Swift无法满足跳跃的限制

Question

我已经启动了Swift IOS编程简介的iOS跳跃，我目前处于此阶段：[图像] [1]代码如下：

 button.translatesAutoresizingMaskIntoConstraints = false;
 button.heightAnchor.constraint(equalToConstant: 44.0).isActive = true
 button.widthAnchor.constraint(equalToConstant: 44.0).isActive = true

这会产生以下错误：

    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. 
    NSLayoutConstraint:0x604000091760 UIButton:0x7f7f95519110.width == 44   (active)
    NSLayoutConstraint:0x600000097020 'UISV-canvas-connection' FoodTracker.RatingControl:0x7f7f95412d20.leading == UIButton:0x7f7f95519110.leading   (active),
    NSLayoutConstraint:0x600000093bf0 'UISV-canvas-connection' H:[UIButton:0x7f7f95519110]-(0)-|   (active, names: '|':FoodTracker.RatingControl:0x7f7f95412d20 ),
    NSLayoutConstraint:0x600000099fa0 'UIView-Encapsulated-Layout-Width' FoodTracker.RatingControl:0x7f7f95412d20.width == 200   (active)

Will attempt to recover by breaking constraint 
NSLayoutConstraint:0x604000091760 UIButton:0x7f7f95519110.width == 44   (active)

这是在链接到水平堆栈视图的"自定义"类中，我尝试设置self。设置self.translateautoresizingmaskIntoconstraints = false确实删除了错误，但是x，y堆栈视图的位置默认为0,0。如果：

，如何有约束冲突

 button.translatesAutoresizingMaskIntoConstraints = false;

删除按钮上的所有约束。

编辑，完成代码：

class RatingControl: UIStackView {
//MARK: init
override init(frame: CGRect) {
    super.init(frame: frame)
    setupButtons()
}
required init(coder: NSCoder) {
    super.init(coder: coder)
    setupButtons()
}
//MARK: Actions
func ratingButtonTapped(button: UIButton) {
    print("HELLO WORLD!");
}
//MARK: private methods
private func setupButtons() {
    // Create the button
    let button = UIButton()
    button.backgroundColor = UIColor.red
    //self.translatesAutoresizingMaskIntoConstraints = false;


    // Add constraints
    button.translatesAutoresizingMaskIntoConstraints = false;
    button.heightAnchor.constraint(equalToConstant: 44.0).isActive = true
    button.widthAnchor.constraint(equalToConstant: 44.0).isActive = true
    // Add the button to the stack
    addArrangedSubview(button)
}

}

Answer 1

在这里，这种错误称为不满意的布局。基本上，对于您定义的约束，系统无法找到尊重您所有约束的有效解决方案。通过您发布的内容，我可以轻松确定这组约束：

• button.height = 44//用编程方式定义的
定义
• button.width = 44//定义的高度布局编程

然后，您还具有基于接口构建器的其他约束：

• ratingcontrol.heading = uibutton.Leading
• 我认为
的水平堆栈视图带有按钮和评分控件
• ratingcontrol.with = 200

要避免这种错误：

• 删除一个约束。您认为正在创建冲突的一种

或 - 通过降低其优先级

Answer 2

我在通过教程工作时遇到了类似的问题。

我意识到的是，在"实现自定义控件"一章中我的水平堆栈视图未嵌入在垂直堆栈视图中，该视图是在"构建更好的UI"一章中早些时候创建的。查看是否为您修复。