Develop Reference

Summary doesn't persists on dynamically load data in ListPreference

In my SettingActivity I'm loading some data to be shown in ListPreference from Room, once the items are selected all works correctly, the value is saved to `SharedPreferences and the summary is shown correctly, but once I return to SettingsActivity the summary value is reset to null.
Here is what is happening:
My code is pretty simple, onViewCreated() I start observing LiveData to be shown in ListPreference and then I set the values for entries and entryValues
override fun onViewCreated(view: View, savedInstanceState: Bundle?) {
super.onViewCreated(view, savedInstanceState)
viewModel.shops.observe(viewLifecycleOwner) {
setShopsPreferences(it)
}
}
private fun setShopsPreferences(shops: List<Shop>) {
val shopsPreference = preferenceManager.findPreference<ListPreference>("defaultShop")
if (shops.isEmpty()) {
shopsPreference?.isEnabled = false
return
} else {
shopsPreference?.isEnabled = true
}
val entries: ArrayList<String> = ArrayList()
val entryValues: ArrayList<String> = ArrayList()
shops.forEach {
entries.add(it.description)
entryValues.add(it.id)
}
shopsPreference?.entryValues = entryValues.toArray(arrayOfNulls<CharSequence>(entryValues.size))
shopsPreference?.entries = entries.toArray(arrayOfNulls<CharSequence>(entries.size))
}
ViewModel:
#HiltViewModel
class ShopsViewModel #Inject constructor(repository: ShopsRepository) : ViewModel() {
private val _shops = MutableLiveData<List<Shop>>()
val shops: LiveData<List<Shop>> = _shops
init {
repository.getAllShops().observeForever {
_shops.value = it
}
}
}
Repository:
fun getAllShops(): LiveData<List<Shop>> {
return shops.select()
}
DAO:
#Dao
interface ShopsDAO {
#Query("SELECT * FROM shops")
fun select(): LiveData<List<Shop>>
}

You are populating list entries dynamically after the preference hierarchy is already created by inflating the xml. But during that time there was no entry, hence the value was null. The data was then retrieved asynchronously but the change will not be reflected. So you have to set the summary manually.
Another approach I'm not sure about is to call recreate on the activity after populating the data inside the observer listener.

To resolve the issue with dynamic data in a ListPreference I've made some changes to my code, first of call in onCreatePreferences() I've added a preference listener to my ListPreference like this:
override fun onCreatePreferences(savedInstanceState: Bundle?, rootKey: String?) {
setPreferencesFromResource(R.xml.root_preferences, rootKey)
val shopsPreference = preferenceManager.findPreference<ListPreference>("defaultShop")
shopsPreference?.setOnPreferenceChangeListener { preference, newValue ->
val description = viewModel.shops.value?.find { it.id == newValue }
preference.summary = description?.description
true
}
}
So in that way on each new selection, I'm looking for the matching value for that preference in my ViewModel and getting the description for it which then is set as the summary.
While to set the summary every time the list has been changed or the SettingsActivity is opened I've added the following code to my setShopsPreferences() function:
private fun setShopsPreferences(shops: List<Shop>?) {
if (shops == null) {
return
}
val shopsPreference = preferenceManager.findPreference<ListPreference>("defaultShop")
// The preference is enabled only if there are shows inside the list
shopsPreference?.isEnabled = shops.isNotEmpty()
// Getting the defaultShop preference value, which will be used to find the actual shop description
val defaultShop = sharedPreferences.getString("defaultShop", "0")
defaultShop?.let { shopId ->
// Setting the summary based on defaultShop saved preference
shopsPreference?.summary = shops.find { it.id == shopId }?.description
}
val entries: ArrayList<String> = ArrayList()
val entryValues: ArrayList<String> = ArrayList()
shops.forEach {
entries.add(it.description)
entryValues.add(it.id)
}
shopsPreference?.entryValues =
entryValues.toArray(arrayOfNulls<CharSequence>(entryValues.size))
shopsPreference?.entries = entries.toArray(arrayOfNulls<CharSequence>(entries.size))
}

