IBOutlets约束冲突

Question

当我尝试手动设置IBOutlet的约束时，我遇到了一个IBOutlet冲突。本质上，我只是在故事板中放置视图，以了解视图的外观，然后创建IBOutlet来引用它们。但所有约束都是在代码中添加的：

class LoginViewController: UIViewController, UITextFieldDelegate {


    @IBOutlet weak var view1: UIView!
    @IBOutlet weak var view2: UView2!
    @IBOutlet weak var name: UITextField!

    override func viewDidLoad() {
        super.viewDidLoad()


        view2.addSubview(name)

        //add constraints
        NSLayoutConstraint(item: view1, attribute: .CenterX, relatedBy: .Equal, toItem: self.view, attribute: .CenterX, multiplier: 1, constant: 0).active = true
        NSLayoutConstraint(item: view1, attribute: .CenterY, relatedBy: .Equal, toItem: self.view, attribute: .CenterY, multiplier: 1, constant: -self.view.frame.height * 0.07).active = true
        NSLayoutConstraint(item: view1, attribute: .Width, relatedBy: .Equal, toItem: self.view, attribute: .Width, multiplier: 0.8, constant: 0).active = true
        NSLayoutConstraint(item: view1, attribute: .Height, relatedBy: .Equal, toItem: self.view, attribute: .Height, multiplier: 0.4, constant: 0).active = true

        NSLayoutConstraint(item: view2, attribute: .Width, relatedBy: .Equal, toItem: view1, attribute: .Width, multiplier: 1, constant: 0).active = true
        NSLayoutConstraint(item: view2, attribute: .CenterX, relatedBy: .Equal, toItem: view1, attribute: .CenterX, multiplier: 1, constant: 0).active = true
        NSLayoutConstraint(item: view2, attribute: .Top, relatedBy: .Equal, toItem: view1, attribute: .Bottom, multiplier: 1, constant: self.view.frame.height * 0.01).active = true
        NSLayoutConstraint(item: view2, attribute: .Height, relatedBy: .Equal, toItem: self.view, attribute: .Height, multiplier: 0.1, constant: 0).active = true



      }
 }

当我只是在代码中创建视图，即var view2 = UIView()，或者如果我注释掉view2的约束时，var view2 = UIView()冲突就消失了，我不明白。

编辑:基于日志，问题似乎是NSIBPrototypingLayoutConstraint和UIView-Encapsulated-Layout-Height' for view2，尽管故事板中没有设置自动布局约束。让我困惑的是，为什么view1没有这个问题，因为它们都是在故事板中添加的？

Answer 1

您还没有在故事板中对view2设置约束，所以Xcode正在秘密地为您添加约束。您需要做的是在故事板中添加view2的约束，并告诉Xcode在构建时删除这些约束：

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