T
}
}) [SingleMovieViewModel::class.java]
}
}
Errors while using tools:viewBindingIgnore="true"
Unresolved reference: ActivitySingleMovieBinding
Errors without using tools:viewBindingIgnore="true"
Unresolved reference: progress_bar
and similar for all the views

View Binding converts underscores to camelCase, the correct syntax is binding.progressBar
<ProgressBar
android:id="#+id/progress_bar"
android:layout_width="wrap_content"
android:layout_height="match_parent"
android:layout_gravity="center"
android:visibility="gone"/>
binding.progressBar.setVisibility(if (it == NetworkState.LOADING) View.VISIBLE else View.GONE)

Related

Why am I getting NullPointerException error ? trying to pass a value from an edit text [duplicate]

This question already has answers here:
What is a NullPointerException, and how do I fix it?
(12 answers)
Closed 6 days ago.
Manual Search Activity Code:
package com.example.theweathertoday
import android.os.AsyncTask
import android.os.Bundle
import android.view.View
import android.widget.Button
import android.widget.EditText
import android.widget.ProgressBar
import android.widget.RelativeLayout
import android.widget.TextView
import androidx.appcompat.app.AppCompatActivity
import org.json.JSONObject
import java.net.URL
import java.text.SimpleDateFormat
import java.util.*
class ManualSearchActivity : AppCompatActivity()
{
val API : String = "your api"
val EnterCityEditText: String = findViewById<EditText>(R.id.enter_city_edit_text).text.toString()
override fun onCreate(savedInstanceState: Bundle?)
{
super.onCreate(savedInstanceState)
setContentView(R.layout.activity_manual_search)
val SearchCityButton = findViewById<Button>(R.id.button_search_city)
SearchCityButton.setOnClickListener(View.OnClickListener { weatherCall().execute() })
}
inner class weatherCall() : AsyncTask<String, Void, String>()
{
override fun onPreExecute()
{
super.onPreExecute()
findViewById<ProgressBar>(R.id.loader).visibility = View.VISIBLE
findViewById<RelativeLayout>(R.id.mainRelativeContainer).visibility = View.GONE
findViewById<TextView>(R.id.ErrorText).visibility = View.GONE
}
override fun doInBackground(vararg p0: String?): String?
{
var response:String?
try
{
response = URL( "https://api.openweathermap.org/data/2.5/weather?q=$EnterCityEditText&units=metric&APPID=yourapi").readText(Charsets.UTF_8)
}
catch (e: Exception)
{
response = null
}
return response
}
override fun onPostExecute(result: String?)
{
super.onPostExecute(result)
try
{
//JSON Return Values from the API
val jsonObj = JSONObject(result)
val main = jsonObj.getJSONObject("main")
val sys = jsonObj.getJSONObject("sys")
val wind = jsonObj.getJSONObject("wind")
val weather = jsonObj.getJSONArray("weather").getJSONObject(0)
val updatedAt:Long = jsonObj.getLong("dt")
val updatedAtText = "Updated at: "+ SimpleDateFormat("dd/MM/yyyy hh:mm a", Locale.ENGLISH).format(Date(updatedAt*1000))
val temp = main.getString("temp")+"°C"
val tempMin = "Min Temp: " + main.getString("temp_min")+"°C"
val tempMax = "Max Temp: " + main.getString("temp_max")+"°C"
val pressure = main.getString("pressure")
val humidity = main.getString("humidity")
val sunrise:Long = sys.getLong("sunrise")
val sunset:Long = sys.getLong("sunset")
val windSpeed = wind.getString("speed")
val weatherDescription = weather.getString("description")
val address = jsonObj.getString("name")+", "+sys.getString("country")
/* Populating extracted data into our views */
findViewById<TextView>(R.id.location_xml_id).text = address
findViewById<TextView>(R.id.updated_at_xml_id).text = updatedAtText
findViewById<TextView>(R.id.status_xml_id).text = weatherDescription.capitalize()
findViewById<TextView>(R.id.temperature_xml_id).text = temp
findViewById<TextView>(R.id.min_temp_xml_id).text = tempMin
findViewById<TextView>(R.id.max_temp_xml_id).text = tempMax
findViewById<TextView>(R.id.sunrise).text = SimpleDateFormat("hh:mm a", Locale.ENGLISH).format(Date(sunrise*1000))
findViewById<TextView>(R.id.sunset).text = SimpleDateFormat("hh:mm a", Locale.ENGLISH).format(Date(sunset*1000))
findViewById<TextView>(R.id.wind).text = windSpeed
findViewById<TextView>(R.id.pressure).text = pressure
findViewById<TextView>(R.id.humidity).text = humidity
/* Views populated, Hiding the loader, Showing the main design */
findViewById<ProgressBar>(R.id.loader).visibility = View.GONE
findViewById<RelativeLayout>(R.id.mainRelativeContainer).visibility = View.VISIBLE
} catch (e: Exception) {
findViewById<ProgressBar>(R.id.loader).visibility = View.GONE
findViewById<TextView>(R.id.ErrorText).visibility = View.VISIBLE
}
}
}
}
activity_manual_search.xml
<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout 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"
android:orientation="vertical"
android:background="#drawable/gradient_bg"
tools:context=".ManualSearchActivity">
<RelativeLayout
android:id="#+id/mainRelativeContainer"
android:visibility="visible"
android:layout_width="match_parent"
android:layout_height="match_parent">
<LinearLayout
android:id="#+id/locationContainer"
android:orientation="vertical"
android:gravity="center"
android:layout_width="match_parent"
android:layout_height="wrap_content">
<TextView
android:id="#+id/enter_city_text"
android:text="Enter City Name: "
android:textSize="25sp"
android:layout_width="wrap_content"
android:layout_height="wrap_content" />
<EditText
android:id="#+id/enter_city_edit_text"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_below="#+id/enter_city_text"
android:maxLines="1"
android:singleLine="true"/>
<Button
android:id="#+id/button_search_city"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="Search for City"
android:layout_gravity="center"
android:layout_below="#+id/enter_city_edit_text"
android:layout_centerHorizontal="true"
android:textColor="#ffffff"
android:background="#0048ff"/>