Progressbar not updating after Redux Event

I know this question has been asked quite often here, but non of the answers helped me.
I am writting a gallery app with a thumbes-regeneration feature. In oder to show the progress i added the progressbar which should count the number of created thumbnails. After each finished thumbnail-generation i dispatch a Redux event and listen to it in my Fragement, in order to change the progressbar.
Generating all thumbnails for all visible photos/videos
private fun onMenuRefreshThumbs(activity: Activity) {
val mediaPath = Redux.store.currentState.mediaPath
val fileRepository = FileRepository(context = activity, mediaPath = mediaPath)
activity.runOnUiThread {
fileRepository.regenerateThumbs(activity)
}
}
Functions inside the above used FileRepository:
fun regenerateThumbs(context: Context) {
val success = File(getAbsoluteThumbsDir(context, mediaPath)).deleteRecursively()
getMediaItems()
}
fun getMediaItems(): MediaItemList {
val success = File(thumbPath).mkdirs()
val isThumbsEmpty = File(thumbPath).listFiles().isEmpty()
val mediaFileList = File(mediaPath).listFiles().
.sortedByDescending { it.lastModified() }
val list = MediaItemList()
mediaFileList.apply {
forEach {
list.add(MediaItem(it.name, 0, 0))
if (isThumbsEmpty) {
getOrCreateThumb(it)
Redux.store.dispatch(FileUpdateAction(it))
}
}
}
return list
}
Subscribing to Redux in the Fragement:
private fun subscribeRedux() {
val handler = Handler(Looper.getMainLooper())
val activity = requireActivity()
subscriber = { state: AppState ->
when (state.action) {
...
is ClearSelection -> {
progressCounter = 0
// fragment_gallery_progress.visibility = View.GONE
}
is FileUpdateAction -> {
Handler().post {
progressCounter++
fragment_gallery_progress.visibility = View.VISIBLE
fragment_gallery_progress.progress = progressCounter
// fragment_gallery_progress.invalidate()
log.d("test: Thumb Index $progressCounter ${state.action.mediaItem.name} was created")
}
Unit
}
}
}.apply {
Redux.store.subscribe(this)
}
}
I tried all difference version of calling a thread in both cases. But no matter if its done with the handler or by activity.runOnUiThread, the progressbar never changes untill all thumbs are finished and the progressbar jumps from 0 to the maximum number. I can see the logs which are written in the right time, but not the progressbar changing.

I could fix my problem with following steps:
Removing the runOnUiThread() call
private fun onMenuRefreshThumbs(activity: Activity) {
val mediaPath = Redux.store.currentState.mediaPath
val fileRepository = FileRepository(context = activity, mediaPath = mediaPath)
fileRepository.regenerateThumbs(activity)
}
Adding a thread for each Thumbs-Generation:
fun getMediaItems(): MediaItemList {
val success = File(thumbPath).mkdirs()
val isThumbsEmpty = File(thumbPath).listFiles().isEmpty()
val mediaFileList = File(mediaPath).listFiles().
.sortedByDescending { it.lastModified() }
val list = MediaItemList()
mediaFileList.apply {
forEach {
list.add(MediaItem(it.name, 0, 0))
if (isThumbsEmpty) {
Thread {
getOrCreateThumb(it)
Redux.store.dispatch(FileUpdateAction(it))
}.start()
}
}
...

Dynamically created radio button is disappearing while clicking

I am getting the all views but when I click the button and scroll down at that time the it will be unchecked. I added the removeall views on the onBindViewHolder. because the radiobuttons are generated infinite times. Here I shared the code please check it.
override fun onBindViewHolder(holder: MyViewHolder, position: Int) {
holder.radioGrp.setOrientation(RadioGroup.VERTICAL)
holder.radioGrp.removeAllViews()
holder.bindView(position)
}
inner class MyViewHolder(itemView: View) : RecyclerView.ViewHolder(itemView) {
val radioGrp = itemView.findViewById<RadioGroup>(R.id.radio_group)
fun bindView(position: Int) {
itemView.tv_question.text = feedback[position].questions
var newAnswer = feedback[position].answser as ArrayList<String>
if (newAnswer.isEmpty()) {
itemView.linear2.visibility = View.VISIBLE
} else {
newAnswer.forEach {
itemView.linear2.visibility = View.GONE
val rb = RadioButton(context)
rb.text = it
rb.id = position
radioGrp.addView(rb)
rb?.setOnCheckedChangeListener(CompoundButton.OnCheckedChangeListener {
buttonView, isChecked ->
if (isChecked) {
rb.isChecked = true
examinationListener.addAnswer(names)
} else {
rb.isChecked = false
examinationListener.removeAnswer(names as String)
}
})
}
}
}
}

