Develop Reference

RecyclerView load only one item

Here RecyclerView loads only one item however the loops works prefect but with RecyclerView loads only one item and not load all items
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GetJson.kt
class GetJson : AppCompatActivity() {
lateinit var recyclerView: RecyclerView
var arrayList = ArrayList<JsonModel>()
private var requestQueue : RequestQueue? = null
override fun onCreate(savedInstanceState: Bundle?) {
super.onCreate(savedInstanceState)
setContentView(R.layout.activity_get_json)
recyclerView = findViewById(R.id.recyclerView2)
recyclerView.layoutManager = LinearLayoutManager(this)
val getButton : Button = findViewById(R.id.ShowButtonJson)
requestQueue = Volley.newRequestQueue(this)
getButton.setOnClickListener {
getFromServer()
}
}
fun getFromServer(){
val url = "http://..../testapp/getjson.php"
val request = JsonObjectRequest(Request.Method.GET,url,null, {
response -> try {
val jsonArray = response.getJSONArray("names")
for (i in 0 until jsonArray.length()){
val name = jsonArray.getJSONObject(i)
val firstname = name.getString("firstname")
val middlename = name.getString("middlename")
val lastname = name.getString("lastname")
arrayList.add(JsonModel(firstname,middlename,lastname))
}
val namesAdapter = jsonAdapter(arrayList)
recyclerView.adapter = namesAdapter
namesAdapter.notifyDataSetChanged()
} catch (e: JSONException){
e.printStackTrace()
}
}, { response -> response.printStackTrace()
})
requestQueue?.add(request)
}
}
jsonAdapter.kt
class jsonAdapter(val data : List<JsonModel>) : RecyclerView.Adapter<jsonAdapter.ViewHolder>() {
class ViewHolder(view : View) : RecyclerView.ViewHolder(view) {
val firstnameText : TextView = view.findViewById(R.id.firstnameView)
val middlenameText : TextView = view.findViewById(R.id.middleNameView)
val lastnameText : TextView = view.findViewById(R.id.lastNameView)
}
override fun onCreateViewHolder(parent: ViewGroup, viewType: Int): jsonAdapter.ViewHolder {
val view = LayoutInflater.from(parent.context).inflate(R.layout.jsonlist,parent,false)
return ViewHolder(view)
}
override fun onBindViewHolder(holder: jsonAdapter.ViewHolder, position: Int) {
val namesModel = data[position]
holder.firstnameText.text = namesModel.firstname
holder.middlenameText.text = namesModel.middlename
holder.lastnameText.text = namesModel.lastname
}
override fun getItemCount(): Int {
return data.size
}
}

Why is the .update("field","value") not working?