<TextView
android:id="#+id/location_xml_id"
android:textSize="25sp"
android:text="Location"
android:layout_width="wrap_content"
android:layout_height="wrap_content">
</TextView>
<TextView
android:id="#+id/updated_at_xml_id"
android:textSize="15sp"
android:text="Updated at"
android:layout_width="wrap_content"
android:layout_height="wrap_content">
</TextView>
</LinearLayout>
<LinearLayout
android:id="#+id/overviewContainer"
android:orientation="vertical"
android:layout_centerInParent="true"
android:layout_width="match_parent"
android:layout_height="wrap_content">
<TextView
android:id="#+id/status_xml_id"
android:textSize="35sp"
android:layout_gravity="center"
android:text="Clear Sky"
android:layout_width="wrap_content"
android:layout_height="wrap_content">
</TextView>
<TextView
android:id="#+id/temperature_xml_id"
android:textSize="70sp"
android:fontFamily="sans-serif-thin"
android:layout_gravity="center"
android:text="Temperature"
android:gravity="center"
android:layout_width="wrap_content"
android:layout_height="wrap_content">
</TextView>
<LinearLayout
android:id="#+id/temperature_min_max_xml_id"
android:orientation="horizontal"
android:gravity="center"
android:layout_width="match_parent"
android:layout_height="wrap_content">
<TextView
android:id="#+id/min_temp_xml_id"
android:text="Min Temperature"
android:layout_width="wrap_content"
android:layout_height="wrap_content">
</TextView>
<Space
android:layout_width="50dp"
android:layout_height="wrap_content">
</Space>
<TextView
android:id="#+id/max_temp_xml_id"
android:text="Max Temperature"
android:layout_width="wrap_content"
android:layout_height="wrap_content">
</TextView>
</LinearLayout>
</LinearLayout>
<LinearLayout
android:id="#+id/detailsContainer"
android:orientation="vertical"
android:layout_alignParentBottom="true"
android:layout_width="match_parent"
android:layout_height="wrap_content">
<LinearLayout
android:orientation="horizontal"
android:weightSum="3"
android:layout_width="match_parent"
android:layout_height="wrap_content">
<LinearLayout
android:orientation="vertical"
android:layout_weight="1"
android:gravity="center"
android:padding="9dp"
android:background="#969696"
android:layout_width="0dp"
android:layout_height="wrap_content">
<ImageView
android:layout_width="25dp"
android:layout_height="25dp"
android:src="#drawable/sunrise"
app:tint="#FFF">
</ImageView>
<Space
android:layout_width="wrap_content"
android:layout_height="5dp">
</Space>
<TextView
android:textSize="12sp"
android:text="Sunrise"
android:layout_width="wrap_content"
android:layout_height="wrap_content">
</TextView>
<TextView
android:id="#+id/sunrise"
android:textSize="14sp"
android:text="AM"
android:layout_width="wrap_content"
android:layout_height="wrap_content">
</TextView>
</LinearLayout>
<Space
android:layout_width="10dp"
android:layout_height="wrap_content">
</Space>
<LinearLayout
android:orientation="vertical"
android:layout_weight="1"
android:gravity="center"
android:padding="9dp"
android:background="#969696"
android:layout_width="0dp"
android:layout_height="wrap_content">
<ImageView
android:layout_width="25dp"
android:layout_height="25dp"
android:src="#drawable/sunset"
app:tint="#FFF">
</ImageView>
<Space
android:layout_width="wrap_content"
android:layout_height="5dp">
</Space>
<TextView
android:textSize="12sp"
android:text="Sunset"
android:layout_width="wrap_content"
android:layout_height="wrap_content">
</TextView>
<TextView
android:id="#+id/sunset"
android:textSize="14sp"
android:text="PM"
android:layout_width="wrap_content"
android:layout_height="wrap_content">
</TextView>
</LinearLayout>
<Space
android:layout_width="10dp"
android:layout_height="wrap_content">
</Space>
<LinearLayout
android:orientation="vertical"
android:layout_weight="1"
android:gravity="center"
android:padding="9dp"
android:background="#969696"
android:layout_width="0dp"
android:layout_height="wrap_content">
<ImageView
android:layout_width="25dp"
android:layout_height="25dp"
android:src="#drawable/wind"
app:tint="#FFF">
</ImageView>
<Space
android:layout_width="wrap_content"
android:layout_height="5dp">
</Space>
<TextView
android:textSize="12sp"
android:text="Wind"
android:layout_width="wrap_content"
android:layout_height="wrap_content">
</TextView>
<TextView
android:id="#+id/wind"
android:textSize="14sp"
android:text="Wind"
android:layout_width="wrap_content"
android:layout_height="wrap_content">
</TextView>
</LinearLayout>
<Space
android:layout_width="10dp"
android:layout_height="wrap_content">
</Space>
</LinearLayout>
<Space
android:layout_width="wrap_content"
android:layout_height="10dp"></Space>
<LinearLayout
android:orientation="horizontal"
android:weightSum="3"
android:layout_width="match_parent"
android:layout_height="wrap_content">
<LinearLayout
android:orientation="vertical"
android:layout_weight="1"
android:gravity="center"
android:padding="9dp"
android:background="#969696"
android:layout_width="0dp"
android:layout_height="wrap_content">
<ImageView
android:layout_width="25dp"
android:layout_height="25dp"
android:src="#drawable/pressure"
app:tint="#FFF">
</ImageView>
<Space
android:layout_width="wrap_content"
android:layout_height="5dp">
</Space>
<TextView
android:textSize="12sp"
android:text="Pressure"
android:layout_width="wrap_content"
android:layout_height="wrap_content">
</TextView>
<TextView
android:id="#+id/pressure"
android:textSize="14sp"
android:text="Pressure"
android:layout_width="wrap_content"
android:layout_height="wrap_content">
</TextView>
</LinearLayout>
<Space
android:layout_width="10dp"
android:layout_height="wrap_content">
</Space>
<LinearLayout
android:orientation="vertical"
android:layout_weight="1"
android:gravity="center"
android:padding="9dp"
android:background="#969696"
android:layout_width="0dp"
android:layout_height="wrap_content">
<ImageView
android:layout_width="25dp"
