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android - RecyclerView and Intent : No value passed for parameter 'ListUserAdapter'

hi im currently using kotlin for my android project,as per instruction,i was told to make an apps that has recycleview to show list item and intent when you click on one of the list shown.
but i have this error when i want to run the app,the error was "No value passed for parameter 'ListUserAdapter'"
here is my code
ListUserAdapter.kt
class ListUserAdapter(private val ListUserAdapter: ArrayList<User>) : RecyclerView.Adapter<ListUserAdapter.ListViewHolder>() {
private lateinit var onItemClickCallBack: OnItemClickCallBack
fun setOnItemClickCallback(onItemClickCallback: OnItemClickCallBack) {
this.onItemClickCallBack = onItemClickCallback
}
override fun onCreateViewHolder(parent: ViewGroup, viewType: Int): ListViewHolder {
val view: View = LayoutInflater.from(parent.context).inflate(R.layout.row_user, parent, false)
return ListViewHolder(view)
}
override fun onBindViewHolder(holder: ListViewHolder, position: Int) {
val (name, username) = ListUserAdapter[position]
holder.tvName.text = name
holder.tvUserName.text= username
holder.itemView.setOnClickListener {
onItemClickCallBack.onItemClicked(ListUserAdapter[holder.adapterPosition])
}
}
override fun getItemCount(): Int = ListUserAdapter.size
class ListViewHolder(itemView: View) : RecyclerView.ViewHolder(itemView) {
var tvName: TextView = itemView.findViewById(R.id.tv_username)
var tvUserName: TextView = itemView.findViewById(R.id.tv_name)
}
interface OnItemClickCallBack {
fun onItemClicked(data : User)
}
}
MainActivity.kt
class MainActivity : AppCompatActivity() {
private lateinit var adapter: ListUserAdapter
private lateinit var dataName: Array<String>
private lateinit var dataUsername: Array<String>
private lateinit var dataLocation: Array<String>
private lateinit var dataRepo: Array<String>
private lateinit var dataCompany: Array<String>
private lateinit var dataFollowers: Array<String>
private lateinit var dataFollowing: Array<String>
private lateinit var dataPhoto: TypedArray
private var users = arrayListOf<User>()
private lateinit var binding: ActivityMainBinding
override fun onCreate(savedInstanceState: Bundle?) {
super.onCreate(savedInstanceState)
binding = ActivityMainBinding.inflate(layoutInflater)
setAdapter()
prepare()
addItem()
}
private fun setAdapter() {
adapter = ListUserAdapter() //error in here
with(binding) {
rvList.adapter = adapter
rvList.layoutManager =
GridLayoutManager(this#MainActivity, 2, GridLayoutManager.HORIZONTAL, false)
rvList.setHasFixedSize(true)
}
adapter.setOnItemClickCallback(object : ListUserAdapter.OnItemClickCallBack{
override fun onItemClicked(user: User) {
val intent = Intent(this#MainActivity, DetailActivity::class.java)
intent.putExtra(DetailActivity.KEY_USER, user)
startActivity(intent)
}
})
}
private fun prepare() {
dataName = resources.getStringArray(R.array.name)
dataUsername = resources.getStringArray(R.array.username)
dataPhoto = resources.obtainTypedArray(R.array.avatar)
dataLocation = resources.getStringArray(R.array.location)
dataRepo = resources.getStringArray(R.array.repository)
dataCompany = resources.getStringArray(R.array.company)
dataFollowers = resources.getStringArray(R.array.followers)
dataFollowing = resources.getStringArray(R.array.following)
}
private fun addItem() {
for (position in dataName.indices) {
val user = User(
dataUsername[position],
dataName[position],
dataLocation[position],
dataCompany[position],
dataRepo[position],
dataFollowers[position],
dataFollowing[position],
dataPhoto.getResourceId(position, -1)
)
users.add(user)
}
}
}
DetailActivity.kt
class DetailActivity : AppCompatActivity() {
private lateinit var binding: ActivityDetailBinding
override fun onCreate(savedInstanceState: Bundle?) {
super.onCreate(savedInstanceState)
binding = ActivityDetailBinding.inflate(layoutInflater)
setContentView(binding.root)
setData()
}
private fun setData() {
val dataUser = intent.getParcelableExtra<User>(KEY_USER) as User
with(binding) {
Glide.with(root)
.load(dataUser.photo)
.circleCrop()
.into(ivDetailAvatar)
}
}
companion object {
const val KEY_USER = "key_user"
}
}

just you need to replace adapter = ListUserAdapter() //error in here with adapter = ListUserAdapter(users) then your problem solve

