calculateDistanceToFinalSnap.java

@Override
int[] calculateDistanceToFinalSnap(@NonNull RecyclerView.LayoutManager layoutManager, @NonNull View targetView) {
    int[] out = new int[2];
    if (layoutManager.canScrollHorizontally()) {
        out[0] = getDistance(layoutManager, targetView, OrientationHelper.createHorizontalHelper(layoutManager));
    } else {
        out[0] = 0;
    }

    if (layoutManager.canScrollVertically()) {
        out[1] = getDistance(layoutManager, targetView, OrientationHelper.createVerticalHelper(layoutManager));
    } else {
        out[1] = 0;
    }
    return out;
}

int getDistance(RecyclerView.LayoutManager layoutManager, View targetView, OrientationHelper helper) {
    final int childStart = helper.getDecoratedStart(targetView);
    final int containerStart = helper.getStartAfterPadding();
    return childStart - containerStart;
}