在Swift中,如何使用Layout Anchor将多个子视图设置为具有相同的宽度(不是常量)？

例如,我有一个包含3个子视图的父视图.我以编程方式使用Layout Anchor并尝试实现以下布局

|--subview 1--|--subview 2--|--subview 3--|

三个子视图中的每一个具有相等的宽度.换一种说法,

subView1.width = subView2.width = subView3.width subView1.width + subView2.width + subView3.width = parentView.width

我知道我可以使用乘法器来设置subView 1和subView 2的宽度:

subView1.widthAnchor.constraintEqualToAnchor(contentView.widthAnchor, multiplier: 1/3).active = true
subView2.widthAnchor.constraintEqualToAnchor(contentView.widthAnchor, multiplier: 1/3).active = true

和subView3可以使前导锚与subView2的尾随锚对齐.

但是,我在某处看到Interface Builder实际上可以将这三个宽度直接分配(不使用常量或乘数).是否可以通过编程方式对Layout Anchor进行相同的操作？如何？谢谢.

这是一套完整的锚点(我已经尝试过并且它有效):

// Create subView1
let subView1 = UIView()
subView1.backgroundColor = UIColor.redColor()
subView1.translatesAutoresizingMaskIntoConstraints = false
contentView.addSubview(subView1)

// Create subView2
let subView2 = UIView()
subView2.backgroundColor = UIColor.blueColor()
subView2.translatesAutoresizingMaskIntoConstraints = false
contentView.addSubview(subView2)

// Create subView3
let subView3 = UIView()
subView3.backgroundColor = UIColor.greenColor()
subView3.translatesAutoresizingMaskIntoConstraints = false
contentView.addSubview(subView3)

subView1.leadingAnchor.constraintEqualToAnchor(contentView.leadingAnchor).active = true
subView1.topAnchor.constraintEqualToAnchor(contentView.topAnchor).active = true
subView1.bottomAnchor.constraintEqualToAnchor(contentView.bottomAnchor).active = true

subView2.topAnchor.constraintEqualToAnchor(contentView.topAnchor).active = true
subView2.bottomAnchor.constraintEqualToAnchor(contentView.bottomAnchor).active = true

subView3.topAnchor.constraintEqualToAnchor(contentView.topAnchor).active = true
subView3.trailingAnchor.constraintEqualToAnchor(contentView.trailingAnchor).active = true
subView3.bottomAnchor.constraintEqualToAnchor(contentView.bottomAnchor).active = true

subView1.trailingAnchor.constraintEqualToAnchor(subView2.leadingAnchor).active = true
subView2.trailingAnchor.constraintEqualToAnchor(subView3.leadingAnchor).active = true

// Add equal width anchors
subView1.widthAnchor.constraintEqualToAnchor(subView2.widthAnchor).active = true
subView2.widthAnchor.constraintEqualToAnchor(subView3.widthAnchor).active = true

希望这可以帮助.:)