在Swift中设置UITabBarController的视图控制器 [英] Set view controllers of UITabBarController in Swift

问题描述

我正在尝试以编程方式设置我的自定义TabBarController的视图控制器：

  import UIKit 
 
 class TabBarViewController：UITabBarController，UITabBarControllerDelegate {
 
 var cameraViewController：UIViewController？ 
 var profileViewController：UIViewController？ 
 
覆盖func viewDidLoad（）{
 super.viewDidLoad（）
 
 self.delegate = self 
 
 
 // self.viewControllers = [cameraViewController，profileViewController] as！ [AnyObject]？ 
让控制器：[UIViewController？] = [cameraViewController，profileViewController] 
 self.setViewControllers（控制器为！[AnyObject]，动画：true）
 
} 
  

但是行

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

我收到错误，我无法将[UIViewController]转换为[AnyObject？]

和行

  self.setViewControllers（控制器为！[AnyObject]，动画： true）
  

我收到错误消息：

 无法使用类型'（[AnyObject]，animated：Bool）'
   
 
 
我的问题是AnyObject和类型转换我想。
解决方案
问题是您尝试使用的视图控制器被声明为可选：
  var cameraViewController：UIViewController？ 
 var profileViewController：UIViewController？ 
  
所以你有三个选择：
 
 
 
 
 
 
不要让它们成为可选项。这要求您在初始化 TabBarViewController 时初始化它们。也许是最安全的选择。
 
 
 
 
如果您知道 cameraViewController 和 profileViewController 永远 nil  in  viewDidLoad ：
  self.viewControllers = [cameraViewController！，profileViewController！] 
  
 
 
 
 
检查 cameraViewController 和 profileViewController 在 viewDidLoad 。这对我来说闻起来很糟糕。
 如果让c = cameraViewController，让p = profileViewController {
 self。 viewControllers = [c，p] 
} 
  
 
 
 
 
 
 
因此，归结为如何初始化 cameraViewController 和 profileViewController 。是否在显示标签栏视图控制器之前设置了它们？如果是这样，我建议您在班级中添加自定义 init 。
 
I am trying to programatically set view controllers of my custom TabBarController:
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)

}
But with line
self.viewControllers = [cameraViewController, profileViewController] as! [AnyObject]?
I get an error that I cannot convert [UIViewController] to [AnyObject?]

and with line
self.setViewControllers(controllers as! [AnyObject], animated: true)
I get an error saying:
Cannot invoke 'setViewControllers' with an argument list of type '([AnyObject], animated: Bool)'
My problem is with AnyObject and typecasting I guess.
解决方案
The problem is that the view controllers you are trying to use are declared optional:
var cameraViewController: UIViewController?
var profileViewController: UIViewController?
So you have three options:


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]
}



So it boils down to how you initialize cameraViewController and profileViewController. Are they set before the tab bar view controllers is shown? If so, I recommend adding a custom init to your class.

                        
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