My observer is working and it's getting called whenever a new record is entered,
The problem is with recycler view is only showing one record to begin with and it never updates itself to show additional records as a result of save setClickListener.
I can verify in the my database (Room with LiveData) that I've more than one record, there's some problem with the Adapter or the ViewHolder.
P.S. Plus any modifications to how things should be done when it comes to patterns with adapter are most welcome. I hope I got it right.
MainActivity onCreate method
viewModel = ViewModelProvider(this).get(BookViewModel::class.java)
save.setOnClickListener {
val book = Book(UUID.randomUUID().toString(), "author 2", "book 2")
viewModel.insert(book)
}
val bookListAdapter = BookListAdapter(this)
recyclerView.adapter = bookListAdapter
recyclerView.layoutManager = LinearLayoutManager(this)
viewModel.allBooks.observe(this, Observer { books ->
books?.let {
Log.d(TAG, "onCreate: changed")
bookListAdapter.setBooks(books)
}
})
static classes in MainActivity
private class BookListAdapter(private val context: Context): RecyclerView.Adapter<BookListAdapter.BookViewHolder>() {
private var bookList: List<Book> = mutableListOf()
// getting called only once
override fun onCreateViewHolder(parent: ViewGroup, viewType: Int): BookListAdapter.BookViewHolder {
val itemView = LayoutInflater.from(context).inflate(R.layout.list_item, parent, false)
return BookViewHolder(itemView)
}
override fun onBindViewHolder(holder: BookListAdapter.BookViewHolder, position: Int) {
val book = bookList[position]
holder.setData(book.author, book.book, position)
}
override fun getItemCount(): Int {
Log.d("inner", "getItemCount: ${bookList.size}") // this return correct size
return bookList.size
}
fun setBooks(it: List<Book>?) {
bookList = it!!
notifyDataSetChanged()
}
private class BookViewHolder(itemView: View): RecyclerView.ViewHolder(itemView) {
fun setData(a: String, b: String, p: Int) {
itemView.author.text = a
itemView.book.text = b
}
}
}
Based on this answer: How to update RecyclerView Adapter Data? I think that You have to notifyDataSetChanged from observer method not inside the adapter class.
viewModel.allBooks.observe(this, Observer { books ->
books?.let {
Log.d(TAG, "onCreate: changed")
bookListAdapter.setBooks(books)
bookListAdapter.notifyDataSetChanged()
}
})
fun setBooks(it: List<Book>) {
bookList = it
}
Also, when You use Room I think You can try to use DiffUtil. It will automatically refresh layout when it has to be refreshed and is much faster than calling notifyDataSetChanged every time Your data is changed.
Related
The problem I am facing with the RecyclerView is the data is coming from Server and the API response is getting printed correctly in the console.
but when I am trying to set data in the adapter what is wrong or something is not going correctly with the flow that the data is not being updated on UI.
//This is my adapter class
class DashboardAdapter(val context: Context) : RecyclerView.Adapter<DashBoardHolder>() {
private var transactionList = ArrayList<DashboardData>()
override fun onCreateViewHolder(parent: ViewGroup, viewType: Int): DashBoardHolder {
val inflator = LayoutInflater.from(parent.context)
val view = ActivityDashboardDataBinding.inflate(inflator, parent, false)
val viewHolder = DashBoardHolder(view)
return viewHolder
}
override fun onBindViewHolder(holder: DashBoardHolder, position: Int) {
val quickModel = transactionList[position]
holder.tvName.text = quickModel.bookingTitle
}
fun showListItems(dashboardlist: List<DashboardData>?, aboolean: Boolean) {
when {
aboolean -> transactionList.clear()
}
if (dashboardlist != null && !dashboardlist.isEmpty())
this.transactionList.addAll(dashboardlist)
notifyDataSetChanged()
}
override fun getItemCount(): Int {
return transactionList.size
}
}
MyHolderClass
class DashBoardHolder(val binding: ActivityDashboardDataBinding) :
RecyclerView.ViewHolder(binding.root) {
var tvName: TextView = binding.textViewGrandrukName
var tvTime: TextView = binding.tvGrandrukTripDetails
var tvPlace: ImageView = binding.btnGhandruk
var ivRectangle: ImageView = binding.imageView5
}
Similarly,I set the adapter in view section like this way:
//setting adapter in Presenter class
fun setAdapter() {
var layoutmanager: LinearLayoutManager? = LinearLayoutManager(appCompatActivity)
val firstVisiblePosition = layoutmanager!!.findFirstVisibleItemPosition()
binding!!.includesDashboardRecyclerview.rvBookingList.setHasFixedSize(true)
binding!!.includesDashboardRecyclerview.rvBookingList.layoutManager = layoutmanager
binding!!.includesDashboardRecyclerview.rvBookingList.adapter = dashboardAdapter
layoutmanager!!.scrollToPositionWithOffset(firstVisiblePosition, 0)
}
In Presenter Class, calling setAdapter class from presenter like this way
class DashboardPresenter(
private val dashboardView: DashboardView,
private val dashboardModel: DashboardModel
) {
fun onCreateView() {
onClick()
dashboardView.setAdapter()
getDashboardRequest()
}
//calling adpter function here
fun showList(termlist: List<DashboardData>?, aboolean: Boolean) {
(null as DashboardAdapter?)?.showListItems(termlist!!, aboolean)
}
}
I'm not able to understand what is getting wrong here.