You're just forgetting the constructor parameter :)
Your adapter class needs to receive a ArrayList of User to be instantiated, you already have it in your Activity, you just need to pass it as the constructor parameter :)
I would also rename the parameter name to something like users or usersList instead of `ListUserAdapter but because currently it is misleading, since this parameter is not an adapter, it is a list of users.
Just change the line with error to
adapter = ListUserAdapter(users)
But I think it is best for you to first call prepare() and addItem() and then instantiate your adapter. Or you can instantiate your adapter, but also create a addItems function, since it is a best practice for adapters.
fun addItems(users: List<User>) {
this.ListUserAdapter.addAll(users)
notifyDataSetChanged()
}
and use it after setting everything up inside onCreate doing something like
override fun onCreate(savedInstanceState: Bundle?) {
super.onCreate(savedInstanceState)
binding = ActivityMainBinding.inflate(layoutInflater)
setAdapter()
prepare()
addItem()
adapter.addItems(users)
}
but you could probably reorganize these methods to improve readability as well, but it will work :)

RecylerView Data not showing

I am new to Kotlin, I have this Kotlin code, the loaded data is not displayed at first but after navigating to another activity and coming back the data appears.
In online I have checked they said to add notifyOnChnaged but I am unable to implement it, If you know how to add notifyOnChanged or any other solution please help me out.
class SecretsActivity : AppCompatActivity() {
lateinit var bind : ActivitySecretsBinding
override fun onCreate(savedInstanceState: Bundle?) {
val secretsList = firebaseSecretsData()
super.onCreate(savedInstanceState)
bind = ActivitySecretsBinding.inflate(layoutInflater)
setContentView(bind.root)
bind.secretsRecyclerView.adapter = SecretsAdapter(secretsList)
bind.secretsRecyclerView.layoutManager = StaggeredGridLayoutManager(2, StaggeredGridLayoutManager.VERTICAL)
bind.secretsRecyclerView.setHasFixedSize(true)
bind.secretsRecyclerView.adapter = SecretsAdapter(secretsList)
bind.ButtonWrite.setOnClickListener {
val intent = Intent(this, WriteActivity::class.java)
startActivity(intent)
overridePendingTransition(R.transition.fadein, R.transition.fadeout)
finish()
}
}
override fun onBackPressed() {
super.onBackPressed()
val intent = Intent(this, MainActivity::class.java)
startActivity(intent)
overridePendingTransition(R.transition.fadein, R.transition.fadeout)
finish()
}
private fun firebaseSecretsData() : List<SecretsModel>{
val list = ArrayList<SecretsModel>()
val dbref = FirebaseDatabase.getInstance().getReference("Secrets")
dbref.addValueEventListener(object : ValueEventListener{
override fun onDataChange(snapshot: DataSnapshot) {
if(snapshot.exists()){
for(i in snapshot.children){
val item = SecretsModel(i.value.toString())
list+=item
}
}
}
override fun onCancelled(error: DatabaseError) {
TODO("Not yet implemented")
}
})
return list
}
}

//Initialize this first
val myAdapter = SecretsAdapter(secretsList)
.
.
.
.
.
private fun firebaseSecretsData() : List<SecretsModel>{
val list = ArrayList<SecretsModel>()
val dbref =
FirebaseDatabase.getInstance().getReference("Secrets")
dbref.addValueEventListener(object : ValueEventListener{
override fun onDataChange(snapshot: DataSnapshot) {
if(snapshot.exists()){
for(i in snapshot.children){
val item = SecretsModel(i.value.toString())
list+=item
}
//Add this code
myAdapter.notifyDataSetChanged()
}
}
.
.
.
.
.
Moreover, you should use DiffUtil if possible for performance reasons.

why is the key not added to the data in firebase?

