Question

我想将2个按钮移动到屏幕宽度的中心。它应该看起来像：|＆lt ;-(100)FirstButton（50） - ＆gt; SecondButton（100） - ＆gt; |

我从第一个按钮开始。

var const = NSLayoutConstraint(item: firstButton, 
    attribute: NSLayoutAttribute.Left, 
    relatedBy: NSLayoutRelation.Equal, 
    toItem: view.superview, 
    attribute: NSLayoutAttribute.Left, 
    multiplier: 1.0, 
    constant: 100)

为什么它不起作用？

Answer 1

似乎firstButton未将属性translatesAutoresizingMaskIntoConstraints设置为false

Apple translatesAutoresizingMaskIntoConstraints的文档说明：

/* By default, the autoresizing mask on a view gives rise to constraints that fully determine the view's position. This allows the auto layout system to track the frames of views whose layout is controlled manually (through -setFrame:, for example). When you elect to position the view using auto layout by adding your own constraints, you must set this property to NO. IB will do this for you. */ @available(iOS 6.0, *) open var translatesAutoresizingMaskIntoConstraints: Bool // Default YES

因此，当您添加自己的约束时，必须将firstButton＆＃39; s translatesAutoresizingMaskIntoConstraints设置为false

NSLayoutConstraint不起作用

1 个答案: