Swift 中 UIViewController 的自定义初始化，在情节提要中设置界面 [英] Custom init for UIViewController in Swift with interface setup in storyboard

问题描述

我在为 UIViewController 的子类编写自定义 init 时遇到问题，基本上我想通过 viewController 的 init 方法传递依赖项，而不是像 viewControllerB.property = value 那样直接设置属性>

所以我为我的 viewController 做了一个自定义的 init 并调用超级指定的 init

init(meme: Meme?) {self.meme = memesuper.init(nibName: nil, bundle: nil)}

视图控制器接口驻留在故事板中，我还将自定义类的接口作为我的视图控制器.即使你没有在这个方法中做任何事情，Swift 也需要调用这个 init 方法.否则编译器会报错...

required init?(coder aDecoder: NSCoder) {super.init(编码器:aDecoder)}

问题是当我尝试使用 MyViewController(meme: meme) 调用我的自定义 init 时，它根本没有在我的 viewController 中初始化属性...

我试图调试，我在我的 viewController 中发现，init(coder aDecoder: NSCoder) 首先被调用，然后我的自定义 init 被调用.然而，这两个 init 方法返回不同的 self 内存地址.

我怀疑我的 viewController 的 init 有问题，它总是会返回 self 和 init?(coder aDecoder: NSCoder)，它有没有实现.

有谁知道如何正确为您的 viewController 制作自定义初始化?注意:我的viewController的界面是在storyboard中设置的

这是我的视图控制器代码:

class MemeDetailVC : UIViewController {var meme : 模因！@IBOutlet 弱变量editedImage:UIImageView！//TODO: 不正确的初始化初始化(模因:模因?){self.meme = memesuper.init(nibName: nil, bundle: nil)}需要初始化?(编码器aDecoder:NSCoder){super.init(编码器:aDecoder)}覆盖 func viewDidLoad() {///设置导航标题title = "详细信息"super.viewDidLoad()}覆盖 func viewWillAppear(动画:布尔){super.viewWillAppear(动画)编辑图像 = UIImageView(图像:meme.editedImage)}}

解决方案

正如上述答案之一所指定的，您不能同时使用自定义 init 方法和故事板.

但是您仍然可以使用静态方法从情节提要中实例化 ViewController 并对其执行其他设置.

它看起来像这样:

class MemeDetailVC : UIViewController {var meme : 模因！static func makeMemeDetailVC(meme: Meme) ->MemeDetailVC {let newViewController = UIStoryboard(name: "Main", bundle: nil).instantiateViewController(withIdentifier: "IdentifierOfYouViewController") as!MemeDetailVCnewViewController.meme = meme返回新的视图控制器}}

不要忘记在故事板中指定 IdentifierOfYouViewController 作为视图控制器标识符.您可能还需要更改上面代码中故事板的名称.

I'm having issue for writing custom init for subclass of UIViewController, basically I want to pass the dependency through the init method for viewController rather than setting property directly like viewControllerB.property = value

So I made a custom init for my viewController and call super designated init

init(meme: Meme?) {
        self.meme = meme
        super.init(nibName: nil, bundle: nil)
    }

The view controller interface resides in storyboard, I've also make the interface for custom class to be my view controller. And Swift requires to call this init method even if you are not doing anything within this method. Otherwise the compiler will complain...

required init?(coder aDecoder: NSCoder) {
        super.init(coder: aDecoder)
    }

The problem is when I try to call my custom init with MyViewController(meme: meme) it doesn't init properties in my viewController at all...

I was trying to debug, I found in my viewController, init(coder aDecoder: NSCoder) get called first, then my custom init get called later. However these two init method return different self memory addresses.

I'm suspecting something wrong with the init for my viewController, and it will always return self with the init?(coder aDecoder: NSCoder), which, has no implementation.

Does anyone know how to make custom init for your viewController correctly ? Note: my viewController's interface is set up in storyboard

here is my viewController code:

class MemeDetailVC : UIViewController {

    var meme : Meme!

    @IBOutlet weak var editedImage: UIImageView!

    // TODO: incorrect init
    init(meme: Meme?) {
        self.meme = meme
        super.init(nibName: nil, bundle: nil)
    }

    required init?(coder aDecoder: NSCoder) {
        super.init(coder: aDecoder)
    }

    override func viewDidLoad() {
        /// setup nav title
        title = "Detail Meme"

        super.viewDidLoad()
    }

    override func viewWillAppear(animated: Bool) {
        super.viewWillAppear(animated)
        editedImage = UIImageView(image: meme.editedImage)
    }

}

解决方案

As it was specified in one of the answers above you can not use both and custom init method and storyboard.

But you still can use a static method to instantiate ViewController from a storyboard and perform additional setup on it.

It will look like this:

class MemeDetailVC : UIViewController {
    
    var meme : Meme!
    
    static func makeMemeDetailVC(meme: Meme) -> MemeDetailVC {
        let newViewController = UIStoryboard(name: "Main", bundle: nil).instantiateViewController(withIdentifier: "IdentifierOfYouViewController") as! MemeDetailVC
        
        newViewController.meme = meme
        
        return newViewController
    }
}

Don't forget to specify IdentifierOfYouViewController as view controller identifier in your storyboard. You may also need to change the name of the storyboard in the code above.

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