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Button lose listener after fragment replace

I have the weirdest bug on Kotlin, and after two days of trying I finally asking for help.
The problem is simple : I have two fragment and one activity, the first fragment A is a form, with a validate button, when I click on validate, the fragment B replace the fragment A, and if I press back, the fragment A show up again with the form filled.
My problem is that after the fragment is shown again, I can click on the button but the listener is not call, so I can't go to the fragment B again. The strange thing is that the other listener are properly working, so I'm thinking it's because the previous fragment is catching the onClick, but idk what to do. Here is some code :
ViewUtils :
fun addFragment(activity: Activity, fragment: androidx.fragment.app.Fragment, container: Int) {
val fragmentManager = (activity as AppCompatActivity).supportFragmentManager
val pendingTransaction = fragmentManager.beginTransaction().add(container, fragment, fragment.javaClass.name)
pendingTransaction.commitAllowingStateLoss()
}
fun replaceFragment(manager: FragmentManager, fragment: androidx.fragment.app.Fragment, container: Int) {
if (fragment.isAdded) return
val pendingTransaction = mangaer.beginTransaction()
pendingTransaction.replace(container, fragment, fragment.javaClass.name)
pendingTransaction.commitAllowingStateLoss()
}
fun removeFragment(activity: Activity, fragment: Fragment) {
val manager = (activity as AppCompatActivity).supportFragmentManager
val trans = manager.beginTransaction()
trans.remove(fragment)
trans.commit()
manager.popBackStack()
}
Activity :
fun displayFragmentA() {
ViewUtils.replaceFragment(supportFragmentManager, FragmentA,
R.id.fragmentLayout)
}
fun FragmentB() {
ViewUtils.replaceFragment(supportFragmentManager, FragmentB,
R.id.fragmentLayout)
}
Fragment A
class AFragment : BaseFragment(), AContract.View {
companion object {
#JvmStatic
fun newInstance(): AFragment {
val fragment = AFragment()
return fragment
}
}
#Inject
lateinit var APresenter: AContract.Presenter<AContract.View>
//end region
//region lifecycle
override fun onCreateView(inflater: LayoutInflater, container: ViewGroup?,
savedInstanceState: Bundle?): View? {
return inflater.inflate(R.layout.fragment_A_layout, container, false)
}
override fun onResume() {
super.onResume()
button_validate.setOnClickListener {
presenter.goToNextStep()
}
}
override fun onAttach(context: Context) {
AndroidSupportInjection.inject(this)
super.onAttach(context)
}
The listener was set in the onViewCreated but I tried moving it to onResume (didn't change anything)
Fragment B code is not important I think, but I can add it if it helps.
Any help is welcome, I really don't know what's going on, the replace/add methods were there before I came to the project, they are not perfect but they are working elsewhere on the project.
I try using breakpoint, the button is not null but we never enter the listener.
Edit : I tried on 3 differents devices, I don't have the bug with a Sony Android 9, but with Huawei et One plus 6 Android 10, the problem persist ..

Ok so after asking to a lot of people, the only solution I found is not using kotlin.synthetic, and using findById instead :
view.findViewById<Button>(R.id.button_validate.setOnClickListener

