README.md

Selectors

RecyclerViewExtensions module providing utilities for selections, akin to ListView's choice modes.

SingleSelector

Tracks a single selection, similar to ListView#CHOICE_MODE_SINGLE.

The state can be updated using toggleSelected(int) or setSelected(int, boolean), typically inside a click listener.

notifyItemChanged(int, Object) is invoked automatically with the PAYLOAD_SELECT payload whenever the selection changes. Callbacks are also provided, via OnSelectionChangedListener.

Selector also provides a bind(ViewHolder, boolean) method, which will set/unset the activated state depending on whether an item is selected or not (see android.R.attr#state_activated).

Example

public class MyAdapter<T extends RecyclerView.ViewHolder>
        extends RecyclerView.Adapter<T>
        implements Selector.OnSelectionChangedListener {
    
    // ...

    private Selector selector;

    @Override
    public void onAttachedToRecyclerView(@NonNull RecyclerView recyclerView) {
        selector = new SingleSelector(recyclerView, this);
    }

    @Override
    public void onBindViewHolder(@NonNull T holder, int position) {
        selector.bind(holder, true);
    }

    @Override
    public void onSelectionChanged(long[] selectedIds, long[] previousSelectedIds) {
        // The selection has changed.
    }

    private class MyViewHolder extends RecyclerView.ViewHolder
            implements View.OnClickListener {
        
        public MyViewHolder(View itemView) {
            super(itemView);
            itemView.setOnClickListener(this);
        }

        @Override
        public void onClick(View v) {
            selector.toggleSelected(getItemId());
        }
    }
}

MultiSelector

Tracks multiple selections, similar to ListView#CHOICE_MODE_MULTIPLE.

Other than this, the behavior and workflow is the same as with SingleSelector.