Kotlin. Get two firebase queries in one viewmodel - android

There are multiple RecyclerView in my application. Each one consists of the same records, but with different filters.
For example, the first RecyclerView contains new records, the second RecyclerView contains the most popular, etc.
I am trying to get "voices" with different filters. But in the end I get 2 identical lists.
My ViewModel:
private var recentlyAddedVoices = MutableLiveData<List<VoicesModel>>()
private val topFreeVoices = MutableLiveData<List<VoicesModel>>()
private val favExists = MutableLiveData<Boolean>()
private val addToFavoriteResult = MutableLiveData<Boolean>()
val homeVoicesData: MutableLiveData<Pair<List<VoicesModel>?, List<VoicesModel>?>> =
object: MediatorLiveData<Pair<List<VoicesModel>?, List<VoicesModel>?>>() {
var voices: List<VoicesModel>? = null
var freeVoices: List<VoicesModel>? = null
init {
addSource(recentlyAddedVoices) { voices ->
this.voices = voices
voices?.let { value = voices to it }
}
addSource(topFreeVoices) { free ->
this.freeVoices = free
freeVoices?.let { value = freeVoices to it }
}
}
}
fun loadRecentlyAddedVoices(){
REF_DATABASE_ROOT.child(NODE_STICKERS).addValueEventListener(object :
ValueEventListener {
override fun onDataChange(snapshot: DataSnapshot) {
val tmpList: MutableList<VoicesModel> = mutableListOf()
for (ds in snapshot.children) {
val voices: VoicesModel? = ds.getValue(VoicesModel::class.java)
voices!!.pushKey = ds.key.toString()
tmpList.add(voices)
}
recentlyAddedVoices.postValue(tmpList)
}
override fun onCancelled(error: DatabaseError) {
}
})
}
fun loadTopFree(){
REF_DATABASE_ROOT.child(NODE_STICKERS).
orderByChild(CHILD_IS_FREE).
equalTo(true).
addValueEventListener(object : ValueEventListener {
override fun onDataChange(snapshot: DataSnapshot) {
val tmpList: MutableList<VoicesModel> = mutableListOf()
for (ds in snapshot.children) {
val voices: VoicesModel? = ds.getValue(VoicesModel::class.java)
voices!!.pushKey = ds.key.toString()
tmpList.add(voices)
}
topFreeVoices.postValue(tmpList)
}
override fun onCancelled(error: DatabaseError) {
}
})
}
Observe in Fragment:
firebaseViewModel.homeVoicesData.observe(this){ (recentlyAdded, topFree) ->
// recentlyAdded and topFree equals identical value
UpdateUI()
}

Related

Change color of un/selected Items in RecyclerView

My problem is that I want to select an item in a RecyclerView and it should change the color and if I click on another the first selected item should change to the default color (and the last clicked should have the selected color).
I have already a color change of the selected one and if I click on the selected one again it changes to default color. Now I am only missing that if I click on an unselected item and if I have already a selected item they "switch" the color
This is my SubItem class:
class SubItem(val channel: Channel) : Item<GroupieViewHolder>() {
#SuppressLint("ResourceAsColor")
override fun bind(viewHolder: GroupieViewHolder, position: Int) {
val profileImageUrl = channel.channel_logo
viewHolder.itemView.sub_item_name.text = channel.channel_name
viewHolder.itemView.sub_item_layout.setBackgroundResource(R.color.white)
viewHolder.itemView.sub_item_name.setTextColor(R.color.colorSecondaryText)
val targetImageView = viewHolder.itemView.sub_item_profile
try {
Picasso.get().load(profileImageUrl)
.placeholder(R.drawable.ic_baseline_account_circle_24)
.into(targetImageView)
}catch (e:Exception){
Log.d("SubItem","${e.message}")
}
viewHolder.itemView.sub_item_layout.setOnClickListener {
if (selected_position == position){
selected_position = null
viewHolder.itemView.sub_item_layout.setBackgroundResource(R.color.white)
viewHolder.itemView.sub_item_name.setTextColor(R.color.colorSecondaryText)
}
else{
selected_position = position
viewHolder.itemView.sub_item_layout.setBackgroundResource(R.color.colorSecondaryText)
viewHolder.itemView.sub_item_name.setTextColor(R.color.black)
}
}
}
override fun getLayout(): Int {
return R.layout.subscription_item
}
}
If it is helping here is my function where I add the items to the RecyclerView
private fun fetchSubs() {
val uid = auth.uid
val user = database.getReference("/users/$uid/subscriptions")
val adapter = GroupAdapter<GroupieViewHolder>()
user.addListenerForSingleValueEvent(object : ValueEventListener{
#SuppressLint("NotifyDataSetChanged")
override fun onDataChange(p0: DataSnapshot) {
p0.children.forEach{
val sub = it.getValue(Subscription::class.java) ?: return
if (sub.subscribed == true) {
val ref = database.getReference("/channels/${sub.channel_uid}")
ref.addListenerForSingleValueEvent(object : ValueEventListener {
override fun onDataChange(p0: DataSnapshot) {
val channel = p0.getValue(Channel::class.java) ?: return
adapter.add(SubItem(channel))
}
override fun onCancelled(error: DatabaseError) {
}
})
}
}
adapter.setOnItemClickListener{ item, view ->
val subItem = item as SubItem
val channelName = subItem.channel.channel_name
val channelUid = subItem.channel.uid
Toast.makeText(requireContext(),"$channelName : $channelUid", Toast.LENGTH_SHORT).show()
fetchSubs()
}
sub_recyclerview.adapter = adapter
}
override fun onCancelled(error: DatabaseError) {
}
})
}
sorry that I am not using Models and Adapter
For everyone who uses groupie like me this could help you in future.
This is my solution for my Problem.
SubItem class
class SubItem(val channel: Channel) : Item<GroupieViewHolder>() {
#SuppressLint("ResourceAsColor")
override fun bind(viewHolder: GroupieViewHolder, position: Int) {
val profileImageUrl = channel.channel_logo
viewHolder.itemView.sub_item_name.text = channel.channel_name
val targetImageView = viewHolder.itemView.sub_item_profile
try {
Picasso.get().load(profileImageUrl)
.placeholder(R.drawable.ic_baseline_account_circle_24)
.into(targetImageView)
}catch (e:Exception){
Log.d("SubItem","${e.message}")
// Toast.makeText(,e.message,Toast.LENGTH_SHORT).show()
}
checkFilter(viewHolder,position)
}
#SuppressLint("ResourceAsColor")
private fun checkFilter(v: GroupieViewHolder, p: Int) {
when (SubscriptionsFragment.list[p]) {
true -> {
v.itemView.sub_item_layout.setBackgroundResource(R.color.colorDivider)
v.itemView.sub_item_name.setTextColor(R.color.black)
}
false -> {
v.itemView.sub_item_layout.setBackgroundResource(R.color.white)
v.itemView.sub_item_name.setTextColor(R.color.colorSecondaryText)
}
}
}
override fun getLayout(): Int {
return R.layout.subscription_item
}
}
My function with setOnItemClickListener
private fun fetchSubs() {
val uid = auth.uid
val user = database.getReference("/users/$uid/subscriptions")
val adapter = GroupAdapter<GroupieViewHolder>()
user.addListenerForSingleValueEvent(object : ValueEventListener{
#SuppressLint("NotifyDataSetChanged")
override fun onDataChange(p0: DataSnapshot) {
list = mutableListOf()
p0.children.forEach{
val sub = it.getValue(Subscription::class.java) ?: return
if (sub.subscribed == true) {
val ref = database.getReference("/channels/${sub.channel_uid}")
ref.addListenerForSingleValueEvent(object : ValueEventListener {
override fun onDataChange(p0: DataSnapshot) {
val channel = p0.getValue(Channel::class.java) ?: return
list.add(false) // created in companion object: var list = mutableListOf<Boolean>()
oldList.add(false) // created in companion object: var oldlist = mutableListOf<Boolean>()
adapter.add(SubItem(channel))
}
override fun onCancelled(error: DatabaseError) {
}
})
}
}
adapter.setOnItemClickListener{ item, view ->
val subItem = item as SubItem
val pos = adapter.getAdapterPosition(subItem)
// Here happens the magic
list[pos] = !list[pos] // change selected item from false to true or from true to false
val l = list[pos] // saving Boolean
list = mutableListOf()
oldList.forEach{ // using oldList to loop so many times I need
list.add(false) // setting all to false
}
if (l){ // if Boolean is true
list[pos] = !list[pos] // change selected item from false to true
}
val channelUid = subItem.channel.uid
fetchVideos(channelUid)
adapter.notifyDataSetChanged() // refresh all items in SubItem
}
try {
sub_recyclerview.adapter = adapter
} catch(e:Exception){
Log.d("fetchSubs","${e.message}")
}
}
override fun onCancelled(error: DatabaseError) {
}
})
}

How do I set a child value of a Firebase Realtime Database when using a ViewModel and LiveData?