android:layout_height="25dp"
android:src="#drawable/humidity"
app:tint="#FFF">
</ImageView>
<Space
android:layout_width="wrap_content"
android:layout_height="5dp">
</Space>
<TextView
android:textSize="12sp"
android:text="Humidity"
android:layout_width="wrap_content"
android:layout_height="wrap_content">
</TextView>
<TextView
android:id="#+id/humidity"
android:textSize="14sp"
android:text="Humidity"
android:layout_width="wrap_content"
android:layout_height="wrap_content">
</TextView>
</LinearLayout>
<Space
android:layout_width="10dp"
android:layout_height="wrap_content">
</Space>
<LinearLayout
android:orientation="vertical"
android:layout_weight="1"
android:gravity="center"
android:padding="9dp"
android:background="#969696"
android:layout_width="0dp"
android:layout_height="wrap_content">
<ImageView
android:layout_width="25dp"
android:layout_height="25dp"
android:src="#drawable/info"
app:tint="#FFF">
</ImageView>
<Space
android:layout_width="wrap_content"
android:layout_height="5dp">
</Space>
<TextView
android:textSize="12sp"
android:text="Weather Forecast"
android:layout_width="wrap_content"
android:layout_height="wrap_content">
</TextView>
<TextView
android:id="#+id/info"
android:textSize="14sp"
android:text="Next 10 days"
android:layout_width="wrap_content"
android:layout_height="wrap_content">
</TextView>
</LinearLayout>
<Space
android:layout_width="10dp"
android:layout_height="wrap_content">
</Space>
</LinearLayout>
</LinearLayout>
</RelativeLayout>
<ProgressBar
android:id="#+id/loader"
android:layout_centerInParent="true"
android:visibility="gone"
android:layout_width="wrap_content"
android:layout_height="wrap_content">
</ProgressBar>
<TextView
android:id="#+id/ErrorText"
android:layout_centerInParent="true"
android:text="Error couldn't connect ?"
android:visibility="gone"
android:layout_width="wrap_content"
android:layout_height="wrap_content">
</TextView>
</RelativeLayout>
Error here:
E/AndroidRuntime: FATAL EXCEPTION: main Process: com.example.theweathertoday, PID: 18698 java.lang.RuntimeException: Unable to instantiate activity ComponentInfo{com.example.theweathertoday/com.example.theweathertoday.ManualSearchActivity}: java.lang.NullPointerException: Attempt to invoke virtual method 'android.content.pm.ApplicationInfo android.content.Context.getApplicationInfo()' on a null object reference at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:3365) at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:3601) at android.app.servertransaction.LaunchActivityItem.execute(LaunchActivityItem.java:85) at android.app.servertransaction.TransactionExecutor.executeCallbacks(TransactionExecutor.java:135) at android.app.servertransaction.TransactionExecutor.execute(TransactionExecutor.java:95) at android.app.ActivityThread$H.handleMessage(ActivityThread.java:2066) at android.os.Handler.dispatchMessage(Handler.java:106) at android.os.Looper.loop(Looper.java:223) at android.app.ActivityThread.main(ActivityThread.java:7656) at java.lang.reflect.Method.invoke(Native Method) at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:592) at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:947) Caused by: java.lang.NullPointerException: Attempt to invoke virtual method 'android.content.pm.ApplicationInfo android.content.Context.getApplicationInfo()' on a null object reference at android.content.ContextWrapper.getApplicationInfo(ContextWrapper.java:173) at android.view.ContextThemeWrapper.getTheme(ContextThemeWrapper.java:174) at android.content.Context.obtainStyledAttributes(Context.java:744) at androidx.appcompat.app.AppCompatDelegateImpl.createSubDecor(AppCompatDelegateImpl.java:922) at androidx.appcompat.app.AppCompatDelegateImpl.ensureSubDecor(AppCompatDelegateImpl.java:889) at androidx.appcompat.app.AppCompatDelegateImpl.findViewById(AppCompatDelegateImpl.java:691) at androidx.appcompat.app.AppCompatActivity.findViewById(AppCompatActivity.java:264) at com.example.theweathertoday.ManualSearchActivity.<init>(ManualSearchActivity.kt:22) at java.lang.Class.newInstance(Native Method) at android.app.AppComponentFactory.instantiateActivity(AppComponentFactory.java:95) at androidx.core.app.CoreComponentFactory.instantiateActivity(CoreComponentFactory.java:45) at android.app.Instrumentation.newActivity(Instrumentation.java:1253) at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:3353) at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:3601)  at android.app.servertransaction.LaunchActivityItem.execute(LaunchActivityItem.java:85)  at android.app.servertransaction.TransactionExecutor.executeCallbacks(TransactionExecutor.java:135)  at android.app.servertransaction.TransactionExecutor.execute(TransactionExecutor.java:95)  at android.app.ActivityThread$H.handleMessage(ActivityThread.java:2066)  at android.os.Handler.dispatchMessage(Handler.java:106)  at android.os.Looper.loop(Looper.java:223)  at android.app.ActivityThread.main(ActivityThread.java:7656)  at java.lang.reflect.Method.invoke(Native Method)  at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:592)  at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:947) 
I am trying to pass a value from an edit text to a function, that value is the city name
You can see it inside the URL $EnterCityEditText, I converted the Edit Text entry to String I guess ?
A city name should appear and replace the placeholder value of course
Edit this is the solution, Thanks for David Wasser for hinting
override fun doInBackground(vararg p0: String?): String?
{
var response:String?
try
{
val EnterCityEditText = findViewById<EditText>(R.id.enter_city_edit_text).text.toString()
response = URL( "https://api.openweathermap.org/data/2.5/weather?q=$EnterCityEditText&units=metric&APPID=yourapi").readText(Charsets.UTF_8)
}
catch (e: Exception)
{
response = null
}
return response
}