You need to track the checked state of your answers externally to the views and apply the state when binding the views. Assuming the answers for each list item are all unique Strings, you could use a Map to store the states.
// In your adapter:
val answerStates = mutableMapOf<Int, MutableMap<String, Boolean>>()
inner class MyViewHolder(itemView: View) : RecyclerView.ViewHolder(itemView) {
val radioGrp = itemView.findViewById<RadioGroup>(R.id.radio_group)
fun bindView(position: Int) {
itemView.tv_question.text = feedback[position].questions
val newAnswer = feedback[position].answser as ArrayList<String>
if (newAnswer.isEmpty()) {
itemView.linear2.visibility = View.VISIBLE
} else {
itemView.linear2.visibility = View.GONE
// Lazily create answer states map for this list item
val answerStates = answerStates[position]
?: mutableMapOf<String, Boolean>().also { answerStates[position] = this }
newAnswer.forEach {
val rb = RadioButton(context)
rb.text = it
rb.id = position
rb.checked = answerStates[it] ?: false // Bind last known state, default false
radioGrp.addView(rb)
rb?.setOnCheckedChangeListener(CompoundButton.OnCheckedChangeListener {
buttonView, isChecked ->
answerStates[it] = isChecked // Save state
if (isChecked) {
rb.isChecked = true
examinationListener.addAnswer(names)
} else {
rb.isChecked = false
examinationListener.removeAnswer(names as String)
}
})
}
}
}
}
If your data can change, this gets more complicated. You would need to store this Boolean in your actual Feedback class so it can be restored when there is fresh data.

Android how to interact with nested recyclerView from fragment

How does one properly send data to child adapter in a fragment?
I'm basically trying to implement an Instagram like comments-section, e.g. a bunch of comments that can each have more comments (replies).
To do that, I use one main recyclerView + main adapter, which instances are retained in my fragment, and within the main adapter I bind the children comments (recyclerView + adapter).
Adding comments to the main adapter is easy since the object is always available in the fragment, so I just call mainAdapter.addComments(newComments):
MainAdapter
fun addComments(newComments: List<Comment>){
comments.addAll( 0, newComments) //loading comments or previous comments go to the beginning
notifyItemRangeInserted(0, newComments.size)
}
But how to call addComments of one particular nested-rV? I read I should not save the adapter instances and only use positions.
I'm trying to do that in my Fragment as follows:
val item = rVComments.findViewHolderForItemId(mAdapter.itemId)!!.itemView
val adapt = item.rVReplies.adapter as ChildCommentsAdapter
adapt.addComment(it.data.comment)
But that doesn't work very well: since we have only RecyclerViews, that particular ViewHolder is often already recycled if the user scrolled after posting or fetching items, which leads to a NullPointerException.
Hence the initial question: how does one properly interact with nested recyclerviews and their adapter? If the answer is via Interface, please provide an example as I've tried it without success since I shouldn't save adapter objects.

You can achieve that using a single multi-view type adapter by placing the comments
as part of the parent item, with that, you add the child items below the parent item and call notifyItemRangeInserted.
That way you don't have to deal with most of the recycling issues.
When you want to update a comment you just update the comment inside the parent item and call notifyItemChanged.
If you want I created a library that can generate that code for you in compile time.
It supports the exact case you wanted and much more.

