ios - NSLayoutFormatOptions 没有成员 'allZeros' 错误

Question

我正在尝试在 Controller 内以编程方式添加几个约束。

private func setupDownView(view: UIView) {
    let downView = try? DownView(frame: view.bounds, markdownString: "")
    downView!.addConstraint(NSLayoutConstraint.constraints(
        withVisualFormat: "V:|-0-[view]-0-|",
        options: .allZeros,
        metrics: nil,
        views: ["view": downView!]))
    view.addSubview(downView!);
}

自动补全可以完成这个 allZeros我的情况。但是，我遇到了 no member allZeros 的错误。 .

Answer 1

使用[]反而。

private func setupDownView(view: UIView) {
    let downView = try? DownView(frame: view.bounds, markdownString: "")
    downView!.addConstraint(NSLayoutConstraint.constraints(
        withVisualFormat: "V:|-0-[view]-0-|",
        options: [],
        metrics: nil,
        views: ["view": downView!]))
    view.addSubview(downView!);
}