Autolayout调整UIView不工作

Question

我试图让UIView courseView自动布局。我希望UIView的比例保持不变，直到最外边缘距离超视图边缘15点。 由于某些原因courseView填充整个超视图（减去15分），并没有调整大小以适应。所以有些不显示并被切断。

self.view.addSubview(courseView!) 

    let aspectConstraint = NSLayoutConstraint(item: courseView, 
     attribute: .Height, 
     relatedBy: .Equal, 
     toItem: courseView, 
     attribute: .Width, 
     multiplier: courseView.frame.size.height/courseView.frame.size.width, 
     constant: 0.0) 
    aspectConstraint.active = true 

    let topConstraint = courseView.topAnchor.constraintGreaterThanOrEqualToAnchor(topLayoutGuide.bottomAnchor, constant: 15) 
    topConstraint.active = true 
    let leadingConstraint = courseView.leadingAnchor.constraintLessThanOrEqualToAnchor(view.leadingAnchor, constant: 15) 
    leadingConstraint.active = true 
    let trailingConstraint = courseView.trailingAnchor.constraintGreaterThanOrEqualToAnchor(view.trailingAnchor, constant: -15) 
    trailingConstraint.active = true 
    let bottomConstraint = courseView.bottomAnchor.constraintLessThanOrEqualToAnchor(view.bottomAnchor, constant: -15) 
    bottomConstraint.active = true 

任何想法？谢谢！

Answer 1

只需在添加约束之前禁用translatesAutoresizingMaskIntoConstraints，它应该可以正常工作。

courseView.translatesAutoresizingMaskIntoConstraints = false; 

顺便说一句，你不需要aspectConstraint，因为这将最有可能打破constratints（它确实对我来说，当我试图）。