在Swift中使用簡單的NSLayoutContraint？

Question

我正在為子視圖尋找一個簡單的Swift解決方案，以編程方式使用NSLayoutContraint填充超級視圖。 它應該很容易理解。 我覺得目前大多數答案都比需要的更復雜。

Answer 1

extension NSLayoutConstraint {

    public static func simpleConstraints( view:NSView, direction:NSString = "H", padding1:Int = 0, padding2:Int = 0 ) -> [NSLayoutConstraint] {
        view.translatesAutoresizingMaskIntoConstraints = false
        let constraint = NSLayoutConstraint.constraintsWithVisualFormat("\(direction):|-\(padding1)-[view]-\(padding2)-|", options: NSLayoutFormatOptions(rawValue: 0), metrics: nil, views: ["view":view])
        return constraint
    }
}

用法：

parent.addConstraints( NSLayoutConstraint.simpleConstraints(child, direction: "H") )
parent.addConstraints( NSLayoutConstraint.simpleConstraints(child, direction: "V") )

Answer 2

假設您已將translatesAutoresizingMaskIntoConstraints設置為false並將subview添加為subview的子view ，則可以設置四個約束，如下所示：

NSLayoutConstraint.activateConstraints([
    subview.leadingAnchor.constraintEqualToAnchor(view.leadingAnchor),
    subview.trailingAnchor.constraintEqualToAnchor(view.trailingAnchor),
    subview.topAnchor.constraintEqualToAnchor(view.topAnchor),
    subview.bottomAnchor.constraintEqualToAnchor(view.bottomAnchor)
])

或者在Swift 3中：

NSLayoutConstraint.activate([
    subview.leadingAnchor.constraint(equalTo: view.leadingAnchor),
    subview.trailingAnchor.constraint(equalTo: view.trailingAnchor),
    subview.topAnchor.constraint(equalTo: view.topAnchor),
    subview.bottomAnchor.constraint(equalTo: view.bottomAnchor)
])

Answer 3

這是一個使用可視格式的簡單解決方案：

    subview.translatesAutoresizingMaskIntoConstraints = false
    let views = ["subview":subview]
    view.addConstraints(NSLayoutConstraint.constraintsWithVisualFormat("|[subview]|", options: [], metrics: nil, views: views))
    view.addConstraints(NSLayoutConstraint.constraintsWithVisualFormat("V:|[subview]|", options: [], metrics: nil, views: views))

一個更簡單的解決方案，根本不使用自動布局：

    subview.frame = view.bounds
    subview.autoresizingMask = [.FlexibleWidth, .FlexibleHeight]

Answer 4

結合Rob的建議和我的NSLayoutConstraint擴展概念，我已經確定了這一點，以便有一行簡單的“填充superview”命令：

extension NSLayoutConstraint {

    public static func activateConstraintsEqualToSuperview(child: NSView) {

        if ( child.superview == nil ) {
            Swift.print("NSLayoutConstraint.fillSuperview() superview of child is nil")
            return;
        }

        child.translatesAutoresizingMaskIntoConstraints = false

        NSLayoutConstraint.activateConstraints( [
            child.leadingAnchor.constraintEqualToAnchor( child.superview!.leadingAnchor ),
            child.trailingAnchor.constraintEqualToAnchor( child.superview!.trailingAnchor ),
            child.topAnchor.constraintEqualToAnchor( child.superview!.topAnchor ),
            child.bottomAnchor.constraintEqualToAnchor( child.superview!.bottomAnchor )
            ])
    }
}

用法：

NSLayoutConstraint.activateConstraintsEqualToSuperview(child)