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How to evaluate a variable (changing value) in a Fragment from a RecyclerView Adapter (Kotlin) for conditional processing?

I'm new to all of this and was making good progress but I have hit a brick wall with working out how to do the next thing. I am using Kotlin and have a Fragment with an associated Recyclerview Adapter. I would like to set OnClick (On or Off) against items in a row depending upon a value in the Fragment which could change at any time.
My adapter works fine to show and update the array of data and also to implement OnClick.
I have tried sending a data element via a constructor which changed in the fragment but always showed as the initial setting in the adapter. The same with trying to call a method.
Many other questions touch on the issue but only show snippets of code, and it seems that I'm not advanced enough to get them working successfully in my code.
Could anyone please provide a pointer to a working set of Kotlin code that includes parsing a variable from fragment to adapter - perhaps in Git or a tutorial. I'm sure that if I can study a working program I can move forward. Thank you.

It would have been better if you had included your Adapter and Fragment code in the question, that would have helped us in understanding how you have setup everything and what data model are you passing to adapter.
But looking at your question, one solution that comes to my mind is to add an enabled boolean in your data model that is displayed in the ViewHolder. Using this you can set view.clickable = model.enabled. Now whenever your "value in the Fragment" changes you can update this list and let the adapter rebind items.
Note that the above solution is when you want to selectively enable/disable clicks on individual items. If you want to do this for all items at once, it's better to create a variable in adapter that you can change from the Fragment, and inside the clickListener you can check the value of that adapter variable. If it's false, just return out of the click listener. Something like,
view.setOnClickListener {
if(adapterValue) {
// handle Click
}
}
If this approach doesn't help, I would ask you to add more context in your question and show what you have done so far.

How to create functionality as TikTok / Musical.ly for android app?

Screen 1: GridView
Screen 2: Detail Page
Task Achieve:
1) Load all the videos in gridview from the server.
2) User clicks at any position of gridview item.
3) Open and play the particular video in detail screen.
4) On vertical scroll play next or previous videos.
Current Implementation:
GridFragment {
ArrayList<VideoPostModel> videoPostList;
RecyclerView gridView;
onnItemClick() {
Intent intent = new Intent(this, DetailActivity.class);
intent.putExtra("data", videoPostList);
intent.putExtra("click_index", clickedIndex);
intent.putExtra("pagination_index", paginationIndex);
startActivity(intent);
}
}
DetailActivity {
VerticlaViewPager vertiCalViewPager;
ArrayList<VideoPostModel> videoPostList;
onCreate() {
videoPostList = getIntent().getParcelableArrayListExtra("data");
clickedIndex = getIntent().getIntExtra("clickindex", 0);
paginationIndex = getIntent().getIntExtra("pagination_index", 0);
VideoFragmentStatePagerAdapter viewPagerAdapter = new VideoFragmentStatePagerAdapter(videoPostList);
vertiCalViewPager.setAdapter(viewPagerAdapter);
}
}
Problem:
If videoPostList has more data(approx 100+ objects of VideoPostModel) while passing data from fragment to activity then app crashes, as there is a limitation of sending data with intent(https://stackoverflow.com/a/37054839/3598052).
Hacky Alternatives:
1) Static arraylist
2) Arraylist in Application class
Looking for the OPTIMAL and EFFICIENT solution to achieve above functionality.
Any suggestion, reference link or code in the direction of achieving this would be highly appreciated, and thanks in advance.
Update 1:
Another solution I found is passing data with enum, but as per comments I'm not sure about it's performance. Refrence: https://stackoverflow.com/a/14706456/3598052

I think you can write in an activity or use Arraylist in the application as you mentioned. Or it could be a library that recently appeared in the Android Jetpack. It is similar in nature to the Arraylist in application.
ViewModel objects that make it easier to manage and store data.
It lets you access data at different activities or fragments in an application. You try it and hope it will be useful to you

