Question

我有一个UITabBarController的子类，声明如下

class TabbarViewController: UITabBarController, UITabBarControllerDelegate {
    func tabBarController(_ tabBarController: UITabBarController, shouldSelect viewController: UIViewController) -> Bool {
        self.currentTabIndex = tabBarController.selectedIndex

        if self.currentTabIndex == 2 {
            let reportVC = UIWindow.getVisibleViewControllerFrom(tabBarController) as? ReportsViewController

            if let reportsViewController = reportVC {
                if reportsViewController.reportTableView.numberOfRows(inSection: 0) > 0 {
                    reportVC?.reportTableView.scrollToRow(at: IndexPath(row: 0, section: 0), at: .top, animated: true)

                    let navVC = viewController as? UINavigationController
                    let destinationVC = navVC?.viewControllers.last as? ReportsViewController

                    return (destinationVC != nil) ? false : true
                }
            }
        }
        return true
    }

    func tabBarController(_ tabBarController: UITabBarController, didSelect viewController: UIViewController) {
        let newIndex = tabBarController.selectedIndex

        let tabIndexList = [0, 1]

        if self.currentTabIndex == newIndex && tabIndexList.contains(newIndex)  {
            let hbgViewController = (newIndex == 2)
                ? tabBarController.selectedViewController as! UINavigationController
                : tabBarController.selectedViewController as! DLHamburguerNavigationController

            switch newIndex {
            case 0:
                let alertsViewController = hbgViewController.viewControllers[0] as! AlertsViewController
                alertsViewController.alertsTableView.scrollToRow(at: IndexPath(row: 0, section: 0), at: .top, animated: true)
                break
            case 1:
                let newsViewController = hbgViewController.viewControllers[0] as! NewsViewController
                newsViewController.newsTableView.scrollToRow(at: IndexPath(row: 0, section: 0), at: .top, animated: true)
                break
            default:
                break
            }
        }
    }
}

当用户点击当前选定的标签时，桌面视图会滚动到顶部。这可以按预期工作，但是，当用户点击表视图中的项目时，webview将加载远程新闻文章。视图被解除后，上面的代码不再有效，导航标签有效，但didSelect和shouldSelect不再被调用。我不明白为什么。

以下是webview的呈现方式：

func tableView(_ tableView: UITableView, didSelectRowAt indexPath: IndexPath) {
    let newImageSource = self.newsArticles?[indexPath.row].getImageUrl(type: Article.FireNewsImageType.NewsFeed)

    let articleURLString = self.newsArticles?[indexPath.row].url

    let webViewController = GDWebViewController()
    webViewController.title = self.newsArticles?[indexPath.row].title
    let webVCNav = UINavigationController(rootViewController: webViewController)

    webViewController.showsToolbar = false
    webViewController.progressIndicatorStyle = .both
    webViewController.loadURLWithString(articleURLString!)

    let cancel = UIBarButtonItem(barButtonSystemItem: .cancel, target: self, action: #selector(NewsViewController.dismissVC))
    webViewController.navigationItem.rightBarButtonItem = cancel

    self.present(webVCNav, animated: true, completion: nil)
}

如果需要，可以在此处找到GDWebViewController： https://gist.github.com/elimence/91cf35dfe677b38b23a27c6d54d44285

任何指针都将不胜感激，谢谢：）

Answer 1

您似乎没有将UITabBarController的{{1}}设置为delegate班级

您可以将其放在TabbarViewController或代码的其他部分，如下所示。

viewDidLoad()

UITabBarController didSelect并且在呈现和解除webView后不再调用

1 个答案: