Develop Reference

Why the data from firebase database is not showing in my recyclerview while searching?

MainActivity.kt Code
class MainActivity : AppCompatActivity() {
private lateinit var binding: ActivityMainBinding
val db = Firebase.firestore
val firebaseFirestore : FirebaseFirestore = FirebaseFirestore.getInstance()
private var searchList: List<dataClass> = ArrayList()
private val adapter = adapter(searchList)
override fun onCreate(savedInstanceState: Bundle?) {
binding = ActivityMainBinding.inflate(layoutInflater)
super.onCreate(savedInstanceState)
setContentView(binding.root)
supportActionBar?.hide()
val search_list :RecyclerView = findViewById(R.id.search_list)
search_list.hasFixedSize()
search_list.layoutManager = LinearLayoutManager(this)
search_list.adapter = adapter
binding.searchField.addTextChangedListener(object : TextWatcher{
override fun beforeTextChanged(p0: CharSequence?, p1: Int, p2: Int, p3: Int) {
}
override fun onTextChanged(p0: CharSequence?, p1: Int, p2: Int, p3: Int) {
val search : String = binding.searchField.text.toString()
//Search in Firestore
searchInFirestore(search.toLowerCase())
}
override fun afterTextChanged(p0: Editable?) {
}
})
}
private fun searchInFirestore(search: String) {
firebaseFirestore.collection("mechanic").orderBy("city").startAt(search).endAt("$search\uf8ff").get()
.addOnCompleteListener {
if(it.isSuccessful){
searchList = it.result!!.toObjects(dataClass::class.java)
adapter.searchlist =searchList
adapter.notifyDataSetChanged()
}
else{
Log.d(TAG,"Error:${it.exception!!.message}")
}
}
}
}
Adapter.kt code
class adapter(var searchlist: List<dataClass> ) : RecyclerView.Adapter<adapter.viewholder>(){
inner class viewholder(itemView: View):RecyclerView.ViewHolder(itemView) {
val mname: TextView = itemView.findViewById(R.id.name)
val mphone : TextView = itemView.findViewById(R.id.phone)
val addres: TextView = itemView.findViewById(R.id.address)
fun bind(dataClass: dataClass){
mname.text = dataClass.name
mphone.text = dataClass.phone
addres.text = dataClass.address
}
}
override fun onCreateViewHolder(parent: ViewGroup, viewType: Int): viewholder {
val view = LayoutInflater.from(parent.context).inflate(R.layout.single_search,parent,false)
return viewholder(view)
}
override fun onBindViewHolder(holder: viewholder, position: Int) {
holder.bind(searchlist[position])
}
override fun getItemCount(): Int {
return searchlist.size
}
}
the view in which i have to bind data
<?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/name"
android:layout_width="0dp"
android:layout_height="wrap_content"
android:text="TextView"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintHorizontal_bias="0.0"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toTopOf="parent"
app:layout_constraintVertical_bias="0.022" />
<TextView
android:id="#+id/textView2"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="Phone no"
app:layout_constraintBaseline_toBaselineOf="#+id/phone"
app:layout_constraintStart_toStartOf="parent" />
<TextView
android:id="#+id/phone"
android:layout_width="144dp"
android:layout_height="19dp"
android:layout_marginTop="12dp"
android:layout_marginBottom="20dp"
android:text="TextView"
app:layout_constraintBottom_toTopOf="#+id/address"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintHorizontal_bias="0.088"
app:layout_constraintStart_toEndOf="#+id/textView2"
app:layout_constraintTop_toBottomOf="#+id/name" />
<TextView
android:id="#+id/textView5"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="Address"
app:layout_constraintBaseline_toBaselineOf="#+id/address"
app:layout_constraintStart_toStartOf="parent" />
<TextView
android:id="#+id/address"
android:layout_width="260dp"
android:layout_height="65dp"
android:layout_marginTop="86dp"
android:text="TextView"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintHorizontal_bias="0.229"
app:layout_constraintStart_toEndOf="#+id/textView5"
app:layout_constraintTop_toTopOf="parent" />
</androidx.constraintlayout.widget.ConstraintLayout>
Mainactivity.xml file
<?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">
<EditText
android:id="#+id/search_field"
android:layout_width="0dp"
android:layout_height="wrap_content"
android:ems="10"
android:inputType="textPersonName"
android:paddingTop="20sp"
android:text="Search here"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toTopOf="parent" />
<androidx.recyclerview.widget.RecyclerView
android:layout_width="408dp"
android:layout_height="642dp"
android:id="#+id/search_list"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toBottomOf="#+id/search_field" />
</androidx.constraintlayout.widget.ConstraintLayout>
i want to implement a live search view in my app using firestore database but when i running the above code it doesn't showing any thing to me. I think there is a mistake in my adapter.kt and mainactivity.kt file. Please help me to correct it.
I am expecting to see the data while searching but it is not showing the data from firestore. I want it to be appear in search result.
dataclass.kt data class dataClass ( val name: String ="",val phone:String = "", val address : String ="" )

I think the issue is that you're setting content to binding and then not referencing the RecyclerLayout from that binding. Try using val search_list = binding.searchList instead of val search_list :RecyclerView = findViewById(R.id.search_list)

NullPointerException on RecyclerView setLayoutManager

I have faced the problem that my application will keep stopping when clicking search page fragments. I do not understand why this problem will happen? I directly used my other success code in another fragment but in this fragment suddenly appear this problem. Can somebody help me? Thank you for your help!!
My problem error :
java.lang.NullPointerException: Attempt to invoke virtual method
'void androidx.recyclerview.widget.RecyclerView.setLayoutManager(androidx.recyclerview.widget.RecyclerView$LayoutManager)'
on a null object reference at com.example.assignment_mad.Search_Page_Fragment.onViewCreated(Search_Page_Fragment.kt:153)
My main frgment ( Search_Page_Fragment ) :
package com.example.assignment_mad
import android.content.Intent
import android.os.Bundle
import androidx.fragment.app.Fragment
import android.view.LayoutInflater
import android.view.View
import android.view.ViewGroup
import android.widget.Toast
import androidx.recyclerview.widget.LinearLayoutManager
import androidx.recyclerview.widget.RecyclerView
import kotlinx.android.synthetic.main.fragment_notification_.*
class Search_Page_Fragment : Fragment() {
private lateinit var newRecyclerView: RecyclerView
private lateinit var newArrayList: ArrayList<Company_Search>
private lateinit var tempArrayList: ArrayList<Company_Search>
lateinit var imageId:Array<Int>
lateinit var job_name:Array<String>
lateinit var saveicon:Array<Int>
lateinit var company_name:Array<String>
lateinit var place:Array<String>
lateinit var salary:Array<String>
lateinit var news:Array<String>
private var layoutManager: RecyclerView.LayoutManager? = null
private var adapter: RecyclerView.Adapter<Search_Page_Adapter.MyViewHolder>? = null
override fun onCreateView(
inflater: LayoutInflater, container: ViewGroup?,
savedInstanceState: Bundle?
): View? {
var views =inflater.inflate(R.layout.fragment_search__page_, container, false)
newRecyclerView=views.findViewById(R.id.recyclerView_Search)
// Inflate the layout for this fragment
return views
}
override fun onViewCreated(itemView: View, savedInstanceState: Bundle?) {
imageId= arrayOf(
R.drawable.company_logo_1,
R.drawable.company_logo_2,
R.drawable.company_logo_3,
R.drawable.company_logo_4,
R.drawable.company_logo_5,
R.drawable.company_logo_6,
R.drawable.company_logo_7,
R.drawable.company_logo_8,
R.drawable.company_logo_9,
R.drawable.company_logo_10
)
job_name= arrayOf(
"Engineer",
"Computer",
"Coder",
"Teacher",
"Engineer",
"Engineer",
"Engineer",
"Engineer",
"Engineer",
"Engineer"
)
saveicon= arrayOf(
R.drawable.ic_baseline_bookmark_added_24,
R.drawable.ic_baseline_bookmark_added_24,
R.drawable.ic_baseline_bookmark_added_24,
R.drawable.ic_baseline_bookmark_added_24,
R.drawable.ic_baseline_bookmark_added_24,
R.drawable.ic_baseline_bookmark_added_24,
R.drawable.ic_baseline_bookmark_added_24,
R.drawable.ic_baseline_bookmark_added_24,
R.drawable.ic_baseline_bookmark_added_24,
R.drawable.ic_baseline_bookmark_added_24
)
company_name= arrayOf(
"Phonix Sdn Bhd",
"Computer Sdn Bhd",
"Coder",
"Teacher",
"Engineer",
"Engineer",
"Engineer",
"Engineer",
"Engineer",
"Engineer"
)
place= arrayOf(
"Kuala Lumpur",
"Kuala Lumpur",
"Selangor",
"Rimbunan",
"Kuala Lumpur",
"Kuala Lumpur",
"Kuala Lumpur",
"Kuala Lumpur",
"Kuala Lumpur",
"Kuala Lumpur"
)
salary= arrayOf(
"RM3000",
"RM4000",
"RM3500",
"RM2000",
"RM1000",
"RM3000",
"RM3000",
"RM3000",
"RM3000",
"RM3000",
)
news= arrayOf(
getString(R.string.news_a),
getString(R.string.news_b),
getString(R.string.news_c),
getString(R.string.news_d),
getString(R.string.news_e),
getString(R.string.news_f),
getString(R.string.news_g),
getString(R.string.news_h),
getString(R.string.news_i),
getString(R.string.news_j)
)
newArrayList= arrayListOf<Company_Search>()
tempArrayList= arrayListOf<Company_Search>()
getUserdata()
super.onViewCreated(itemView, savedInstanceState)
newRecyclerView.apply {
layoutManager= LinearLayoutManager(activity)
newRecyclerView.setHasFixedSize(true)
}
recyclerView.apply {
// set a LinearLayoutManager to handle Android
// RecyclerView behavior
layoutManager= LinearLayoutManager(activity)
// set the custom adapter to the RecyclerView
adapter = Search_Page_Adapter(newArrayList)
}
}
private fun getUserdata() {
for (i in imageId.indices){
val companySearch=Company_Search(imageId[i],job_name[i],saveicon[i],company_name[i],place[i],salary[i])
newArrayList.add(companySearch)
}
// tempArrayList.addAll(newArrayList)
//
// val adapter = Notification_Fragment(tempArrayList)
var adapter=Search_Page_Adapter(newArrayList)
newRecyclerView.adapter=adapter
adapter.setOnItemClickListener(object :Search_Page_Adapter.onItemClickListener{
override fun onItemClick(position: Int) {
Toast.makeText(context,"You clicked in item no . $position",Toast.LENGTH_SHORT).show()
val intent= Intent(context,Search_Page_Detail::class.java)
intent.putExtra("name",newArrayList[position].job_name)
intent.putExtra("imageId",newArrayList[position].titleImage)
intent.putExtra("news",news[position])
startActivity(intent)
}
})
}
}
The page adapter :
package com.example.assignment_mad
import android.view.LayoutInflater
import android.view.View
import android.view.ViewGroup
import android.widget.TextView
import androidx.recyclerview.widget.RecyclerView
import com.google.android.material.imageview.ShapeableImageView
class Search_Page_Adapter(private val companysList:ArrayList<Company_Search>):RecyclerView.Adapter<Search_Page_Adapter.MyViewHolder>() {
private var mListener:onItemClickListener?=null
interface onItemClickListener{
fun onItemClick(position: Int)
}
fun setOnItemClickListener(listener: onItemClickListener){
mListener=listener
}
override fun onCreateViewHolder(parent: ViewGroup, viewType: Int): MyViewHolder {
val itemView=LayoutInflater.from(parent.context).inflate(R.layout.list_item_search,parent,false)
return MyViewHolder(itemView,mListener)
}
override fun onBindViewHolder(holder: MyViewHolder, position: Int) {
val currentItem=companysList[position]
holder.titleImage.setImageResource(currentItem.titleImage)
holder.job_name.text=currentItem.job_name
holder.save_icon.setImageResource(currentItem.save_icon)
holder.company_name.text=currentItem.company_name
holder.place.text=currentItem.place
holder.salary.text=currentItem.salary
}
override fun getItemCount(): Int {
return companysList.size
}
//to insert the post detail
class MyViewHolder(itemView: View,listener: onItemClickListener?):RecyclerView.ViewHolder(itemView){
val titleImage:ShapeableImageView=itemView.findViewById(R.id.title_image2)
val job_name:TextView=itemView.findViewById(R.id.job_name)
val save_icon:ShapeableImageView=itemView.findViewById(R.id.save_icon)
val company_name:TextView=itemView.findViewById(R.id.company_name)
val place:TextView=itemView.findViewById(R.id.detail_place)
val salary:TextView=itemView.findViewById(R.id.detail_salary)
init {
itemView.setOnClickListener{
listener?.onItemClick(adapterPosition)
}
}
}
}
The xml file for Search_Page_Fragment :
<?xml version="1.0" encoding="utf-8"?>
<FrameLayout
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:background="#color/white"
tools:context=".Search_Page_Fragment">
<androidx.constraintlayout.widget.ConstraintLayout
android:layout_width="match_parent"
android:layout_height="wrap_content">
<EditText
android:id="#+id/search_bar"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:hint="Search Job"
android:inputType="text"
android:minHeight="48dp"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toTopOf="parent"/>
<TextView
android:id="#+id/place_name"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:textColor="#color/black"
android:text="Area, City or Town"
android:textSize="16sp"
android:layout_marginStart="16dp"
android:layout_marginEnd="32dp"
android:layout_marginTop="8dp"
app:layout_constraintTop_toBottomOf="#+id/search_bar"
app:layout_constraintStart_toStartOf="parent"/>
<Spinner
android:id="#+id/spinner_job"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:minWidth="200dp"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toBottomOf="#+id/place_name" />
<TextView
android:id="#+id/job_specialize"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:textColor="#color/black"
android:text="Job Specialize"
android:textSize="16sp"
android:layout_marginStart="16dp"
android:layout_marginEnd="32dp"
android:layout_marginTop="8dp"
app:layout_constraintTop_toBottomOf="#+id/search_bar"
app:layout_constraintEnd_toEndOf="parent" />
<Spinner
android:id="#+id/spinner_place"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:minWidth="200dp"
app:layout_constraintTop_toBottomOf="#+id/job_specialize"
app:layout_constraintEnd_toEndOf="parent"
/>
<androidx.recyclerview.widget.RecyclerView
android:id="#+id/recyclerView_Search"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:layout_marginTop="108dp"
app:layout_constraintTop_toBottomOf="#+id/spinner_job"
tools:layout_editor_absoluteX="-16dp"
tools:listitem="#layout/list_item_search" />
</androidx.constraintlayout.widget.ConstraintLayout>
</FrameLayout>
The list_item_search_xml :
<?xml version="1.0" encoding="utf-8"?>
<androidx.constraintlayout.widget.ConstraintLayout
xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="wrap_content"
xmlns:app="http://schemas.android.com/apk/res-auto"
android:layout_margin="8dp">
<com.google.android.material.imageview.ShapeableImageView
android:layout_width="80dp"
android:layout_height="80dp"
android:id="#+id/title_image2"
android:scaleType="centerCrop"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintTop_toTopOf="parent"
app:shapeAppearanceOverlay="#style/RoundCorner"
android:src="#drawable/company_logo_1"/>
<TextView
android:id="#+id/job_name"
android:layout_width="0dp"
android:layout_height="wrap_content"
android:textColor="#color/blue"
android:text="Gradute Engineer"
android:textSize="20sp"
android:textStyle="bold"
android:layout_marginStart="16dp"
android:layout_marginEnd="32dp"
android:layout_marginTop="8dp"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toBottomOf="#+id/title_image2"/>
<ImageView
android:layout_width="40dp"
android:layout_height="40dp"
android:id="#+id/save_icon"
android:scaleType="centerCrop"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintTop_toBottomOf="#+id/title_image2"
android:layout_marginEnd="32dp"
app:shapeAppearanceOverlay="#style/RoundCorner"
android:src="#drawable/ic_baseline_bookmark_added_24"/>
<TextView
android:id="#+id/company_name"
android:layout_width="0dp"
android:layout_height="wrap_content"
android:textColor="#color/black"
android:text="Neric Compat"
android:textSize="18sp"
android:layout_marginStart="16dp"
android:layout_marginEnd="32dp"
android:layout_marginTop="8dp"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toBottomOf="#+id/job_name"/>
<TextView
android:id="#+id/detail_place"
android:layout_width="0dp"
android:layout_height="wrap_content"
android:textColor="#color/black"
android:text="Petaling Jaya"
android:textSize="16sp"
android:textStyle="bold"
android:layout_marginStart="16dp"
android:layout_marginEnd="32dp"
android:layout_marginTop="8dp"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toBottomOf="#+id/company_name"/>
<TextView
android:id="#+id/detail_salary"
android:layout_width="0dp"
android:layout_height="wrap_content"
android:textColor="#color/black"
android:text="MYR 3,700 - 4,300 /Month"
android:textSize="16sp"
android:layout_marginStart="16dp"
android:layout_marginEnd="32dp"
android:layout_marginTop="8dp"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toBottomOf="#+id/detail_place"/>
<View
android:layout_width="match_parent"
android:layout_height="1dp"
android:layout_margin="8dp"
style="bold"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toBottomOf="#+id/detail_salary"
android:background="#color/underline"/>
</androidx.constraintlayout.widget.ConstraintLayout>