(null as DashboardAdapter?)?.showListItems(termlist!!, aboolean)
You are calling showListItems() on the DashboardAdapter as a type not the instance dashboardAdapter. Assuming that dashboardAdapter is a local class field.
Also I guess this type casting is not necessary as you already using the optional ?
So, it can be simplified to:
dashboardAdapter?.showListItems(termlist!!, aboolean)
Assuming that this should be called whenever you retrieve the API response. So, showList() must be called when there's new API data.
I have an app which uses Room Database to show data in recycleview. It works fine when i load data seperately from different tables. But i want to show data from both tables in a single recycleview with multiple viewtypes, i know how to combine tables in room but it's not working. I get empty cards in recycleview when i load the data. Here is what i have tried so far.
My Adapter Class
class CategoriesAdapter : RecyclerView.Adapter<RecyclerView.ViewHolder>() {
companion object {
private const val TYPE_CATEGORIES = 0
private const val TYPE_ARTICLES = 1
}
private val items: MutableList<Any> by lazy {
ArrayList<Any>()
}
fun setItems(list: List<Any>) {
items.addAll(list)
notifyDataSetChanged()
}
override fun getItemViewType(position: Int): Int {
return if (items[position] is Categories) TYPE_CATEGORIES else TYPE_ARTICLES
}
override fun onCreateViewHolder(viewGroup: ViewGroup, viewType: Int): RecyclerView.ViewHolder {
return when (viewType) {
TYPE_CATEGORIES -> CategoriesViewHolder.create(viewGroup)
else -> ArticlesViewHolder.create(viewGroup)
}
}
override fun onBindViewHolder(holder: RecyclerView.ViewHolder, position: Int) {
when (holder) {
is CategoriesViewHolder -> {
if (items[position] is Categories)
holder.bind(items[position] as Categories)
}
is ArticlesViewHolder -> {
if (items[position] is Articles)
holder.bind(items[position] as Articles)
}
}
}
override fun getItemCount(): Int {
return items.size
}
}
class CategoriesViewHolder (parent: View) : RecyclerView.ViewHolder(parent) {
val textView: TextView = parent.findViewById(R.id.categories_textView)
fun bind(category: Categories) {
textView.text = category.categoryName
}
companion object {
fun create(parent: ViewGroup): CategoriesViewHolder {
return CategoriesViewHolder(LayoutInflater.from(parent.context).inflate(R.layout.categories_item_layout, parent, false))
}
}
}
class ArticlesViewHolder (parent: View) : RecyclerView.ViewHolder(parent) {
val textView: TextView = parent.findViewById(R.id.titleText)
fun bind(articles : Articles) {
textView.text = articles.articleName
}
companion object {
fun create(parent: ViewGroup): ArticlesViewHolder {
return ArticlesViewHolder(LayoutInflater.from(parent.context).inflate(R.layout.article_item_layout, parent, false))
}
}
}
this is how i set data from my activity
val db = AppDatabase.getDatabase(applicationContext)
dao = db.articleDao()
val recyclerView = findViewById<RecyclerView>(R.id.categories_recycle_view)
recyclerView.layoutManager = LinearLayoutManager(this)
recyclerView.adapter = CategoriesAdapter()
adapter.setItems(dao.getAllArticlesAndCategories())
Can anyone help.
