I'm using Navigation component in one of project which is having bottom navigation view with three menu items(for example home,profile and about). Landing page of my app is home fragment(for example) at which one API is called(in onCreateView() method) to get user lists; its working fine but whenever user navigates to some other page like profile and come back means again API gets called in home fragment.
I referred this link - https://github.com/googlesamples/android-architecture-components.git
class Home : Fragment() {
override fun onCreateView(inflater: LayoutInflater, container: ViewGroup?,
savedInstanceState: Bundle?): View? {
// Inflate the layout for this fragment
val view = inflater.inflate(R.layout.fragment_home, container, false)
view.findViewById<Button>(R.id.signup_btn).setOnClickListener {
findNavController().navigate(R.id.action_home_to_registered)
}
callUserListApi()
return view
}
private fun callUserListApi() {
val client = ServiceGenerator.getApiService(requireContext()).getJsonbyWholeUrl("http://dummy.restapiexample.com/api/v1/employees")
client.enqueue(object : Callback<JsonArray> {
override fun onFailure(call: Call<JsonArray>, t: Throwable) {
println("callUserListApi onFailure ${t.message}")
}
override fun onResponse(call: Call<JsonArray>, response: Response<JsonArray>) {
println("callUserListApi onResponse ${response.isSuccessful}")
}
})
}
}
Using navigation componentthe fragment were recreate every time when you select the tab. So here i've inflate fragment if my view is null when come back to those fragment at that moment view is not null so fragment should not recreate.
private var homeFragment: View? = null
override fun onCreateView(inflater: LayoutInflater, container: ViewGroup?, savedInstanceState: Bundle?): View? {
if (view == null){
homeFragment = inflater.inflate(R.layout.fragment_home, container, false)
callUserListApi()
}
return view
}
Using the Navigation component, the Fragment were recreated each time the it was selected on the navigation, meaning the onCreateView() is called that includes youre callUserListApi()
Since you are using AAC, you can create a ViewModel on your activity and initialize it, then re-initializing it from the Home(Fragment). Add a MutableLiveData() variable which you can check if you alread called callUserListApi().
Dont forget to call it inside onActivityCreated()
On Home
override fun onActivityCreated(savedInstanceState: Bundle?) {
super.onActivityCreated(savedInstanceState)
mainActivityViewModel.calledUserList.observe(viewLifecycleOwner, Observer {
if(it != true) {
callUserListApi()
}
})
}
private fun callUserListApi() {
val client = ServiceGenerator.getApiService(requireContext()).getJsonbyWholeUrl("http://dummy.restapiexample.com/api/v1/employees")
client.enqueue(object : Callback<JsonArray> {
override fun onFailure(call: Call<JsonArray>, t: Throwable) {
println("callUserListApi onFailure ${t.message}")
}
override fun onResponse(call: Call<JsonArray>, response: Response<JsonArray>){
println("callUserListApi onResponse ${response.isSuccessful}")
mainActivityViewModel.setCalledUserList(true)
}
})
}
Inside youre MainActivityViewModel
val _calledUserList = MutableLiveData<Boolean?>()
val calledUserList = _calledUserList
fun setCalledUserList(bool: Boolean?) {
_calledUserList.value = bool
}
Related
GameActivity
____FragmentQuest
____FragmentFight
class MapLvl.kt
this is a text RPG Fragment Quest displays a journey through different maps (changing the content in one fragment according to a template) text, pictures, navigation buttons. if there is a mob on the map, then the "Fight" button appears and a fragment of the turn-based fight FightFragment opens (hit the head \ legs\ body protect the head \ legs\ body). after the battle, return to QuestFragment
class MapLvl fills with the content of FightFragment
I need to change QuestFragment from classLvl to FightFragment. how to do it?