This is your problem:
val EnterCityEditText: String = findViewById<EditText>(R.id.enter_city_edit_text).text.toString()
You've declared this variable as a member variable in your class. When the instance of the class is instantiated, Android attempts to initialize this variable by calling findViewById(). This fails because the Activity has not yet been completely initialized (onCreate() has not yet been called) and you must also wait until after setContentView() has been called.
Move the initialization of the variable into onCreate() after you have called setContentView().

You need to move this
val EnterCityEditText: String =
findViewById(R.id.enter_city_edit_text).text.toString()
after
setContentView()
You can not use findViewById before "setContentView()"

Add and Remove Views in Android Dynamically in Kotlin

I modified my code by referring to the "https://www.tutorialspoint.com/add-and-remove-views-in-android-dynamically-in-kotlin". There was no error in my code, but the view added when running in the app was not visible. I have no idea what the problem is. Please help me!!
Activity to which the view is added
package com.akj.callback
import android.content.Context
import android.content.Intent
import androidx.appcompat.app.AppCompatActivity
import android.os.Bundle
import android.view.LayoutInflater
import android.view.View
import android.widget.*
import com.akj.callback.databinding.ActivitySearchSubject2Binding
import kotlinx.android.synthetic.main.activity_main.*
import kotlinx.android.synthetic.main.activity_search_subject_2.*
import kotlinx.android.synthetic.main.activity_search_subject_2.to_go_check
import kotlinx.android.synthetic.main.choiced_subject_list.*
import java.util.*
class search_subject_2 : AppCompatActivity() {
lateinit var binding3:ActivitySearchSubject2Binding
private var parentLinearLayout: LinearLayout? = null
override fun onCreate(savedInstanceState: Bundle?) {
super.onCreate(savedInstanceState)
setContentView(R.layout.activity_search_subject_2)
parentLinearLayout = findViewById(R.id.parent_linear_layout)
binding3= ActivitySearchSubject2Binding.inflate(layoutInflater)
setContentView(binding3.root)
userList3.onItemClickListener= AdapterView.OnItemClickListener{
parent, view, position, id ->
//parent?.getItemAtPosition(position).toString()
onAddField()
}
val user = arrayOf("abc", "bcd", "cde", "def", "efg")
val userAdapter: ArrayAdapter<String> = ArrayAdapter(
this,android.R.layout.simple_list_item_1,user)
to_go_check.setOnClickListener {
val intent6=Intent(this#search_subject_2,checkthesetting::class.java)
startActivity(intent6)
}
binding3.searchView3.setOnQueryTextListener(object :androidx.appcompat.widget.SearchView.OnQueryTextListener{
override fun onQueryTextSubmit(query: String?): Boolean {
binding3.searchView3.clearFocus()
if(user.contains(query)){
userAdapter.filter.filter(query)
}
return false
}
override fun onQueryTextChange(newText: String?): Boolean {
if(newText==""){
}
else{
binding3.userList3.adapter=userAdapter
userAdapter.filter.filter(newText)
}
return false
}
})
}
fun onDelete(view: View) {
parentLinearLayout!!.removeView(view.parent as View)
}
fun onAddField() {
val inflater =
getSystemService(Context.LAYOUT_INFLATER_SERVICE) as LayoutInflater
val rowView: View = inflater.inflate(R.layout.choiced_subject_list, null)
parentLinearLayout!!.addView(rowView, parentLinearLayout!!.childCount - 1)
Toast.makeText(applicationContext,"fdsvkgjh", Toast.LENGTH_SHORT).show()
}
}
choiced_subject_list.xml
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout
xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="50dp"
android:orientation="horizontal">
<TextView
android:id="#+id/number_edit_text"
android:text="title_fdskhdsffsd"
android:textColor="#color/black"
android:textSize="30dp"
android:layout_width="0dp"
android:layout_height="match_parent"
android:layout_weight="5"
android:inputType="phone"
/>
<Button
android:id="#+id/delete_button"
android:layout_width="0dp"
android:layout_height="40dp"
android:layout_weight="1"
android:background="#android:drawable/ic_delete"
android:onClick="onDelete" />
</LinearLayout>
activity_search_subject_2.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=".search_subject_2">
<androidx.constraintlayout.widget.Guideline
android:id="#+id/guideline1"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:orientation="horizontal"
app:layout_constraintGuide_percent="0.04" />
<androidx.constraintlayout.widget.Guideline
android:id="#+id/guideline2"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:orientation="horizontal"
app:layout_constraintGuide_percent="0.94" />
<androidx.constraintlayout.widget.Guideline
android:id="#+id/guideline3"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:orientation="vertical"
app:layout_constraintGuide_percent="0.03" />
<androidx.constraintlayout.widget.Guideline
android:id="#+id/guideline4"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:orientation="vertical"
app:layout_constraintGuide_percent="0.97" />
<androidx.constraintlayout.widget.Guideline
android:id="#+id/guideline5"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:orientation="horizontal"
app:layout_constraintGuide_percent="0.06" />
<androidx.constraintlayout.widget.Guideline
android:id="#+id/guideline6"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:orientation="horizontal"
app:layout_constraintGuide_percent="0.11" />
<androidx.constraintlayout.widget.Guideline
android:id="#+id/guideline7"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:orientation="horizontal"
app:layout_constraintGuide_percent="0.87" />
<androidx.constraintlayout.widget.Guideline
android:id="#+id/guideline8"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:orientation="horizontal"
app:layout_constraintGuide_percent="0.5" />
<androidx.appcompat.widget.SearchView
android:id="#+id/searchView3"
android:layout_width="0dp"
android:layout_height="0dp"
android:background="#drawable/coner_search_bar"
android:theme="#style/AppSearchView"
app:layout_constraintBottom_toTopOf="#id/guideline6"
app:layout_constraintEnd_toEndOf="#id/guideline4"
app:layout_constraintStart_toStartOf="#id/guideline3"
app:layout_constraintTop_toBottomOf="#id/guideline5"
app:queryHint="강좌 검색"
app:iconifiedByDefault="false"
/>
<androidx.appcompat.widget.AppCompatButton
android:id="#+id/to_go_check"
android:layout_width="0dp"
android:layout_height="wrap_content"
app:layout_constraintStart_toEndOf="#id/guideline3"
app:layout_constraintEnd_toStartOf="#id/guideline4"
app:layout_constraintTop_toBottomOf="#id/guideline1"
app:layout_constraintBottom_toTopOf="#id/guideline2"
app:layout_constraintVertical_bias="0.98"
android:text="확인"
android:textColor="#FFF"
android:textSize="20dp"
android:background="#drawable/coner_search_bar"
android:stateListAnimator="#null"
/>
<HorizontalScrollView
android:id="#+id/scrollView"
android:layout_width="0dp"
android:layout_height="50dp"
android:layout_marginTop="10dp"
android:layout_marginBottom="10dp"
android:scrollbars="none"
app:layout_constraintBottom_toTopOf="#+id/to_go_check"
app:layout_constraintEnd_toStartOf="#id/guideline4"
app:layout_constraintHorizontal_bias="0.0"
app:layout_constraintStart_toEndOf="#id/guideline3"
>
<LinearLayout
android:id="#+id/linear_button"
android:layout_width="wrap_content"
android:layout_height="match_parent"
android:orientation="horizontal"
>
<androidx.appcompat.widget.AppCompatButton
android:id="#+id/njklsfd"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_marginRight="5dp"
android:background="#drawable/search_subject_bar"
android:stateListAnimator="#null"
android:text="전공검색" />
<androidx.appcompat.widget.AppCompatButton
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_marginRight="5dp"
android:background="#drawable/search_subject_bar"
android:stateListAnimator="#null"
android:text="교양검색" />
<androidx.appcompat.widget.AppCompatButton
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_marginRight="5dp"
android:background="#drawable/search_subject_bar"
android:stateListAnimator="#null"
android:text="교수검색" />
<androidx.appcompat.widget.AppCompatButton
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_marginRight="5dp"
android:background="#drawable/search_subject_bar"
android:stateListAnimator="#null"
android:text="정렬" />
<androidx.appcompat.widget.AppCompatButton
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_marginRight="5dp"
android:background="#drawable/search_subject_bar"
android:stateListAnimator="#null"
android:text="학점:3" />
<androidx.appcompat.widget.AppCompatButton
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_marginRight="5dp"
android:background="#drawable/search_subject_bar"
android:stateListAnimator="#null"
android:text="학점:2" />
<androidx.appcompat.widget.AppCompatButton
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_marginRight="5dp"
android:background="#drawable/search_subject_bar"
android:text="학점:1"
/>
</LinearLayout>
</HorizontalScrollView>
<ListView
android:id="#+id/userList3"
android:layout_width="0dp"
android:layout_height="0dp"
app:layout_constraintBottom_toTopOf="#+id/guideline8"
app:layout_constraintEnd_toStartOf="#+id/guideline4"
app:layout_constraintHorizontal_bias="0.0"
app:layout_constraintStart_toStartOf="#id/guideline3"
app:layout_constraintTop_toTopOf="#+id/guideline6"
app:layout_constraintVertical_bias="0.0" />
<LinearLayout
android:orientation="vertical"
android:id="#+id/parent_linear_layout"
android:layout_width="0dp"
android:layout_height="0dp"
android:layout_marginTop="7dp"
android:layout_marginBottom="7dp"
app:layout_constraintBottom_toTopOf="#id/scrollView"
app:layout_constraintEnd_toStartOf="#+id/guideline4"
app:layout_constraintStart_toEndOf="#id/guideline3"
app:layout_constraintTop_toBottomOf="#id/guideline8" />
</androidx.constraintlayout.widget.ConstraintLayout>

Try this:
val inflater = getSystemService(Context.LAYOUT_INFLATER_SERVICE) as LayoutInflater
val rowView: View = inflater.inflate(R.layout.row_child_view, null, false)
Mainview.removeView(rowView)