P.s i'm new to kotlin
Instead of
adapter.setItems(dao.getAllArticlesAndCategories())
Use live data observer to avoid processing on main thread and debug in observe function of live data to confirm you are receiving correct data from DB.
calling code one line of code is missing
val db = AppDatabase.getDatabase(applicationContext)
dao = db.articleDao()
val recyclerView = findViewById<RecyclerView>(R.id.categories_recycle_view)
recyclerView.layoutManager = LinearLayoutManager(this)
recyclerView.adapter = CategoriesAdapter()
adapter.setItems(dao.getAllArticlesAndCategories())
it should be:
val db = AppDatabase.getDatabase(applicationContext)
dao = db.articleDao()
val recyclerView = findViewById<RecyclerView>(R.id.categories_recycle_view)
recyclerView.layoutManager = LinearLayoutManager(this)
adapter=CategoriesAdapter()
adapter.setItems(dao.getAllArticlesAndCategories())
recyclerView.adapter = adapter
I would like to thank for the question and the code
I am trying to update my nested RecyclerView list using submitList in a LiveData Observer.
The list is submitted, but the UI only updates when you touch the screen.
The issue arose when I added nested RecyclerViews in my master RecyclerView.
So I think it has something to do with it.
I want it to update after the submitList is called.
What am I doing wrong?
Outer ListAdapter:
class ReservationAdapter(
private val changeState: (visit: Visit, newState: Visit.State) -> MutableLiveData<Visit?>
) : ListAdapter<Reservation, ReservationViewHolder>(ReservationDiffCallback()) {
private val recycledViewPool = RecyclerView.RecycledViewPool()
/// Filters \\\
// Building
var filterBuildingId = ""
set(value) {
field = value
filteredVisits = visits.filter(Visit.filter(value, filterSearchString))
}
// Search string
var filterSearchString = ""
set(value) {
field = value
filteredVisits = visits.filter(Visit.filter(filterBuildingId, value))
}
/// Filtering chain \\\
// Visits come in and get filtered
var visits = arrayListOf<Visit>()
set(value) {
field = value
filteredVisits = value.filter(Visit.filter(filterBuildingId, filterSearchString))
}
// Filtered visits come in, a reservation map is made
var filteredVisits = listOf<Visit>()
set(value) {
field = value
reservationVisits = Reservation.extractMapFromVisits(value)
}
// Reservation map comes in, and submits a list of reservations
private var reservationVisits = hashMapOf<Reservation, ArrayList<Visit>>()
set(value) {
field = value
_reservationVisits.value = value
submitList(value.keys.toMutableList())
notifyDataSetChanged()
}
private val _reservationVisits = MutableLiveData<HashMap<Reservation, ArrayList<Visit>>>()
/**
* Inflate items
*/
override fun onCreateViewHolder(parent: ViewGroup, viewType: Int): ReservationViewHolder {
return ReservationViewHolder(
LayoutInflater.from(parent.context).inflate(
R.layout.list_reservation,
parent,
false
),
recycledViewPool,
changeState,
_reservationVisits
)
}
/**
* Bind items
*/
override fun onBindViewHolder(holder: ReservationViewHolder, position: Int) {
val reservation = getItem(position)
holder.bind(reservation, reservationVisits[reservation])
}
}
Outer ViewHolder:
class ReservationViewHolder(
private val view: View,
private val recycledViewPool: RecyclerView.RecycledViewPool,
changeState: (visit: Visit, newState: Visit.State) -> MutableLiveData<Visit?>,
reservationVisits: MutableLiveData<HashMap<Reservation, ArrayList<Visit>>>
) : RecyclerView.ViewHolder(view) {
private val adapter = VisitAdapter(changeState)
private var _reservation: Reservation? = null
init {
/*
THIS IS WHERE I SETS THE VALUE, BUT DOESN'T UPDATE THE UI.
