iOS Swift 2.0完成按钮

Question

我正在尝试向键盘添加一个完成按钮。下面的代码用于工作：

func addDoneButtonOnKeyboard() 
{ 
    let doneToolbar: UIToolbar = UIToolbar(frame: CGRectMake(0, 0, screenWidth, 50)) 
    //doneToolbar.barStyle = UIBarStyle.BlackTranslucent 

    let flexSpace = UIBarButtonItem(barButtonSystemItem: UIBarButtonSystemItem.FlexibleSpace, target: nil, action: nil) 
    let done: UIBarButtonItem = UIBarButtonItem(title: "Done", style: UIBarButtonItemStyle.Done, target: self, action: Selector("doneButtonAction")) 

    var items: [UIBarButtonItem]? 
    items?.append(flexSpace) 
    items?.append(done) 

    doneToolbar.items = items 
    doneToolbar.sizeToFit() 
    commentsField.inputAccessoryView=doneToolbar 
} 

它将工具栏放在键盘上方，但没有完成按钮。

Answer 1

问题来自于线

var items: [UIBarButtonItem]? 

你的UIBarButtonItem阵列永远不会初始化。将此行更换为

var items: [UIBarButtonItem]? = [UIBarButtonItem]()