将值从子视图页面快速传递到 Pageview 控制器

Posted 2023-03-13

【中文标题】将值从子视图页面快速传递到 Pageview 控制器

【英文标题】：Pass value from child view page to Pageview controller in swift

【发布时间】：2020-07-22 11:10:21

【问题描述】：

我是 android 开发者，对 ios 很陌生。

我有一个pageView Controller 说A。它连接到三个子View Controller。我想从子视图控制器取回一个值回到根页面视图控制器。 在android中可以通过接口传递轻松完成，而在iOS中使用协议会遇到麻烦。

我就是这样的

protocol Z  
func runZ()



Class A: UIViewController, Z 


func runZ( withValue value: String)

//Perform some function



 var orderedViewControllers: [UIViewController] = 
    var myViewController = UIStoryboard(name: "Main", bundle: nil).instantiateViewController(withIdentifier: "myViewController") as! MyViewController
    myViewController.z  = self
    return [ myViewController,
             UIStoryboard(name: "Main", bundle: nil).instantiateViewController(withIdentifier: "C")]
()



Class B : UIViewController
var z = A.self
func sendBackToA()
(z as! Z).runZ(withValue : "CustomString")

我在 myViewController.z = self 处收到错误 无法将类型 '(A) -> () -> A' 的值分配给类型 'A.Type'。

我通过这样的初始化使其以某种方式工作

myViewController.z = A.self

但我的应用程序崩溃了

无法将类型“A.Type”（0x1e0d854d8）的值转换为“Z”

【问题讨论】：

嘿，您已使用此链接的第三个答案***.com/questions/39285588/…。如果你的问题没有解决，请告诉我，我会在这个问题的帖子中写完整的代码。

【参考方案1】：

protocol Z:class 
  func runZ(withValue value: String?)



class A: UIViewController, Z, UINavigationControllerDelegate 



func runZ(withValue value: String?)

//Perform some function



 var orderedViewControllers: [UIViewController] = 
    var myViewController = UIStoryboard(name: "Main", bundle: nil).instantiateViewController(withIdentifier: "B") as! B
    myViewController.z = self
    return [ myViewController,
             UIStoryboard(name: "Main", bundle: nil).instantiateViewController(withIdentifier: "C")]
()

   

class B : UIViewController
    weak var z:Z?
   func sendBackToA()
    z?.runZ(withValue : "CustomString")
   

【参考方案2】：

一些事情......

protocol Z 
    func runZ(withValue value: String)


class A: UIViewController, Z  // "class" rather than "Class"

    func runZ( withValue value: String)
    
    //Perform some function
    

    func orderedViewControllers() -> [UIViewController]   // func because variable declarations don't have a "self"

        // Should get rid of the forced unwrap in the next line
        let myViewController = UIStoryboard(name: "Main", bundle: nil).instantiateViewController(withIdentifier: "myViewController") as! B

        myViewController.z  = self
        return [ myViewController, UIStoryboard(name: "Main", bundle: nil).instantiateViewController(withIdentifier: "C")]
    


class B : UIViewController  // "class" rather than "Class"
    var z: Z?  // The other controller will do the initialization.
    func sendBackToA()

        // Verify that the delegate is registered
        if let z = z 
            z.runZ(withValue : "CustomString")
         else 
            print("Missing delegate assignment")