ios - Swift:无效参数不满足:约束

Question

我收到错误:

Invalid parameter not satisfying: [constraint isKindOfClass:[NSLayoutConstraint class]]

对于我用 Swift 编写的自动布局约束代码:

    let d:NSDictionary = ["scrollView": scrollView]
    let hc:NSArray = [NSLayoutConstraint.constraintsWithVisualFormat("H:|[scrollView]|", options: NSLayoutFormatOptions.allZeros, metrics: nil, views: d)]
    let vc:NSArray = [NSLayoutConstraint.constraintsWithVisualFormat("V:|[scrollView]|", options: NSLayoutFormatOptions.allZeros, metrics: nil, views: d)]
    view.addConstraints(hc)
    view.addConstraints(vc)

有谁知道这个错误试图告诉我什么？据我所知，该参数是 NSArray 类型，其中包含 NSLayoutConstraint 对象。我怀疑我必须将数组显式定义为 NSArray 但这并不能解决问题。

Answer 1

NSLayoutConstraint.constraintsWithVisualFormat 已经返回一个 NSArray 所以你不需要将它包装在另一个数组中。所以尝试:

let d:NSDictionary = ["scrollView": scrollView]
let hc:NSArray = NSLayoutConstraint.constraintsWithVisualFormat("H:|[scrollView]|", options: NSLayoutFormatOptions.allZeros, metrics: nil, views: d)
let vc:NSArray = NSLayoutConstraint.constraintsWithVisualFormat("V:|[scrollView]|", options: NSLayoutFormatOptions.allZeros, metrics: nil, views: d)
view.addConstraints(hc)
view.addConstraints(vc)