使用滚动视图管理键盘

Posted 2023-03-14

【中文标题】使用滚动视图管理键盘

【英文标题】：Managing keyboard with scroll view

【发布时间】：2017-04-18 02:00:07

【问题描述】：

我目前正在学习来自 raywenderlich 的关于滚动视图的课程。有一个课程是关于如何将观察者添加到通知中心以跟踪键盘何时显示。这是代码的外观。

NotificationCenter.default.addObserver(self, selector: #selector(keyboardWillShow(notification:)), name: .UIKeyboardWillShow, object: nil)
NotificationCenter.default.addObserver(self, selector: #selector(keyboardWillHide(notification:)), name: .UIKeyboardWillHide, object: nil)


func keyboardWillHide(notification: Notification) 
    adjustKeyboardInset(false, notification: notification)


func keyboardWillShow(notification: Notification) 
    adjustKeyboardInset(true, notification: notification)


func adjustKeyboard(isShown: Bool, notification: Notification) 
    let userInfo = notification.userInfo ?? [:]
    let keyboardFrame = (userInfo[UIKeyboardFrameBeginUserInfoKey] as! NSValue).cgRectValue

    let adjustedHeight = keyboardFrame.height * (isShown ? 1 : -1) + 20

    mySV.contentInset.bottom += adjustedHeight
    mySV.scrollIndicatorInsets.bottom += adjustedHeight

这在第一次单击文本字段时可以正常工作。但是，当您继续单击 textField 时，它会不断为其添加空间。

不胜感激。 :)

【参考方案1】：

最好不要使用“+=”操作。替代解决方案可能是：

var originalBottom:CGFloat = 0.0
var originalIndicatorBottom:CGFloat = 0.0

override func viewDidLoad() 
    super.viewDidLoad()
    originalBottom = mySV.contentInset.bottom.constant
    originalIndicatorBottom:CGFloat = mySV.scrollIndicatorInsets.bottom.constant


//......    

func adjustKeyboard(isShown: Bool, notification: Notification) 
    let userInfo = notification.userInfo ?? [:]
    let keyboardFrame = (userInfo[UIKeyboardFrameBeginUserInfoKey] as! NSValue).cgRectValue

    let adjustedHeight = keyboardFrame.height + 20

    if isShown 
        mySV.contentInset.bottom = originalBottom + adjustedHeight
        mySV.scrollIndicatorInsets.bottom = originalIndicatorBottom + adjustedHeight
    
    else
    
       mySV.contentInset.bottom = originalBottom 
       mySV.scrollIndicatorInsets.bottom = originalIndicatorBottom