在scrollView中以编程方式添加的按钮的自动版式约束

Question

我正在努力使自动布局适用于填充了未知数量的按钮的水平滚动视图（在这种情况下，该数目存储在sceneCount中）。 我也尝试过以其他方式解决该问题，但这似乎是我最接近结果的方法（没有矛盾的约束）。 不幸的是，我在运行时只得到白屏，没有错误。 这是我多么希望我的滚动视图会是什么样子。 希望你们能发现问题！

import UIKit

class ViewController: UIViewController {

let sceneCount = 4
var button = UIButton.buttonWithType(UIButtonType.System) as! UIButton
var buttons: [UIButton] = [UIButton]()


func makeLayout(){

    //Make the content view
    let view1 = UIScrollView()
    view1.setTranslatesAutoresizingMaskIntoConstraints(false)
    view1.backgroundColor = UIColor.redColor()

    //Make the scroll view
    let view2 = UIScrollView()
    view2.setTranslatesAutoresizingMaskIntoConstraints(false)
    view2.backgroundColor = UIColor(red: 0.75, green: 0.75, blue: 0.1, alpha: 1.0)

    view.addSubview(view1)
    view2.addSubview(view1)

    //Create the buttons
    for i in 0...(sceneCount-1) {
        button.setTranslatesAutoresizingMaskIntoConstraints(false)
        button.addTarget(self, action: Selector("scene\(i)Pressed"), forControlEvents: UIControlEvents.TouchUpInside)
        button.setBackgroundImage(UIImage(named: "Scene\(i+1)"), forState: UIControlState.Normal)
        button.sizeThatFits(CGSizeMake(40, 40))

        buttons.append(button)
        view1.addSubview(button)

    }

    //set horizontal spacing between the buttons
    for i in 1...(sceneCount-2) {
        var button1 = UIButton.buttonWithType(UIButtonType.System) as! UIButton
        var button2 = UIButton.buttonWithType(UIButtonType.System) as! UIButton
        button1 = buttons[i - 1]
        button2 = buttons[i]
        var dictionary1 = [String: UIButton]()
        dictionary1.updateValue(button1, forKey: "scene1")
        dictionary1.updateValue(button2, forKey: "scene2")

        view1.addConstraints(NSLayoutConstraint.constraintsWithVisualFormat("H:[scene1]-[scene2]", options: NSLayoutFormatOptions(0), metrics: nil, views: dictionary1) as [AnyObject])
    }

    //set vertical spacing for all buttons
    for i in 0...(sceneCount-1) {
        var button1 = UIButton.buttonWithType(UIButtonType.System) as! UIButton
        button1 = buttons[i]
        var dictionary2 = [String: UIButton]()
        dictionary2.updateValue(button1, forKey: "button1")

        view1.addConstraints(NSLayoutConstraint.constraintsWithVisualFormat("V:|-0-[button1]-0-|", options: NSLayoutFormatOptions(0), metrics: nil, views: dictionary2) as [AnyObject])
    }

    //set horizontal distance to container for first button
    if sceneCount > 0 {
        var buttonFirst: UIButton = buttons[0]
        var dictionary3 = [String: UIButton]()
        dictionary3.updateValue(buttonFirst, forKey: "buttonFirst")
        view1.addConstraints(NSLayoutConstraint.constraintsWithVisualFormat("H:|-0-[buttonFirst]", options: NSLayoutFormatOptions(0), metrics: nil, views: dictionary3) as [AnyObject])
    }

    //set horizontal distance to container for last button
    if sceneCount > 0 {
        var buttonLast: UIButton = buttons[sceneCount-1]
        var dictionary4 = [String: UIButton]()
        dictionary4.updateValue(buttonLast, forKey: "buttonLast")
        view1.addConstraints(NSLayoutConstraint.constraintsWithVisualFormat("H:[buttonLast]-0-|", options: NSLayoutFormatOptions(0), metrics: nil, views: dictionary4) as [AnyObject])
    }

}

override func viewDidLoad() {
    super.viewDidLoad()
    makeLayout()
}


override func didReceiveMemoryWarning() {
    super.didReceiveMemoryWarning()
}

}

Answer 1

我设法通过以下三个主要更改使您的代码起作用：

1-您的内容视图必须为UIView类型

let view1 = UIView()

该视图将包含一个UIScrollView（view2），并且必须设置其约束。 在view1上，您可以设置滚动视图的大小，这就是为什么我将视图2与超级视图的距离设为0的原因。

view1.addSubview(view2)

var dictionary = [String: UIView]()
dictionary.updateValue(view1, forKey: "view1")
view.addConstraints(NSLayoutConstraint.constraintsWithVisualFormat("V:|-0-[view1]-0-|", options: NSLayoutFormatOptions(0), metrics: nil, views: dictionary) as [AnyObject])
view.addConstraints(NSLayoutConstraint.constraintsWithVisualFormat("H:|-0-[view1]-0-|", options: NSLayoutFormatOptions(0), metrics: nil, views: dictionary) as [AnyObject])

dictionary = [String: UIView]()
dictionary.updateValue(view2, forKey: "view2")
view1.addConstraints(NSLayoutConstraint.constraintsWithVisualFormat("V:|-0-[view2]-0-|", options: NSLayoutFormatOptions(0), metrics: nil, views: dictionary) as [AnyObject])
view1.addConstraints(NSLayoutConstraint.constraintsWithVisualFormat("H:|-0-[view2]-0-|", options: NSLayoutFormatOptions(0), metrics: nil, views: dictionary) as [AnyObject])

