Question

如何使用带有委托的协议将ViewController中的字符串值传递到Container中？

protocol VCDelegate {
    func passData(theData:String)        
}

class ViewController: UIViewController {

var delegate : VCDelegate?

@IBAction func getRestaurantInformation(_ sender: Any) {

    let ViewC = ViewController()
    let ContainerV = ContainerView()      

    ViewC.delegate = ContainerV
    ViewC.delegate?.passData(theData: "pass this text")

}
override func viewDidLoad() {

    super.viewDidLoad()

}


class ContainerView: UIViewController, FirstVCDelegate {


func passData(theData: String) {

    print(theData)
    textLabelOut.text = theData //it leaves an error "found nil while implicitly unwrapping optional value"

}


@IBOutlet weak var textLabelOut: UILabel!

override func viewWillAppear(_ animated: Bool) {

}
}

我不断收到错误消息“在隐式展开Optional值时意外发现nil”。但是据我了解，价值并不为零。正在打印。它只是不会将其传递给文本标签

Answer 1

您应该用

加载容器

let containerV = self.storyboard!.......

不是

let containerV = ContainerView()

因为它使所有门店都没有了

在显示vc之前，请勿访问vc的插座

ViewC.delegate?.passData(theData: "pass this text")

因为即使您从情节提要中加载它，出口也将一直为零，直到它加载

如何使用协议将数据从View Controller传递到其中的容器？

1 个答案: