How to get Position?

[erfannf]

For animating items in ViewBinder method, I need to check if RecyclerView is scrolling up or down. In custom adapters, I usually add a global variable LASTPOSITION and compare it to current position for detecting up or down scroll for proper animation. How can we do so in RendererRecyclerViewAdapter? Also, how can access adapterPosition or position in ViewBinder?

FYI:

  @Override
    public void onBindViewHolder(final RecyclerView.ViewHolder viewHolder, int position) {
           Animation animation = AnimationUtils.loadAnimation(mActivity, (position > lastPosition) ? R.anim.up_from_bottom : R.anim.down_from_top);
         viewHolder.itemView.startAnimation(animation);
         lastPosition = position;
}

[vivchar]

You should extend ViewBinder and put new argument to constructor:

public class AnimatedViewBinder <M extends ViewModel> extends ViewBinder<M> {

	@NonNull
	private final Delegate mDelegate;

	public AnimatedViewBinder(final int layoutID,
	                         @NonNull final Class<M> type,
	                         @NonNull final Delegate delegate,
	                         @NonNull final Binder<M> binder) {
		super(layoutID, type, binder);
 		mDelegate = delegate;
	}

	@Override
	public void bindView(@NonNull final M model, @NonNull final ViewHolder viewHolder) {
		final boolean isUp = viewHolder.getAdapterPosition() > mDelegate.getLastPosition(); 
		Animation animation = AnimationUtils.loadAnimation(getContext(), isUp ? R.anim.up_from_bottom : R.anim.down_from_top);
		viewHolder.itemView.startAnimation(animation);

		mDelegate.setPosition(viewHolder.getAdapterPosition());
		super.bindView(model, viewHolder);
	}

	public interface Delegate {
		int getLastPosition();
		void setPosition(int position);
	}
}

Usages:

rendererDelegate = new AnimatedViewBinder.Delegate() { /* implementation */ }

adapter.registerRenderer(new AnimatedViewBinder(
	R.layout.your_layout,
	YourModel.class,
	rendererDelegate,
	(model, finder, payload) -> { /* ... */ }
));
adapter.registerRenderer(new AnimatedViewBinder(
	R.layout.your_layout2,
	YourModel2.class,
	rendererDelegate,
	(model, finder, payload) -> { /* ... */ }
));