How to get child view from RecyclerView?

Question

I am trying to get child view by position. I could get view when one item is clicked:

rvSellRecords.addOnItemTouchListener(new RecyclerItemClickListener(         


        

Answer 1

I wouldn't recommend tracking the view list yourself. It could lead to weird issues with item updates, position updates, etc.

Instead on your SellRecordChangedEvent, use findViewHolderForAdapterPosition() instead of adapter.getView().

@Subscribe
public void onEvent(SellRecordChangedEvent event){
    sell.getSellRecords().set(event.getSellRecordPosition(), event.getSellRecord());
    sell.recalculate();
    int position = event.getSellRecordPosition();
    View view = yourrecyclerview.findViewHolderForAdapterPosition(position);
    bus.post(new TransactionTitleChangedEvent(null, view));
}

http://developer.android.com/reference/android/support/v7/widget/RecyclerView.html#findViewHolderForAdapterPosition(int)

And as a side note, it's better to implement an actual item click listener to the itemView on the ViewHolder instead of using touch listener. There's lots of examples of this online.

Answer 2

Write this method in adapter.

 public Object getItem(int position) {
        return yourArrayList.get(position);
    }

and you just need to call it like

yourAdapter.getItem(2);

pass your required position. Hope it solves your problem.

Answer 3

So the recyclerview and your product information are in 2 different fragments yes? You are expecting the recyclerview's views to update when they are not even in foreground? also you are changing adapter data item's data at position event.getSellRecordPosition() , but you are not notifying the adapter that its dataset changed, either by adapter.notifyDataSetChanged() or the other notifyItemChanged(position) methods.

I'd modify your onEvent() like so:

@Subscribe
public void onEvent(SellRecordChangedEvent event){
    sell.getSellRecords().set(event.getSellRecordPosition(), event.getSellRecord());
    sell.recalculate();
    int position = event.getSellRecordPosition();
    MyViewHolder holder = adapter.onCreateViewHolder(yourRecyclerView, 0);
    adapter.onBindViewHolder(holder,position);
    View view = adapter.getView(position);
    bus.post(new TransactionTitleChangedEvent(null, view));
}

Calling on createViewHolder and next BindViewHolder on your adapter will definitely update the views for that position, then your adapter.getView(position) should return you the latest view.

Here MyViewHolder is your viewholder class and yourRecyclerview, is the reference to your recycler view

Answer 4

Hope this helps someone: I was getting null pointer exceptions with:

• recyclerView.findViewHolderForAdapterPosition
• recyclerView.findViewHolderForItemId
• layoutManager.findViewByPosition.

The reason was that there is a slight delay for the viewholder to be created. I found the solution here: https://stackoverflow.com/a/33414430/7952427

Answer 5

now I understand your problem. you need to use interface for join recyclerview item and activity. you must define an interface class like below:

public interface IViewClick {
    public void onClickButtonAdd();
}

add this parameter to your adapter class:

private IViewClick mListener;

and initialize it in constructor with value that get from inputs. when user click on PLUS button, you send event to activity by this line:

 mListener.onClickButtonAdd();

in your activity class you must implements IViewClick interface and add your code there, like this:

@Override
    public void onClickButtonAdd() {
         ///  TODO every thing that you want.
         /// change your toolbar values.
    }

it is not good solution for you.

RecyclerView.ViewHolder holder = mRecyclerView.findViewHolderForItemId(mAdapter.getItemId(i));