Using #Gil Goldzweig's suggestion, here is what I did: in case of an Instagram like comments' system with replies, I did use a nested recyclerView system. It just makes it easier to add and remove items. However, as for the question How does one properly send data to child adapter in a fragment? You don't. It gets super messy. From my fragment, I sent the data to my mainAdapter, which in turn sent the data to the relevant childAdapter. The key to make it smooth is using notifyItemRangeInserted when adding a comment to the mainAdapter and then notifyItemChanged when adding replies to a comment. The second event will allow sending data to the child adapter using the payload. Here's the code in case other people are interested:
Fragment
class CommentsFragment : androidx.fragment.app.Fragment(), Injectable,
SendCommentButton.OnSendClickListener, CommentsAdapter.Listener {
#Inject
lateinit var viewModelFactory: ViewModelProvider.Factory
private val viewModel by lazy {
ViewModelProviders.of(requireActivity(), viewModelFactory).get(CommentsViewModel::class.java)
}
private val searchViewModel by lazy {
ViewModelProviders.of(requireActivity(), viewModelFactory).get(SearchViewModel::class.java)
}
private val mAdapter = CommentsAdapter(this)
private var contentid: Int = 0 //store the contentid to process further posts or requests for more comments
private var isLoadingMoreComments: Boolean = false //used to check if we should fetch more comments
override fun onCreateView(inflater: LayoutInflater, container: ViewGroup?,
savedInstanceState: Bundle?): View? {
return inflater.inflate(R.layout.fragment_comments, container, false)
}
override fun onActivityCreated(savedInstanceState: Bundle?) {
super.onActivityCreated(savedInstanceState)
//hide the action bar
activity?.findViewById<BottomNavigationView>(R.id.bottomNavView)?.visibility = View.GONE
contentid = arguments!!.getInt("contentid") //argument is mandatory, since comment is only available on content
ivBackArrow.setOnClickListener{ activity!!.onBackPressed() }
viewModel.initComments(contentid) //fetch comments
val layoutManager = LinearLayoutManager(this.context)
layoutManager.stackFromEnd = true
rVComments.layoutManager = layoutManager
mAdapter.setHasStableIds(true)
rVComments.adapter = mAdapter
setupObserver() //observe initial comments response
setupSendCommentButton()
post_comment_text.setSearchViewModel(searchViewModel)
setupScrollListener(layoutManager) //scroll listener to load more comments
iVCancelReplyTo.setOnClickListener{
//reset ReplyTo function
resetReplyLayout()
}
}
private fun loadMoreComments(){
viewModel.fetchMoreComments(contentid, mAdapter.itemCount)
setupObserver()
}
/*
1.check if not already loading
2.check scroll position 0
3.check total visible items != total recycle items
4.check itemcount to make sure we can still make request
*/
private fun setupScrollListener(layoutManager: LinearLayoutManager){
rVComments.addOnScrollListener(object: RecyclerView.OnScrollListener(){
override fun onScrolled(recyclerView: RecyclerView, dx: Int, dy: Int) {
super.onScrolled(recyclerView, dx, dy)
val visibleItemCount = rVComments.childCount
val totalItemCount = layoutManager.itemCount
val pos = layoutManager.findFirstCompletelyVisibleItemPosition()
if(!isLoadingMoreComments && pos==0 && visibleItemCount!=totalItemCount && mAdapter.itemCount%10==0){
//fetch more comments
isLoadingMoreComments = true
loadMoreComments()
}
}
})
}
private fun setupSendCommentButton() {
btnSendComment.setOnSendClickListener(this)
}
override fun onSendClickListener(v: View?) {
if(isInputValid(post_comment_text.text.toString())) {
val isReply = mAdapter.commentid!=null
viewModel.postComment(post_comment_text.text.toString(), mAdapter.commentid?: contentid, isReply) //get reply ID, otherwise contentID
observePost()
post_comment_text.setText("")
btnSendComment.setCurrentState(SendCommentButton.STATE_DONE)
}
}
override fun postCommentAsReply(username: String) {
//main adapter method to post a reply
val replyText = "${getString(R.string.replyingTo)} $username"
tVReplyTo.text = replyText
layoutReplyTo.visibility=View.VISIBLE
post_comment_text.requestFocus()
}
override fun fetchReplies(commentid: Int, commentsCount: Int) {
//main adapter method to fetch replies
if(!isLoadingMoreComments){ //load one series at a time
isLoadingMoreComments = true
viewModel.fetchReplies(commentid, commentsCount)
viewModel.replies.observe(this, Observer<Resource<List<Comment>>> {
if (it?.data != null) when (it.status) {
Resource.Status.LOADING -> {
//showProgressBar(true)
}
Resource.Status.ERROR -> {
//showProgressBar(false)
isLoadingMoreComments = false
}
Resource.Status.SUCCESS -> {
isLoadingMoreComments = false
mAdapter.addReplies(mAdapter.replyCommentPosition!!, it.data)
rVComments.scrollToPosition(mAdapter.replyCommentPosition!!)
}
}
})
}
}
private fun isInputValid(text: String): Boolean = text.isNotEmpty()
private fun observePost(){
viewModel.postComment.observe(this, Observer<Resource<PostCommentResponse>> {
if (it?.data != null) when (it.status) {
Resource.Status.LOADING -> {
//showProgressBar(true)
}
Resource.Status.ERROR -> {
//showProgressBar(false)
}
Resource.Status.SUCCESS -> {
if(it.data.asReply){
//dispatch comment to child adapter via main adapter
mAdapter.addReply(mAdapter.replyCommentPosition!!, it.data.comment)
rVComments.scrollToPosition(mAdapter.replyCommentPosition!!)
}else{
mAdapter.addComment(it.data.comment)
}
resetReplyLayout()
//showProgressBar(false)
}
}
})
}
private fun setupObserver(){
viewModel.comments.observe(this, Observer<Resource<List<Comment>>> {
if (it?.data != null) when (it.status) {
Resource.Status.LOADING -> {
//showProgressBar(true)
}
Resource.Status.ERROR -> {
isLoadingMoreComments = false
//showProgressBar(false)
}
Resource.Status.SUCCESS -> {
mAdapter.addComments(it.data)
isLoadingMoreComments = false
//showProgressBar(false)
}
}
})
}
private fun resetReplyLayout(){
layoutReplyTo.visibility=View.GONE
mAdapter.replyCommentPosition = null
mAdapter.commentid = null
}
override fun onStop() {
