xcode 按钮重叠，尽管有限制

Question

我正在使用一系列 4 个按钮。所有相同的宽度和高度组合在一起会拉伸视图的宽度。我已经尝试在视觉上将它们彼此约束并限制在它们上方的标签（也是视图的宽度）。我使用前缘查看最左边按钮上的约束，使用后缘查看最右边按钮上的约束。我还在所有按钮上使用了水平 space 约束（应该为零）。尽管如此，当我运行我的模拟器时，第三个按钮总是在某种程度上与第四个按钮重叠。我已经完成并删除了所有约束并尝试再次添加它们并且发生了相同的重叠。我有什么地方 missing/doing 错了吗？为什么我的所有按钮都不会缩小以适应视图而不是重叠？

Answer 1

我的代码中有类似的东西，如果你以编程方式设置按钮约束，我有一个滚动视图和一个内容视图，并在情节提要中设置约束，但我以编程方式添加其他东西

button1.setTranslatesAutoresizingMaskIntoConstraints(false)

    constX = NSLayoutConstraint(item: button1, attribute: NSLayoutAttribute.CenterX, relatedBy: NSLayoutRelation.Equal, toItem: ContentView, attribute: NSLayoutAttribute.CenterX, multiplier: 1, constant: 0)
    view.addConstraint(constX)

    constTop = NSLayoutConstraint(item: button1, attribute: NSLayoutAttribute.Top, relatedBy: NSLayoutRelation.Equal, toItem: ContentView, attribute: NSLayoutAttribute.Top, multiplier: 1, constant: 20)
    view.addConstraint(constTop)

    constL = NSLayoutConstraint(item: button1, attribute: NSLayoutAttribute.Leading, relatedBy: NSLayoutRelation.Equal, toItem: ContentView, attribute: NSLayoutAttribute.Leading, multiplier: 1, constant: 20)
    view.addConstraint(constL)

    constR = NSLayoutConstraint(item: button1, attribute: NSLayoutAttribute.Trailing, relatedBy: NSLayoutRelation.Equal, toItem: ContentView, attribute: NSLayoutAttribute.Trailing, multiplier: 1, constant: -20)
    view.addConstraint(constR)

    constH = NSLayoutConstraint(item: button1, attribute: NSLayoutAttribute.Height, relatedBy: NSLayoutRelation.Equal, toItem: nil, attribute: NSLayoutAttribute.NotAnAttribute, multiplier: 1, constant: 50)
    button1.addConstraint(constH)


    button2.setTranslatesAutoresizingMaskIntoConstraints(false)

    constX = NSLayoutConstraint(item: button2, attribute: NSLayoutAttribute.CenterX, relatedBy: NSLayoutRelation.Equal, toItem: ContentView, attribute: NSLayoutAttribute.CenterX, multiplier: 1, constant: 0)
    view.addConstraint(constX)

    constTop = NSLayoutConstraint(item: button2, attribute: NSLayoutAttribute.Top, relatedBy: NSLayoutRelation.Equal, toItem: button1, attribute: NSLayoutAttribute.Bottom, multiplier: 1, constant: 10)
    view.addConstraint(constTop)

    constL = NSLayoutConstraint(item: button2, attribute: NSLayoutAttribute.Leading, relatedBy: NSLayoutRelation.Equal, toItem: ContentView, attribute: NSLayoutAttribute.Leading, multiplier: 1, constant: 20)
    view.addConstraint(constL)

    constR = NSLayoutConstraint(item: button2, attribute: NSLayoutAttribute.Trailing, relatedBy: NSLayoutRelation.Equal, toItem: ContentView, attribute: NSLayoutAttribute.Trailing, multiplier: 1, constant: -20)
    view.addConstraint(constR)

    constH = NSLayoutConstraint(item: button2, attribute: NSLayoutAttribute.Height, relatedBy: NSLayoutRelation.Equal, toItem: nil, attribute: NSLayoutAttribute.NotAnAttribute, multiplier: 1, constant: 50)
    button2.addConstraint(constH)


    button3.setTranslatesAutoresizingMaskIntoConstraints(false)

    constX = NSLayoutConstraint(item: button3, attribute: NSLayoutAttribute.CenterX, relatedBy: NSLayoutRelation.Equal, toItem: ContentView, attribute: NSLayoutAttribute.CenterX, multiplier: 1, constant: 0)
    view.addConstraint(constX)

    constL = NSLayoutConstraint(item: button3, attribute: NSLayoutAttribute.Leading, relatedBy: NSLayoutRelation.Equal, toItem: ContentView, attribute: NSLayoutAttribute.Leading, multiplier: 1, constant: 20)
    view.addConstraint(constL)

    constR = NSLayoutConstraint(item: button3, attribute: NSLayoutAttribute.Trailing, relatedBy: NSLayoutRelation.Equal, toItem: ContentView, attribute: NSLayoutAttribute.Trailing, multiplier: 1, constant: -20)
    view.addConstraint(constR)

    constTop = NSLayoutConstraint(item: button3, attribute: NSLayoutAttribute.Top, relatedBy: NSLayoutRelation.Equal, toItem: button2, attribute: NSLayoutAttribute.Bottom, multiplier: 1, constant: 20)
    view.addConstraint(constTop)

    constH = NSLayoutConstraint(item: button3, attribute: NSLayoutAttribute.Height, relatedBy: NSLayoutRelation.Equal, toItem: nil, attribute: NSLayoutAttribute.NotAnAttribute, multiplier: 1, constant: 50)
    button3.addConstraint(constH)

    button4.setTranslatesAutoresizingMaskIntoConstraints(false)

    constX = NSLayoutConstraint(item: button4, attribute: NSLayoutAttribute.CenterX, relatedBy: NSLayoutRelation.Equal, toItem: ContentView, attribute: NSLayoutAttribute.CenterX, multiplier: 1, constant: 0)
    view.addConstraint(constX)

    constTop = NSLayoutConstraint(item: button4, attribute: NSLayoutAttribute.Top, relatedBy: NSLayoutRelation.Equal, toItem: button3, attribute: NSLayoutAttribute.Bottom, multiplier: 1, constant: 10)
    view.addConstraint(constTop)

    var constBottom = NSLayoutConstraint(item: button4, attribute: NSLayoutAttribute.Bottom, relatedBy: NSLayoutRelation.Equal, toItem: ContentView, attribute: NSLayoutAttribute.Bottom, multiplier: 1, constant: -20)
    view.addConstraint(constBottom)

    constL = NSLayoutConstraint(item: button4, attribute: NSLayoutAttribute.Leading, relatedBy: NSLayoutRelation.Equal, toItem: ContentView, attribute: NSLayoutAttribute.Leading, multiplier: 1, constant: 20)
    view.addConstraint(constL)

    constR = NSLayoutConstraint(item: button4, attribute: NSLayoutAttribute.Trailing, relatedBy: NSLayoutRelation.Equal, toItem: ContentView, attribute: NSLayoutAttribute.Trailing, multiplier: 1, constant: -20)
    view.addConstraint(constR)

    constH = NSLayoutConstraint(item: button4, attribute: NSLayoutAttribute.Height, relatedBy: NSLayoutRelation.Equal, toItem: nil, attribute: NSLayoutAttribute.NotAnAttribute, multiplier: 1, constant:50)
    button4.addConstraint(constH)

所以有 4 个按钮，它们自己受限，button1.top 到 Contentview.Top 和 button4.Bottom 到 ContentView.Bottom

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