If you see the read messages function in my activity class below, i wanted to update the isSeen field in firestore, but for some reason it does not work at all. My guess it requires a specific document value but that would not be possible as this a messaging app so there will be a lot of documents created.
Activity Class
class MessageActivity : AppCompatActivity() {
private lateinit var binding: ActivityMessageBinding
private lateinit var chat: ArrayList<Message>
private lateinit var messageAdapter: MessageAdapter
private lateinit var roomID: String
private lateinit var userID: String
private lateinit var recID: String
private var c: Int = 0
override fun onCreate(savedInstanceState: Bundle?) {
super.onCreate(savedInstanceState)
binding = ActivityMessageBinding.inflate(layoutInflater)
setContentView(binding.root)
userID = FirebaseAuth.getInstance().uid.toString()
recID = intent.getStringExtra("userID").toString()
val recName:String = intent.getStringExtra("userName").toString()
binding.userName.text = recName
chat = arrayListOf()
messageAdapter = MessageAdapter(chat)
binding.recyclerView.setHasFixedSize(true)
binding.recyclerView.layoutManager = LinearLayoutManager(this)
when {
userID < recID ->
{
roomID = userID + recID
}
userID.compareTo(recID) == 0 ->
{
Toast.makeText(this, "Error you are chatting with yourself!!!", Toast.LENGTH_SHORT).show()
}
else -> {
roomID = recID + userID
}
}
readMessages(userID,recID)
binding.btnSend.setOnClickListener {
val message: String = binding.textSend.text.toString()
if(message.isNotEmpty()){
sendMessage(userID,recID,message)
binding.textSend.text.clear()
}
else{
Toast.makeText(this,"You can't send empty message", Toast.LENGTH_SHORT).show()
}
}
binding.gps.setOnClickListener {
val uri = "http://maps.google.com/maps?daddr="
val intent = Intent(Intent.ACTION_VIEW, Uri.parse(uri))
intent.setPackage("com.google.android.apps.maps")
startActivity(intent)
}
}
private fun sendMessage(sender: String, rec: String, message: String){
val db = Firebase.firestore
val time: FieldValue = FieldValue.serverTimestamp()
val msg = hashMapOf(
"userID" to sender,
"recID" to rec,
"message" to message,
"time" to time,
"roomID" to roomID,
"isSeen" to false
)
db.collection("chats").document(roomID).collection("messages").document().set(msg,SetOptions.merge())
}
private fun readMessages(userId: String, recId: String){
val rootRef = Firebase.firestore
rootRef.collection("chats").document(roomID).collection("messages").orderBy("time", Query.Direction.ASCENDING).addSnapshotListener(object : EventListener<QuerySnapshot?>
{
override fun onEvent(#Nullable documentSnapshots: QuerySnapshot?, #Nullable e: FirebaseFirestoreException?)
{
if (e != null)
{
Log.e(TAG, "onEvent: Listen failed.", e)
return
}
chat.clear()
if (documentSnapshots != null)
{
for (queryDocumentSnapshots in documentSnapshots)
{
val msg = queryDocumentSnapshots.toObject(Message::class.java)
if (msg.recID == recId && msg.userID == userId || msg.recID == userId && msg.userID == recId)
{
chat.add(msg)
}
if(msg.recID.equals(userID).and(msg.userID.equals(recID))){
rootRef.collection("chats").document(roomID).collection("messages").document().update("isSeen",true)
}
messageAdapter = MessageAdapter(chat)
binding.recyclerView.adapter = messageAdapter
}
}
}
})
}
}
Adapter Class
class MessageAdapter(private val MessageList:ArrayList<Message>):RecyclerView.Adapter<MessageAdapter.MessageViewHolder>() {
private val left = 0
private val right = 1
override fun onCreateViewHolder(parent: ViewGroup, viewType: Int): MessageViewHolder {
return if(viewType==right){
val view1 = LayoutInflater.from(parent.context).inflate(R.layout.chat_sender_item,parent,false)
MessageViewHolder(view1)
}else{
val view2 = LayoutInflater.from(parent.context).inflate(R.layout.chat_receiver_item,parent,false)
MessageViewHolder(view2)
}
}
override fun onBindViewHolder(holder: MessageViewHolder, position: Int) {
val message:Message = MessageList[position]
holder.showMessage.text = message.message
if(position==MessageList.size-1){
if(message.isSeen)
{
holder.textSeen.text = "Seen"
}else{
holder.textSeen.text = "Delivered"
}
}else{
holder.textSeen.visibility = View.GONE
}
}
override fun getItemCount(): Int {
return MessageList.size
}
class MessageViewHolder(itemView:View) : RecyclerView.ViewHolder(itemView){
val showMessage: TextView = itemView.findViewById(R.id.showMessage)
val textSeen: TextView = itemView.findViewById(R.id.textSeen)
}
override fun getItemViewType(position: Int): Int {
val userID = FirebaseAuth.getInstance().currentUser!!.uid
return if(MessageList[position].userID==userID)
{
right
}else
{
left
}
}
}
Model Class
package com.aarondcosta99.foodreuseapp.model
data class Message(var userID:String? = "",var message:String? = "",var recID:String? = "",var isSeen:Boolean=false)
Firestore

