如何从 UICollectionView Cell 引用 Tab Bar Controller [英] how to reference the Tab Bar Controller from a UICollectionView Cell

问题描述

我有一个选项卡栏控制器应用程序，在其中一个选项卡中有一个 UI 集合视图控制器，其操作分配给一个按钮.这个按钮发挥了它的魔力，然后应该将标签栏视图更改为另一个.但是，我无法将其直接引用到选项卡控制器.

I have a tab bar controller application and in one of the tabs a UI Collection View Controller with an action assigned to a button. This button does its magic and then should change the tab bar view to another one. However, I'm not able to reference it right to the tab controller.

tabBarController 是分配给控制器的类名.所以，我试过:

tabBarController is the class name assigned to the controller. So, I tried:

tabBarController.selectedIndex = 3

并直接在tabBarController类中创建一个方法

and also creating a method directly in the tabBarController class

tabBarController.goToIndex(3)

错误提示:goToIndex"的实例成员不能用于类型 tabBarController

The error says: Instance member of 'goToIndex' cannot be used on type tabBarController

有什么想法吗?

谢谢，

推荐答案

我无法理解正确引用它的意思，但希望这会有所帮助.假设 tabBarController 是 UITabBarController 的子类:

Im having a little trouble understanding what you mean by referencing it right, but hopefully this will help. Assuming tabBarController is a subclass of UITabBarController:

class MyTabBarController: UITabBarController {

    /// ...

    func goToIndex(index: Int) {

    }
}

在您的一个选项卡控制器 (UIViewController) 中，您可以使用 self.tabBarController 引用您的 UITabBarController.请注意 self.tabBarController 是可选的.

In one of your tab controllers (UIViewController) you can reference your UITabBarController with self.tabBarController. Note that self.tabBarController is optional.

    self.tabBarController?.selectedIndex = 3

如果您的选项卡 UIViewController 是 UINavigationController 内的 UIViewController，那么您需要像这样引用您的选项卡栏:

If your tab UIViewController is a UIViewController inside a UINavigationController, then you will need to reference your tab bar like this:

self.navigationController?.tabBarController

要在您的子类上调用函数，您需要将标签栏控制器强制转换为您的自定义子类.

To call a function on your subclass you would need to cast the tab bar controller to your custom subclass.

    if let myTabBarController = self.tabBarController as? MyTabBarController {
        myTabBarController.goToIndex(3)
    }

<小时>

根据评论更新:

---

Update based on comments:

您无法访问单元格内的 tabBarController 是正确的，除非您将其设置为单元格本身(不推荐)或应用程序委托的属性.或者，您可以在 UIViewController 上使用目标操作，每次在单元格内点击按钮时调用视图控制器上的函数.

You're correct that you cant access the tabBarController inside the cell unless you made it a property on either the cell itself (not recommended) or the app delegate. Alternatively, you could use target action on your UIViewController to call a function on the view controller every time a button is tapped inside a cell.

class CustomCell: UITableViewCell {
    @IBOutlet weak var myButton: UIButton!
}

class MyTableViewController: UITableViewController {

    override func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {

        let cell = tableView.dequeueReusableCell(withIdentifier: "ReuseIdentifier", for: indexPath) as! CustomCell

        /// Add the indexpath or other data as a tag that we
        /// might need later on. 

        cell.myButton.tag = indexPath.row

        /// Add A Target so that we can call `changeIndex(sender:)` every time a user tapps on the 
        /// button inside a cell.

        cell.myButton.addTarget(self,
                                action: #selector(MyTableViewController.changeIndex(sender:)),
                                for: .touchUpInside)

        return cell
    }


    /// This will be called every time `myButton` is tapped on any tableViewCell. If you need
    /// to know which cell was tapped, it was passed in via the tag property.
    ///
    /// - Parameter sender: UIButton on a UITableViewCell subclass. 

    func changeIndex(sender: UIButton) {

        /// now tag is the indexpath row if you need it.
        let tag = sender.tag

        self.tabBarController?.selectedIndex = 3
    }
}

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