FilipLuch FilipLuch - 4 months ago 79
Android Question

How to update RecyclerView Adapter Data?

For 4 days I can't figure out what exactly is the issue with updating

RecyclerView
's Adapter.

After I get a new List of products, I tried to:


  1. Update the
    ArrayList
    from the fragment where
    recyclerView
    is created, set new data to adapter, then call
    adapter.notifyDataSetChanged()
    ; it did not work.

  2. Create a new adapter, as others did, and it worked for them, but no change for me:
    recyclerView.setAdapter(new RecyclerViewAdapter(newArrayList))

  3. Create a method in
    Adapter
    which updates the data as follows:

    public void updateData(ArrayList<ViewModel> viewModels) {
    items.clear();
    items.addAll(viewModels);
    notifyDataSetChanged();
    }


    Then I call this method whenever I want to update the data list; it did not work.

  4. To check if I can modify the recyclerView in any way, and I tried to remove at least an item:

    public void removeItem(int position) {
    items.remove(position);
    notifyItemRemoved(position);
    }


    Everything remained as it was.



Here is my Adapter:

public class RecyclerViewAdapter extends RecyclerView.Adapter<RecyclerViewAdapter.ViewHolder> implements View.OnClickListener {

private ArrayList<ViewModel> items;
private OnItemClickListener onItemClickListener;

public RecyclerViewAdapter(ArrayList<ViewModel> items) {
this.items = items;
}


public void setOnItemClickListener(OnItemClickListener onItemClickListener) {
this.onItemClickListener = onItemClickListener;
}

@Override
public ViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
View v = LayoutInflater.from(parent.getContext()).inflate(R.layout.item_recycler, parent, false);
v.setOnClickListener(this);
return new ViewHolder(v);
}

public void updateData(ArrayList<ViewModel> viewModels) {
items.clear();
items.addAll(viewModels);
notifyDataSetChanged();
}
public void addItem(int position, ViewModel viewModel) {
items.add(position, viewModel);
notifyItemInserted(position);
}

public void removeItem(int position) {
items.remove(position);
notifyItemRemoved(position);
}



@Override
public void onBindViewHolder(ViewHolder holder, int position) {
ViewModel item = items.get(position);
holder.title.setText(item.getTitle());
Picasso.with(holder.image.getContext()).load(item.getImage()).into(holder.image);
holder.price.setText(item.getPrice());
holder.credit.setText(item.getCredit());
holder.description.setText(item.getDescription());

holder.itemView.setTag(item);
}

@Override
public int getItemCount() {
return items.size();
}

@Override
public void onClick(final View v) {
// Give some time to the ripple to finish the effect
if (onItemClickListener != null) {
new Handler().postDelayed(new Runnable() {
@Override
public void run() {
onItemClickListener.onItemClick(v, (ViewModel) v.getTag());
}
}, 0);
}
}

protected static class ViewHolder extends RecyclerView.ViewHolder {
public ImageView image;
public TextView price, credit, title, description;

public ViewHolder(View itemView) {
super(itemView);
image = (ImageView) itemView.findViewById(R.id.image);
price = (TextView) itemView.findViewById(R.id.price);
credit = (TextView) itemView.findViewById(R.id.credit);
title = (TextView) itemView.findViewById(R.id.title);
description = (TextView) itemView.findViewById(R.id.description);
}
}

public interface OnItemClickListener {

void onItemClick(View view, ViewModel viewModel);

}
}


And I initiate
RecyclerView
as follows:

recyclerView = (RecyclerView) view.findViewById(R.id.recycler);
recyclerView.setLayoutManager(new GridLayoutManager(getActivity(), 5));
adapter = new RecyclerViewAdapter(items);
adapter.setOnItemClickListener(this);
recyclerView.setAdapter(adapter);


So, how do I actually update adapter data in order to display newly received items?




Update: the issue was that the layout where gridView was looked as follows:

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout
xmlns:android="http://schemas.android.com/apk/res/android"
android:orientation="vertical"
android:layout_width="match_parent"
android:tag="catalog_fragment"
android:layout_height="match_parent">

<FrameLayout
android:orientation="vertical"
android:layout_width="match_parent"
android:layout_height="match_parent">

<android.support.v7.widget.RecyclerView
android:id="@+id/recycler"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:clipToPadding="false"/>

<ImageButton
android:id="@+id/fab"
android:layout_gravity="top|end"
style="@style/FabStyle"/>

</FrameLayout>
</LinearLayout>


Then I just removed
LinearLayout
and made
FrameLayout
as parent layout.

Answer

I'm working with RecyclerView and both the remove and the update work well.

1) REMOVE: There are 4 steps to remove an item from a RecyclerView

list.remove(position);
recycler.removeViewAt(position);
mAdapter.notifyItemRemoved(position);                 
mAdapter.notifyItemRangeChanged(position, list.size());

These line of codes work for me.

2) UPDATE THE DATA: The only things I had to do is

mAdapter.notifyDataSetChanged();

You had to do all of this in the Actvity/Fragment code not in the RecyclerView Adapter code.