RecyclerView throwing IndexOutOfBoundsException when trying to insert multiple items and notifying the adapter

Question

I am trying to get unique numbers from call logs of a user and show them in a RecyclerView. By unique I mean if I have shown the number, or corresponding contact once in the list, I have to skip the item. And I want to use a Cursor for showing this to make the rendering quick.

To do this, I have implemented a RecyclerView Adapter which looks like this (Only showing the relevant code, kotlin)

class CallAdapter(val activity: Activity, var cursor: Cursor) : RecyclerView.Adapter<CallAdapter.ViewHolder>() {


        val handler = Handler()
        val contacts = ArrayList<Contact>()

        init {
            cursor.moveToFirst()
            UniqueLogs(this).start()
        }

        companion object {
            const val TAG = "CallAdapter"
        }

        override fun onCreateViewHolder(parent: ViewGroup?, viewType: Int): ViewHolder {
            val inflater = LayoutInflater.from(activity)
            val binding = CallLogItemBinding.inflate(inflater, parent, false)
            return ViewHolder(binding)
        }

        override fun getItemCount(): Int {
            return contacts.count()
        }

        override fun onBindViewHolder(holder: ViewHolder, position: Int) {
            val contact = contacts[position]

            ...

            cursor.moveToNext()
        }

        class ViewHolder(val binding: CallLogItemBinding) : RecyclerView.ViewHolder(binding.root)

        class UniqueLogs(val adapter: CallLogAdapterShobhit) : Thread() {
            private var available = true
            private val cursor = adapter.cursor
            private val hash: HashMap<String, Int> = HashMap<String, Int>()
            private val contacts = adapter.contacts
            private var count = 0

            override fun run() {
                cursor.moveToFirst()
                while (available && cursor.moveToNext()) {
                    var contact = adapter.getCurrentItemContact()

                    while (available && hash[contact.phoneNumber] == 1) {
                        if (cursor.moveToNext()) {
                            contact = adapter.getCurrentItemContact()
                        } else {
                            available = false
                        }
                    }

                    if (available) {
                        contacts.add(contact)
                        val position = count
                        count += 1

                        adapter.handler.post({
                            Log.d(TAG, "Position: $position Size: ${adapter.itemCount}")
                            adapter.notifyItemInserted(position)
                        })

                        hash[contact.phoneNumber] = 1
                    }
                }

            }
        }
    }

When I run this code, I am getting an exception which looks like this :-

java.lang.IndexOutOfBoundsException: Inconsistency detected. Invalid view holder adapter positionViewHolder{c75176c position=5 id=-1, oldPos=4, pLpos:4 scrap [attachedScrap] tmpDetached not recyclable(1) no parent}

The position, id, oldPos, pLpos, etc. are different every time but the error is essentially the same.

I've tried writing logs as well to make sure that I am not trying to insert an element before the element is added to contacts array list, but the logs say that all's well.

Any idea what might be wrong here?

i'll use this like `eventsAdapter.notifyDataSetChanged();` it's work for me — Ali, Feb 22 '18 at 12:47
@MohammadAli Wouldn't that produce a jittering effect because it keeps rendering the whole list? — Shobhit, Feb 22 '18 at 12:49
You're calling `contacts.add(contact)` from a different thread. ArrayList is not thread safe by default, try it with something like `Collections.synchronizedList(new ArrayList())` — Lance Toth, Feb 22 '18 at 12:52
Maybe this might help then https://stackoverflow.com/questions/31759171/recyclerview-and-java-lang-indexoutofboundsexception-inconsistency-detected-in — Lance Toth, Feb 22 '18 at 13:21

score 0 · Answer 1 · answered Feb 22 '18 at 12:52

0

You are updating the data in a background thread, but notifying on the main thread. By the time the notification happens, you may have further altered the data. I would suggest that you do all your updates on the background and then just do a generic notifyDataSetChanged when everything is done.

Another option would be to calculate the entire new list in a background thread and then update the real data once and notify in the main thread.

answered Feb 22 '18 at 12:52

cwbowron

1,015
6
10

I don't want to do that. I wouldn't need a Thread if I wanted to bring all the data in memory together and then render them. I need to sort of "lazy load" contacts. – Shobhit Feb 22 '18 at 12:57

score 0 · Answer 2 · answered Feb 22 '18 at 22:13

0

Modifying the data and calling notifyItemInserted should synchronously or you will have inconsistent data.

Putting contacts.add(contact) just before notifyItemInserted should solve it.

                    adapter.handler.post({
                        Log.d(TAG, "Position: $position Size: ${adapter.itemCount}")
                        contacts.add(contact)
                        adapter.notifyItemInserted(position)
                    })

answered Feb 22 '18 at 22:13

Vedant Agarwala

18,146
4
66
89

Nope. That didn't work. Handling the exception in a try-catch solved it! – Shobhit Feb 23 '18 at 04:11

RecyclerView throwing IndexOutOfBoundsException when trying to insert multiple items and notifying the adapter

2 Answers2