SmoothScrollingLayoutManager

//
// Usage :
//   recyclerView.setLayoutManager(new SmoothScrollingLayoutManager(getContext()));
//   recyclerView.smoothScrollToPosition(0);
//

//
// SmoothScrollingLayoutManager
// Makersphere
//
// Created by Ben on 02/06/2016.
// Copyright (c) 2016 SHAPE A/S. All rights reserved.
//
public class SmoothScrollingLayoutManager extends LinearLayoutManager {

    private static final float SMOOTH_SCROLL_MILLIS = 100;

    LinearSmoothScroller smoothScroller;

    public SmoothScrollingLayoutManager(Context context) {
        super(context);
        smoothScroller = new SmoothScroller(context);
    }

    @Override
    public void smoothScrollToPosition(RecyclerView recyclerView, RecyclerView.State state, final int position) {
        smoothScroller.setTargetPosition(position);
        startSmoothScroll(smoothScroller);
    }

    private class SmoothScroller extends LinearSmoothScroller {

        public SmoothScroller(Context context) {
            super(context);
        }

        @Override
        public PointF computeScrollVectorForPosition(int targetPosition) {
            return SmoothScrollingLayoutManager.this.computeScrollVectorForPosition(targetPosition);
        }

        @Override
        protected float calculateSpeedPerPixel(DisplayMetrics displayMetrics) {
            return SMOOTH_SCROLL_MILLIS / TypedValue.applyDimension(TypedValue.COMPLEX_UNIT_DIP, 1000, displayMetrics);
        }

        @Override
        protected int getVerticalSnapPreference() {
            return SNAP_TO_START;
        }
    }
}