ios - 下拉刷新不适用于空的 TableView

Question

当我清除数据源中的所有数据并重新加载 tableView 时，下拉刷新不再可用。如何在空 tableView 上启用下拉刷新？

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

在我的例子中，我只需要启用弹跳:

self.collectionView.alwaysBounceVertical = YES;

default NO. if YES and bounces is YES, even if content is smaller than bounds, allow drag vertically