如何使用委托将数据从UIPageViewController传递给子ViewController [英] how to pass data from UIPageViewController to child ViewController using delegates
问题描述
我想将数据从 UIPageViewController
传递给它的一个子 ViewControllers
。
我有这样的协议集:
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)
}
并且在 UIPageViewController
:
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)
}
}
In符合要求的孩子 ViewController
:
In the conforming child ViewController
:
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,但仍无法找到答案如何让 PageViewController
知道子 ViewController
是协议方法的接收者。
如果有人可以在不使用prepareForSegue的情况下帮助我完成这项任务(因为没有segues),我们将非常感激。
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
问题是这一行:
let pvc = PageVC()
这使得新的,单独的 PageVC。那不是你想要的。您想要引用现有的,实际的 PageVC,其父级是。该引用是 self.parent
(虽然不是,但可能在 viewDidLoad
中,这是相当早的,可能无法保证我们还是孩子。
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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