This won't work:
rootRef.collection("chats").document(roomID).collection("messages").document().update("isSeen",true)
The document() call without any arguments creates a reference to a new non-existing document, which you then try to update. But update() only works when a document already exists, you can't use update() to create a document, so this code ends up doing nothing.
To update a document, you need to specify the complete path to that document. The fact that you need to update a lot of documents makes no difference to that fact, it just means you'll need to paths to a lot of documents.
As far as I can tell, you are trying to update the document that you read in documentSnapshots, which means you already have the DocumentReference handy and can update it with:
queryDocumentSnapshots.reference.update("isSeen",true)

Can't get received messages

Somehow I see in the app messages I sent, but can't see those which should be received from others. Also when I'm sending a message it's sent to all users. Here I'm sending two classes, adapter and main chat activity. I tried using inner classes, different types of getItemViewType functions but nothing works.
MessageAdapter
class MessageAdapter(val context: Context, val messageList: ArrayList<Message>):
RecyclerView.Adapter<RecyclerView.ViewHolder>() {
val ITEM_RECIEVE = 1
val ITEM_SENT = 2
class SentViewHolder(itemView: View) : RecyclerView.ViewHolder(itemView)
{
val sentMessage = itemView.findViewById<TextView>(R.id.txt_sent_message)
}
class RecieveViewHolder(itemView: View) : RecyclerView.ViewHolder(itemView)
{
val recieveMessage = itemView.findViewById<TextView>(R.id.txt_recieve_message)
}
override fun getItemViewType(position: Int): Int {
val currentMessage = messageList[position]
if (FirebaseAuth.getInstance().currentUser?.uid.equals(currentMessage.senderId)) {
return ITEM_SENT
}
else {
return ITEM_RECIEVE
}
}
override fun onCreateViewHolder(parent: ViewGroup, viewType: Int): RecyclerView.ViewHolder {
if (viewType == 1)
{
val view = LayoutInflater.from(context).inflate(R.layout.recieve, parent, false)
Log.d("tag2", "testrecieveviewholderview11")
return RecieveViewHolder(view)
}
else
{
val view = LayoutInflater.from(context).inflate(R.layout.sent, parent, false)
Log.d("tag", "testsentviewholderview22")
return SentViewHolder(view)
}
}
override fun onBindViewHolder(holder: RecyclerView.ViewHolder, position: Int) {
val currentMessage = messageList[position]
if(holder.javaClass == SentViewHolder::class.java)
{
val viewHolder = holder as SentViewHolder
holder.sentMessage.text = currentMessage.message
}
else
{
val viewHolder = holder as RecieveViewHolder
holder.recieveMessage.text = currentMessage.message
}
}
override fun getItemCount(): Int {
return messageList.size
}
}
And ChatActivity
var firebaseUser: FirebaseUser? = null
private lateinit var messageRecyclerView: RecyclerView
private lateinit var messageBox: EditText
private lateinit var sendButton: ImageButton
private lateinit var messageAdapter: MessageAdapter
private lateinit var messageList: ArrayList<Message>
private lateinit var mRef: DatabaseReference
var recieverRoom: String? = null
var senderRoom: String? = null
override fun onCreate(savedInstanceState: Bundle?) {
super.onCreate(savedInstanceState)
setContentView(R.layout.activity_chat)
val intent = Intent()
val name = intent.getStringExtra("name")
val recieverUid = intent.getStringExtra("uid")
val senderUid = FirebaseAuth.getInstance().currentUser?.uid
mRef = FirebaseDatabase.getInstance().reference
senderRoom = recieverUid + senderUid
recieverRoom = senderUid + recieverUid
messageRecyclerView = findViewById(R.id.RecyclerViewChat)
messageBox = findViewById(R.id.messageBox)
sendButton = findViewById(R.id.sendButton)
messageList = ArrayList()
messageAdapter = MessageAdapter(this, messageList)
messageRecyclerView.layoutManager = LinearLayoutManager(this)
messageRecyclerView.scrollToPosition(messageAdapter.itemCount-1)
messageRecyclerView.adapter = messageAdapter
mRef.child("chats").child(senderRoom!!).child("messages")
.addValueEventListener(object : ValueEventListener{
override fun onDataChange(snapshot: DataSnapshot) {
messageList.clear()
for (postSnapshot in snapshot.children)
{
val message = postSnapshot.getValue(Message::class.java)
messageList.add(message!!)
}
messageAdapter.notifyDataSetChanged()
}
override fun onCancelled(error: DatabaseError) {
}
})
sendButton.setOnClickListener {
if (messageBox.text.toString().isEmpty() || messageBox.text.toString().isBlank())
{
messageBox.setText("")
}
else {
val message = messageBox.text.toString()
val messageObject = Message(message, senderUid)
mRef.child("chats").child(senderRoom!!).child("messages").push()
.setValue(messageObject).addOnSuccessListener {
mRef.child("chats").child(recieverRoom!!).child("messages").push()
.setValue(messageObject)
}
messageBox.setText("")
}
}
}
}