it doesn't work:
class MapLvl.kt:
class MapLevels(){
fun changeLvl (bind: FragmentQuestBinding,hero: Hero, activity: GameActivity,db: Maindb) {
when (hero.mapLvl) {
1 -> MapLevels().mapLevel1(bind, activity, hero, db)
2 -> MapLevels().mapLevel2(bind, activity, hero,db)
else -> {}
}
}
fun mapLevel2 (bind: FragmentQuestBinding,activity: GameActivity,hero:Hero,db: Maindb) {
bind.btnAtack.visibility= View.VISIBLE
//the problem is here:
bind.btnAtack.setOnClickListener {
(activity as GameActivity).supportFragmentManager
.beginTransaction()
.replace(R.id.placeHolder,FightFragment.newInstance())
.commit()
}
}
}
error: FragmentManager has not been attached to a host
QuestFragment:
class QuestFragment : Fragment() {
lateinit var bind:FragmentQuestBinding
override fun onCreateView(
inflater: LayoutInflater, container: ViewGroup?,
savedInstanceState: Bundle?,
): View {
bind = FragmentQuestBinding.inflate(inflater)
return bind.root
}
override fun onViewCreated(view: View, savedInstanceState: Bundle?) {
super.onViewCreated(view, savedInstanceState)
val hero = Hero()
val db = Maindb.heroSetDb(requireActivity())
hero.extractHeroData(db,hero)
scopeMain.launch {
delay(50)
MapLevels().changeLvl(bind,hero,GameActivity(),db)
}
if you make a call directly from a Fragment, then it works: (but it is necessary not from the fragment but from the class)
QuestFragment:
class QuestFragment : Fragment() {
lateinit var bind:FragmentQuestBinding
override fun onCreateView(
inflater: LayoutInflater, container: ViewGroup?,
savedInstanceState: Bundle?,
): View {
bind = FragmentQuestBinding.inflate(inflater)
return bind.root
}
override fun onViewCreated(view: View, savedInstanceState: Bundle?) {
super.onViewCreated(view, savedInstanceState)
val hero = Hero()
val db = Maindb.heroSetDb(requireActivity())
hero.extractHeroData(db,hero)
scopeMain.launch {
delay(50)
MapLevels().changeLvl(bind,hero,GameActivity(),db)
}
bind.btnAtack.setOnClickListener {
(activity as GameActivity).supportFragmentManager
.beginTransaction()
.replace(R.id.placeHolder,FightFragment.newInstance())
.commit()
}
it Work:
class MapLevels(val bind: FragmentQuestBinding,
val hero: Hero,
val db: Maindb,
val activity: FragmentActivity ){
fun changeLvl() {
when (hero.mapLvl) {
1 -> MapLevels(bind,hero,db,activity).mapLevel1()
2 -> MapLevels(bind,hero,db,activity).mapLevel2()
else -> {}
}
}
fun mapLevel2() {
bind.imgLocation.setImageResource(R.drawable.map_loc02)
bind.txtLocationDiscription.text ="text"
bind.btnAtack.visibility= View.VISIBLE
bind.btnAtack.setOnClickListener {
(activity as FragmentActivity).supportFragmentManager
.beginTransaction()
.replace(R.id.placeHolder,FightFragment.newInstance())
.commit()
MapLevels().changeLvl(bind,hero,GameActivity(),db)
It looks like you are creating a new GameActivity instance to pass to your changeLvl() method. YOU SHOULD NEVER DO THIS. The new activity is NOT the same one that currently is displayed on the screen. Instead, you should use the requireAcitivty() to get the fragment's parent activity:
MapLevels().changeLvl(bind,hero,requireActivity(),db)
I can't be sure this will fix your current problem because I'm not even sure what the problem is exactly. But it is one issue that you need to change.
I have a fragment called MainFragment that contains a ViewPager that contains another fragment called LibraryFragment.
LibraryFragment contains a RecyclerView with a list of items that contain an ImageView. The ImageView's contents are loaded with Coil.
When an item is clicked, LibraryFragment navigates to another fragment called ArtistDetailFragment and uses the ImageView from the item.
The problem is that while the enter transition works fine, the ImageView does not return to the list item when navigating back and only fades away. Ive attached an example below:
Ive tried using postponeEnterTransition() and startPostponedEnterTransition() along with adding a SharedElementCallback but neither have worked that well. I've also ruled out Coil being the issue.
Heres LibraryFragment:
class LibraryFragment : Fragment() {
private val musicModel: MusicViewModel by activityViewModels()
private val libraryModel: LibraryViewModel by activityViewModels()
private lateinit var binding: FragmentLibraryBinding
override fun onCreateView(
inflater: LayoutInflater,
container: ViewGroup?,
savedInstanceState: Bundle?
): View? {
binding = FragmentLibraryBinding.inflate(inflater)
binding.libraryRecycler.adapter = ArtistAdapter(
musicModel.artists.value!!,
BindingClickListener { artist, itemBinding ->
navToArtist(artist, itemBinding)
}
)
return binding.root
}
private fun navToArtist(artist: Artist, itemBinding: ItemArtistBinding) {
// When navigation, pass the artistImage of the item as a shared element to create
// the image popup.
findNavController().navigate(
MainFragmentDirections.actionShowArtist(artist.id),
FragmentNavigatorExtras(
itemBinding.artistImage to itemBinding.artistImage.transitionName
)
)
}
}
Heres ArtistDetailFragment:
class ArtistDetailFragment : Fragment() {
override fun onCreateView(
inflater: LayoutInflater,
container: ViewGroup?,
savedInstanceState: Bundle?
): View? {
val binding = FragmentArtistDetailBinding.inflate(inflater)
sharedElementEnterTransition = TransitionInflater.from(requireContext())
.inflateTransition(android.R.transition.move)
val musicModel: MusicViewModel by activityViewModels()
val artistId = ArtistDetailFragmentArgs.fromBundle(requireArguments()).artistId
// Get the transition name used by the recyclerview ite
binding.artistImage.transitionName = artistId.toString()
binding.artist = musicModel.artists.value?.find { it.id == artistId }
return binding.root
}
}
And heres the RecyclerView Adapter/ViewHolder:
class ArtistAdapter(
private val data: List<Artist>,
private val listener: BindingClickListener<Artist, ItemArtistBinding>
) : RecyclerView.Adapter<ArtistAdapter.ViewHolder>() {
override fun getItemCount(): Int = data.size
override fun onCreateViewHolder(parent: ViewGroup, viewType: Int): ViewHolder {
return ViewHolder(
ItemArtistBinding.inflate(LayoutInflater.from(parent.context))
)
}
override fun onBindViewHolder(holder: ViewHolder, position: Int) {
holder.bind(data[position])
}
// Generic ViewHolder for an artist
inner class ViewHolder(
private val binding: ItemArtistBinding
) : RecyclerView.ViewHolder(binding.root) {
// Bind the view w/new data
fun bind(artist: Artist) {
binding.artist = artist
binding.root.setOnClickListener { listener.onClick(artist, binding) }
// Update the transition name with the new artist's ID.
binding.artistImage.transitionName = artist.id.toString()
binding.executePendingBindings()
}
}
}
EDIT: I used postponeEnterTransition and startPostponedEnterTransition like this:
// LibraryFragment
override fun onResume() {
super.onResume()
postponeEnterTransition()
// Refresh the parent adapter to make the image reappear
binding.libraryRecycler.adapter = artistAdapter
// Do the Pre-Draw listener
binding.libraryRecycler.viewTreeObserver.addOnPreDrawListener {
startPostponedEnterTransition()
true
}
}
This only makes the RecyclerView itself refresh however, the shared element still fades away instead of returning to the RecyclerView item.
Chris Banes says;
You may wonder why we set the OnPreDrawListener on the parent rather than the view itself. Well that is because your view may not actually be drawn, therefore the listener would never fire and the transaction would sit there postponed forever. To work around that we set the listener on the parent instead, which will (probably) be drawn.
https://chris.banes.dev/fragmented-transitions/
try this;
change
// LibraryFragment
override fun onResume() {
super.onResume()
postponeEnterTransition()
// Refresh the parent adapter to make the image reappear
binding.libraryRecycler.adapter = artistAdapter
// Do the Pre-Draw listener
binding.libraryRecycler.viewTreeObserver.addOnPreDrawListener {
startPostponedEnterTransition()
true
}
}
enter code here
to
override fun onCreateView(
inflater: LayoutInflater,
container: ViewGroup?,
savedInstanceState: Bundle?
): View? {
postponeEnterTransition()
binding = FragmentLibraryBinding.inflate(inflater)
binding.libraryRecycler.adapter = ArtistAdapter(
musicModel.artists.value!!,
BindingClickListener { artist, itemBinding ->
navToArtist(artist, itemBinding)
}
)
(view?.parent as? ViewGroup)?.doOnPreDraw {
// Parent has been drawn. Start transitioning!
startPostponedEnterTransition()
}
return binding.root
}
I am using BottomSheet Dialog from a fragment. I want to reload fragment data after bottomsheet close.
I am trying by adding reload code in onResume method. But it is not working.
Here My BottomSheet Dialog code.
class LoopResponseDialogueFragment : BottomSheetDialogFragment() {
override fun onCreateView(inflater: LayoutInflater, container: ViewGroup?, savedInstanceState: Bundle?) =
inflater.inflate(R.layout.fragment_loop_response_dialog, container, false)!!
override fun onViewCreated(view: View, savedInstanceState: Bundle?) {
super.onViewCreated(view, savedInstanceState)
var progressDialog = ProgressDialog(context)
acceptButton.setOnClickListener {
priyoLoopService.sendLoopResponse(LoopActionRequest(user.id, "accept"))
.enqueue(object : Callback<GenericLoopResponse> {
override fun onFailure(call: Call<GenericLoopResponse>, t: Throwable) {
}
override fun onResponse(
call: Call<GenericLoopResponse>,
response: Response<GenericLoopResponse>
) {
dismiss()
}
})
}
}
You can create an interface in your LoopResponseDialogueFragment class and use it inside your fragment. Override onDismiss() and onCancel() function and call the interface function.
LoopResponseDialogueFragment Code:
class LoopResponseDialogueFragment : BottomSheetDialogFragment() {
private lateinit var onBottomSheetCloseListener:OnBottomSheetCloseListener
interface OnBottomSheetCloseListener{
fun onBottomSheetClose()
}
fun setOnBottomSheetCloseListener(listener:OnBottomSheetCloseListener) {
onBottomSheetCloseListener = listener
}
// rest of the code
override fun onDismiss(dialog: DialogInterface)
{
super.dismiss(dialog)
listener.onBottomSheetClose()
}
}
Now in your fragment before calling show method, call setOnBottomSheetCloseListener()
In your Fragment:
dialog.setOnBottomSheetCloseListener(object: OnBottomSheetCloseListener{
override fun onBottomSheetClose()
{
//refresh your data here
}
})
You can add code to refresh the fragment data inside onBottomSheetClose method.
Im using ViewModel with states and LiveData with one observer .
I have an activity and a fragment . everything works fine until Im rotating the screen
and then, the states I want to observe , clash.
What can I do in order to prevent it and make it work as expected?
I know I can add more observers but I don't want to solve it in this way , it may lead to problems with the other code.
MainActivity code :
private var appsDetailsHmap = HashMap< String , AppsDetails>()
override fun onCreate(savedInstanceState: Bundle?) {
super.onCreate(savedInstanceState)
setContentView(R.layout.activity_main)
progressBar = CircleProgressBarDialog(this)
viewModel.getState().observe(this, Observer {state->
when(state){
is SettingsViewModelStates.GetAppsDetails->initUI(state.list)
is SettingsViewModelStates.ShowDialog->progressBar.showOrHide(state.visibility)
is SettingsViewModelStates.GetCachedData->setCachedSettings(state.appDetailsHmap,state.selectedApp,state.speechResultAppName)
}
})
if (savedInstanceState==null){
viewModel.initSettingsActivityUI(appsDetailsHmap)
}
else{
viewModel.initCachedSettingsActivityUI()
}
Fragment code
override fun onCreateView(
inflater: LayoutInflater, container: ViewGroup?,
savedInstanceState: Bundle?
): View? {
// Inflate the layout for this fragment
val view= inflater.inflate(R.layout.fragment_added_apps, container, false)
viewModel.getCachedApplist()
return view
}
override fun onViewCreated(view: View, savedInstanceState: Bundle?) {
super.onViewCreated(view, savedInstanceState)
viewModel.getState().observe(viewLifecycleOwner, Observer {state->
when(state){
is SettingsViewModelStates.PassAppsToFragment->{
initRecyclerView(state.list)
}
}
})
}
ViewModel
private var state=MutableLiveData<SettingsViewModelStates>()
private var appsDetailsHmap=HashMap<String,AppsDetails>()
private var addedApps= HashMap<String,Drawable?>()
fun getState()=state as LiveData<SettingsViewModelStates>
fun getCachedApplist(){
if (addedApps.isEmpty()){
getAppsList()
println("empty")
}
else
state.setValue(SettingsViewModelStates.PassAppsToFragment(addedApps))
}
fun initCachedSettingsActivityUI(){
state.setValue(SettingsViewModelStates.GetCachedData(appsDetailsHmap,selectedApp,speechResultAppName))
}
fun initSettingsActivityUI(list:HashMap<String, AppsDetails>) {
appsDetailsHmap=list
state.setValue( SettingsViewModelStates.GetAppsDetails(list))
}
states:
sealed class SettingsViewModelStates {
data class GetAppsDetails(val list:HashMap<String, AppsDetails>):SettingsViewModelStates()
data class ShowDialog(val visibility: Int) : SettingsViewModelStates()
data class PassAppsToFragment(val list:HashMap<String,Drawable?>) : SettingsViewModelStates()
data class GetCachedData(val appDetailsHmap:HashMap<String,AppsDetails>,
val selectedApp: AppsDetails,
val speechResultAppName:String ) : SettingsViewModelStates()
}
I'm currently using a ViewPager and TabLayout for a couple of similar fragments. The fragments hosted within the ViewPager all have a RecyclerView. When I swipe more than one page over, the Fragment (I think?) is destroyed. When I swipe back it's recreated.