super.onStop()
activity?.findViewById<BottomNavigationView>(R.id.bottomNavView)?.visibility = View.VISIBLE
}
}
MainAdapter
class CommentsAdapter(private val listener: Listener) : RecyclerView.Adapter<CommentsAdapter.ViewHolder>(), ChildCommentsAdapter.ChildListener {
//method from child adapter
override fun postChildReply(replyid: Int, username: String, position: Int) {
commentid = replyid
replyCommentPosition = position
listener.postCommentAsReply(username)
}
interface Listener {
fun postCommentAsReply(username: String)
fun fetchReplies(commentid: Int, commentsCount: Int=0)
}
class ViewHolder(val view: View) : RecyclerView.ViewHolder(view)
private var comments = mutableListOf<Comment>()
private var repliesVisibility = mutableListOf<Boolean>() //used to store visibility state for replies
var replyCommentPosition: Int? = null //store the main comment's position
var commentid: Int? = null //used to indicate which comment is replied to
override fun onCreateViewHolder(parent: ViewGroup, viewType: Int): ViewHolder {
val view = LayoutInflater.from(parent.context)
.inflate(R.layout.item_comment, parent, false)
return ViewHolder(view)
}
override fun onBindViewHolder(holder: ViewHolder, position: Int) {
val comment = comments[position]
with(holder.view) {
//reset visibilities (rebinding purpose)
rVReplies.visibility = View.GONE
iVMoreReplies.visibility = View.GONE
tVReplies.visibility = View.GONE
content.loadUserPhoto(comment.avatarThumbnailURL)
text.setCaptionText(comment.username!!, comment.comment)
tvTimestamp.setTimeStamp(comment.timestamp!!)
val child = ChildCommentsAdapter(
//we pass parent commentid and position to child to be able to pass it again on click
this#CommentsAdapter, comments[holder.adapterPosition].id!!, holder.adapterPosition
)
val layoutManager = LinearLayoutManager(this.context)
rVReplies.layoutManager = layoutManager
rVReplies.adapter = child
//initial visibility block when binding the viewHolder
val txtMore = this.resources.getString(R.string.show_more_replies)
if(comment.repliesCount>0) {
tVReplies.visibility = View.VISIBLE
if (repliesVisibility[position]) {
//replies are to be shown directly
rVReplies.visibility = View.VISIBLE
child.addComments(comment.replies!!)
tVReplies.text = resources.getString(R.string.hide_replies)
if (comment.repliesCount > comment.replies!!.size) {
//show the load more replies arrow if we can fetch more replies
iVMoreReplies.visibility = View.VISIBLE
}
} else {
//replies all hidden
val txt = txtMore + " (${comment.repliesCount})"
tVReplies.text = txt
}
}
//second visibility block when toggling with the show more/hide textView
tVReplies.setOnClickListener{
//toggle child recyclerView visibility and change textView text
if(holder.view.rVReplies.visibility == View.GONE){
//show stuff
if(comment.replies!!.isEmpty()){
Timber.d(holder.adapterPosition.toString())
//fetch replies if none were fetched yet
replyCommentPosition = holder.adapterPosition
listener.fetchReplies(comments[holder.adapterPosition].id!!)
}else{
//load comments into adapter if not already
if(comment.replies!!.size>child.comments.size){child.addComments(comment.replies!!)}
}
repliesVisibility[position] = true
holder.view.rVReplies.visibility = View.VISIBLE
holder.view.tVReplies.text = holder.view.resources.getString(R.string.hide_replies)
if (comment.repliesCount > comment.replies!!.size && comment.replies!!.isNotEmpty()) {
//show the load more replies arrow if we can fetch more replies
iVMoreReplies.visibility = View.VISIBLE
}
}else{
//hide replies and change text
repliesVisibility[position] = false
holder.view.rVReplies.visibility = View.GONE
holder.view.iVMoreReplies.visibility = View.GONE
val txt = txtMore + " (${comment.repliesCount})"
holder.view.tVReplies.text = txt
}
}
tvReply.setOnClickListener{
replyCommentPosition = holder.adapterPosition
commentid = comments[holder.adapterPosition].id!!
listener.postCommentAsReply(comments[holder.adapterPosition].username!!)
}
iVMoreReplies.setOnClickListener{
replyCommentPosition = holder.adapterPosition
listener.fetchReplies(comments[holder.adapterPosition].id!!, layoutManager.itemCount) //pass amount of replies too
}
}
}
#Suppress("UNCHECKED_CAST")
override fun onBindViewHolder(holder: ViewHolder, position: Int, payloads: MutableList<Any>) {
if(payloads.isNotEmpty()){
//add reply to child adapter
with(holder.view){
Timber.d(payloads.toString())
val adapter = rVReplies.adapter as ChildCommentsAdapter
if(payloads[0] is Comment){
adapter.addComment(payloads[0] as Comment)
}else{
//will be of type List<Comment>
adapter.addComments(payloads[0] as List<Comment>)
val comment = comments[position]
if (comment.repliesCount > comment.replies!!.size) {
//show the load more replies arrow if we can fetch more replies
iVMoreReplies.visibility = View.VISIBLE
}else{
iVMoreReplies.visibility = View.GONE
}
}
}
}else{
super.onBindViewHolder(holder,position, payloads) //delegate to normal binding process
}
}
override fun getItemCount(): Int = comments.size
//add multiple replies to child adapter at pos 0
fun addReplies(position: Int, newComments: List<Comment>){
comments[position].replies!!.addAll(0, newComments)
notifyItemChanged(position, newComments)
}
//add a single reply to child adapter at last position
fun addReply(position: Int, newComment: Comment){
comments[position].replies!!.add(newComment)
comments[position].repliesCount += 1 //update replies count in case viewHolder gets rebinded
notifyItemChanged(position, newComment)
}
//add a new comment to main adapter at last position
fun addComment(comment: Comment){
comments.add(comment) //new comment just made goes to the end
repliesVisibility.add(false)
notifyItemInserted(itemCount-1)
}
//add multiple new comments to main adapter at pos 0
fun addComments(newComments: List<Comment>){
comments.addAll( 0, newComments) //loading comments or previous comments go to the beginning
repliesVisibility.addAll(0, List(newComments.size) { false })
notifyItemRangeInserted(0, newComments.size)
}
}
The childAdapter is very basic and has nearly 0 logic.

How to retain selection in multi choice dialog in Android on rotation?

I have a dialog to select more than one days of a week as follows:
class DialogSettingsEnabledDays : DialogFragment() {
override fun onCreateDialog(savedInstanceState: Bundle?): Dialog {
return activity.let {
val selectedDaysValue = BooleanArray(7) { _ -> false }
val selectedDaysIndex = ArrayList<Int>()
val daysToIndexMap = mutableMapOf<String, Int>()
val indexToDaysMap = mutableMapOf<Int, String>()
val daysArray = resources.getStringArray(R.array.days_medium)
for (i in 0..6) {
daysToIndexMap[daysArray[i]] = i
indexToDaysMap[i] = daysArray[i]
}
val prefs = it!!.getSharedPreferences(getString(R.string.shared_prefs_settings), Context.MODE_PRIVATE)
val selectedDaysString = prefs.getString("enabled_days", getString(R.string.default_enabled_days))
val selectedDays = selectedDaysString!!.split(", ")
for (day in selectedDays) {
selectedDaysValue[daysToIndexMap.getValue(day)] = true
selectedDaysIndex.add(daysToIndexMap.getValue(day))
}
val enabledDaysBuilder = AlertDialog.Builder(it)
enabledDaysBuilder
.setTitle(R.string.settings_enabled_days)
.setMultiChoiceItems(R.array.days_long, selectedDaysValue) { _, which, isChecked ->
if (isChecked)
selectedDaysIndex.add(which)
else if (selectedDaysIndex.contains(which))
selectedDaysIndex.remove(Integer.valueOf(which))
}
.setPositiveButton(R.string.dialog_ok) { _, _ ->
if (selectedDaysIndex.isEmpty()) {
Toast.makeText(it, "Select atleast one day !!", Toast.LENGTH_SHORT).show()
} else {
selectedDaysIndex.sort()
val selectedDaysList = mutableListOf<String>()
for (i in selectedDaysIndex) {
selectedDaysList.add(indexToDaysMap.getValue(i))
}
val editor = prefs.edit()
editor
.putString("enabled_days", selectedDaysList.joinToString())
.apply()
val enabledDays = it.findViewById<LinearLayout>(R.id.settings_enabled_days)
enabledDays.findViewById<TextView>(R.id.secondary_text).text = selectedDaysList.joinToString()
}
}
.setNegativeButton(R.string.dialog_cancel) { _, _ -> /* do nothing */ }
enabledDaysBuilder.create()
}
}
}
And I am calling this dialog in this way from my activity:
findViewById<LinearLayout>(R.id.settings_enabled_days)
.setOnClickListener {
DialogSettingsEnabledDays().show(this.supportFragmentManager, null)
}
My problem is that my selection of days resets to default on rotation.
By default I mean the selection stored in SharedPreferences, that is selectedDaysValue in .setMultiChoiceItems.
Suppose, these are the selected days when the dialog pops up:
Mon, Tue, Wed, Thu, Fri
Now, I change the selection as:
Mon, Tue
But, when I rotate the phone, the selection sets back to default:
Mon, Tue, Wed, Thu, Fri
How can I retain my selection on orientation change?
Because in some apps I have seen, the Dialog selection remains same on rotation.

