DragDrop

DragDrop

RecyclerViewExtensions module providing utilities for drag & drop.

DragDropHelper

Supports drag & drop for RecyclerView items, provided it is using a LinearLayoutManager.

To use, call attach(RecyclerView, Callback) and provide a Callback to handle the lifecycle of the drag. Afterwards, call start(int) for any position, and DragDropHelper will monitor touch events to handle the drag until it ends.

Example

public class MyAdapter<T extends RecyclerView.ViewHolder>
        extends RecyclerView.Adapter<T>
        implements DragDropHelper.Callback {

    // ...

    private DragDropHelper dragDropHelper = new DragDropHelper();

    @Override
    public void onAttachedToRecyclerView(@NonNull RecyclerView recyclerView) {
        dragDropHelper.attach(recyclerView, this);
    }

    @Override
    public void onDragStarted(@NonNull RecyclerView.ViewHolder holder, boolean create) {
        // Setup the holder.
    }

    @Override
    public void onDragMoved(@NonNull RecyclerView.ViewHolder holder, int x, int y) {
        // Handle drag coordinates.
    }

    @Override
    public int onDragTo(@NonNull RecyclerView.ViewHolder holder, int to) {
        int from = holder.getAdapterPosition();
        dataset.add(to, dataset.remove(from));
        notifyItemMoved(from, to);
        return to;
    }

    @Override
    public void onDragStopped(@NonNull RecyclerView.ViewHolder holder, boolean destroy) {
        // Undo holder setup.
    }
}

Depending on the use case, different flags can be tweaked in DragDropHelper to ensure it behaves as desired.

DragDropTouchDragListener

View.OnDragListener that maps calls to a RecyclerView.OnItemTouchListener.

When the RecyclerView.OnItemTouchListener is DragDropHelper, it enables its use with Android's native drag & drop APIs, reusing its ability to handle view swapping, scrolling, etc.