Upon debugging, I found that the adapter within the Fragment is non null and populated with the data from before. However, once the fragment is visible it no longer displays any entries.
Here's a video of what's going on.
This is a fragment within the ViewPager
class ArtistListFragment : Fragment(), ListView {
override val title: String
get() = "Artists"
private val artistList: RecyclerView by lazy { artist_list }
#Inject lateinit var api: SaddleAPIManager
override fun onCreateView(inflater: LayoutInflater, container: ViewGroup?, savedInstanceState: Bundle?): View?
= container?.inflate(R.layout.fragment_list_artist)
override fun onViewCreated(view: View, savedInstanceState: Bundle?) {
super.onViewCreated(view, savedInstanceState)
artistList.apply {
setHasFixedSize(true)
if (adapter == null) {
adapter = ViewTypeAdapter(mapOf(AdapterConstants.ARTIST to ArtistDelegateAdapter()))
}
layoutManager = LinearLayoutManager(context)
if (savedInstanceState != null && savedInstanceState.containsKey("artist")) {
(adapter as ViewTypeAdapter).setItems(savedInstanceState.getParcelableArrayList<Artist>("artists"))
}
}
(activity?.application as SaddleApplication).apiComponent.inject(this)
refreshData()
}
override fun onSaveInstanceState(outState: Bundle) {
super.onSaveInstanceState(outState)
outState.putParcelableArrayList(
"artists",
(artistList.adapter as ViewTypeAdapter).items as ArrayList<out Parcelable>
)
}
private fun refreshData() = launch(UI) {
val result = withContext(CommonPool) { api.getArtists() }
when(result) {
is Success -> (artistList.adapter as ViewTypeAdapter).setItems(result.data.results)
is Failure -> Snackbar.make(artistList, result.error.message ?: "Error", Snackbar.LENGTH_LONG).show()
}
}
}
This is the Fragment hosting the ViewPager
class NavigationFragment : Fragment() {
private val viewPager: ViewPager by lazy { pager }
private val tabLayout: TabLayout by lazy { tab_layout }
override fun onCreateView(inflater: LayoutInflater, container: ViewGroup?, savedInstanceState: Bundle?): View?
= container?.inflate(R.layout.fragment_navigation)
override fun onViewCreated(view: View, savedInstanceState: Bundle?) {
super.onViewCreated(view, savedInstanceState)
viewPager.apply {
adapter = NavigationPageAdapter(childFragmentManager)
}
tabLayout.apply {
setupWithViewPager(viewPager)
}
}
}
The adapter I'm using for paging
class NavigationPageAdapter(fragmentManager: FragmentManager) : FragmentStatePagerAdapter(fragmentManager) {
companion object {
const val NUM_PAGES = 4
}
private val pages: List<Fragment> = (0 until NUM_PAGES).map {
when (it) {
0 -> ArtistListFragment()
1 -> AlbumListFragment()
2 -> TrackListFragment()
else -> PlaylistListFragment()
} as Fragment
}
override fun getItem(position: Int): Fragment = pages[position]
override fun getCount(): Int = NUM_PAGES
override fun getPageTitle(position: Int): CharSequence? = (pages[position] as ListView).title
}
I've tried overriding onSaveInstanceState and reading the information from the bundle. It doesn't seem to do anything. The problem seems to actually be the RecyclerView displaying? It's populated with data which is why I'm stumped.
Try to use setOffscreenPageLimit for ViewPager to keep containing fragments as below:
viewPager.setOffscreenPageLimit(NavigationPageAdapter.NUM_PAGES)
I've figured out the problem. While setOffScreenPageLimit(NavigationAdapter.NUM_PAGES) did work, I am cautious to use it because of memory consumption concerns.
As it turns out, storing references to views using lazy is bad practice. Since onCreateView gets called many times in the lifecycle of the ArtistListFragment the same view wasn't being referenced that was currently inflated on the screen.
Removing all lazy instantiated views and accessing them directly with the Android Extensions solved my problem.