swift - 无法同时满足约束 - 制图

Question

我在使用 Swift 2.0 编写的应用程序上使用 AutoLayout 和代码，并使用 Cartograph 来帮助解决约束。但有些东西阻止了我的应用程序，否则，我用它以编程方式添加 View 。

func addButtonOne() -> Void {
    buttonOne = UIButton()
    buttonOne.backgroundColor = UIColor.greenColor()
    self.view.addSubview(buttonOne)

    constrain(buttonOne, view) { buttonOne, view in
        buttonOne.left == view.right - 12
        buttonOne.right == view.left + 12
        buttonOne.bottom == view.bottom - 12
    }

}

但编译后，返回:

2015-09-23 00:54:24.489 Fun With Swift[24809:2358352] Unable to simultaneously satisfy constraints.
    Probably at least one of the constraints in the following list is one you don't want. 
Try this: 
(1) look at each constraint and try to figure out which you don't expect;
(2) find the code that added the unwanted constraint or constraints and fix it. 
(Note: If you're seeing NSAutoresizingMaskLayoutConstraints that you don't understand, 
refer to the documentation for the UIView property translatesAutoresizingMaskIntoConstraints) 

(
"<NSLayoutConstraint:0x7afe2160 H:[UIView:0x7afdfe90]-(-12)-[UIButton:0x7afe13b0](LTR)>",
"<NSLayoutConstraint:0x7afe2730 UIButton:0x7afe13b0.right == UIView:0x7afdfe90.left + 12>",
"<NSLayoutConstraint:0x7b0866e0 'UIView-Encapsulated-Layout-Width' H:[UIView:0x7afdfe90(320)]>"
)

有人知道我能做什么吗？这是一个不同的问题，因为我使用一个库。

Answer 1

添加约束代码应如下所示

 constrain(buttonOne, view) { buttonOne, view in
            buttonOne.left == view.left + 12
            buttonOne.right == view.right - 12
            buttonOne.bottom == view.bottom - 12
        }

如果您需要底部有一个按钮，距左右和底部有 12 pt 边距