Pull-to-refresh在空TableView上不起作用

Question

当我清除数据源中的所有数据并重新加载tableView时,不再提供pull-to-refresh.如何在空tableView上启用pull-to-refresh？

override func viewDidLoad() {
    super.viewDidLoad()
    ...
    // Pull to refresh for iPhone
    refreshControl?.addTarget(self, action: "refresh:", forControlEvents: UIControlEvents.ValueChanged)

    tableView.tableFooterView = UIView(frame: CGRectZero) // To remove separator line on empty cells
    tableView.estimatedRowHeight = Constants.DetailTableView.estimatedRowHeight
    tableView.rowHeight = UITableViewAutomaticDimension

    setupRefreshControl()
}

private func setupRefreshControl() {
    // If on iPhone, List becomes the pull-to-refresh handler and the delegate
    if UIScreen.mainScreen().traitCollection.horizontalSizeClass == .Compact {
        SyncService.shared.delegate = self
        refreshControl?.addTarget(self, action: "refresh:", forControlEvents: UIControlEvents.ValueChanged)
        refreshControl?.tintColor = UIColor.whiteColor()
    } else {
        // Otherwise disable the refresh control in List
        refreshControl = nil
    }
}

Answer 1

就我而言,我只需要启用弹跳:

self.collectionView.alwaysBounceVertical = YES;

默认NO.如果是,则弹跳为是,即使内容小于边界,也允许垂直拖动