在快速加载视图后自定义自定义键盘高度

Question

我正在编写自定义键盘，我想自定义高度。苹果文档只在Objective-C中给出了该代码，有人知道如何用Swift语言编写它吗？这是来自苹果的代码：

CGFloat _expandedHeight = 500;
NSLayoutConstraint *_heightConstraint = 
[NSLayoutConstraint constraintWithItem: self.view 
                             attribute: NSLayoutAttributeHeight 
                             relatedBy: NSLayoutRelationEqual 
                                toItem: nil 
                             attribute: NSLayoutAttributeNotAnAttribute 
                            multiplier: 0.0 
                              constant: _expandedHeight];
[self.view addConstraint: _heightConstraint];

我试着这样写，但它什么也没做..：

override func viewDidAppear(animated:Bool) {
    super.viewDidAppear(true)
   let nib = UINib(nibName: "KeyboardView", bundle: nil)
    let objects = nib.instantiateWithOwner(self, options: nil)
    view = objects[0] as UIView;
    let _viewHeight: CGFloat = 256
    let const1 = NSLayoutConstraint(
        item:self.view, attribute:.Height,
        relatedBy:.Equal, toItem:nil,
        attribute:.NotAnAttribute,multiplier:0, constant: _viewHeight)
    view.addConstraint(const1)
 } 

请帮帮我！

Answer 1

你有一个multiplier:0，它应该是multiplier:1.0。

您也可以混合self.view和view = objects[0] as UIView。您应该向主self.view添加一个约束，即 = self.inputView 并在其上添加自定义视图。

let customView = objects[0] as UIView
customView.setTranslatesAutoresizingMaskIntoConstraints(false)
self.view.addSubView(customView)
//layout
let left = NSLayoutConstraint(item: customView, attribute: .Left, relatedBy: .Equal, toItem: view, attribute: .Left, multiplier: 1.0, constant: 0.0)
let top = NSLayoutConstraint(item: customView, attribute: .Top, relatedBy: .Equal, toItem: view, attribute: .Top, multiplier: 1.0, constant: 0.0)
let right = NSLayoutConstraint(item: customView, attribute: .Right, relatedBy: .Equal, toItem: view, attribute: .Right, multiplier: 1.0, constant: 0.0)
let bottom = NSLayoutConstraint(item: customView, attribute: .Bottom, relatedBy: .Equal, toItem: view, attribute: .Bottom, multiplier: 1.0, constant: 0.0)
self.view.addConstraints([left, top, right, bottom])
let const1 = NSLayoutConstraint(
    item:self.view, attribute:.Height,
    relatedBy:.Equal, toItem:nil,
    attribute:.NotAnAttribute,multiplier:1.0, constant: _viewHeight)
self.view.addConstraint(const1)