You have several options. I'll put my opinion here.
Static list
Enum
Singleton class with list
LiveData
Most easy would be making static list at activity or application level. Just make sure you are freeing up List memory after use by making it NULL.
Another solution I found is passing data with enum, but as per
comments I'm not sure about it's performance
There would be sure some differences in each of above approaches. But that would not be measurable difference, because each approach put List in memory, use it and then free up.
Looking for the OPTIMAL and EFFICIENT solution to achieve above
functionality.
Make static List, and make it NULL after use. will be most efficient and easy way.
You can make List NULL in onDestroy() of your Fragment.
You can use LiveData but I think it would be not a good idea to add LiveData library just for one use in app. Also you need to understand it first. So you can go with static list.
in Activity
showFragment();
ApplicationClass.list = myList;
In Fragment
onViewCreated(){
...
setAdapter(ApplicationClass.list);
...
}
onDestroy(){
ApplicationClass.list = null;
}
Important
It is never a good idea to pull all data at once from server. Please do pagination, which you app needs most, because there can be thousands of users online at one time.
So by that approach you will pass only few items to Fragment. then you will do pagination in Fragment.
This approach needs time to change flow a bit. But is most robust way in your case.
Edit
If you are already using pagination and still getting large data at one time, that's again an issue. Because pagination is used to escape these memory issues.
You can do 2 things as solution.
1. Ask for limited data at once, say 50-60 items per request.
2. You can map and remove unnecessary fields from your list when passing in intent.
I would prefer the first one.

I know I'm late but this will help some future visitor.
Add Pagination & transfer data with arraylist & clicked position to detail activity using intent & after, set the current position of clicked position.
like viewpager.setCurrentPosition(clickedPosition);

Dynamically add more cards in a list Row android TV leanback

I am working on a Android TV app for quite some time now and I have come far while working on it. I am trying to develop an app like popcorn time but it's for Google nexus TV box.
The problem where I am stuck in, is really simple but even after a lot of effort I am still unable to figure out the solution.
I am fetching the json data from my database which has all the movies details and links and this works perfectly fine.
Over all app view
Now those who have used the you tube app on Android TV must have noticed that it was built on leanback and as you scroll down in a listrow more cards are added into a row and likewise the app made the json calls to fetch more data according to the category we are scrolling in. (that's what I want to do)
Right now it is impossible, if I request for large data it takes a long time to fetch everything from the server so I have devised a way via which I can make json calls on scroll but I am unable to present them in a listrow at runtime.

To add items to a presenter;
CardPresenter channelCardPresenter = new CardPresenter();
ArrayObjectAdapter channelRowAdapter = new ArrayObjectAdapter(channelCardPresenter);
channelRowAdapter.add(new Movie("Movie Title"));
HeaderItem header = new HeaderItem(0, "My Channels");
mRowsAdapter.add(new ListRow(header, channelRowAdapter));
Of course this may only work for the first time you're creating the UI. Future times may not do this. In my app, https://github.com/Fleker/CumulusTV/blob/master/app/src/main/java/com/felkertech/n/tv/LeanbackFragment.java, I create a method that will be called each time I want to do a full redraw of the app:
public void refreshUI() {
prepareBackgroundManager();
setupUIElements();
loadRows(); //Generate and populate all the rows
setupEventListeners();
}

I have been working with android TV Leanback library from past 7 or 8 months. And I have developed my own presenter class via which you can load more cards dynamically on scroll, but its not possible using Leanback Library, ListAdapter updateds a single row and than move to next category to update it's cards. which take time on run time.
I have used the below answer to create my own presenter class. The Trick while implementing endless loading on scroll is that you have to create two AysncTasks.
Have a look at at post 34
Lazy download images into gridView
it will a little time taking but you will get the idea.

How to modify a ListView item in Android?

