以编程方式创建和推送视图控制器

Question

我正在使用下面的代码作为附加到按钮的实用方法在按钮触摸上创建和推送视图控制器

 func createSmartController() -> UIViewController{

    //Create controller and get view
                var controller = UIViewController()
                var view = controller.view
                var tag:String
                var count = 0

                //Create and layout scroll view
                var scrollView = UIScrollView()
                scrollView.setTranslatesAutoresizingMaskIntoConstraints(false)
                view.addSubview(scrollView)
                view.addConstraint(NSLayoutConstraint(item: scrollView, attribute: NSLayoutAttribute.Top, relatedBy: NSLayoutRelation.Equal, toItem: view, attribute: NSLayoutAttribute.Top, multiplier: 1.0, constant: 0.0))
                view.addConstraint(NSLayoutConstraint(item: scrollView, attribute: NSLayoutAttribute.Bottom, relatedBy: NSLayoutRelation.Equal, toItem: view, attribute: NSLayoutAttribute.Bottom, multiplier: 1.0, constant: 0.0))
                view.addConstraint(NSLayoutConstraint(item: scrollView, attribute: NSLayoutAttribute.Leading, relatedBy: NSLayoutRelation.Equal, toItem: view, attribute: NSLayoutAttribute.Leading, multiplier: 1.0, constant: 0.0))
                view.addConstraint(NSLayoutConstraint(item: scrollView, attribute: NSLayoutAttribute.Trailing, relatedBy: NSLayoutRelation.Equal, toItem: view, attribute: NSLayoutAttribute.Trailing, multiplier: 1.0, constant: 0.0))

                //Create and add content view
                var scrollContent = UIView()
                scrollContent.setTranslatesAutoresizingMaskIntoConstraints(false)
                scrollView.addSubview(scrollContent)
                scrollView.addConstraint(NSLayoutConstraint(item: scrollContent, attribute: NSLayoutAttribute.Top, relatedBy: NSLayoutRelation.Equal, toItem: scrollView, attribute: NSLayoutAttribute.Top, multiplier: 1.0, constant: 0.0))
                scrollView.addConstraint(NSLayoutConstraint(item: scrollContent, attribute: NSLayoutAttribute.Bottom, relatedBy: NSLayoutRelation.Equal, toItem: scrollView, attribute: NSLayoutAttribute.Bottom, multiplier: 1.0, constant: 0.0))
                scrollView.addConstraint(NSLayoutConstraint(item: scrollContent, attribute: NSLayoutAttribute.Leading, relatedBy: NSLayoutRelation.Equal, toItem: scrollView, attribute: NSLayoutAttribute.Leading, multiplier: 1.0, constant: 0.0))
                scrollView.addConstraint(NSLayoutConstraint(item: scrollContent, attribute: NSLayoutAttribute.Trailing, relatedBy: NSLayoutRelation.Equal, toItem: scrollView, attribute: NSLayoutAttribute.Trailing, multiplier: 1.0, constant: 0.0))
                view.addConstraint(NSLayoutConstraint(item: scrollContent, attribute: NSLayoutAttribute.Leading, relatedBy: NSLayoutRelation.Equal, toItem: view, attribute: NSLayoutAttribute.Leading, multiplier: 1.0, constant: 0.0))
                view.addConstraint(NSLayoutConstraint(item: scrollContent, attribute: NSLayoutAttribute.Trailing, relatedBy: NSLayoutRelation.Equal, toItem: view, attribute: NSLayoutAttribute.Trailing, multiplier: 1.0, constant: 0.0))

                //Create all buttons
                var buttons = self.GetMyButtons() //Just returns and array of UIButtons

                //Add buttons to view with constraints
                var prevButton:String
                var constH:NSArray
                var constV:NSArray
                var hString:String
                var vString:String
                var index = 0
                for button in buttons{
                    button.setTranslatesAutoresizingMaskIntoConstraints(false)
                    scrollContent.addSubview(button)
                    button.bounds.size.height = 90
                    scrollContent.addConstraint(NSLayoutConstraint(item: button, attribute: NSLayoutAttribute.Leading, relatedBy: NSLayoutRelation.Equal, toItem: scrollContent, attribute: NSLayoutAttribute.Leading, multiplier: 1.0, constant: 0.0))
                    scrollContent.addConstraint(NSLayoutConstraint(item: button, attribute: NSLayoutAttribute.Trailing, relatedBy: NSLayoutRelation.Equal, toItem: scrollContent, attribute: NSLayoutAttribute.Trailing, multiplier: 1.0, constant: 0.0))
                    if(index == 0){
                        scrollContent.addConstraint(NSLayoutConstraint(item: button, attribute: NSLayoutAttribute.Top, relatedBy: NSLayoutRelation.Equal, toItem: scrollContent, attribute: NSLayoutAttribute.Top, multiplier: 1.0, constant: 8.0))
                    }
                    else{
                        scrollContent.addConstraint(NSLayoutConstraint(item: button, attribute: NSLayoutAttribute.Top, relatedBy: NSLayoutRelation.Equal, toItem: buttons[index-1], attribute: NSLayoutAttribute.Bottom, multiplier: 1.0, constant: 8.0))
                    }
                    if(index == buttons.count-1){
                        scrollContent.addConstraint(NSLayoutConstraint(item: button, attribute: NSLayoutAttribute.Bottom, relatedBy: NSLayoutRelation.Equal, toItem: scrollContent, attribute: NSLayoutAttribute.Bottom, multiplier: 1.0, constant: -8.0))
                    }
                    index++
                }
return controller
    }

在下面的调用中使用此方法来生成并推送按钮 touchupinside 上的视图控制器

var controller = button.getSmartController()
            self.navigationController?.pushViewController(controller, animated: true)

但是，我被推送的视图控制器似乎根本没有视图。它是黑色/空白。推送动画似乎也有一点小问题。

Answer 1

所有背景颜色都不存在并显示为黑色。以编程方式创建元素时，还必须添加样式，否则所有默认值都将返回为 null/black。