如何使用委托将数据从 UIPageViewController 传递到子 ViewController [英] how to pass data from UIPageViewController to child ViewController using delegates

问题描述

我想将数据从 UIPageViewController 传递到其子 ViewControllers 之一.我有一个这样的协议集:

I want to pass data from a UIPageViewController to one of its child ViewControllers. I have a protocol set like so:

protocol Delegate : class{
    func protocolMethod(count:Int)
}

在UIPageViewController中:

class PageVC : UIPageViewController{
    var delegate : Delegate?
    var count : Int = 1

    func classMethod(){
        self.displayPageForIndex(5) //this controlls the tranistion to the child ViewController 
        self.delegate?.protocolMethod(count : self.count) 
    }
}

在符合子ViewController中:

class ChildVC : UIViewController , Delegate{

    func protocolMethod(count : Int){
        print(count)
    }

    override func viewDidLoad() { 
        super.viewDidLoad()
        let pvc = PageVC()
        pvc.delegate = self
    }
}

我在 viewDidLoad 中所做的是我尝试过的最简单的解决方案，但仍然找不到关于如何让 PageViewController 知道的答案子 ViewController 是协议方法的接收者.如果有人可以在不使用 prepareForSegue 的情况下帮助我实现这一点(因为没有 segues)，我们将不胜感激.

What I've done in viewDidLoad is the most simplistic solution I've tried, but still couldn't find the answer as to how to let the PageViewController know that the child ViewController is the receiver of the protocol method. If anyone could help me accomplish that without using prepareForSegue (as there are no segues) it would be very much appreciated.

推荐答案

问题出在这行:

    let pvc = PageVC()

这使得一个新的、独立的 PageVC.那不是你想要的.您想要对 现有的、实际的 PageVC 的引用，它的父级是 this.该引用是 self.parent(虽然可能不是在 viewDidLoad 中，这相当早，可能还不能保证我们是孩子).

That makes a new, separate PageVC. That's not what you want. You want a reference to the existing, actual PageVC whose parent this is. That reference is self.parent (though not, perhaps, in viewDidLoad, which is rather early and might not guarantee that we are the child yet).

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