ios - 如何在没有链接到 View Controller 的情况下快速创建标签栏项目

Question

所以我的问题是我正在创建一个没有 Storyboard 的 UITabBarController，并且我对如何创建一个没有 Viewcontroller 的 UITabBar 项目感到困惑。因为我想要做的是我的 UITabBarItem 的第二项是一个不呈现 View Controller 的 Action 。

Answer 1

虽然我使用 Storyboard，但我在应用程序(关闭按钮)中实现了类似的功能。关闭按钮是一个 viewController，但我使用以下代码让它像普通按钮一样工作:

 func tabBarController(_ tabBarController: UITabBarController, shouldSelect viewController: UIViewController) -> Bool {
    // this provides UI feedback that the button has been pressed, even though it leads to the dismissal
        if viewController == self.viewControllers![4] {

           viewController.tabBarItem.image? = UIImage(named: "TabBarClose")!.imageWithColor(UIColor.red).withRenderingMode(UIImageRenderingMode.alwaysOriginal)

            return false
        } else {
        return true
        }
    }

override func viewDidDisappear(_ animated: Bool) {
//sets the close button back to original image
    self.viewControllers![4].tabBarItem.image = UIImage(named: "TabBarClose")!
}

func tabBarController(_ tabBarController: UITabBarController, didSelect viewController: UIViewController) {
// this is so it never actually goes to the close buttons viewController
    currentTab = self.selectedIndex != 4 ? self.selectedIndex:currentTab
    saveTabIndexToPreferences(currentTab!)

}

override func tabBar(_ tabBar: UITabBar, didSelect item: UITabBarItem) {
    // assign functionality to the close button
    if item.tag == 100 {// this is old code, there is probably a better way to reference the tab
        dismissTabBar()
    } else {

    }        
}

编辑(对于被问到的问题)

func selectTabIndexFromPreferences() {
    let defaults:UserDefaults = UserDefaults.standard
    selectedIndex = defaults.integer(forKey: "songSelectionTabIndex_preference")
}

func saveTabIndexToPreferences(_ index:Int?) {
    if index != nil {
        let defaults:UserDefaults = UserDefaults.standard
        defaults.set(index!, forKey: "songSelectionTabIndex_preference")   
    }
}