Android notifyItemRemoved() Wrong Index notified

Question

Good day. I have a small chat app where i want to simply delete the chat item locally.

By debugging around i can reckon that there is something wrong with notifyItemRemoved() as follows :

• I have debugged the returned index from my List and the index was correct for list.

• I have debugged the returned Model Class from the ViewHolder and the returned model class was correct.

• I have debugged my custom equals() method inside my Model and it was comparing correctly returning correct item.

The main complain about my debugging is i dont know why,but the equals() method is being called 2 times...pretty weird though if you would have time please consider this case as well.

The main problem is the notifyItemRemoved() is always removing not the correct item,but always 1 item above the item which must be deleted (in means of deleted i mean deleted from the view as deleting from the list is happening correctly)

So i have no clue what is going on here.

Here is my custom equals() methods

  @Override
public boolean equals(Object obj) {
    if (obj == null) {
        return false;
    }
    if (obj instanceof ChatModel) {
        ChatModel chatModel = (ChatModel) obj;
        if (chatModel.getMessageId().equals(messageId)) {
            return true;
        }
    }
    return false;
}

@Override
public int hashCode() {
    return messageId.hashCode();
}

Here is how i insert items into adapter list.

For the list of models->

 public void insertChatModelWithItemNotify(List<ChatModel> chatModel, boolean firstPaging) {
    if (firstPaging) {
        this.chatModelList.addAll(chatModel);
        notifyDataSetChanged();
    } else {
        this.chatModelList.addAll(0, chatModel);
        notifyItemRangeInserted(0, chatModel.size());
    }
}

For a single model - >

    public void insertChatModel(ChatModel chatModel) {
    this.chatModelList.add(chatModel);
    notifyDataSetChanged();
}

Here is how i remove the item from the list

  public void removeItem(ChatModel chatModel) {
    int position = this.chatModelList.indexOf(chatModel);
    this.chatModelList.remove(chatModel);
    notifyItemRemoved(position);
}

Any ideas?

Answer 1

You are probably adding some kind of header to the RecyclerView which makes the object index in your object list different from the View index in the RecyclerView.