I have the following data class that holds the child values of a specific reference from the Firebase Realtime Database:
data class Users(
val uid: String = "",
var firstName: String = "",
var lastName: String = "",
)
This is my ViewModel:
class UsersViewModel : ViewModel() {
private val uid = Firebase.auth.currentUser!!.uid
private val USERS_REF: DatabaseReference = FirebaseDatabase.getInstance().getReference("/users/$uid")
private val liveData: FirebaseQueryLiveData = FirebaseQueryLiveData(USERS_REF)
private val usersLiveData: MediatorLiveData<Users> = MediatorLiveData()
init {
usersLiveData.addSource(liveData, object : Observer<DataSnapshot> {
override fun onChanged(dataSnapshot: DataSnapshot?) {
if (dataSnapshot != null) {
usersLiveData.postValue(dataSnapshot.getValue(Users::class.java))
} else {
usersLiveData.value = null
}
}
})
}
#NonNull
fun getUsersLiveData() : LiveData<Users> {
return usersLiveData
}
}
This is my extended LiveData:
class FirebaseQueryLiveData(ref: DatabaseReference) : LiveData<DataSnapshot>() {
private val query: Query = ref
private val listener: MyValueEventListener = MyValueEventListener()
private var listenerRemovePending = false
private val removeListener = object : Runnable {
override fun run() {
query.removeEventListener(listener)
listenerRemovePending = false
}
}
override fun onActive() {
super.onActive()
if (listenerRemovePending) {
Handler(Looper.getMainLooper()).removeCallbacks(removeListener)
} else {
query.addValueEventListener(listener)
}
listenerRemovePending = false
}
override fun onInactive() {
super.onInactive()
Handler(Looper.getMainLooper()).postDelayed(removeListener, 2000)
query.removeEventListener(listener)
}
private inner class MyValueEventListener : ValueEventListener {
override fun onDataChange(snapshot: DataSnapshot) {
value = snapshot
}
override fun onCancelled(error: DatabaseError) {
return
}
}
}
For reading the values from my database in my Activity or Fragment, this is what I've done:
val usersViewModel = ViewModelProvider(this).get(UsersViewModel::class.java)
val usersLiveData = usersViewModel.getUsersLiveData()
usersLiveData.observe(this, object : Observer<Users> {
override fun onChanged(users: Users?) {
if (users != null) {
firstNameTextView.text = users.firstName
lastNameTextView.text = users.lastName
}
}
})
This all works, but my question is how do I write to a specific child for my database in my Activity or Fragment? For example, let's say I want to only modify the lastName child? How do I do that? I don't have any references to FirebaseDatabase in my activities and fragments because the ViewModel and LiveData ensure that I don't need them anymore.

Do not create everytime valueEventListener

How i can optimize my code?
In every function i created valueEventListener.
Here is all code:
class TargetsPresenter(private val contract: SelectTargetViewContract) {
var firebaseUser: FirebaseUser? = null
var targetList: ArrayList<Goal> = ArrayList()
private var databaseReference: DatabaseReference? = null
private var targetsRef: DatabaseReference? = null
private var uid: String? = null
fun setInitialData() {
firebaseUser = FirebaseAuth.getInstance().currentUser
databaseReference = FirebaseDatabase.getInstance().reference
uid = firebaseUser?.uid
targetsRef = databaseReference?.child("targets")
?.child("users")?.child(uid.toString())
?.child("targets")
}
fun getTargetsFromDb() {
val valueEventListener = object : ValueEventListener {
override fun onDataChange(dataSnapshot: DataSnapshot) {
targetList.clear()
dataSnapshot.children
.mapNotNull { it.getValue(Goal::class.java) }
.toCollection(targetList)
contract.updateViewContent()
}
override fun onCancelled(databaseError: DatabaseError) {
Log.d("some", "Error trying to get targets for ${databaseError.message}")
}
}
targetsRef?.addListenerForSingleValueEvent(valueEventListener)
}
fun getTargetsByPriority() {
val valueEventListener = object : ValueEventListener {
override fun onDataChange(dataSnapshot: DataSnapshot) {
targetList.clear()
dataSnapshot.children
.mapNotNull { it.getValue(Goal::class.java) }
.sortedBy { it.priority }
.toCollection(targetList)
contract.updateViewContent()
}
override fun onCancelled(databaseError: DatabaseError) {
Log.d("some", "Error trying to get targets for ${databaseError.message}")
}
}
targetsRef?.addListenerForSingleValueEvent(valueEventListener)
}
fun getTargetsByDeadline() {
val valueEventListener = object : ValueEventListener {
override fun onDataChange(dataSnapshot: DataSnapshot) {
targetList.clear()
dataSnapshot.children
.mapNotNull { it.getValue(Goal::class.java) }
.sortedBy { it.deadline }
.toCollection(targetList)
contract.updateViewContent()
}
override fun onCancelled(databaseError: DatabaseError) {
Log.d("some", "Error trying to get targets for ${databaseError.message}")
}
}
targetsRef?.addListenerForSingleValueEvent(valueEventListener)
}
}
Optimization is the wrong word to describe the issue. The issue is repeating identical code (violating the DRY principle), which can be a problem because it invites error if you need to change something, and it's less readable.
In this case, it's not extreme, but I guess it could be improved somewhat. You can declare a class implementation of the listener that takes a parameter for how to sort the list.
class TargetsPresenter(private val contract: SelectTargetViewContract) {
//...
fun getTargetsFromDb() {
targetsRef?.addListenerForSingleValueEvent(MyValueEventListener<String>())
}
fun getTargetsByPriority() {
targetsRef?.addListenerForSingleValueEvent(MyValueEventListener(Goal::priority))
}
fun getTargetsByDeadline() {
targetsRef?.addListenerForSingleValueEvent(MyValueEventListener(Goal::deadline))
}
private inner class MyValueEventListener<R: Comparable<R>>(
private val sortCriteria: (Goal) -> R? = { null }
) : ValueEventListener {
override fun onDataChange(dataSnapshot: DataSnapshot) {
targetList.clear()
dataSnapshot.children
.mapNotNull { it.getValue(Goal::class.java) }
.sortedBy(sortCriteria)
.toCollection(targetList)
contract.updateViewContent()
}
override fun onCancelled(databaseError: DatabaseError) {
Log.d("some", "Error trying to get targets for ${databaseError.message}")
}
}
}