Your NullPointerException indicates that when this line of code is reached...
layoutManager= LinearLayoutManager(activity)
...that your newRecyclerView is null. Are you sure that you have the right resource ID here when you attempt to set it?
newRecyclerView=views.findViewById(R.id.recyclerView_Search)
Try using the debugger and set a breakpoint on these two lines to confirm is newRecyclerView is indeed null.

You must assign the RecyclerView a LayoutManager. Since you have both of them, place this line as the last statement of recyclerView.apply { … } block(s):
setLayoutManager(layoutManager)
// ↑↑↑↑↑↑↑↑↑↑↑↑↑
// Your LayoutManager

Spinner doesn't display items. I'm making program for inventorization now. I get data from API. And I have the problem. Spinner doesn't show items

Spinner doesn't display items. I'm making program for inventorization now. I get data from API. And I have the problem. Spinner doesn't show items. I add items to ArrayList and then add this list to spinner adapter. I've tried a lot of thing that i found at stackoverflow and another sites. But nothing helps me.
Code:
activity_add_classes.xml:
<pre><code>
<TextView
android:id="#+id/add_class_label"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:text="Добавить кабинет"
android:textAlignment="center"
android:textColor="#color/black"
android:textSize="25sp"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toTopOf="parent"
android:layout_marginTop="25dp"
/>
<EditText
android:id="#+id/class_number_add"
android:layout_width="match_parent"
android:layout_height="wrap_content"
app:layout_constraintTop_toBottomOf="#id/add_class_label"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintEnd_toEndOf="parent"
android:layout_margin="16dp"
android:hint="Номер класса"
android:textSize="20sp"
android:singleLine="true"
android:maxLength="3"
android:digits="1234567890"
/>
<Spinner
android:id="#+id/corps_spinner"
app:layout_constraintTop_toBottomOf="#id/class_number_add"
app:layout_constraintEnd_toEndOf="parent"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:entries="#array/corps"
app:layout_constraintStart_toStartOf="parent"
android:layout_margin="16dp"
/>
<Spinner
android:id="#+id/inventories_spinner"
android:layout_width="match_parent"
android:layout_height="75dp"
app:layout_constraintTop_toBottomOf="#id/corps_spinner"
app:layout_constraintStart_toStartOf="parent"
android:layout_margin="16dp"
android:spinnerMode="dropdown"
app:layout_constraintEnd_toEndOf="parent"
/>
<EditText
android:id="#+id/count_of_inventory"
android:layout_width="100dp"
android:layout_height="wrap_content"
app:layout_constraintTop_toBottomOf="#id/inventories_spinner"
app:layout_constraintStart_toStartOf="parent"
android:layout_margin="16dp"
android:maxLength="2"
android:digits="1234567890"
android:singleLine="true"
/>
<Button
android:id="#+id/add_inventory_list"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="Добавить"
app:layout_constraintTop_toBottomOf="#id/inventories_spinner"
android:layout_margin="16dp"
app:layout_constraintEnd_toEndOf="parent"
/>
AddClassesActivity.kt:
enter code here
package com.example.inventorizationmpt
class AddClassesActivity : AppCompatActivity() {
lateinit var inventoriesSpinner: Spinner
lateinit var listInventory : ArrayList
override fun onCreate(savedInstanceState: Bundle?) {
super.onCreate(savedInstanceState)
setContentView(R.layout.activity_add_classes)
listInventory = ArrayList()
inventoriesSpinner = findViewById(R.id.inventories_spinner)
getInventories()
spinAdapt()
}
fun spinAdapt(){
val spinnerAdapter = ArrayAdapter(this#AddClassesActivity, android.R.layout.simple_spinner_item,listInventory)
spinnerAdapter.setDropDownViewResource(android.R.layout.simple_spinner_dropdown_item)
spinnerAdapter.notifyDataSetChanged()
inventoriesSpinner.adapter = spinnerAdapter
}
fun getInventories(){
val inventorizationService = ServiceBuilder.buildService(InventorizationService::class.java)
val requestCall = inventorizationService.getInventoriesList()
requestCall.enqueue(object : Callback>{
override fun onResponse(
call: Call>,
response: Response>
) {
if (response.isSuccessful){
val listForSpinner = response!!.body()
for (i in 0..listForSpinner!!.size - 1){
listInventory.add(
ItemOfInventory(
listForSpinner[i].id_Inventory,
listForSpinner[i].inventory_Name
)
)
}
}else {
Toast.makeText(this#AddClassesActivity, "Что-то пошло не так. Ошибка со стороны сервера", Toast.LENGTH_LONG).show()
}
}
override fun onFailure(call: Call>, t: Throwable) {
Toast.makeText(this#AddClassesActivity, "Что-то пошло не так. Ошибка со стороны сервера", Toast.LENGTH_LONG).show()
}
})
}
}

How to fix Parameter specified as non-null is null on rotating screen in a Fragment while creating a Spinner in Kotlin?

Hello everyone in my fragment, i have added a spinner in my fragment and little bit of code to calculate moles but when i rotate screen it crashes and throw an error by i don't know why it crashes , When try to check for Non-null object i don't What that is the cause of error , Here is the error :
java.lang.IllegalArgumentException: Parameter specified as non-null is null: method kotlin.jvm.internal.Intrinsics.checkParameterIsNotNull
Here is my first fragment file :
private var mListener: OnFragmentInteractionListener? = null
override fun onCreateView(inflater: LayoutInflater?, container: ViewGroup?, savedInstanceState: Bundle?): View? {
// Inflate the layout for this fragment
return inflater!!.inflate(R.layout.fragment_first, container, false)
}
override fun onViewCreated(view: View?, savedInstanceState: Bundle?) {
super.onViewCreated(view, savedInstanceState)
//activity.setRequestedOrientation(ActivityInfo.SCREEN_ORIENTATION_PORTRAIT)
/*Find the id of spinner*/
val spinner = lol
/*set an adapter with strings array*/
spinner.adapter = ArrayAdapter(activity, R.layout.support_simple_spinner_dropdown_item, resources.getStringArray(R.array.atoms)) as SpinnerAdapter
/*set click listener*/
spinner.onItemSelectedListener = object : AdapterView.OnItemSelectedListener {
override fun onItemSelected(parent: AdapterView<*>, view: View, position: Int, id: Long) {
val num = when (spinner.selectedItem.toString()) {
"H" -> editText.setText("1")
"He" -> editText.setText("4")
"C" -> editText.setText("12")
"O" -> editText.setText("16")
else -> editText.setText("")
}
}
override fun onNothingSelected(parent: AdapterView<*>) {
/*Do something if nothing selected*/
}
}
button.setOnClickListener {
if (
editText2.text.toString().length > 0 &&
editText.text.toString().length > 0) {
val num2 = editText.text.toString().toDouble()
val num1 = editText2.text.toString().toDouble()
val num = num1/num2
textView.setText("$num moles")
}
else {
textView.setText("Please Enter a correct value")
}
}
}
Here is my fragment_first.xml file :
<android.support.constraint.ConstraintLayout
android:layout_width="fill_parent"
android:layout_height="fill_parent">
<TextView
android:id="#+id/textView"
android:layout_width="294dp"
android:layout_height="80dp"
android:layout_weight="1"
android:text="Amswer : No of Moles"
android:textAlignment="center"
android:textSize="20sp"
app:layout_anchorGravity="right|top"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toTopOf="parent"
app:layout_constraintVertical_bias="0.556" />
<TextView
android:id="#+id/textView1"
android:layout_width="143dp"
android:layout_height="46dp"
android:layout_weight="1"
android:text="Amount in Grams "
android:textAlignment="center"
android:textSize="20sp"
app:layout_anchorGravity="left|bottom"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintHorizontal_bias="0.066"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toTopOf="parent"
app:layout_constraintVertical_bias="0.305" />
<Spinner
android:id="#+id/lol"
android:layout_width="145dp"
android:layout_height="57dp"
app:layout_anchorGravity="left|top"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintHorizontal_bias="0.07"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toTopOf="parent"
app:layout_constraintVertical_bias="0.136" />
<Button
android:id="#+id/button"
android:layout_width="138dp"
android:layout_height="43dp"
android:text="Calculate"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toTopOf="parent"
app:layout_constraintVertical_bias="0.788" />
<EditText
android:id="#+id/editText"
android:layout_width="148dp"
android:layout_height="57dp"
android:ems="10"
android:hint="Gram"
android:inputType="numberDecimal|number"
app:layout_anchorGravity="bottom|center"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintHorizontal_bias="0.762"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toTopOf="parent"
app:layout_constraintVertical_bias="0.137" />
<EditText
android:id="#+id/editText2"
android:layout_width="148dp"
android:layout_height="57dp"
android:ems="10"
android:hint="Gram"
android:inputType="numberDecimal|number"
app:layout_anchorGravity="center_horizontal|center"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintHorizontal_bias="0.716"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toTopOf="parent"
app:layout_constraintVertical_bias="0.288" />
</android.support.constraint.ConstraintLayout>

Add ? in
view = View?
Here is code
spinner.onItemSelectedListener = object : AdapterView.OnItemSelectedListener {
override fun onItemSelected(parent: AdapterView<*>, view: View?, position: Int, id: Long) {
val num = when (spinner.selectedItem.toString()) {
"H" -> editText.setText("1")
"He" -> editText.setText("4")
"C" -> editText.setText("12")
"O" -> editText.setText("16")
else -> editText.setText("")
}
}

It is correct, annotating the "view" parameter as nullable does appear to correct the issue.
It appears that the Kotlin generated code is incorrect as the auto-generated code marks "view" without the nullable attribute.

