Swift 3, Xcode 8 实例化视图控制器不工作

Question

Xcode 8 编译时说用标识符更改实例化 viewcontroller 以简单地实例化视图控制器。我这样做了，为什么会报两个错误？

我正在使用 Swift 3. 我想更改页面 programmatically.I已经阅读了很多关于该主题的其他问题。它们都使用带有标识符的实例化视图控制器。他们还没有采用新语言。

@IBAction func switchPage(_ sender: UIButton) {

    let storyboard = UIStoryboard(name: "Main", bundle: nil)
    let viewController = 
storyboard.instantiateViewController("secondViewController") as! 
UIViewController
    self.presentViewController(secondViewController, animated: true, 
completion: nil)    

}

谢谢。我按照建议更改了代码，只收到一个错误：可选类型 'UIStoryboard?' 的值未展开；你是不是想用'！'要么 '？'？我应该在某处加感叹号吗？

import UIKit

class ViewController: UIViewController {

override func viewDidLoad() {
    super.viewDidLoad()
    // Do any additional setup after loading the view, typically from a 
nib.
}

@IBAction func ch(_ sender: UIButton) {



    let viewController = 
storyboard.instantiateViewController(withIdentifier: 
"secondViewController") as! UIViewController
    self.present(viewController, animated: true)



}




override func didReceiveMemoryWarning() {
    super.didReceiveMemoryWarning()
    // Dispose of any resources that can be recreated.
}



}

Answer 1

这样试试。

let storyboard = UIStoryboard(name: "Main", bundle: nil)
let viewController = storyboard.instantiateViewController(withIdentifier :"secondViewController") as! UIViewController
self.present(viewController, animated: true)

Answer 2

这对我有用：

let vc = UIStoryboard(name: "ZWLStaticTabVc", bundle: nil).instantiateInitialViewController()
self.navigationController?.pushViewController(vc!, animated: true)

Answer 3

它对我有用：

 let gameScene = UIStoryboard(name: "Main", bundle:nil).instantiateViewController(withIdentifier: "ViewController") as UIViewController
        let appDelegate = (UIApplication.shared.delegate as! AppDelegate)
        appDelegate.window?.rootViewController = gameScene

Answer 4

在我的例子中，我忘记在情节提要中检查 isInitialViewController 我的 VC。因此，当我调用 instantiateInitialViewController 时它返回 nil。在故事板中检查该选项后，问题解决了。

Swift 3, Xcode 8 实例化视图控制器不工作

Swift 3, Xcode 8 Instantiate View Controller is not working

storyboard

viewcontroller

swift

swift3

xcode8