Trigger refresh with VoiceOver three-finger scroll gesture

[vadim-fueled]

The standard UIRefreshControl triggers refresh when a user swipes down with three fingers while the content is already scrolled to top.
VoiceOver users would expect the same behavior from SSPullToRefresh control.

[vadim-fueled]

I ended up overriding accessibilityScroll in SSPullToRefreshView subclass like this:

override func accessibilityScroll(direction: UIAccessibilityScrollDirection) -> Bool {
    if let scrollView = self.scrollView where scrollView.contentOffset.y == -scrollView.contentInset.top && direction == .Up {
        self.startLoadingAndExpand(true, animated: true)
        UIAccessibilityPostNotification(UIAccessibilityAnnouncementNotification, "Refreshing content…")
        return true
    } else {
        return false
    }
}

However it's not called directly, thus I have to call it from accessibilityScroll in my UIViewController subclass (which is called by the system)

override func accessibilityScroll(direction: UIAccessibilityScrollDirection) -> Bool {
    return self.refreshView?.accessibilityScroll(direction) ?? false
}