在Swift中设置UITabBarController的视图控制器

Question

在Swift中设置UITabBarController的视图控制器

4

我正试图以编程方式设置自定义TabBarController的视图控制器：

import UIKit

class TabBarViewController: UITabBarController, UITabBarControllerDelegate {

var cameraViewController: UIViewController?
var profileViewController: UIViewController?

override func viewDidLoad() {
    super.viewDidLoad()

    self.delegate = self


    //self.viewControllers = [cameraViewController, profileViewController] as! [AnyObject]?
    let controllers: [UIViewController?] = [cameraViewController, profileViewController]
    self.setViewControllers(controllers as! [AnyObject], animated: true)

}

但是使用 line 进行

self.viewControllers = [cameraViewController, profileViewController] as! [AnyObject]?

我遇到了一个错误，无法将[UIViewController]转换为[AnyObject?]

以下是相关代码：

self.setViewControllers(controllers as! [AnyObject], animated: true)

我收到一个错误，提示说：

Cannot invoke 'setViewControllers' with an argument list of type '([AnyObject], animated: Bool)'

我的问题与 AnyObject 和类型转换有关。

- Superian007

1个回答

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- fabian789 · Accepted Answer

问题在于你尝试使用的视图控制器被声明为可选项：

var cameraViewController: UIViewController?
var profileViewController: UIViewController?

所以你有三个选择：

Don't make them optional. This requires that you initialize them with something when you initalize your TabBarViewController. Maybe the safest option.
If you know that cameraViewController and profileViewController are never nil in viewDidLoad:
```
self.viewControllers = [cameraViewController!, profileViewController!]
```
Check if cameraViewController and profileViewController are not nil in viewDidLoad. This smells like bad design to me though.
```
if let c = cameraViewController, let p = profileViewController {
    self.viewControllers = [c, p]
}
```

因此，问题在于如何初始化cameraViewController和profileViewController。它们是在选项卡栏视图控制器显示之前设置的吗？如果是这样，我建议在您的类中添加自定义init。