How to use an ArrayAdapter in a Fragment with Kotlin

I am trying to to create a Spinner inside a Fragment but I am getting error in the ArrayAdapter constructor call. I don't know why, but it has a red underline. Other than that, there is no error. When I'm using the same ArrayAdapter in an Activity it works, but in a Fragment, it gives an error.
My FirstFragment.kt:
class FirstFragment : Fragment() {
private var mListener: OnFragmentInteractionListener? = null
override fun onCreateView(inflater: LayoutInflater?, container: ViewGroup?, savedInstanceState: Bundle?): View? {
// Inflate the layout for this fragment
return inflater!!.inflate(R.layout.fragment_first, container, false)
}
override fun onViewCreated(view: View?, savedInstanceState: Bundle?) {
super.onViewCreated(view, savedInstanceState)
/*Find the id of spinner*/
val spinner = lol
/*set an adapter with strings array*/
spinner.adapter = ArrayAdapter(this, R.layout.support_simple_spinner_dropdown_item, resources.getStringArray(R.array.atoms)) as SpinnerAdapter?
/*set click listener*/
spinner.onItemSelectedListener = object : AdapterView.OnItemSelectedListener {
override fun onItemSelected(parent: AdapterView<*>, view: View, position: Int, id: Long) {
val num = when (spinner.selectedItem.toString()) {
"H" -> editText.setText("1")
"He" -> editText.setText("4")
"C" -> editText.setText("12")
"O" -> editText.setText("16")
else -> editText.setText("")
}
}
override fun onNothingSelected(parent: AdapterView<*>) {
/*Do something if nothing selected*/
}
}
button.setOnClickListener {
if (
editText2.text.toString().length > 0 &&
editText.text.toString().length > 0) {
val num2 = editText.text.toString().toDouble()
val num1 = editText2.text.toString().toDouble()
val num = num1/num2
textView.setText("$num moles")
}
else {
textView.setText("Please Enter a correct value")
}
}
}
}
My fragment_first.xml:
<FrameLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
xmlns:app="http://schemas.android.com/apk/res-auto"
tools:context="com.a3.aakap.ftrial.FirstFragment">
<android.support.constraint.ConstraintLayout
android:layout_width="fill_parent"
android:layout_height="fill_parent">
<TextView
android:id="#+id/textView"
android:layout_width="294dp"
android:layout_height="80dp"
android:layout_weight="1"
android:text="Amswer : No of Moles"
android:textAlignment="center"
android:textSize="20sp"
app:layout_anchorGravity="right|top"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toTopOf="parent"
app:layout_constraintVertical_bias="0.556" />
<TextView
android:id="#+id/textView1"
android:layout_width="143dp"
android:layout_height="46dp"
android:layout_weight="1"
android:text="Amount in Grams "
android:textAlignment="center"
android:textSize="20sp"
app:layout_anchorGravity="left|bottom"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintHorizontal_bias="0.066"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toTopOf="parent"
app:layout_constraintVertical_bias="0.305" />
<Spinner
android:id="#+id/lol"
android:layout_width="145dp"
android:layout_height="57dp"
app:layout_anchorGravity="left|top"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintHorizontal_bias="0.07"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toTopOf="parent"
app:layout_constraintVertical_bias="0.136" />
<Button
android:id="#+id/button"
android:layout_width="138dp"
android:layout_height="43dp"
android:text="Calculate"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toTopOf="parent"
app:layout_constraintVertical_bias="0.788" />
<EditText
android:id="#+id/editText"
android:layout_width="148dp"
android:layout_height="57dp"
android:ems="10"
android:hint="Gram"
android:inputType="numberDecimal|number"
app:layout_anchorGravity="bottom|center"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintHorizontal_bias="0.762"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toTopOf="parent"
app:layout_constraintVertical_bias="0.137" />
<EditText
android:id="#+id/editText2"
android:layout_width="148dp"
android:layout_height="57dp"
android:ems="10"
android:hint="Gram"
android:inputType="numberDecimal|number"
app:layout_anchorGravity="center_horizontal|center"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintHorizontal_bias="0.716"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toTopOf="parent"
app:layout_constraintVertical_bias="0.288" />
</android.support.constraint.ConstraintLayout>
</FrameLayout>

The problem is in this constructor call:
spinner.adapter = ArrayAdapter(
this,
R.layout.support_simple_spinner_dropdown_item,
resources.getStringArray(R.array.atoms)
) as SpinnerAdapter
The argument this must be a reference to a Context, and a Fragment is not a Context. In an Activity it works because an Activity is a Context.
The solution is to replace this with activity:
spinner.adapter = ArrayAdapter(
activity,
R.layout.support_simple_spinner_dropdown_item,
resources.getStringArray(R.array.atoms)
)

i came here looking for some answers but i found my solution better and shorter i guess and complete the mission i'll just drop it here in case
override fun onViewCreated(view: View, savedInstanceState: Bundle?) {
super.onViewCreated(view, savedInstanceState)
getCates()
}
the function
private fun getCates() {
val categories = MyApplication().getCategories()
val adapter = ArrayAdapter(requireContext(), R.layout.list_item, categories)
(binding.autocomplete as? AutoCompleteTextView)?.setAdapter(adapter)
binding.autocomplete.setOnItemClickListener { _, _, i, _ ->
category = categories[i]
Log.d(TAG,"$category")
}
}
PS : i get the list items from firebase you can add items lovaly