ios - 以编程方式使用自动布局的 ScrollView

Question

我正在尝试在 View 中添加 2 个 UIScrollView。我添加了一个 ScrollView ，它运行良好。然后我添加了其他 ScrollView 。但是现在它在第一个 ScrollView 中崩溃了..

func setupTopModelScrollView()
{

    var viewBindingsDictBoth = [String: AnyObject]()
    viewBindingsDictBoth["shortListedScrollView"] = shortListedScrollView
    viewBindingsDictBoth["scrollViewTopModels"] = scrollViewTopModels
    viewBindingsDictBoth["contentView"] = contentView
    viewBindingsDictBoth["contentViewShortListed"] = contentViewShortListed
    viewBindingsDictBoth["lblTitle"] = lblTitle
    viewBindingsDictBoth["mainView"] = self.view

    scrollViewTopModels = UIScrollView(frame:CGRectZero)

    scrollViewTopModels.sizeToFit()

    view.addSubview(scrollViewTopModels)

    scrollViewTopModels.backgroundColor = UIColor.blueColor()

    contentView = UIView()
    contentView.backgroundColor = UIColor.redColor()
    scrollViewTopModels.addSubview(contentView)

    view.translatesAutoresizingMaskIntoConstraints = false
    scrollViewTopModels.translatesAutoresizingMaskIntoConstraints = false
    contentView.translatesAutoresizingMaskIntoConstraints = false

    view.addConstraints(NSLayoutConstraint.constraintsWithVisualFormat("H:|-0-[scrollViewTopModels]-0-|",options: [], metrics: nil,  views:viewBindingsDictBoth))

    let contentViewWidth : Int = arrTopModels.count * Int(SCREENWIDTH)

    scrollViewTopModels.addConstraints(NSLayoutConstraint.constraintsWithVisualFormat("V:|-0-[contentView]-0-|",options: [], metrics: nil,  views:viewBindingsDictBoth))
    scrollViewTopModels.addConstraints(NSLayoutConstraint.constraintsWithVisualFormat("H:|-0-[contentView]-0-|",options: [], metrics: nil,  views:viewBindingsDictBoth))

    view.addConstraints(NSLayoutConstraint.constraintsWithVisualFormat("H:|[contentView(\(contentViewWidth))]|",options: [], metrics: nil, views:viewBindingsDictBoth))
    view.addConstraints(NSLayoutConstraint.constraintsWithVisualFormat("V:[contentView(==scrollViewTopModels)]",options: [], metrics: nil, views:viewBindingsDictBoth))

    scrollViewTopModels.showsHorizontalScrollIndicator = false
    scrollViewTopModels.bounces = false
    scrollViewTopModels.pagingEnabled = true


    for i in 0..<arrTopModels.count
    {

        let topModelView = TopModelCell(frame:CGRectZero)
        contentView.addSubview(topModelView)

        let spaceFromLeft : Int = i * Int(SCREENWIDTH)

        topModelView.translatesAutoresizingMaskIntoConstraints = false
        topModelView.imgModel.image = UIImage(named: arrTopModels.objectAtIndex(i) as! String)

        contentView.addConstraints(NSLayoutConstraint.constraintsWithVisualFormat("H:|-\(spaceFromLeft)-[topModelView(\(SCREENWIDTH))]",options: [], metrics: nil, views:viewBindingsDictBoth))

        contentView.addConstraints(NSLayoutConstraint.constraintsWithVisualFormat("V:|-0-[topModelView(==contentView)]-0-|",options: [], metrics: nil,  views:viewBindingsDictBoth))

        print(topModelView)

        contentView.contentMode = UIViewContentMode.Redraw

    }

}

我收到这个错误并崩溃了..

*** Terminating app due to uncaught exception 'NSInvalidArgumentException', reason: 'Unable to parse constraint format: 
Unable to interpret '|' character, because the related view doesn't have a superview 
H:|-0-[scrollViewTopModels]-0-| 
                           ^'

我卡住了..如果有人能帮忙的话。

提前致谢..

Answer 1

我找到了答案。我们需要在添加 subview 后声明字典。否则它将花费 nill。

var viewBindingsDictBoth = [String: AnyObject]()
viewBindingsDictBoth["shortListedScrollView"] = shortListedScrollView
viewBindingsDictBoth["scrollViewTopModels"] = scrollViewTopModels
viewBindingsDictBoth["contentView"] = contentView
viewBindingsDictBoth["contentViewShortListed"] = contentViewShortListed
viewBindingsDictBoth["lblTitle"] = lblTitle
viewBindingsDictBoth["mainView"] = self.view

我们必须在分配所有 View 后编写此代码..