Does notifydatasetchanged call onCreateViewHolder when using RecyclerView

Question

I want to use a toggle to toggle between two different views but using the same RecyclerView. Basically, once you toggle, I want the RecyclerView adapter to recall onCreateViewHolder() but this time it will use a different layout item file.

Does notifydatasetchanged() cause the adapter to rebuild itself? Or is there another way?

Proofread

one way to find out is simply put Logs inside onCreateViewHolder and check if they are being called on notifydatasetchanged()... :P is that so hard? – Selwin

Fair enough, but i actually want to know what the process is. I tried looking it up. Also that wasn't my only question. Sorry I asked – Proofread

No worries if you have another question then either edit this question or delete this question and post a new question :). you might wanna read this – Selwin

No I am saying in my above post I asked what is another way of doing this. I had a feeling that the notifydatasetchanged() wouldn't do what I wanted. – Proofread

Answer 1

I needed to have two types on Views on my RecyclerView Adapter as well, one for 'regular' mode and one for multi-select mode.

So, you can override getItemViewType to force the Adapter to call your onCreateViewHolder for all views.

Add this to the Adapter code:

public void setActionMode(ActionMode actionMode) {
    this.actionMode = actionMode;
    notifyDataSetChanged();
}

@Override
public int getItemViewType(int position) {
    return (actionMode == null ? 0 : 1);
}

Add this to the ViewHolder:

@Override
public ViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
    View view;
    if (viewType == 0) {
        view = inflater.inflate(R.layout.layout_1, parent, false);
    } else {
        view = inflater.inflate(R.layout.layout_2, parent, false);
    }
    ...
}

Since you return a different ViewType when in an ActionMode, the Adapter is forced to throw away all created views, and recreate everything again.

Malaspina

Omg this works. Just by overriding getItemViewType, even though we can technically the actionMode directly in onCreateViewHolder, forces the adapter to call onCreateViewHolder like you said. Thanks! – Tupi

i cant belive this answers save my day :D – Bosun

Answer 2

notifyDataSetChanged() calls onBindViewHolder() in case of RecyclerView

Witchy

It never calls it for me. – Togliatti

Answer 3

THE SIMPLEST SOLUTION

If you want to refresh RecyclerView items and onCreateView() be called too, say for Grid and List LayoutManagers.

  void refreshRecyclerView(RecyclerView recyclerView){
            Adapter adapterRef=recyclerView.getAdapter();
            recyclerView.setAdapter(null);
            recyclerView.setAdapter(adapterRef);
        }

it will completely refresh the RecyclerView

//example usage
refreshRecyclerView(yourRecyclerView);

Diella

By far the simplest solution. I have a Recycler view that adds/deletes various types of items with different view holders in different locations. Refreshing the adapter as this solution states works perfectly. Thank you. – Bechtel

Answer 4

To remove and update layout in RecyclerView, you can call

mRecyclerView.removeView(view);

OR

mRecyclerView.removeViewAt(position);

after removing object in your dataset

Testament

Answer 5

I spent more than 6 hours on this issue without any success. Finally!!! I set a global variable in the adapter and had to set it up every time i toggled the view from list to grid (in my case). the funny thing this approauch was there but I forgot to do it as static!! So my solution could be related to yours , just try it and hope it works out.

public static int mCurrentViewType;

then override the getItemType()

  @Override
    public int getItemViewType(int position) {

       return mCurrentViewType;


    }

my toggleItemViewType method:

public void toggleItemViewType () {
        if (mCurrentViewType == LIST_ITEM){
            mCurrentViewType = GRID_ITEM;
        } else {
            mCurrentViewType = LIST_ITEM;
        }
    }

I am accessing the variable from different classes, which is not right, but for now and for the sake of the onCreateViewHolder issue, it worked! if you have a better solution then good luck and share it with us. don't forget to make the global variable as "static" :)

Shir

Answer 6

Yes it will assume that its current data set is invalid and would need to relayout and rebind all layouts.

Ron

No, it seems it only calls the onBindViewHolder when the notifydatasetchanged() is called. Thanks for trying to help though. – Proofread

No problem thanks well there are always 20 ways to achieve a result you want, its just choosing which one :) – Ron

Haha, I would like just one please :P – Proofread

maybe call setAdapter rather than notifyDataSetChanged – Ron

haha thanks! Tyring that now.. Also tried calling invalidate() but that did nothing – Proofread