ios - 尝试在 Swift 中使用 AutoLayout curl / curl 两个 View

Question

使用自动布局，我在屏幕上居中了两个 UIView，现在我尝试使用 CurlUp 从一个 View 转换到另一个 View ，然后使用此函数使用 CurlDown 转换:

func curlUp() {
    let transitionOptions = UIViewAnimationOptions.TransitionCurlUp

    UIView.transitionFromView(cardFront,
        toView: cardBack,
        duration: 5.0,
        options: transitionOptions,
        completion: { _ in

            let transitionOptions = UIViewAnimationOptions.TransitionCurlDown

            UIView.transitionFromView(self.cardBack,
                toView: self.cardFront,
                duration: 5.0,
                options: transitionOptions,
                completion: { _ in
                    //
            })

    })

}

发生的情况是整个屏幕 curl ，如下图所示:

View Controller 的完整源代码在这里: https://github.com/melling/Swift/blob/master/TransitionWithView/TransitionWithView/ViewController.swift

Github 项目使用 Xcode 6.3.1 构建并运行

这是用于添加 subview 的代码:

func buildView() {

    cardBack = UIView()
    cardBack.setTranslatesAutoresizingMaskIntoConstraints(false)
    cardBack.backgroundColor = UIColor.redColor()
    self.view.addSubview(cardBack)

    cardFront = UIView()
    cardFront.setTranslatesAutoresizingMaskIntoConstraints(false)
    cardFront.backgroundColor = UIColor.greenColor()
    self.view.addSubview(cardFront)

    let height = 50
    let width = 50

    let viewDictionary:Dictionary<String,UIView> = ["cardFront": cardFront, "cardBack": cardBack]

    let metrics:Dictionary<String,Int> = ["width": width, "height": height]
    let hConstraint = "H:[cardFront(==width)]"
    let vConstraint = "V:[cardFront(==height)]"

    addStandardConstraints(hConstraint, viewDictionary: viewDictionary, metrics: metrics)
    addStandardConstraints(vConstraint, viewDictionary: viewDictionary, metrics: metrics)

    centerViewXY(self.view, child: cardFront)

    let h1Constraint = "H:[cardBack(==width)]"
    let v1Constraint = "V:[cardBack(==height)]"

    addStandardConstraints(h1Constraint, viewDictionary: viewDictionary, metrics: metrics)
    addStandardConstraints(v1Constraint, viewDictionary: viewDictionary, metrics: metrics)

    centerViewXY(self.view, child: cardBack)

    NSTimer.scheduledTimerWithTimeInterval(2, target: self, selector: "curlUp", userInfo: nil, repeats: false)


}

func centerViewXY(parent: UIView, child: UIView) {

    var constX = NSLayoutConstraint(item: child, attribute: NSLayoutAttribute.CenterX, relatedBy: NSLayoutRelation.Equal, toItem: parent, attribute: NSLayoutAttribute.CenterX, multiplier: 1, constant: 0)
    parent.addConstraint(constX)

    var constY = NSLayoutConstraint(item: child, attribute: NSLayoutAttribute.CenterY, relatedBy: NSLayoutRelation.Equal, toItem: parent, attribute: NSLayoutAttribute.CenterY, multiplier: 1, constant: 0)
    parent.addConstraint(constY)

}

func addStandardConstraints(aConstraint:String, viewDictionary:Dictionary<String,UIView!>, metrics:Dictionary<String, Int>) {

    self.view.addConstraints(NSLayoutConstraint.constraintsWithVisualFormat(aConstraint, options: nil, metrics: metrics, views: viewDictionary))

}

[更新]

创建容器成功了。我将工作代码提交到Github:https://github.com/melling/Swift

TransitionWithView 是 Xcode 项目。

Answer 1

是的，一个常见问题。您需要使用另一个 View 来包含您正在转换的两个 View 。参见 this other SO answer .