The error coming in this code is "Unresolved reference: message" and "Unresolved reference: senderId" in MessageAdapter. MessageAdapter is not able to take variables that are declared in Message class(message and senderId).

how to filter list data in descending order in kotlin?

From the Android app, I wrote for I want to add, add a button in the toolbar that acts as a toggle. When the toggle is disabled (the default state) all posts should be shown, when it is enabled (after a tap) the list should only show the posts having user_id set to 1 and sorted by descending published_at. Tapping on the button again will return it to its default state.
Note that publishedAt returning date and publishedAt and user_id coming from postList from the server I want to know how can I implement above requirement what kind of steps should I have to follow
below my logic implementation in MainActivity.kt
class MainActivity : AppCompatActivity() {
#Inject
lateinit var restInterface: RestInterface
private fun initializeDagger() = App.appComponent.inject(this)
var context: Context? = null
private var filteredList: List<Post>? = null
private var recyclerView: RecyclerView? = null
private var switch1: Switch? = null
private var restAdapter: RestAdapter? = null
private var postList: List<Post>? = null
private var restList: RestList? = null
override fun onCreate(savedInstanceState: Bundle?) {
super.onCreate(savedInstanceState)
setContentView(R.layout.activity_main)
initializeDagger()
recyclerView = findViewById(R.id.recycler_view)
switch1 = findViewById(R.id.switch1)
fetchPosts()
switch1.setOnclickListener {
postList.forEach { postItem: Post ->
if (postItem.userId == 1)
filteredList.add(postItem)
}
recyclerView.post = filteredList
recyclerView.notifyDatasetChanged()
}
// Collections.sort( filteredList.get(4).publishedAt, Collections.reverseOrder());
}
private fun fetchPosts() {
val progress = ProgressDialog(this)
progress.setMessage("Loading... ")
progress.isIndeterminate = true
progress.show()
restInterface?.getPosts?.subscribeOn(Schedulers.newThread())
.observeOn(AndroidSchedulers.mainThread())
.subscribe(object : DisposableSingleObserver<Response<RestList>>() {
override fun onSuccess(response: Response<RestList>) {
restList = response.body()
val layoutManager = LinearLayoutManager(applicationContext)
recyclerView?.layoutManager = layoutManager
// initialize postList with posts
postList = restList?.posts
restAdapter = postList?.let { RestAdapter(it, restList) }
recyclerView?.adapter = restAdapter
}
override fun onError(e: Throwable) {
progress.dismiss()
Toast.makeText(context, "" + e.message, Toast.LENGTH_SHORT).show()
}
})
}
}
below my RestAdapter.kt
class RestAdapter(val post: List<Post>,val restList: RestList?) : RecyclerView.Adapter<RestAdapter.PostHolder>() {
override fun onCreateViewHolder(parent: ViewGroup, viewType: Int): PostHolder {
val itemView = LayoutInflater.from(parent.context).inflate(R.layout.post_list, null)
return PostHolder(itemView)
}
override fun getItemCount(): Int {
return post.size
}
override fun onBindViewHolder(holder: PostHolder, position: Int) {
val posts = post[position]
Picasso
.get() // give it the context
.load(posts.image) // load the image
.into(holder.postImage)
holder.userId.text = posts.userId.toString()
holder.postTitle.text = posts.title
holder.postTime.text = posts.publishedAt
holder.postDescription.text = posts.description
}
class PostHolder(itemView: View) : RecyclerView.ViewHolder(itemView) {
val postImage: ImageView = itemView.findViewById(R.id.postImage)
val userId: TextView = itemView.findViewById(R.id.userId)
val postTitle: TextView = itemView.findViewById(R.id.postTitle)
val postTime: TextView = itemView.findViewById(R.id.postTime)
val postDescription: TextView = itemView.findViewById(R.id.postDescription)
}
}