ArcGIS map crashes under android ViewPager2

Dear StackOverflow Community!
My question might be a rookie one, I feel like I'm missing something very basic. I tried to make an ArcGIS map work under an android ViewPager2 structure. The map diplays nicely but when I navigate away to another fragment in the view pager, then back to the map, the app crashes with the following exception.
com.esri.arcgisruntime.ArcGISRuntimeException: vector:
/home/jenkins/100.7.0/dev_android_java_RTCA_release/runtimecore/c_api/src/mapping/map_view/geo_view.cpp(701) : error : Exception caught in __FUNCTION__
at com.esri.arcgisruntime.internal.jni.CoreGeoView.nativeDraw(Native Method)
at com.esri.arcgisruntime.internal.jni.CoreGeoView.a(SourceFile:346)
at com.esri.arcgisruntime.internal.h.b.o.a(SourceFile:132)
at com.esri.arcgisruntime.mapping.view.MapView.onDrawFrame(SourceFile:156)
at com.esri.arcgisruntime.mapping.view.GeoView$b.onDrawFrame(SourceFile:1363)
at android.opengl.GLSurfaceView$GLThread.guardedRun(GLSurfaceView.java:1573)
at android.opengl.GLSurfaceView$GLThread.run(GLSurfaceView.java:1272)
This seems to happen every time when the onResume() method of the Fragment containing the MapView is called. In this function (ie. the onResume()) I manually call onResume() on the MapView instance as indicated in this walkthrough:
https://developers.arcgis.com/labs/android/create-a-starter-app/
I extracted the problematic part of the code to a test app, I removed all layers, now it's just an empty basemap in an empty app (under the view pager structure) and the crash persists.
The reason why I think this problem could be connected with the ViewPager2 is because in a previous version of the app, I used a different navigation structure without the view pager and the map was working fine.
The difference between my actual code and the above walkthrough is that it puts the MapView directly under the MainActivity while I put it in a fragment as I'm working with a view pager.
It was not absolutely clear to me if I still have to put the appropriate onPause(), onResume(), onDestroy() calls under the fragment class or under the main activity so I tried both (you can see the former in the code below) and I also tried removing those override functions completely. The exception was the same in each case.
Here is the test app MainActivity class building the view pager.
class MainActivity : AppCompatActivity() {
private lateinit var adapter: ViewPagerFragmentAdapter
private lateinit var viewPager: ViewPager2
override fun onCreate(savedInstanceState: Bundle?) {
super.onCreate(savedInstanceState)
setContentView(R.layout.activity_main)
adapter = ViewPagerFragmentAdapter(supportFragmentManager, lifecycle)
viewPager = findViewById(R.id.view_pager)
viewPager.adapter = adapter
}
}
And the MapFragment class.
class MapFragment: Fragment() {
lateinit var mMapView: MapView
override fun onCreateView(
inflater: LayoutInflater,
container: ViewGroup?,
savedInstanceState: Bundle?
): View? {
val view = inflater.inflate(R.layout.fragment_map, container, false)
ArcGISRuntimeEnvironment.setLicense(resources.getString(R.string.arcgis_license_key))
mMapView = view.findViewById(R.id.map_view)
val basemapType = Basemap.Type.IMAGERY_WITH_LABELS
val latitude = 48.0166175
val longitude = 19.0339708
val levelOfDetail = 2
mMapView.map = ArcGISMap(basemapType, latitude, longitude, levelOfDetail)
return view
}
override fun onPause() {
if (mMapView != null) {
mMapView.pause()
}
super.onPause()
}
override fun onResume() {
super.onResume()
if (mMapView != null) {
mMapView.resume()
}
}
override fun onDestroy() {
if (mMapView != null) {
mMapView.dispose()
}
super.onDestroy()
}
}
Could you please give me any indicaton on where I could go wrong?
Thank you very much for any help in advance!
Mark

For anyone bumping into problems like this, always check your dependencies first :)
In my case, the ESRI lib was outdated. When I switched from the outdated dependency:
dependencies {
...
implementation 'com.esri.arcgisruntime:arcgis-android:100.7.0'
...
}
to the latest one:
dependencies {
...
implementation 'com.esri.arcgisruntime:arcgis-android:100.8.0'
...
}
the exception disappeared and the app works as expected.

Splash fragment wont display when using button.performClick()

edit: 2020.4.12 correct typo from Button.performClick() to button.performClick()
I am writing an app which should display a splash page/fragment for a
few seconds at start then display the next fragment in the navgraph. There are seven fragments in the navgraph which I can navigate around those fragments just fine.
The issue is with the splash fragment, I can only get the splash fragment to display/inflate when the button.onClickListener is set to accept a manual user
input -> click. (vs using button.performClick())
The desired end result is to display a fragment layout consisting of an image view and a text view for a few seconds at app start before displaying the next fragment layout in the navgraph, without having the user to click or press anything.
I have tried using threadsleep, a runnable with a handler, and even a while loop with performClick(). None of which have yielded acceptable results. The closest I have come to getting the desired result is the following:
class SplashFragment : Fragment() {
override fun onCreateView(inflater: LayoutInflater,
rootContainer: ViewGroup?,
savedInstanceState: Bundle?): View {
return inflater.inflater(R.layout.fragment_splash, rootContainer, false)
}
override fun onActivityCreated(savedInstanceState: Bundle?) {
super.onActivityCreated(savedInstanceState)
button.setOnClickListener {
updateABode()
}
// pizzaLoop initialized to give about 4 seconds delay
val pizzaLoop = 1500000000
while (pizzaLoop > 0) {
pizzaLoop--
if (pizzaLoop == 0) {
button.performClick()
}
}
private fun updateABode {
val ABode = "A" // hard coded for testing purposes
when (ABode) {
"B" -> // for testing purposes only -- does nothing
"A" -> findNavController().navigate(R.id.action_splashFragment_to_firmwareFragment)
}
}
}
With the pizzaLoop installed, the splash fragment will not inflate, but I do see the delay via the firmware screen update. (intially all I get is a white blank screen then subsequent calls to the SplashFragment class show nothing but the firmwareFragment screen (next in the navgraph) -- and the pizzaLoop delay is noticable).
When I comment out the pizzaLoop then the splash fragment displays as intended but I have to click the button to bring up the next fragment in the navgraph (the rest of the navgraph works fine).
It's like the button.performClick() method is preventing the inflation of the splash fragment.

EDIT: 2020.4.12 TO PROPERLY POST SOLUTION.
class SplashFragment : Fragment() {
private val handler: Handler = Handler()
private val updateRunnable: Runnable = Runnable { updateABode() }
override fun onCreateView(inflater: LayoutInflater,
rootContainer: ViewGroup?,
savedInstanceState: Bundle?): View {
return inflater.inflater(R.layout.fragment_splash, rootContainer, false)
}
override fun onActivityCreated(savedInstanceState: Bundle?) {
super.onActivityCreated(savedInstanceState)
button.setOnClickListener {
handler.removeCallbacks(updateRunnable)
}
handler.postDelayed(updateRunnable, 4000)
}
private fun updateABode {
val ABode = "A" // hard coded for testing purposes
when (ABode) {
"B" -> // for testing purposes only -- does nothing
"A" -> findNavController().navigate(R.id.action_splashFragment_to_firmwareFragment)
}
}
}

Retaining Int after view gets destroyed

I am using a gridlayout in a fragment on which the user can switch the amount of items shown per line (by pressing a button he can switch currently between 6 and 4 but might extend on adding a third option).
When the user leaves the the fragment (switches to another fragment) and comes back later, I want to retain the information of how many items per line are shown.
After having tried different options (savedInstanceState: doesn't work as the activity is never recreated, getArguments: not a feasible option afaik, as I have to pass the information several times) I am using a sharedViewModel that is implemented anyways as some of information is observed.
I feel like it's an overkill, as it is "just" an int (or even a bool, if there are just 2 states) and there might be a more simple ("built in"?) solution which might be similiar to activity's savedInstanceState.
Here is some code:
Fragment with GridLayout
class LibraryFragment : Fragment() {
private val model: SharedViewModel by activityViewModels()
private lateinit var gridlayoutManager: GridLayoutManager
private lateinit var thumbnailAdapter: ThumbnailAdapter
private lateinit var thumbnailRecyclerView: RecyclerView
private var booksPerLine = 4
override fun onCreateView(
inflater: LayoutInflater,
container: ViewGroup?,
savedInstanceState: Bundle?
): View? {
_binding = FragmentLibraryViewerBinding.inflate(layoutInflater)
val view = libraryFragmentBinding.root
initRecyclerView()
return view
}
override fun onViewCreated(view: View, savedInstanceState: Bundle?) {
super.onViewCreated(view, savedInstanceState)
model.booksPerLine.observe(viewLifecycleOwner, Observer {
booksPerLine = it
switchNoOfBooksPerLine()
})
}
private fun initRecyclerView() {
thumbnailRecyclerView = libraryFragmentBinding.thumbnailRecyclerView
switchNoOfBooksPerLine()
thumbnailAdapter = ThumbnailAdapter { selectedBook: Book -> displaySelectedBook(selectedBook) }
thumbnailAdapter.setThumbnailList(listOf())
thumbnailRecyclerView.adapter = thumbnailAdapter
}
private fun switchNoOfBooksPerLine() {
gridlayoutManager = GridLayoutManager(requireContext(), booksPerLine, LinearLayoutManager.VERTICAL, false)
thumbnailRecyclerView.layoutManager = gridlayoutManager
}
override fun onOptionsItemSelected(item: MenuItem): Boolean {
return when (item.itemId) {
R.id.change_grid -> {
when (booksPerLine) {
4 -> model.setBooksPerLine(6)
6 -> model.setBooksPerLine(4)
}
true
}
}
}
}
SharedViewModel with grid information
class SharedViewModel : ViewModel() {
val booksPerLine = MutableLiveData<Int>()
internal fun setBooksPerLine(_booksPerLine: Int) {
booksPerLine.value = _booksPerLine
}
}
So the questions is, if there is a more simple/efficient way of retaining the Int? (bonus question: how efficient (in terms of ressource usage like memory) is a SharedViewModel actually?
Is there a built in method like savedInstanceState for activities for fragments, too?