I've been struggling with the problem for a long time and I can't solve it.I'm in EditActivity trying to add a key to the data from the firebase that I get from it with the help of Ad and process it using the AdsManager.
The key should not be equal to zero. In this line I check if the key is zero, then the Firebase writes data to empty.db.child (ad.key?: "Empty"). SetValue (ad). When I load the data to the Firebase, it shows them empty. Without displaying the key. You know what the problem is?
Ad
data class Ad(
var user_id : String? = null ,
var name : String? = null ,
var button1 : String? = null ,
val textTex : String? = null ,
val textk : String? = null ,
val description : String? = null,
val name_ads: String?=null,
val key :String? =null
)
AdsManager
class AdsManager(val readDataColbak : ReadDataColbak?) {
private lateinit var auth: FirebaseAuth
val db =Firebase.database.getReference("main")
fun pubilshAd(ad :Ad) {
db.child(ad.key?: "empty").setValue(ad)
}
fun ReadDataDb() {
db.addListenerForSingleValueEvent(object :ValueEventListener{
override fun onDataChange(snapshot : DataSnapshot) {
val adArray =ArrayList<Ad>()
for (item in snapshot.children){
val ad =item.children.iterator().next().child("ad").getValue(Ad::class.java)
adArray.add(ad !!)
}
readDataColbak?.readData(adArray)
}
override fun onCancelled(error : DatabaseError) {
}
})
}
}
EditActivity1
class EditActivity1: AppCompatActivity(), FfragmentInterfes{
lateinit var mBinder : ActivityEdit1Binding
private var dialog=D()
private var chooseImageFrog:FragmentList? =null
val adsManager = AdsManager(null)
public override fun onCreate(savedInstanceState: Bundle?) {
super.onCreate(savedInstanceState)
imageAdapter = ImageAdapter()
mBinder=ActivityEdit1Binding.inflate(layoutInflater)
setContentView(mBinder.root)
init()
}
fun onClickPublish(view : View) {
adsManager.pubilshAd(fillAd())
}
private fun fillAd() : Ad {
var ad : Ad
mBinder.apply {
ad= Ad(
name_ads.text.toString(),
user_id.text.toString(),
name.text.toString(),
button1.text.toString(),
description.text.toString(),
textk.text.toString(),
adsManager.db.push().key
)
}
return ad
}

Kotlin] I want to send some data from One class to Other class by using Intent

I just want to say sorry to my English skill
I've studied the Android Studio and Kotlin these days.
but I'd got a problem on RecyclerViewer and Adapter, for Intent method
work flow chart
this image, this is what i want to do
so i coded the three classes
ShoppingAppActivity.kt, MyAdapter.kt, CartActivity.kt
At ShoppingAppActivity, If I click the itemId ( in the Red box texts)
I make it move to other context(CartActivity)
ShoppingAppActivity working
if i clicked the red box then
cartStatus
go to cart Activity
it worked but already I said, I just want to send only send itemID
covert to String (i will use toString())
SO i tried to use Intent method in ShoppingAppActivity.kt
///PROBLEM PART
adapter?.setOnItemClickListener{
val nextIntent = Intent(this, CartActivity::class.java)
//nextIntent.putExtra("itemID", )
startActivity(nextIntent)
}
///PROBLEM PART
like this but the problem is I don't know what am i have to put the parameter in
nextIntent.putExtra("itemID", )
what should i do?
I think, I should fix MyAdaptor.kt or ShopingAppActivity.kt for this problem.
But in my knowledge, this is my limit. :-(
below
Full Codes of ShoppingAppActivity.kt, MyAdapter.kt, CartActivity.kt
ShoppingAppActivity.kt
class ShoppingAppActivity : AppCompatActivity() {
lateinit var binding: ActivityShoppingAppBinding
private var adapter: MyAdapter? = null
private val db : FirebaseFirestore = Firebase.firestore
private val itemsCollectionRef = db.collection("items")
override fun onCreate(savedInstanceState: Bundle?) {
super.onCreate(savedInstanceState)
binding = ActivityShoppingAppBinding.inflate(layoutInflater)
setContentView(binding.root)
updateList()
binding.recyclerViewItems.layoutManager = LinearLayoutManager(this)
adapter = MyAdapter(this, emptyList())
binding.recyclerViewItems.adapter = adapter
///PROBLEM PART
adapter?.setOnItemClickListener{
val nextIntent = Intent(this, CartActivity::class.java)
//nextIntent.putExtra("itemID", )
startActivity(nextIntent)
}
///PROBLEM PART
}
private fun updateList() {
itemsCollectionRef.get().addOnSuccessListener {
val items = mutableListOf<Item>()
for (doc in it) {
items.add(Item(doc))
}
adapter?.updateList(items)
}
}
}
MyAdapter.kt
data class Item(val id: String, val name: String, val price: Int, val cart: Boolean) {
constructor(doc: QueryDocumentSnapshot) :
this(doc.id, doc["name"].toString(), doc["price"].toString().toIntOrNull() ?: 0, doc["cart"].toString().toBoolean() ?: false)
constructor(key: String, map: Map<*, *>) :
this(key, map["name"].toString(), map["price"].toString().toIntOrNull() ?: 0, map["cart"].toString().toBoolean() ?: false)
}
class MyViewHolder(val binding: ItemBinding) : RecyclerView.ViewHolder(binding.root)
class MyAdapter(private val context: Context, private var items: List<Item>)
: RecyclerView.Adapter<MyViewHolder>() {
fun interface OnItemClickListener {
fun onItemClick(student_id: String)
}
private var itemClickListener: OnItemClickListener? = null
fun setOnItemClickListener(listener: OnItemClickListener) {
itemClickListener = listener
}
fun updateList(newList: List<Item>) {
items = newList
notifyDataSetChanged()
}
override fun onCreateViewHolder(parent: ViewGroup, viewType: Int): MyViewHolder {
val inflater = LayoutInflater.from(parent.context)
val binding: ItemBinding = ItemBinding.inflate(inflater, parent, false)
return MyViewHolder(binding)
}
override fun onBindViewHolder(holder: MyViewHolder, position: Int) {
val item = items[position]
val itemID : String
holder.binding.textID.text = item.id
holder.binding.textName.text = item.name
if(item.cart)
{
holder.binding.textCart.text = "in Cart"
}
else
{
holder.binding.textCart.text = ""
}
holder.binding.textID.setOnClickListener {
AlertDialog.Builder(context).setMessage("You clicked ${item.id}.").show()
itemClickListener?.onItemClick(item.id)
}
holder.binding.textName.setOnClickListener {
//AlertDialog.Builder(context).setMessage("You clicked ${student.name}.").show()
itemClickListener?.onItemClick(item.id)
}
//return item.id.toString()
}
override fun getItemCount() = items.size
}
CartActivity.kt
class CartActivity : AppCompatActivity() {
lateinit var binding: ActivityCartBinding
private val db: FirebaseFirestore = Firebase.firestore
private val itemsCollectionRef = db.collection("items")
private var adapter: MyAdapter? = null
override fun onCreate(savedInstanceState: Bundle?) {
super.onCreate(savedInstanceState)
binding = ActivityCartBinding.inflate(layoutInflater)
setContentView(binding.root)
updateList()
//binding.recyclerViewItems.layoutManager = LinearLayoutManager(this)
//adapter = MyAdapter(this, emptyList())
//binding.recyclerViewItems.adapter = adapter
binding.changeCartStatus.setOnClickListener{
//change the button's text if the itemID is corrected
//if(){
// binding.changeCartStatus.text = ""
//}
}
}
private fun updateList() {
itemsCollectionRef.get().addOnSuccessListener {
val items = mutableListOf<Item>()
for (doc in it) {
items.add(Item(doc))
}
adapter?.updateList(items)
}
}
}