*/
reservationVisits.observe(view.context as LifecycleOwner) {
if (_reservation != null) {
(view.context as MainActivity).runOnUiThread {
adapter.submitList(null)
adapter.notifyDataSetChanged()
adapter.submitList(it[_reservation!!]?.toMutableList())
adapter.notifyDataSetChanged()
view.refreshDrawableState()
}
}
}
}
fun bind(reservation: Reservation, visits: ArrayList<Visit>?): View = with(view) {
println("3: ${visits?.size}")
_reservation = reservation
// Initialize values
txtSubject.text = reservation.subject
txtTime.text = "TIME"
// Recycler view for visits
rcvVisits.apply {
(itemAnimator as SimpleItemAnimator).supportsChangeAnimations = false
layoutManager = LinearLayoutManager(context)
adapter = this#ReservationViewHolder.adapter
setRecycledViewPool(this#ReservationViewHolder.recycledViewPool)
}
// Add visits to adapter
adapter.submitList(visits)
// Return view
view
}
}
Inner ListAdapter:
class VisitAdapter(
private val changeState: (visit: Visit, newState: Visit.State) -> MutableLiveData<Visit?>
) : ListAdapter<Visit, VisitViewHolder>(VisitDiffCallback()) {
// Sorter
private val _visitSorter = compareBy<Visit>({ it.state }, { it.expectedArrival }, { it.visitor?.name })
// ListAdapter create
override fun onCreateViewHolder(parent: ViewGroup, viewType: Int): VisitViewHolder {
return VisitViewHolder(
LayoutInflater.from(parent.context).inflate(
R.layout.list_visitor,
parent,
false
),
changeState
)
}
// ListAdapter bind
override fun onBindViewHolder(holder: VisitViewHolder, position: Int) {
holder.bind(getItem(position))
}
// ListAdapter submit
override fun submitList(list: List<Visit>?) {
super.submitList(list?.sortedWith(_visitSorter) ?: listOf())
}
}
I checked your code these are what I found:
you created an instance of the adapter and an observer in view holder class.
view holder will instantiate multiple times, so you shouldn't instantiate the adapter in it. check this link
and if you want to pass data to your view holder, you should do it in the constructor, never observe for data change in view holder class.
so you can observe data in activity and pass data to your adapter.
and there is no need to call runOnUiThread in an observer. its already on main Thread (UI Thread).
The events are dispatched on the main thread. If LiveData already has data set, it will be delivered to the observer.
LiveData
I solved it.
The issue was with the com.mikepenz:aboutlibraries:7.0.4#aar library.
After I removed it and commented out any code that used it, it started working.
I am trying to access data once it is completely retrieved from database? initially I apply adapter to fragment. With in the Adapter I tried to retrieve data from firebase database. So here give problem it send the null arraylist. It should send back the arraylist when complete data is retrieved?
Adapter code :
class FirebaseAdapter(context: Context): RecyclerView.Adapter<FirebaseAdapter.Holder>() {
var dataList: ArrayList<DatabaseOperations.ImageInfo> = arrayListOf()
var context: Context? = null
init {
if (context == null)
this.context = context
dataList= DatabaseOperations().retriveInfo(context!!)
}
override fun onCreateViewHolder(parent: ViewGroup, viewType: Int): Holder {
var itemView: View = LayoutInflater.from(parent.context).inflate(R.layout.imagelist_row,parent)
var viewHolder: FirebaseAdapter.Holder = FirebaseAdapter.Holder(itemView)
return viewHolder
}
override fun getItemCount(): Int {
Log.e("itemCoutn",dataList.size.toString()) // it give output 0
return dataList.size
}
override fun onBindViewHolder(holder: Holder, position: Int) {
try {
//----------------get bitmap from image url-----------------
var downloadUri: String = dataList.get(position).downloadUri
Log.e("fire adapter",downloadUri.toString())
//------------------Assign Data to item here-----------------
holder.image_name.text = dataList.get(position).imageName
Glide.with(this!!.context!!)