2-当您使用相同的引用创建新按钮时，最终数组在每个位置都将具有相同的按钮。 我将每个按钮的初始化移到内以创建按钮。

var button = UIButton.buttonWithType(UIButtonType.System) as! UIButton
view2.addSubview(button)

3-之后，我刚刚更新了要在按钮和滚动视图（view2）之间插入的约束。

这是最终代码：

import UIKit

class ViewController: UIViewController {

let sceneCount = 4
var buttons: [UIButton] = [UIButton]()

func makeLayout(){

    //Make the content view
    let view1 = UIView()
    view1.setTranslatesAutoresizingMaskIntoConstraints(false)
    view1.backgroundColor = UIColor.redColor()

    //Make the scroll view
    let view2 = UIScrollView()
    view2.setTranslatesAutoresizingMaskIntoConstraints(false)
    view2.backgroundColor = UIColor(red: 0.75, green: 0.75, blue: 0.1, alpha: 1.0)

    view.addSubview(view1)
    view1.addSubview(view2)

    var dictionary = [String: UIView]()
    dictionary.updateValue(view1, forKey: "view1")

    view.addConstraints(NSLayoutConstraint.constraintsWithVisualFormat("V:|-0-[view1]-0-|", options: NSLayoutFormatOptions(0), metrics: nil, views: dictionary) as [AnyObject])
    view.addConstraints(NSLayoutConstraint.constraintsWithVisualFormat("H:|-0-[view1]-0-|", options: NSLayoutFormatOptions(0), metrics: nil, views: dictionary) as [AnyObject])

    dictionary = [String: UIView]()
    dictionary.updateValue(view2, forKey: "view2")

    view1.addConstraints(NSLayoutConstraint.constraintsWithVisualFormat("V:|-0-[view2]-0-|", options: NSLayoutFormatOptions(0), metrics: nil, views: dictionary) as [AnyObject])
    view1.addConstraints(NSLayoutConstraint.constraintsWithVisualFormat("H:|-0-[view2]-0-|", options: NSLayoutFormatOptions(0), metrics: nil, views: dictionary) as [AnyObject])

    //Create the buttons
    for i in 0...(sceneCount-1) {
        var button = UIButton.buttonWithType(UIButtonType.System) as! UIButton

        button.setTranslatesAutoresizingMaskIntoConstraints(false)
        button.addTarget(self, action: Selector("scene\(i)Pressed"), forControlEvents: UIControlEvents.TouchUpInside)
        button.setBackgroundImage(UIImage(named: "Scene\(i+1)"), forState: UIControlState.Normal)
        button.sizeThatFits(CGSizeMake(40, 40))

        buttons.append(button)
        view2.addSubview(button)
    }

    //set vertical spacing for all buttons
    for i in 0...(sceneCount-1) {
        var button1 = buttons[i]
        var dictionary2 = [String: UIButton]()
        dictionary2.updateValue(button1, forKey: "button1")

        view2.addConstraints(NSLayoutConstraint.constraintsWithVisualFormat("V:|-0-[button1]-0-|", options: NSLayoutFormatOptions(0), metrics: nil, views: dictionary2) as [AnyObject])
    }

    //set horizontal distance to container for first button
    if sceneCount > 0 {
        var buttonFirst: UIButton = buttons[0]
        var dictionary3 = [String: UIButton]()
        dictionary3.updateValue(buttonFirst, forKey: "buttonFirst")
        view2.addConstraints(NSLayoutConstraint.constraintsWithVisualFormat("H:|-[buttonFirst]", options: NSLayoutFormatOptions(0), metrics: nil, views: dictionary3) as [AnyObject])
    }

    //set horizontal spacing between the buttons
    for i in 1...(sceneCount-1) {
        var button1 = buttons[i - 1]
        var button2 = buttons[i]

        var dictionary1 = [String: UIButton]()
        dictionary1.updateValue(button1, forKey: "scene1")
        dictionary1.updateValue(button2, forKey: "scene2")

        view2.addConstraints(NSLayoutConstraint.constraintsWithVisualFormat("H:[scene1]-[scene2]", options: NSLayoutFormatOptions(0), metrics: nil, views: dictionary1) as [AnyObject])
    }

    //set horizontal distance to container for last button
    if sceneCount > 0 {
        var buttonLast: UIButton = buttons[sceneCount-1]
        var dictionary4 = [String: UIButton]()
        dictionary4.updateValue(buttonLast, forKey: "buttonLast")
        view2.addConstraints(NSLayoutConstraint.constraintsWithVisualFormat("H:[buttonLast]-|", options: NSLayoutFormatOptions(0), metrics: nil, views: dictionary4) as [AnyObject])
    }

}

override func viewDidLoad() {
    super.viewDidLoad()
    makeLayout()
}


override func didReceiveMemoryWarning() {
    super.didReceiveMemoryWarning()
}
}