You can use method .sortedByDescending or .sortedBy on list :)
[Edit]
I give you a simple solution for that, maybe not the best but should work
1. Change RestAdapter constructor to (var post: List,val restList: RestList?)
Add method to updateData in apadapter:
fun filterData(isChecked: Boolean) {
if (isChecked) {
val filteredList = arrayListOf<Post>()
filteredList.addAll(restList?posts.filter { it.user_id == 1 }.sortedByDescending { it.published_at })
post = filteredList
} else {
post = restList?.posts
}
notifyDatasetChanged()
}
And in your class use this:
switch1.setOnclickListener {
restAdapter?.filterData(switch1.isChecked()//state of your switch i.e isChecked() which return true or false)
}

Blank screen with RecyclerView No adapter attached

I'm tying to parse JSON in recyclerview. App compiles fine but it's outputting empty/blank screen
BlogAdapter.kt
class BlogAdapter(private val blogList: List<Blog>) : RecyclerView.Adapter<BlogAdapter.ViewHolder>() {
override fun getItemCount()= blogList.size
private var mContext: Context? = null
override fun onCreateViewHolder(parent: ViewGroup, viewType: Int): ViewHolder {
this.mContext=parent.context;
return ViewHolder(
LayoutInflater.from(parent.context).inflate(
R.layout.character_item,
parent,
false
)
)
}
override fun onBindViewHolder(holder: ViewHolder, position: Int) {
val mBlog = this.blogList[position]
if (mBlog.img != null) {
Glide.with(mContext!!)
.load(mBlog.img)
.into(holder.ivThumbnail)
}
if (mBlog.name != null) {
holder.tvTitle.text = mBlog.name
println("Log: Kabe "+mBlog.name)
}
}
class ViewHolder(itemView:View):RecyclerView.ViewHolder(itemView){
val ivThumbnail:ImageView = itemView.findViewById(R.id.ivThumbnail);
val tvTitle:TextView = itemView.findViewById(R.id.tvTitle);
}
}
MainActivity.kt
class MainActivity : AppCompatActivity() {
var mainViewModel: MainViewModel? = null
var mBlogAdapter: BlogAdapter? = null
override fun onCreate(savedInstanceState: Bundle?) {
super.onCreate(savedInstanceState)
setContentView(R.layout.activity_main)
mainViewModel = ViewModelProvider(this).get(MainViewModel::class.java)
getPopularBlog()
swipe_refresh.setOnRefreshListener { getPopularBlog() }
}
private fun getPopularBlog() {
swipe_refresh.isRefreshing = false
mainViewModel!!.allBlog.observe(this, Observer { charactersList ->
prepareRecyclerView(charactersList)
})
}
private fun prepareRecyclerView(blogList: List<Blog>) {
mBlogAdapter = BlogAdapter(blogList)
if (this.resources.configuration.orientation == Configuration.ORIENTATION_PORTRAIT) {
blogRecyclerView.layoutManager = LinearLayoutManager(this)
} else {
blogRecyclerView.layoutManager = GridLayoutManager(this, 4)
}
blogRecyclerView.itemAnimator = DefaultItemAnimator()
blogRecyclerView.adapter = mBlogAdapter
}
}
My Json file looks like this:
[
{
"id": 1,
"name": "potter",
"img": "https://images.example.com/potter.jpg"
},
{ …}
]
I've created it based on this tutorial: https://itnext.io/kotlin-wrapping-your-head-around-livedata-mutablelivedata-coroutine-networking-and-viewmodel-b552c3a74eec
Any suggestions please
EDIT:
class BlogRepository() {
private var character = mutableListOf<ABCCharacters>()
private var mutableLiveData = MutableLiveData<List<ABCCharacters>>()
val completableJob = Job()
private val coroutineScope = CoroutineScope(Dispatchers.IO + completableJob)
private val thisApiCorService by lazy {
RestApiService.createCorService()
}
fun getMutableLiveData():MutableLiveData<List<ABCCharacters>> {
coroutineScope.launch {
val request = thisApiCorService.getPopularBlog()
withContext(Dispatchers.Main) {
try {
val response = request.await()
val mBlogWrapper = response;
if (/*mBlogWrapper != null &&*/ mBlogWrapper.isNotEmpty()) {
character = mBlogWrapper as MutableList<ABCCharacters>
mutableLiveData.value = character
}
} catch (e: HttpException) {
// Log exception //
} catch (e: Throwable) {
// Log error //)
}
}
}
return mutableLiveData;
}
}