Can't display list of my targets with firebase

I add targets to the database this way:
private fun addTarget(name: String, description: String) {
if (!TextUtils.isEmpty(name)) {
val target = Target(guid = "some", name = name, description = description)
databaseReference?.child("users")
?.child(mUserId.toString())?.child("targets")?.push()?.setValue(target)
} else Log.d("some", "Enter a name")
}
And get the following structure in my firebase database:
Next, I try to display my list of targets in TargetsFragment
In onViewCreated i call next functions:
private fun updateListData() {
databaseReference = FirebaseDatabase.getInstance().getReference()
getTargetsFromDb()
}
private fun getTargetsFromDb() {
databaseReference?.child("users")?.child(mUserId.toString())?.
child("targets")?.addValueEventListener(object : ValueEventListener {
override fun onDataChange(dataSnapshot: DataSnapshot) {
for (targetSnapshot in dataSnapshot.children) {
val target = targetSnapshot.getValue(Target::class.java)
target?.let { targetList.add(it) }
}
recyclerView?.adapter = adapter
}
override fun onCancelled(databaseError: DatabaseError) {
Log.d("some", "Error trying to get targets for ${databaseError.message}")
}
})
}
As I said, because I cannot see what changes do you make, I wrote the code that can help you get the data from the database:
val uid = FirebaseAuth.getInstance().currentUser!!.uid
val rootRef = FirebaseDatabase.getInstance().reference
val targetsRef = rootRef!!.child("targets").child("users").child(uid).child("targets")
val valueEventListener = object : ValueEventListener {
override fun onDataChange(dataSnapshot: DataSnapshot) {
for (ds in dataSnapshot.children) {
val target = ds.getValue(Target::class.java)
targetList.add(target)
}
adapter.notifyDataSetChanged()
}
override fun onCancelled(databaseError: DatabaseError) {
Log.d(TAG, databaseError.getMessage()) //Don't ignore errors!
}
}
targetsRef.addListenerForSingleValueEvent(valueEventListener)
The output in the logcat will be:
uuuuu
yyyyy
Even if you are using two nodes with the same name targets, both should be mentioned in the reference.

LiveData Obserever catch only first value

I get list of issues from Firebase Database and return LiveData.
fun getAllIssues(): MutableLiveData<IssueEntity> {
val issues: MutableLiveData<IssueEntity> = MutableLiveData()
val issuesReference = FirebaseDatabase.getInstance().reference.child("issues")
issuesReference.addValueEventListener(object : ValueEventListener {
override fun onCancelled(p0: DatabaseError?) {
}
override fun onDataChange(snapshot: DataSnapshot?) {
if (snapshot == null) {
return
}
snapshot.children.forEach({
val issueMessage = it.child("message").value.toString()
val issueTitle = it.child("title").value.toString()
val issueOwner = it.child("owner").value.toString()
issues.postValue(IssueEntity(issueTitle, issueMessage, issueOwner))
})
}
})
return issues
}
Code of my Activity:
override fun onCreate(savedInstanceState: Bundle?) {
super.onCreate(savedInstanceState)
setContentView(R.layout.activity_all_issues)
val issues: MutableList<IssueEntity> = mutableListOf()
issuesList.adapter = IssuesAdapter(issues)
IssueRepository().getAllIssues().observe(this, Observer {
if (it != null) {
issues.add(it)
val issuesAdapter = issuesList.adapter as IssuesAdapter
issuesAdapter.notifyDataSetChanged()
}
})
}
But Observer gets only first value. Could you please tell me why?
Sorry for the confusion. I just need to return not just MutableLiveData and MutableLiveData>

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