recyclerview shows only on the second click of another button in kotlin

Now, the question here, whenever I click btnCash it should directly display a row on recyclerview. But, it only does it if I clikc another button after I click btnCash.
Lets say that I want to pay 2.50. After I enter this value, I click btnCash but it doesn't display anything yet. I must click another (numeric buttons 0-9) for that display happens.
by using println I can see that when I clikc btnCash, it adds to ArrayList.
Is there any solution for this?
Why can't I put it on display at first btnCash click?
Any help arraciated.
I have payment.xml
<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout 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="wrap_content"
android:layout_height="wrap_content"
android:background="#ecf0f1"
android:orientation="vertical">
<android.support.v7.widget.RecyclerView
android:id="#+id/recyclerView_payment"
android:layout_width="match_parent"
android:layout_height="284dp"
android:background="#color/qtr_gray6"
android:textSize="30sp"
/>
<android.support.constraint.ConstraintLayout
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_marginTop="280dp"
android:orientation="horizontal">
<EditText
android:id="#+id/textPayment"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:gravity="end"
android:hint="00.0"
android:inputType="numberDecimal"
android:paddingRight="30dp"
android:textAlignment="textEnd"
app:layout_constraintEnd_toEndOf="parent" />
</android.support.constraint.ConstraintLayout>
<LinearLayout
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_marginTop="340dp"
android:orientation="horizontal">
<Button
android:id="#+id/btnFifty"
android:layout_width="20dp"
android:layout_height="match_parent"
android:layout_margin="1dp"
android:layout_weight="0.25"
android:background="#color/qtr_primary"
android:text="£50"
android:textColor="#ecf0f1"
android:textSize="20sp" />
<Button
android:id="#+id/btnTwenty"
android:layout_width="20dp"
android:layout_height="match_parent"
android:layout_margin="1dp"
android:layout_weight="0.25"
android:background="#color/qtr_primary"
android:text="£20"
android:textColor="#ecf0f1"
android:textSize="20sp" />
<Button
android:id="#+id/btnTen"
android:layout_width="20dp"
android:layout_height="match_parent"
android:layout_margin="1dp"
android:layout_weight="0.25"
android:background="#color/qtr_primary"
android:text="£10"
android:textColor="#ecf0f1"
android:textSize="20sp" />
<Button
android:id="#+id/btnFivePound"
android:layout_width="20dp"
android:layout_height="match_parent"
android:layout_margin="1dp"
android:layout_weight="0.25"
android:background="#color/qtr_primary"
android:text="£5"
android:textColor="#ecf0f1"
android:textSize="20sp" />
</LinearLayout>
<LinearLayout
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_marginTop="390dp"
android:orientation="horizontal">
<Button
android:id="#+id/btnOne"
android:layout_width="wrap_content"
android:layout_height="match_parent"
android:layout_margin="1dp"
android:layout_weight="0.25"
android:background="#color/qtr_primary2"
android:onClick="onDigit"
android:text="1"
android:textColor="#ecf0f1"
android:textSize="20sp" />
<Button
android:id="#+id/btnTwo"
android:layout_width="wrap_content"
android:layout_height="match_parent"
android:layout_margin="1dp"
android:layout_weight="0.25"
android:background="#color/qtr_primary2"
android:onClick="onDigit"
android:text="2"
android:textColor="#ecf0f1"
android:textSize="20sp" />
<Button
android:id="#+id/btnThree"
android:layout_width="wrap_content"
android:layout_height="match_parent"
android:layout_margin="1dp"
android:layout_weight="0.25"
android:background="#color/qtr_primary2"
android:onClick="onDigit"
android:text="3"
android:textColor="#ecf0f1"
android:textSize="20sp" />
<Button
android:id="#+id/btnBack"
android:layout_width="wrap_content"
android:layout_height="match_parent"
android:layout_margin="1dp"
android:layout_weight="0.25"
android:background="#color/qtr_btn8"
android:onClick="onBack"
android:text="Back"
android:textColor="#ecf0f1"
android:textSize="14sp" />
</LinearLayout>
<LinearLayout
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_marginTop="442dp"
android:orientation="horizontal">
<Button
android:id="#+id/btnFour"
android:layout_width="wrap_content"
android:layout_height="match_parent"
android:layout_margin="1dp"
android:layout_weight="0.25"
android:background="#color/qtr_primary2"
android:onClick="onDigit"
android:text="4"
android:textColor="#ecf0f1"
android:textSize="20sp" />
<Button
android:id="#+id/btnFive"
android:layout_width="wrap_content"
android:layout_height="match_parent"
android:layout_margin="1dp"
android:layout_weight="0.25"
android:background="#color/qtr_primary2"
android:onClick="onDigit"
android:text="5"
android:textColor="#ecf0f1"
android:textSize="20sp" />
<Button
android:id="#+id/btnSix"
android:layout_width="wrap_content"
android:layout_height="match_parent"
android:layout_margin="1dp"
android:layout_weight="0.25"
android:background="#color/qtr_primary2"
android:onClick="onDigit"
android:text="6"
android:textColor="#ecf0f1"
android:textSize="20sp" />
<Button
android:id="#+id/btnStaff"
android:layout_width="wrap_content"
android:layout_height="match_parent"
android:layout_margin="1dp"
android:layout_weight="0.25"
android:background="#color/qtr_btn9"
android:onClick="onStaff"
android:text="Staff"
android:textColor="#ecf0f1"
android:textSize="14sp" />
</LinearLayout>
<LinearLayout
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_marginTop="495dp"
android:orientation="horizontal">
<Button
android:id="#+id/btnSeven"
android:layout_width="wrap_content"
android:layout_height="match_parent"
android:layout_margin="1dp"
android:layout_weight="0.25"
android:background="#color/qtr_primary2"
android:onClick="onDigit"
android:text="7"
android:textColor="#ecf0f1"
android:textSize="20sp" />
<Button
android:id="#+id/btnEight"
android:layout_width="wrap_content"
android:layout_height="match_parent"
android:layout_margin="1dp"
android:layout_weight="0.25"
android:background="#color/qtr_primary2"
android:onClick="onDigit"
android:text="8"
android:textColor="#ecf0f1"
android:textSize="20sp" />
<Button
android:id="#+id/btnNine"
android:layout_width="wrap_content"
android:layout_height="match_parent"
