ios - 将数据从 Container View 不带 Segue 传递到 MainVC

Question

想法是在按下容器 View (带有 ViewController)中的按钮后将值 trackNumber 发送到 Main ViewController 到 recivedTrackNumber 而无需 segue 因为它们在同一 View 中。如何通知主视图 Controller (recivedTrackNumber)关于 trackNumber 的值？

Container View(with ViewController) 看起来像带按钮的

 import UIKit
 class SelectSoundVC: UIViewController {

   var trackNumber: Int!

   @IBAction func winterSoundBut(_ sender: UIButton) {
    trackNumber = 1

  } 

}

和主视图 Controller

class MainVC: UIViewController {

   var recivedTrackNumber: Int!

}

Main.storyboard Screenshot

Answer 1

Delegate 模式应该对您有所帮助。首先，您需要委托(delegate)协议(protocol):

protocol SelectSoundVCDelegate {
    func didSelectTrackNumber(_ trackNumber: Int)
}

使用接受 trackNumber 值的函数。接下来，您需要在 SelectSoundVC 中创建 delegate 属性:

class SelectSoundVC: UIViewController {

    weak var delegate: SelectSoundVCDelegate?
    var trackNumber: Int!

    @IBAction func winterSoundBut(_ sender: UIButton) {
        trackNumber = 1
        delegate?.didSelectTrackNumber(trackNumber)
    } 

}  

这将调用 @IBAction 中的 didSelectTrackNumber。请注意，delegate 属性应该是 weak 以避免引用循环。最后一步，在 MainVC 中，您应该设置 SelectSoundVC 的 delegate 属性:

selectSoundVC.delegate = self  

这部分有点棘手，因为您需要 SelectSoundVC 的实例来设置委托(delegate)。可以在prepareFoSegue方法中设置，例如:

override func prepare(for segue: UIStoryboardSegue, sender: Any?) {
    if let viewController = segue.destination as? SelectSoundVC, segue.identifier == "SelectSoundVC" {
        viewController.delegate = self
    }
}