I'm starting learning Android and I want to know if there is some option in Android that let you modify each item or view (I don't know how it's named exactly, I mean each of the items from an ArrayList that you show in a ListView).
Well, I made a ListView that is going to show some books that were located in an ArrayList named "books".
I made a custom adapter that I associate to the ListView to show each item with the corresponding layout in the application. I also have a class "book" for each item that is going to be shown in the ListView.
Further, I made an Intent that I call from MainActivity with startForActivityResult(), that I process in Book class and that I return to MainActivity with all data of a book with the method setResult and got the information with onActivityResult() and the requestCode.
So I don't have any problem to add items to the ListView, just I have the problems if I want to modify some of the items (or views) that are located in the ListView (for example if I have title and author of a book, if I put some wrong information, I want have the option to change it).
I have that, in the same moment that you click on some of the items of the ListView, a new layout will be show to modify the information that it's wrong so I use the method setOnItemClickListener with onItemClick event on the custom adapter that I created before. Here it's where I call the new Intent to modify the wrong information with the method startActivityForResult().
I made the same as before to add a new item but, instead of add a new item with custom_adapter.addBook(title,author) I want to know if there is some option to made something like this: custom_adapter.modify(title,author) or custom_adapter.update(title,author), I mean, when you have modify all the items that were wrong of a book (for example an EditText that were "title") and you have all the information in the MainActivity class (because you returned it with setResult), how to put it again in the same item updating it in the custom_adapter and also in the ArrayList.
I searched it on the Internet but I didn't find anything.
I'm sorry if I have a poor English, but I expect that it can be understand.
Thank you very much!

If I am understanding your problem correctly - you could simply modify the ArrayList of type Book that is backing your ArrayAdapter.
So if you know what Book object you want to modify then you can simply make your changes to the Book object itself. As long as this Book is a reference to the same object that you originally added to the ArrayList you instantiated your ArrayAdapter with then you can then call custom_adapter.notifyDataSetChanged() to tell the adapter to redraw its childviews with the new data.

There are some good code samples on the Internet but you have to understand the code for your purposes. So...here is a start, look at Using an ArrayAdapter with ListView. The code shows the use of ArrayAdapter with getView() method. And I hope it shows how to define the listeners, which you need.
How about that for a start? Have fun...

Thank you very much for all help you gave to me. I'm very pleased with you. :)
Finally, I just send the info with a Bundle when I started the Intent, also with the position. And after, I just used this position to set the new info to my items (in my case, books).
Again, thank you very much ;)

Flex ActionScript - ArrayList Issues

I am banging my head for the last couple days in order to get this done but Im unable to. Someone please help me out!
Let me not tell u the whole thing and will try to explain it simply n clearly.
Im having 1 ArrayList. I am trying to replicate that into another one and trying to delete an item at a particular index. But this not only deletes the item in the replicated ArrayList but also the original ArrayList.
For ex:
var DuplicateList:ArrayList = new ArrayList();
DuplicateList = OriginalList;
DuplicateList.removeItemAt(2);
The above not only deletes the "Item 3" at Index-2 in the DuplicateList but also in the OriginalList.
I just need some workaround with this approach as this is the only way by which whatever I typed inside the controls present in an ItemRenderer of a FLEX List control that uses the OriginalList as a dataProvider is RETAINED, when I change the dataProvider of the List Control from OriginalList to DuplicateList. The following approach does not retain all the data.
var DuplicateList:ArrayList = new ArrayList();
DuplicateList.addAll(OriginalList);
DuplicateList.removeItemAt(2);
ListCntrl.dataProvider = DuplicateList;
Thanks for your help in advance...

A very, very important thing to understand:
ActionScript3 uses references to objects. Because of that, the two variables in this line of code refer to the exact same instance of an ArrayList:
DuplicateList = OriginalList;
So, when you remove an item from one reference, it is gone from the next. If you want two separate instances of ArrayList, then you need to clone it like you are suggesting later in your code.
So far, so good... but why is your ListCntrl retaining the data from the OriginalList? That doesn't make any sense at all. If you remove an item from DuplicateList and then use it as the data provider, then that item shouldn't be there. I think there is more to this story...