在swift中加载视图后自定义customKeyboard高度

Question

我正在编写自定义键盘，我想自定义高度.. Apple文档仅在Objective-C中给出该代码，是否有人知道如何使用Swift语言编写它？这是苹果公司代码：

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]; 

我试图把它写这样，但它不会做任何事情..：

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) 

} 

请帮助我！

Answer 1

你有一个multiplier:0，它应该是multiplier:1.0。

你也可能混合self.view和view = objects[0] as UIView。您应该添加约束到您的主self.view这是= self.inputView并添加您的自定义视图。

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)