以编程方式应用自动布局时标签消失-iOS Swift

说明：

在我的ViewController中，我希望根据单选按钮以编程方式创建和调整视图。当我以编程方式创建视图和设置约束时，会出现一个问题，其中一个标签会消失，如果我继续使用该标签，ViewController中的大多数组件会消失并移动

图片：

func serviceHoursRadioButtonAction(button: DLRadioButton) {
    if button.currentTitle == "yes" {
        serviceHoursView = UIView()
        if let myView = serviceHoursView {
            myView.backgroundColor = UIColor.lightGrayColor()
            view.addSubview(myView)
            NSLayoutConstraint(item: myView,
                               attribute: .Top,
                               relatedBy: .Equal,
                               toItem: serviceHoursLabel,
                               attribute: .Bottom,
                               multiplier: 1, constant: 10).active = true
            NSLayoutConstraint(item: myView,
                               attribute: .LeftMargin,
                               relatedBy: .Equal,
                               toItem: self.view,
                               attribute: .LeftMargin,
                               multiplier: 1, constant: 0).active = true
            NSLayoutConstraint(item: myView,
                               attribute: .RightMargin,
                               relatedBy: .Equal,
                               toItem: self.view,
                               attribute: .RightMargin,
                               multiplier: 1, constant: 0).active = true
            NSLayoutConstraint(item: myView,
                               attribute: .BottomMargin,
                               relatedBy: .Equal,
                               toItem: self.view,
                               attribute: .BottomMargin,
                               multiplier: 1, constant: 0).active = true

        }


    } else {
        //do nothing, or remove the created view if any.
    }
}

代码：

func serviceHoursRadioButtonAction(button: DLRadioButton) {
    if button.currentTitle == "yes" {
        serviceHoursView = UIView()
        if let myView = serviceHoursView {
            myView.backgroundColor = UIColor.lightGrayColor()
            view.addSubview(myView)
            NSLayoutConstraint(item: myView,
                               attribute: .Top,
                               relatedBy: .Equal,
                               toItem: serviceHoursLabel,
                               attribute: .Bottom,
                               multiplier: 1, constant: 10).active = true
            NSLayoutConstraint(item: myView,
                               attribute: .LeftMargin,
                               relatedBy: .Equal,
                               toItem: self.view,
                               attribute: .LeftMargin,
                               multiplier: 1, constant: 0).active = true
            NSLayoutConstraint(item: myView,
                               attribute: .RightMargin,
                               relatedBy: .Equal,
                               toItem: self.view,
                               attribute: .RightMargin,
                               multiplier: 1, constant: 0).active = true
            NSLayoutConstraint(item: myView,
                               attribute: .BottomMargin,
                               relatedBy: .Equal,
                               toItem: self.view,
                               attribute: .BottomMargin,
                               multiplier: 1, constant: 0).active = true

        }


    } else {
        //do nothing, or remove the created view if any.
    }
}

---

将视图属性TranslateAuthoreSizingMaskinToConstraints设置为false。

设置为

self.view.layoutSubviews（）

修复了我的错误