.load(downloadUri)
.into(holder.row_image)
}
catch(e: Exception){
Log.e("Firebase Adapter","Error "+e.toString())
}
}
class Holder(itemView: View?) : RecyclerView.ViewHolder(itemView) {
val row_image: ImageView
val image_name: TextView
init {
row_image = itemView!!.findViewById<ImageView>(R.id.row_image)
image_name = itemView!!.findViewById<TextView>(R.id.image_name)
}
}
}
Information retrieve code :
fun retriveInfo( context: Context): ArrayList<ImageInfo>{
var data = ArrayList<ImageInfo>()
if (mDatabaseRefrence == null)
mDatabaseRefrence = FirebaseDatabase.getInstance().getReference(getUid())
val menuListener = object : ValueEventListener {
override fun onDataChange(dataSnapshot: DataSnapshot) {
var dataSnap: DataSnapshot? = null
var it: Iterable<DataSnapshot> = dataSnapshot.children
it.forEach { dataSnapshot ->
data.add(ImageInfo(
dataSnapshot!!.child("imageName").toString(),
dataSnapshot!!.child("imageInfo").toString(),
dataSnapshot!!.child("downloadUri").toString()
))
}
FirebaseAdapter(context).notifyDataSetChanged()
Log.e("db size 0",data.size.toString())
}
override fun onCancelled(databaseError: DatabaseError) {
println("loadPost:onCancelled ${databaseError.toException()}")
}
}
mDatabaseRefrence!!.addValueEventListener(menuListener)
Log.e("db size",data.size.toString())
return data
}
You cannot return something now that hasn't been loaded yet. With other words, you cannot simply return the data list as a result of a function because the list it will always be empty due the asynchronous behaviour of this function. This means that by the time you are trying to return that result, the data hasn't finished loading yet from the database and that's why is not accessible.
Basically, you're trying to return a value synchronously from an API that's asynchronous. That's not a good idea. You should handle the APIs asynchronously as intended.
A quick solve for this problem would be to use the data list only inside the callback (inside the onDataChange() method). If you want to use it outside, I recommend you see the last part of my anwser from this post in which I have explained how it can be done using a custom callback. You can also take a look at this video for a better understanding.
Been using realm and it's awesome.
Came up against something. Wondering if I'm doing something wrong.
I have a RealmRecyclerViewAdapter that I'm using to show the results of a realm query. This works perfectly if I add or update records in the realm. I had to setHasFixedSize(false) on the recycler view to get it to update on the fly. Not sure if this is correct but it worked.
Anyway, that's not my issue.
I'm experimenting with filtering my data. I have the following query:
realm.where(Person::class.java).contains("name", nameFilter, Case.INSENSITIVE).findAllSorted("name")
I'm passing this RealmResults to my recycler view and it works great on add/update.
However, when I attempt a filter, it doesn't update automatically.
Am I right in saying that simply changing my filter (specified by nameFilter) isn't enough for the query to be re-run? This would be fair enough I suppose. Since I guess there's no trigger for realm to know I've changed the value of the string.
However, even if I recalculate my query, it doesn't seem to update in the Recycler View unless I explicitly call updateData on my adapter. I'm not sure if this is the best or most efficient way to do this. Is there a better way?
Complete Code:
Main Activity
class MainActivity : AppCompatActivity(), View.OnClickListener {
private val TAG: String = this::class.java.simpleName
private val realm: Realm = Realm.getInstance(RealmConfiguration.Builder().deleteRealmIfMigrationNeeded().build())
private var nameFilter = ""
private var allPersons: RealmResults<Person> = realm.where(Person::class.java).contains("name", nameFilter, Case.INSENSITIVE).findAllSorted("name")
private val adapter: PersonRecyclerViewAdapter = PersonRecyclerViewAdapter(allPersons)
private lateinit var disposable: Disposable
override fun onCreate(savedInstanceState: Bundle?) {
super.onCreate(savedInstanceState)
setContentView(R.layout.activity_main)
realm.executeTransaction({
// realm.deleteAll()
})
Log.i(TAG, "Deleted all objects from Realm")
buttonAddOrUpdatePerson.setOnClickListener(this)
setUpRecyclerView()
disposable = RxTextView.textChangeEvents(editTextNameFilter)
// .debounce(400, TimeUnit.MILLISECONDS) // default Scheduler is Computation
.observeOn(AndroidSchedulers.mainThread())
.subscribeWith<DisposableObserver<TextViewTextChangeEvent>>(getSearchObserver())
}
private fun getSearchObserver(): DisposableObserver<TextViewTextChangeEvent> {
return object : DisposableObserver<TextViewTextChangeEvent>() {
override fun onComplete() {
Log.i(TAG,"--------- onComplete")
}
override fun onError(e: Throwable) {
Log.i(TAG, "--------- Woops on error!")
}
override fun onNext(onTextChangeEvent: TextViewTextChangeEvent) {
nameFilter = editTextNameFilter.text.toString()
allPersons = realm.where(Person::class.java).contains("name", nameFilter, Case.INSENSITIVE).findAllSorted("name")
// this is necessary or the recycler view doesn't update
adapter.updateData(allPersons)
Log.d(TAG, "Filter: $nameFilter")
}
}
}
override fun onDestroy() {
super.onDestroy()
realm.close()
}
override fun onClick(view: View?) {
if(view == null) return
when(view) {
buttonAddOrUpdatePerson -> handleAddOrUpdatePerson()
}
}
private fun handleAddOrUpdatePerson() {
val personToAdd = Person()
personToAdd.name = editTextName.text.toString()
personToAdd.email = editTextEmail.text.toString()
realm.executeTransactionAsync({
bgRealm -> bgRealm.copyToRealmOrUpdate(personToAdd)
})
}
private fun setUpRecyclerView() {
recyclerViewPersons.layoutManager = LinearLayoutManager(this)
recyclerViewPersons.adapter = adapter
recyclerViewPersons.setHasFixedSize(false)
recyclerViewPersons.addItemDecoration(DividerItemDecoration(this, LinearLayoutManager.VERTICAL))
}
}
PersonRecyclerViewAdapter
internal class PersonRecyclerViewAdapter(data: OrderedRealmCollection<Person>?, autoUpdate: Boolean = true) : RealmRecyclerViewAdapter<Person, PersonRecyclerViewAdapter.PersonViewHolder>(data, autoUpdate) {
override fun onCreateViewHolder(parent: ViewGroup, viewType: Int): PersonViewHolder {
val itemView = LayoutInflater.from(parent.context).inflate(R.layout.person_row, parent, false)
return PersonViewHolder(itemView)
}
override fun onBindViewHolder(holder: PersonViewHolder?, position: Int) {
if(holder == null || data == null) return
val personList = data ?: return
val person = personList[position]
holder.bind(person)
}
internal class PersonViewHolder(view: View) : RecyclerView.ViewHolder(view) {
var textViewName: TextView = view.findViewById(R.id.textViewNameDisplay)
var textViewEmail: TextView = view.findViewById(R.id.textViewEmailDisplay)
internal fun bind(person: Person) {
textViewEmail.text = person.email
textViewName.text = person.name
}
}
}
Yeah, updateData() is the way to do it. Since you updated the query, the Results you want to show becomes a different object. updateData() has to be called to notify the adapter that the data source is changed.
However, you may lose the nice animation for the RecyclerView in this way since the whole view will be refreshed because of the data source is changed. There are some ways to work around this.
eg.: You can add one field isSelected to Person. Query the results by isSelected field and pass it to the adaptor:
allPersons = realm.where(Person::class.java).equalTo("isSelected", true).findAllSorted("name")
adapter = PersonRecyclerViewAdapter(allPersons)
When changing the query:
realm.executeTransactionAsync({
var allPersons = realm.where(Person::class.java).equalTo("isSelected", true).findAllSorted("name")
for (person in allPersons) person.isSelected = false; // Clear the list first
allPersons = realm.where(Person::class.java).contains("name", nameFilter, Case.INSENSITIVE).findAllSorted("name") // new query
for (person in allPersons) person.isSelected = true;
})
It depends on your use case, if the list to show is long, this approach might be slow, you could try to add all the filtered person to a RealmList and set the RealmList as the data source of the adapter. RealmList.clear() is a fast opration than iterating the whole results set to set the isSelected field.
If the filter will mostly cause the whole view gets refreshed, updateData() is simply good enough, just use it then.