I would suggest to keep the data in the activity. And in fragment get the data from activity in onViewCreated method like-
val data = (activity as MyActivity)?.data
Also, put back the data into the activity the other way when data changed-
(activity as MyActivity)?.data = changedData
This is the manual way. Keep in mind the data is nullable.

Fragment loses listener at orientation change

I have an activity using fragments. To communicate from the fragment to the activity, I use interfaces. Here is the simplified code:
Activity:
class HomeActivity : AppCompatActivity(), DiaryFragment.IAddEntryClickedListener, DiaryFragment.IDeleteClickedListener {
override fun onAddEntryClicked() {
//DO something
}
override fun onEntryDeleteClicked(isDeleteSet: Boolean) {
//Do something
}
private val diaryFragment: DiaryFragment = DiaryFragment()
override fun onCreate(savedInstanceState: Bundle?) {
super.onCreate(savedInstanceState)
setContentView(R.layout.activity_home)
diaryFragment.setOnEntryClickedListener(this)
diaryFragment.setOnDeleteClickedListener(this)
supportFragmentManager.beginTransaction().replace(R.id.content_frame, diaryFragment)
}
}
The fragment:
class DiaryFragment: Fragment() {
private var onEntryClickedListener: IAddEntryClickedListener? = null
private var onDeleteClickedListener: IDeleteClickedListener? = null
override fun onCreateView(inflater: LayoutInflater, container: ViewGroup?, savedInstanceState: Bundle?): View? {
val view: View = inflater.inflate(R.layout.fragment_diary, container, false)
//Some user interaction
onDeleteClickedListener!!.onEntryDeleteClicked()
onDeleteClickedListener!!.onEntryDeleteClicked()
return view
}
interface IAddEntryClickedListener {
fun onAddEntryClicked()
}
interface IDeleteClickedListener {
fun onEntryDeleteClicked()
}
fun setOnEntryClickedListener(listener: IAddEntryClickedListener) {
onEntryClickedListener = listener
}
fun setOnDeleteClickedListener(listener: IDeleteClickedListener) {
onDeleteClickedListener = listener
}
}
This works, but when the fragment is active and the orientation changes from portrait to landscape or otherwise, the listeners are null. I can't put them to the savedInstanceState, or can I somehow? Or is there another way to solve that problem?

Your Problem:
When you switch orientation, the system saves and restores the state of fragments for you. However, you are not accounting for this in your code and you are actually ending up with two (!!) instances of the fragment - one that the system restores (WITHOUT the listeners) and the one you create yourself. When you observe that the fragment's listeners are null, it's because the instance that has been restored for you has not has its listeners reset.
The Solution
First, read the docs on how you should structure your code.
Then update your code to something like this:
class HomeActivity : AppCompatActivity(), DiaryFragment.IAddEntryClickedListener, DiaryFragment.IDeleteClickedListener {
override fun onAddEntryClicked() {
//DO something
}
override fun onEntryDeleteClicked(isDeleteSet: Boolean) {
//Do something
}
// DO NOT create new instance - only if starting from scratch
private lateinit val diaryFragment: DiaryFragment
override fun onCreate(savedInstanceState: Bundle?) {
super.onCreate(savedInstanceState)
setContentView(R.layout.activity_home)
// Null state bundle means fresh activity - create the fragment
if (savedInstanceState == null) {
diaryFragment = DiaryFragment()
supportFragmentManager.beginTransaction().replace(R.id.content_frame, diaryFragment)
}
else { // We are being restarted from state - the system will have
// restored the fragment for us, just find the reference
diaryFragment = supportFragmentManager().findFragment(R.id.content_frame)
}
// Now you can access the ONE fragment and set the listener on it
diaryFragment.setOnEntryClickedListener(this)
diaryFragment.setOnDeleteClickedListener(this)
}
}
Hope that helps!

the short answer without you rewriting your code is you have to restore listeners on activiy resume, and you "should" remove them when you detect activity losing focus. The activity view is completely destroyed and redrawn on rotate so naturally there will be no events on brand new objects.
When you rotate, "onDestroy" is called before anything else happens. When it's being rebuilt, "onCreate" is called. (see https://developer.android.com/guide/topics/resources/runtime-changes)
One of the reasons it's done this way is there is nothing forcing you to even use the same layout after rotating. There could be different controls.
All you really need to do is make sure that your event hooks are assigned in OnCreate.
See this question's answers for an example of event assigning in oncreate.
onSaveInstanceState not working