在scrollView中以編程方式添加的按鈕的自動版式約束

Question

我正在努力使自動布局適用於填充了未知數量的按鈕的水平滾動視圖（在這種情況下，該數目存儲在sceneCount中）。 我也嘗試過以其他方式解決該問題，但這似乎是我最接近結果的方法（沒有矛盾的約束）。 不幸的是，我在運行時只得到白屏，沒有錯誤。 這是我多么希望我的滾動視圖會是什么樣子。 希望你們能發現問題！

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

我設法通過以下三個主要更改使您的代碼起作用：

1-您的內容視圖必須為UIView類型

let view1 = UIView()

該視圖將包含一個UIScrollView（view2），並且必須設置其約束。 在view1上，您可以設置滾動視圖的大小，這就是為什么我將視圖2與超級視圖的距離設為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-當您使用相同的引用創建新按鈕時，最終數組在每個位置都將具有相同的按鈕。 我將每個按鈕的初始化移到內以創建按鈕。

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

3-之后，我剛剛更新了要在按鈕和滾動視圖（view2）之間插入的約束。

這是最終代碼：

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()
}
}