You just need to implement listener to your activity
class ShoppingAppActivity : AppCompatActivity() ,MyAdapter.OnItemClickListener {
In oncreate add below line after adapter
adapter?.setOnItemClickListener(this)
Then override its method
override fun onItemClick(id: String){
val nextIntent = Intent(this, CartActivity::class.java)
nextIntent.putExtra("itemID",id )
startActivity(nextIntent)
}

FirebaseRecyclerAdapter - populateViewHolder not accessing data

I am trying to display some data from my real time DB into a recycler adapter with no luck. I have made the FirebaseRecyclerAdapter work on another activity(java) but on this one it just does not work(kotlin). The strange thing is that if I use a ValueEventListener the data return just fine, but the FirebaseRecyclerAdapter do not work.
CLASS:
class FriendsActivity : AppCompatActivity() {
private lateinit var friendsDb: DatabaseReference
private var currentUser: FirebaseUser? = null
override fun onCreate(savedInstanceState: Bundle?) {
super.onCreate(savedInstanceState)
setContentView(R.layout.activity_friends)
supportActionBar?.title = "Friends"
friends_main_rec.layoutManager = LinearLayoutManager(this)
friends_main_rec.setHasFixedSize(true)
currentUser = FirebaseAuth.getInstance().currentUser
friendsDb = FirebaseDatabase.getInstance().reference.child("FRIENDS")
.child(currentUser!!.uid)
val friendsRecyclerViewAdapter = object : FirebaseRecyclerAdapter<Friends, FriendsViewHolder>(
Friends::class.java,
R.layout.friend_single,
FriendsViewHolder::class.java,
friendsDb) {
override fun populateViewHolder(viewHolder: FriendsViewHolder, model: Friends, position: Int) {
Log.d("FriendsList", model.toString())
viewHolder.setDate(model.date)
}
}
friends_main_rec.adapter = friendsRecyclerViewAdapter
}
class FriendsViewHolder(itemView: View) : RecyclerView.ViewHolder(itemView) {
fun setDate(date: String) {
itemView.friend_single_date.text = date
Log.d("FriendsList", date)
}
}
POJO:
data class Friends(var date: String)
The code seems fine to me, but obviously it is not correct.

There seems to be some problem in this line
friendsDb = FirebaseDatabase.getInstance().reference.child("FRIENDS")
.child(currentUser!!.uid)
Here it will get value from "FRIENDS/currentUser.uid",
which is either of
NBHxxxxxxxxxxxxxxxON2
it3xxxxxxxxxxxxxxxfj1
You can not directly access date object from here, as date is under freind user id