Question

我有两个视图控制器 - A＆amp; B. ViewController A有一个文本字段。点击ViewController A的文本字段，出现View Controller B，它有另一个Textfield。在ViewController B的键盘上单击完成，调用dissmissViewController，textfield的数据应从viewController B移动到A.

我无法将数据从B传递到A.我会在dissmissviewcontroller之前调用A的ViewdidLoad（）。在A的viewdidLoad（）中，我有这个textfieldA.text = textfieldB。它在扔 -

致命错误：在展开可选值＆＃34;
时意外发现nil

Answer 1

委托模式：

<强> ViewController2：

means = c(paste("mean_Age =",roumean(survey_clean_data[Smoke == "Heavy","Age"],na.rm =T)),
          paste("mean_Age =",mean(survey_clean_data[Smoke == "Never","Age"],na.rm =T)),
          paste("mean_Age =",mean(survey_clean_data[Smoke == "Regul","Age"],na.rm =T)),
          paste("mean_Age =",mean(survey_clean_data[Smoke == "Occas","Age"],na.rm =T)))


text(50,survey_clean_data$Smoke,labels =  means)

<强> ViewController1：

//Define Protocol
@protocol VC2Delegate {
    doneClicked(val:String)
}

Class:VC2 {
    //Create Delegate variable
    var delegate:VC2Delegate?

    //method of done clicked
    func btnDoneClicked(sender:UIButton) {

        //call delegate method
        delegate.doneClicked(vc2TextField.text)
        //dismiss view controller
        self.dismissViewController......
    }

}

在dismissViewController期间无法为文本字段赋值

1 个答案: