从标签栏控制器以模态方式呈现视图

Question

如何从标签栏控制器以模态方式呈现视图，以便视图覆盖实际视图？

我想用相机构建一个视图。 像“WhatsApp”或“Ins​​tagram”这样的东西，中间有一个按钮，用户可以点击并显示摄像机视图。

此外，用户应该在单击关闭按钮之前移动他之前的选项卡。

这就是我的ViewController连接到TabBarController的方式：

Answer 1

我必须在我正在构建的应用程序中实现类似的东西，这是相对简单的，你需要实现UITabBarController的委托方法才能实现这一点。

你需要实现的委托方法是： tabBarController(_ tabBarController: UITabBarController, shouldSelect viewController: UIViewController) -> Bool

从此方法返回false将阻止选项卡控制器选择选项卡，然后您只需要实现自己的逻辑以编程方式呈现UIViewController 。

这是一个例子：

func tabBarController(_ tabBarController: UITabBarController, shouldSelect viewController: UIViewController) -> Bool {

    // If your view controller is emedded in a UINavigationController you will need to check if it's a UINavigationController and check that the root view controller is your desired controller (or subclass the navigation controller)
    if viewController is YourViewControllerClass {

        let storyboard = UIStoryboard(name: "Main", bundle: nil)
        if let controller = storyboard.instantiateViewController(withIdentifier: "storyboardID") as? YourViewControllerClass {
            controller.modalPresentationStyle = .fullScreen
            self.present(controller, animated: true, completion: nil)
        }

        return false
    }

    // Tells the tab bar to select other view controller as normal
    return true
}

我没有测试上面的代码，因为我的实现略有不同，并且有更多的变量。 一般原则是一样的。

让我知道你如何继续，如有必要，我会更新答案。

Answer 2

假设您符合UITabBarControllerDelegate ，您可以实现：

func tabBarController(_ tabBarController: UITabBarController, didSelect viewController: UIViewController) {

    // here, you should edit "0" to be matched with your selected item
    // for instance, if there is 5 items and the desired item is in the middle, the compared value should be "2"
    if tabBarController.selectedIndex == 0 {

        // simply, you will need to get the desired view controller and persent it:
        let desiredStoryboard = UIStoryboard(name: "Main", bundle: nil)
        let desiredViewController = desiredStoryboard.instantiateViewController(withIdentifier: "storyboard id")

        present(desiredViewController, animated: true, completion: nil)

    }
}

Answer 3

    let modalVC = self.storyboard?.instantiateViewController(withIdentifier: "ViewControllerIdentifier") 
    modalVC.modalTransitionStyle = .crossDissolve
    modalVC.modalPresentationStyle = .full or .overfullscreen // please check which of the options work
    self.present(modalVC, animated: true, completion: {

    })