android:layout_margin="1dp"
android:layout_weight="0.25"
android:background="#color/qtr_primary2"
android:onClick="onDigit"
android:text="9"
android:textColor="#ecf0f1"
android:textSize="20sp" />
<Button
android:id="#+id/btnVoucher"
android:layout_width="wrap_content"
android:layout_height="match_parent"
android:layout_margin="1dp"
android:layout_weight="0.25"
android:background="#color/qtr_btn10"
android:onClick="onVoucher"
android:text="Voucher"
android:textColor="#ecf0f1"
android:textSize="14sp" />
</LinearLayout>
<LinearLayout
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_marginTop="547dp"
android:orientation="horizontal">
<Button
android:id="#+id/btnZero"
android:layout_width="wrap_content"
android:layout_height="match_parent"
android:layout_margin="1dp"
android:layout_weight="0.25"
android:background="#color/qtr_primary2"
android:onClick="onDigit"
android:text="0"
android:textColor="#ecf0f1"
android:textSize="20sp" />
<Button
android:id="#+id/btnClear"
android:layout_width="wrap_content"
android:layout_height="match_parent"
android:layout_margin="1dp"
android:layout_weight="0.25"
android:background="#color/qtr_primary2"
android:onClick="onClear"
android:text="cl"
android:textColor="#ecf0f1"
android:textSize="20sp" />
<Button
android:id="#+id/btnCard"
android:layout_width="wrap_content"
android:layout_height="match_parent"
android:layout_margin="1dp"
android:layout_weight="0.25"
android:background="#color/qtr_btn6"
android:onClick="onClick_Action_Function"
android:text="Card"
android:textColor="#ecf0f1"
android:textSize="30sp" />
<Button
android:id="#+id/btnCash"
android:layout_width="wrap_content"
android:layout_height="match_parent"
android:layout_margin="1dp"
android:layout_weight="0.25"
android:clickable="true"
android:background="#color/qtr_btn7"
android:text="Cash"
android:textColor="#ecf0f1"
android:textSize="30sp" />
</LinearLayout>
and, PaymentActivity.kt
package com.soyut.su.epos01
import android.os.Bundle
import android.support.v7.app.AppCompatActivity
import android.text.Editable
import android.view.View
import android.widget.Button
import android.widget.EditText
import kotlinx.android.synthetic.main.payment.*
import android.text.TextWatcher
import android.support.v7.widget.LinearLayoutManager
import android.support.v7.widget.RecyclerView
import java.lang.ref.WeakReference
import java.math.BigDecimal
import java.util.*
class PaymentActivity : AppCompatActivity() {
lateinit var pRecyclerView: RecyclerView
lateinit var txtInput: EditText
var lastNumeric: Boolean = false
var stateError: Boolean = false
var lastDot: Boolean = false
var list = ArrayList<Payment>()
override fun onCreate(savedInstanceState: Bundle?) {
super.onCreate(savedInstanceState)
setContentView(R.layout.payment)
txtInput = textPayment
txtInput.addTextChangedListener(MoneyTextWatcher(txtInput))
pRecyclerView = recyclerView_payment
pRecyclerView.layoutManager = LinearLayoutManager(this)
pRecyclerView.adapter = PaymentAdapter(this, list)
btnCash.setOnClickListener {
var paymAmnt: String = txtInput.text.toString()
list.add(Payment("Cash", paymAmnt))
for (i in list){
println(i.paymentDesc+ " - " +i.paymentAmnt)
}
}
}
fun onClick_Action_Function(view: View) {
var paymAmnt: String = txtInput.text.toString()
list.add(Payment("Card", paymAmnt))
}
fun onDigit(view: View) {
// If not, already there is a valid expression so append to it
txtInput.append((view as Button).text)
// Set the flag
lastNumeric = true
}
fun onBack(view: View) {
var sz = txtInput.text.length
println(sz)
val textString = txtInput.getText().toString()
if (textString.length > 0) {
txtInput.setText(textString.substring(0, textString.length - 1))
}
}
fun onClear(view: View) {
var sz = txtInput.text.length
txtInput.text = txtInput.text.dropLast(sz) as Editable
}
/**
* Append . to the TextView
*/
fun onDecimalPoint(view: View) {
if (lastNumeric && !stateError && !lastDot) {
txtInput.append(".")
lastNumeric = false
lastDot = true
}
}
fun onOperator(view: View) {
if (lastNumeric && !stateError) {
txtInput.append((view as Button).text)
lastNumeric = false
lastDot = false // Reset the DOT flag
}
}
inner class MoneyTextWatcher(editText: EditText) : TextWatcher {
private val editTextWeakReference: WeakReference<EditText>
init {
editTextWeakReference = WeakReference<EditText>(editText)
}
override fun beforeTextChanged(s: CharSequence, start: Int, count: Int, after: Int) {}
override fun onTextChanged(s: CharSequence, start: Int, before: Int, count: Int) {}
override fun afterTextChanged(editable: Editable) {
val editText = editTextWeakReference.get() ?: return
val s = editable.toString()
if (s.isEmpty()) return
editText.removeTextChangedListener(this)
val cleanString = s.replace("[$,.]".toRegex(), "")
val parsed = BigDecimal(cleanString).setScale(2, BigDecimal.ROUND_FLOOR)
.divide(BigDecimal(100), BigDecimal.ROUND_FLOOR)
// val formatted = NumberFormat.getCurrencyInstance(Locale.UK).format(parsed)
editText.setText(parsed.toString())
editText.setSelection(parsed.toString().length)
editText.addTextChangedListener(this)
}
}
}
and,finally PaymentAdapter.kt
package com.soyut.su.epos01
import android.content.Context
import android.support.v7.widget.RecyclerView
import android.view.LayoutInflater
import android.view.View
import android.view.ViewGroup
import kotlinx.android.synthetic.main.single_payment.view.*
class PaymentAdapter(val context: Context, val items: List<Payment>) : RecyclerView.Adapter<PaymentAdapter.PaymentViewHolder>() {
override fun onBindViewHolder(p0: PaymentAdapter.PaymentViewHolder, p1: Int) {
p0.bindItems(items[p1])
}
override fun getItemId(position: Int): Long {
return super.getItemId(position)
}
override fun getItemCount(): Int {
return items.size
}
override fun onCreateViewHolder(parent: ViewGroup, viewType: Int): PaymentViewHolder {
val inflater = LayoutInflater.from(parent.context)
val view = inflater.inflate(R.layout.single_payment, parent, false)
view.requestFocus()
return PaymentViewHolder(view)
}
inner class PaymentViewHolder(itemView: View) : RecyclerView.ViewHolder(itemView) {
fun bindItems(pym: Payment) {
val textPaymentDesc = itemView.txtPaymentDescription
val textPaymentAmnt = itemView.txtPaymentAmount
textPaymentDesc.text = pym.paymentDesc
textPaymentAmnt.text = pym.paymentAmnt
}
}
}
Kind Regards

Use notifyDataSetChanged() after add, update or delete data from data set.
Try like the following
var adapter: PaymentAdapter ?=null // decleare it before onCreate()
adapter = PaymentAdapter(this, list) // here you shoule initialize you adapter
pRecyclerView.adapter = adapter // assigne your adapter to recyclerview
btnCash.setOnClickListener {
var paymAmnt: String = txtInput.text.toString()
list.add(Payment("Cash", paymAmnt))
adapter?.notifyDataSetChanged() // add this line to notify your adapter that data set is changed.
//....
}

All RecyclerView items are not visible when using RecyclerView in ConstraintLayout

I am using ConstraintLayout as a parent and put recyclerview in it to populate the list. Suppose I have to give item count 5 to populate the list and run the code then the list is showing perfectly but the last item of the recyclerview is showing half and not fully visible, and scroll stops at there. I found a solution for this is if am giving height match_parent to the recyclerview then it works fine but then all other view is hidden behind the recyclerview.
If I use another parent view like LinearLayout or RelativeLayout, then recyclerview with height wrap_content works fine and all the list item are fully visible.
I have tried by 2 ways that work for me but I found that wrong programming practice
I give height match_parent to recyclerview and give top_margin to the recylerview so all the other UI item show.
I give padding_bottom to the recyclerview until all the list item position visible
My XML file "activity_per_day_sale.xml" is below.
<?xml version="1.0" encoding="utf-8"?>
<android.support.constraint.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"
android:background="#color/black">
<android.support.v7.widget.Toolbar
android:id="#+id/toolbar"
android:layout_width="match_parent"
android:layout_height="?attr/actionBarSize"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toTopOf="parent"
app:layout_constraintEnd_toEndOf="parent"
app:popupTheme="#style/AppTheme.PopupOverlay">
<RelativeLayout
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:gravity="center_vertical">
<ImageView
android:layout_width="40dp"
android:layout_height="40dp"
android:id="#+id/btn_back"
android:padding="5dp"
android:onClick="OnClickPerDaySale"
android:background="?attr/selectableItemBackground"
android:src="#drawable/icon_back_white"
/>
<TextView android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="Signup"
android:layout_centerInParent="true"
android:id="#+id/home_title_text"
android:textColor="#color/black"
android:visibility="gone"
android:fontFamily="#font/seguisb"
android:textSize="18sp"/>
<TextView android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="SKIP"
android:padding="10dp"
android:layout_centerVertical="true"
android:visibility="gone"
android:id="#+id/skip"
android:textColor="#color/black"
android:fontFamily="#font/seguisb"
android:textSize="18sp"/>
</RelativeLayout>
</android.support.v7.widget.Toolbar>
<TextView android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:textSize="25sp"
android:layout_marginTop="10dp"
android:text="Per Day Sale Details"
android:textColor="#color/yellow_app_logo_color"
android:fontFamily="#font/segoeuib"
app:layout_constraintTop_toBottomOf="#+id/toolbar"
app:layout_constraintStart_toStartOf="parent"
android:id="#+id/TV_signupScreenText"
android:layout_marginLeft="45dp"/>
<android.support.v7.widget.RecyclerView
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:id="#+id/rv_perday_sale"
android:layout_marginTop="10dp"
android:layout_marginHorizontal="10dp"
app:layout_constraintTop_toBottomOf="#+id/TV_signupScreenText"/>
</android.support.constraint.ConstraintLayout>
Activity class is "PerDaySaleActivity.kt"
import android.content.Context
import android.content.Intent
import android.os.Bundle
import android.support.v7.widget.StaggeredGridLayoutManager
import android.view.View
import com.nq.NQManager.R
import com.nq.NQManager.utils.BaseActivity
import kotlinx.android.synthetic.main.activity_per_day_sale.*
class PerDaySaleActivity:BaseActivity(){
var adapterPerdaySale : AdapterPerdaySale? = null
companion object {
fun start(context: Context) {
val starter = Intent(context, PerDaySaleActivity::class.java)
context.startActivity(starter)
}
}
override fun getID(): Int {
return R.layout.activity_per_day_sale
}
override fun iniView(savedInstanceState: Bundle?) {
initViews()
}
fun OnClickPerDaySale(v: View){
when(v){
btn_back->{
finish()
}
}
}
fun initViews() {
adapterPerdaySale = AdapterPerdaySale( this)
rv_perday_sale.layoutManager = StaggeredGridLayoutManager(1, 1)
rv_perday_sale.adapter = adapterPerdaySale
}
private fun setUpRecyclerView() {
runOnUiThread { adapterPerdaySale!!.notifyDataSetChanged() }
}
My Adapter class "AdapterPerdaySale.kt"
mport android.content.Context
import android.support.v7.widget.RecyclerView
import android.view.LayoutInflater
import android.view.View
import android.view.ViewGroup
import com.nq.NQManager.R
import kotlinx.android.synthetic.main.adapter_perday_sale.view.*
class AdapterPerdaySale(context: Context):
RecyclerView.Adapter<AdapterPerdaySale.MyViewHOlder>() {
private var ctx:Context?=context
override fun onCreateViewHolder(p0: ViewGroup, p1: Int): MyViewHOlder {
return MyViewHOlder(LayoutInflater.from(ctx).inflate(R.layout.adapter_perday_sale, p0, false))
}
override fun getItemCount(): Int {
return 5
}
override fun onBindViewHolder(holder: MyViewHOlder, position: Int) {
if (position==1){
holder.tv_date.text="26 June, 2019"
}else if(position==2){
holder.tv_date.text="27 June, 2019"
}
}
inner class MyViewHOlder(view: View) : RecyclerView.ViewHolder(view) {
val tv_date=view.tv_date
}
}
My Adapter xml file "adapter_perday_sale.xml"
<?xml version="1.0" encoding="utf-8"?>
<android.support.constraint.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="wrap_content"
android:paddingVertical="5dp"
android:background="#color/black">
<TextView
android:id="#+id/tv_date"
android:layout_below="#+id/txt_today"
android:layout_centerHorizontal="true"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:textColor="#color/white"
android:fontFamily="#font/segoeuib"
android:text="25 June, 2019"
android:textSize="23sp"
android:layout_marginEnd="8dp" app:layout_constraintEnd_toEndOf="parent"
android:layout_marginRight="8dp" android:layout_marginStart="8dp"
app:layout_constraintStart_toStartOf="parent"
android:layout_marginLeft="8dp" android:layout_marginTop="8dp"
app:layout_constraintTop_toTopOf="parent"/>
<LinearLayout
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:id="#+id/linearLayout1"
android:orientation="horizontal"
app:layout_constraintTop_toBottomOf="#+id/tv_date">
<LinearLayout
android:layout_width="0dp"
android:layout_weight="1"
android:layout_gravity="center"
android:gravity="center"
android:layout_height="wrap_content"
android:orientation="vertical">
<TextView android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:textSize="25sp"
android:layout_marginTop="5dp"
android:text="Orders"
android:layout_centerHorizontal="true"
android:textColor="#color/white"
android:fontFamily="#font/segoeuib"/>
<TextView android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:textSize="50sp"
android:layout_marginTop="0dp"
android:text="50"
android:layout_centerHorizontal="true"
android:textColor="#color/order_history_txt_color"
android:fontFamily="#font/segoeui"/>
</LinearLayout>
<LinearLayout
android:layout_width="0dp"
android:layout_weight="1"
android:gravity="center"
android:layout_height="wrap_content"
android:orientation="vertical">
<TextView android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:textSize="25sp"
android:layout_marginTop="5dp"
android:text="Revenue"
android:layout_centerHorizontal="true"
android:textColor="#color/white"
android:fontFamily="#font/segoeuib"/>
<TextView android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:textSize="50sp"
android:layout_marginTop="0dp"
android:text="£550"
android:layout_centerHorizontal="true"
android:textColor="#color/order_history_txt_color"
android:fontFamily="#font/segoeui"/>
</LinearLayout>
</LinearLayout>
<View android:layout_width="match_parent"
android:layout_height="1.5dp"
android:background="#color/gray"
android:id="#+id/view_1"
app:layout_constraintTop_toBottomOf="#+id/linearLayout1"
android:layout_marginLeft="8dp"
android:layout_marginTop="10dp"
android:layout_marginBottom="10dp"
app:layout_constraintStart_toStartOf="parent"
android:layout_marginStart="8dp"/>
</android.support.constraint.ConstraintLayout>

Add this app:layout_constraintBottom_toBottomOf="parent" property to your recyclerview
<androidx.appcompat.widget.Toolbar
android:id="#+id/toolbar"
android:layout_width="match_parent"
android:layout_height="?attr/actionBarSize"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toTopOf="parent"
app:popupTheme="#style/AppTheme.PopupOverlay">
<RelativeLayout
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:gravity="center_vertical">
<ImageView
android:id="#+id/btn_back"
android:layout_width="40dp"
android:layout_height="40dp"
android:background="?attr/selectableItemBackground"
android:onClick="OnClickPerDaySale"
android:padding="5dp"
android:src="#drawable/ic_background" />
<TextView
android:id="#+id/home_title_text"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_centerInParent="true"
android:text="Signup"
android:textColor="#000"
android:textSize="18sp"
android:visibility="gone" />
<TextView
android:id="#+id/skip"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_centerVertical="true"
android:padding="10dp"
android:text="SKIP"
android:textColor="#000"
android:textSize="18sp"
android:visibility="gone" />
</RelativeLayout>
</androidx.appcompat.widget.Toolbar>
<TextView
android:id="#+id/TV_signupScreenText"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_marginLeft="45dp"
android:layout_marginTop="10dp"
android:text="Per Day Sale Details"
android:textColor="#AD4E4E"
android:textSize="25sp"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toBottomOf="#+id/toolbar" />
<androidx.recyclerview.widget.RecyclerView
android:id="#+id/rv_perday_sale"
android:layout_width="match_parent"
android:layout_height="0dp"
android:layout_marginTop="8dp"
android:layout_marginBottom="8dp"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintTop_toBottomOf="#+id/TV_signupScreenText" />
</androidx.constraintlayout.widget.ConstraintLayout>