You forget to call notifyDataSetChanged, when you setup your RecyclerView widget. Below the full method call, to make it works.
private fun prepareRecyclerView(blogList: List<Blog>) {
mBlogAdapter = BlogAdapter(blogList)
if (this.resources.configuration.orientation == Configuration.ORIENTATION_PORTRAIT) {
blogRecyclerView.layoutManager = LinearLayoutManager(this)
} else {
blogRecyclerView.layoutManager = GridLayoutManager(this, 4)
}
blogRecyclerView.itemAnimator = DefaultItemAnimator()
blogRecyclerView.adapter = mBlogAdapter
mBlogAdapter.notifyDataSetChanged()
}

Try using below implementation:
class MainActivity : AppCompatActivity() {
lateinit var mainViewModel: MainViewModel
var mBlogAdapter: BlogAdapter? = null
var blogList: List<Blog> = arrayListOf()
override fun onCreate(savedInstanceState: Bundle?) {
super.onCreate(savedInstanceState)
setContentView(R.layout.activity_main)
mainViewModel = ViewModelProvider(this).get(MainViewModel::class.java)
// init your RV here
prepareRecyclerView()
getPopularBlog()
swipe_refresh.setOnRefreshListener { mainViewModel.getAllBlog() }
}
private fun getPopularBlog() {
swipe_refresh.isRefreshing = false
mainViewModel.getAllBlog().observe(this, Observer { charactersList ->
blogList = charactersList
mBlogAdapter?.notifyDataSetChanged()
})
}
private fun prepareRecyclerView() {
mBlogAdapter = BlogAdapter(blogList)
if (this.resources.configuration.orientation == Configuration.ORIENTATION_PORTRAIT) {
blogRecyclerView.layoutManager = LinearLayoutManager(this)
} else {
blogRecyclerView.layoutManager = GridLayoutManager(this, 4)
}
blogRecyclerView.itemAnimator = DefaultItemAnimator()
blogRecyclerView.adapter = mBlogAdapter
}
}
Modify your view model like below:
class MainViewModel() : ViewModel() {
val characterRepository= BlogRepository()
fun getAllBlog(): MutableLiveData<List<ABCCharacters>> {
return characterRepository.getMutableLiveData()
}
override fun onCleared() {
super.onCleared()
characterRepository.completableJob.cancel()
}
}