Android system will automatically restore your fragment state, while the state changed fragment is not actually getting destroyed but only its view is recreated, so what ever value is inside your fragment variables will be kept as it is, all you have to do is reassign that variables value to your view, here's the reference link https://inthecheesefactory.com/blog/fragment-state-saving-best-practices/en

Well, this is the final solution I have made by making changes in the DialogFragment code only:
Changing the scope of data to be stored:
override fun onCreateDialog(savedInstanceState: Bundle?): Dialog {
return activity.let {
val selectedDaysValue = BooleanArray(7) { _ -> false }
val selectedDaysIndex = ArrayList<Int>()
to:
private var selectedDaysValue = BooleanArray(7) { _ -> false }
private var selectedDaysIndex = ArrayList<Int>()
override fun onCreateDialog(savedInstanceState: Bundle?): Dialog {
return activity.let {
Storing the data:
override fun onSaveInstanceState(outState: Bundle) {
outState.putBooleanArray("selected_days_value", this.selectedDaysValue)
outState.putIntegerArrayList("selected_days_index", this.selectedDaysIndex)
}
And where I read the data as:
val prefs = it!!.getSharedPreferences(getString(R.string.shared_prefs_settings), Context.MODE_PRIVATE)
val selectedDaysString = prefs.getString("enabled_days", getString(R.string.default_enabled_days))
val selectedDays = selectedDaysString!!.split(", ")
for (day in selectedDays) {
selectedDaysValue[daysToIndexMap.getValue(day)] = true
selectedDaysIndex.add(daysToIndexMap.getValue(day))
}
to read from saved state as:
val prefs = activity!!.getSharedPreferences(getString(R.string.shared_prefs_settings), Context.MODE_PRIVATE)
if (savedInstanceState == null) {
val selectedDaysString = prefs.getString("enabled_days", getString(R.string.default_enabled_days))
val selectedDays = selectedDaysString!!.split(", ")
for (day in selectedDays) {
selectedDaysValue[daysToIndexMap.getValue(day)] = true
selectedDaysIndex.add(daysToIndexMap.getValue(day))
}
} else {
with(savedInstanceState) {
selectedDaysValue = getBooleanArray("selected_days_value")!!
selectedDaysIndex = getIntegerArrayList("selected_days_index")!!
}
}