Kotlin : same fragment, children with same tag

In my fragment, I have two linear layout with the same tag "result". Inside theses linear layouts, I have another layout with the tag "toggle" and a button with the tag "toggleButton".
I want that : when I click on my button, it toggle the linear layout "toggle" of its linear layout parent "result"
But when I do this :
override fun onViewCreated(view: View, savedInstanceState: Bundle?) {
super.onViewCreated(view, savedInstanceState)
val root = rootLayoutResultSearch
root.findViewWithTag<Button>("toToggleButton")
val buttonToggle = view.findViewWithTag<Button>("toToggleButton")
buttonToggle.setOnClickListener{
Log.i(TAG, "click")
val toggle = view.findViewWithTag<LinearLayout>("toToggle")
if(toggle.visibility == View.GONE){
toggle.visibility = View.VISIBLE
}else{
toggle.visibility = View.GONE
}
}
}
it's working only for my first linear layout "result". When I click on my second button, it's not doing anything
Here the xml of the layouts "result" (I only post the first, the second is the exact same one)
<LinearLayout
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:orientation="vertical"
android:tag="result"
android:contentDescription="result">
<LinearLayout
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:orientation="vertical"
android:padding="35dp"
android:background="#drawable/whit_bg_and_shadow"
android:tag="visibleNotChangeable"
>
<LinearLayout
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:orientation="horizontal">
<TextView
style="#style/hoursSearch"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_weight=".1"
android:fontFamily="#font/rubik_medium_italic"
android:tag="heureDepart"
android:text="#string/fillHoursRecherche1"
android:textStyle="italic" />
<TextView
style="#style/citySearch"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_marginStart="15dp"
android:layout_weight=".9"
android:fontFamily="#font/rubik_medium"
android:tag="villeDepart"
android:text="#string/fillVilleRecherche1"
android:textSize="18sp" />
</LinearLayout>
<LinearLayout
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:orientation="horizontal">
<TextView
style="#style/hoursSearch"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_weight=".1"
android:fontFamily="#font/rubik_medium_italic"
android:tag="heureDepart"
android:text="#string/fillHoursRecherche2"
android:textFontWeight="500"
android:textStyle="italic" />
<TextView
style="#style/citySearch"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_marginStart="15dp"
android:layout_weight=".9"
android:fontFamily="#font/rubik_medium"
android:tag="villeDepart"
android:text="#string/fillVilleRecherche2"
android:textSize="18sp" />
</LinearLayout>
<LinearLayout
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:gravity="end"
android:orientation="horizontal">
<TextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_marginStart="15dp"
android:fontFamily="#font/roboto"
android:tag="villeArrivee"
android:text="#string/jourCircuRecherche" />
<TextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:fontFamily="#font/roboto"
android:tag="villeArrivee"
android:text="#string/fillJourCircuRecherche" />
</LinearLayout>
<View style="#style/HorizontalLine" />
<LinearLayout
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:orientation="horizontal">
<ImageView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:src="#drawable/bus" />
<TextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_gravity="center"
android:layout_marginStart="15dp"
android:background="#drawable/dark_blue_rectangle"
android:text="3"
android:textColor="#color/colorWhite" />
</LinearLayout>
<View style="#style/HorizontalLine" />
<LinearLayout
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:orientation="horizontal">
<ImageView
android:layout_width="20dp"
android:layout_height="20dp"
android:src="#drawable/horaire" />
<TextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_gravity="center"
android:layout_marginStart="15dp"
android:fontFamily="#font/roboto"
android:text="#string/fillTempsRecherche" />
</LinearLayout>
</LinearLayout>
<LinearLayout
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:orientation="vertical"
android:padding="35dp"
android:background="#drawable/gray_bg"
android:visibility="gone"
android:tag="toToggle"
>
<LinearLayout
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:orientation="horizontal">
<TextView
style="#style/hoursSearch"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_weight=".1"
android:fontFamily="#font/rubik_medium_italic"
android:tag="heureDepart"
android:text="#string/fillHoursRecherche1"
android:textStyle="italic" />
<TextView
style="#style/citySearch"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_marginStart="15dp"
android:layout_weight=".9"
android:fontFamily="#font/rubik_medium"
android:tag="villeDepart"
android:text="#string/fillVilleRecherche1"
android:textSize="18sp" />
</LinearLayout>
<LinearLayout
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:orientation="horizontal">
<TextView
style="#style/hoursSearch"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_weight=".1"
android:fontFamily="#font/rubik_medium_italic"
android:tag="heureDepart"
android:text="#string/fillHoursRecherche2"
android:textFontWeight="500"
android:textStyle="italic" />
<TextView
style="#style/citySearch"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_marginStart="15dp"
android:layout_weight=".9"
android:fontFamily="#font/rubik_medium"
android:tag="villeDepart"
android:text="#string/fillVilleRecherche2"
android:textSize="18sp" />
</LinearLayout>
<LinearLayout
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:gravity="end"
android:orientation="horizontal">
<TextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_marginStart="15dp"
android:fontFamily="#font/roboto"
android:tag="villeArrivee"
android:text="#string/jourCircuRecherche" />
<TextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:fontFamily="#font/roboto"
android:tag="villeArrivee"
android:text="#string/fillJourCircuRecherche" />
</LinearLayout>
<View style="#style/HorizontalLine" />
<LinearLayout
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:orientation="horizontal">
<ImageView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:src="#drawable/bus" />
<TextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_gravity="center"
android:layout_marginStart="15dp"
android:background="#drawable/dark_blue_rectangle"
android:text="3"
android:textColor="#color/colorWhite" />
</LinearLayout>
<View style="#style/HorizontalLine" />
<LinearLayout
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:orientation="horizontal">
<ImageView
android:layout_width="20dp"
android:layout_height="20dp"
android:src="#drawable/horaire" />
<TextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_gravity="center"
android:layout_marginStart="15dp"
android:fontFamily="#font/roboto"
android:text="#string/fillTempsRecherche" />
</LinearLayout>
</LinearLayout>
<Button
android:id="#+id/ToggleSearchResult"
android:layout_width="40dp"
android:layout_height="40dp"
android:background="#drawable/arrow_down_blue_circle"
android:layout_gravity="center"
android:layout_marginTop="-20dp"
android:tag="toToggleButton"
/>
</LinearLayout>

Okay, I've thrown together a quick idea of what I think you want to accomplish. It excludes all the error and consistency checking one would normally want to do.
package com.example.toggler
import android.os.Bundle
import android.support.v7.app.AppCompatActivity
import android.view.View
import android.widget.LinearLayout
import kotlinx.android.synthetic.main.activity_main.*
class MainActivity : AppCompatActivity() {
override fun onCreate(savedInstanceState: Bundle?) {
super.onCreate(savedInstanceState)
setContentView(R.layout.activity_main)
val list = arrayListOf<View>()
root_View.findViewsWithText(list, "toToggleButton", View.FIND_VIEWS_WITH_CONTENT_DESCRIPTION)
list.forEach { button ->
button.setOnClickListener { v: View ->
val viewParent = v.parent
if (viewParent is LinearLayout) {
val taggedView = viewParent.findViewWithTag<View>("toggle")
taggedView.visibility = when {
taggedView.visibility == View.GONE -> View.VISIBLE
else -> View.GONE
}
}
}
}
}
}
activity_main.xml
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:id="#+id/root_View"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical"
tools:context=".MainActivity">
<LinearLayout
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:orientation="vertical">
<Button
android:id="#+id/button1"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_gravity="bottom|end"
android:contentDescription="toToggleButton"
android:tag="toToggleButton"
android:text="toggle"
tools:ignore="HardcodedText" />
<View
android:layout_width="match_parent"
android:layout_height="50dp"
android:background="#F44336"
android:tag="toggle" />
</LinearLayout>
<LinearLayout
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:orientation="vertical">
<Button
android:id="#+id/button2"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_gravity="bottom|end"
android:contentDescription="toToggleButton"
android:tag="toToggleButton"
android:text="toggle"
tools:ignore="HardcodedText" />
<View
android:layout_width="match_parent"
android:layout_height="50dp"
android:background="#9C27B0"
android:tag="toggle" />
</LinearLayout>
<LinearLayout
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:orientation="vertical">
<Button
android:id="#+id/button3"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_gravity="bottom|end"
android:contentDescription="toToggleButton"
android:tag="toToggleButton"
android:text="toggle"
tools:ignore="HardcodedText" />
<View
android:layout_width="match_parent"
android:layout_height="50dp"
android:background="#FFEB3B"
android:tag="toggle" />
</LinearLayout>
</LinearLayout>
[EDIT]
Or, if you prefer to use tags:
class MainActivity : AppCompatActivity() {
override fun onCreate(savedInstanceState: Bundle?) {
super.onCreate(savedInstanceState)
setContentView(R.layout.activity_main)
root_View.findViewsWithTag("toToggleButton").forEach { button ->
button.setOnClickListener { v: View ->
val viewParent = v.parent
if (viewParent is LinearLayout) {
val taggedView = viewParent.findViewWithTag<View>("toggle")
taggedView.visibility = when {
taggedView.visibility == View.GONE -> View.VISIBLE
else -> View.GONE
}
}
}
}
}
}
private fun ViewGroup.findViewsWithTag(tag: String): Sequence<View> {
return sequence {
for (index in 0 until childCount) {
val child = getChildAt(index)
when (child) {
is ViewGroup -> yieldAll(child.findViewsWithTag(tag))
is View -> if (child.tag == tag) yield(child)
}
}
}
}

Develop Reference

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