ios – 键盘可见时更改Y原点时的奇怪UIView行为

概述语境： 我有一个包含UITextView的UIView.我想在键盘可见时移动UIView.所以想法是change the Y position. 问题： 有时,当键盘仍然可见时,UIView会返回其初始Y位置.即使我关注输入,它也不会再回来了.我真的不知道为什么. 插图(gif)： https://d17oy1vhnax1f7.cloudfront.net/items/2K0z3P1j1x2f0X 语境：

我有一个包含UITextVIEw的UIVIEw.我想在键盘可见时移动UIVIEw.所以想法是change the Y position.

问题：

有时,当键盘仍然可见时,UIVIEw会返回其初始Y位置.即使我关注输入,它也不会再回来了.我真的不知道为什么.

插图(gif)：

https://d17oy1vhnax1f7.cloudfront.net/items/2K0z3P1j1x2f0X2X1B2v/ci.gif

PS：键盘在Gif中出现3次.它循环,所以很难区分结束.

码

我做了什么,首先我添加了通知观察员：

NotificationCenter.default.addobserver(self,selector: #selector(self.keyboarDWillChangeFrame),name: NSNotification.name.UIKeyboarDWillChangeFrame,object: nil)

然后我定义了键盘切换处理程序：

func keyboarDWillChangeFrame(notification: NSNotification) {    let info = notification.userInfo!    let keyboardFrame: CGRect = (info[UIKeyboardFrameEndUserInfoKey] as! NSValue).cgRectValue    self.keyboardInfo["isVisible"] = self.vIEw.frame.size.height - keyboardFrame.origin.y != 0    self.keyboardInfo["height"] = keyboardFrame.size.height    self.keyboardInfo["animationDuration"] = info[UIKeyboardAnimationDurationUserInfoKey] as! Double    self.keyboardInfo["animationCurve"] = info[UIKeyboardAnimationCurveUserInfoKey] as! UInt    if self.keyboardInfo["isVisible"] as! Bool {        self.moveCommentinputUp()    } else {        self.moveCommentinputDown()    }}

之后,我已经定义了在注释输入视图中向上/向下移动的方法：

func moveCommentinputUp() {    print("Moving up... ",self.commentFormVIEw.frame.origin.y," to ",self.vIEw.frame.size.height - (self.keyboardInfo["height"] as! CGfloat) - self.commentFormVIEw.frame.size.height)    UIVIEw.beginAnimations(nil,context: nil)    UIVIEw.setAnimationDuration(self.keyboardInfo["animationDuration"] as! TimeInterval)    UIVIEw.setAnimationCurve(UIVIEwAnimationCurve(rawValue: Int(self.keyboardInfo["animationCurve"] as! UInt))!)    UIVIEw.setAnimationBeginsFromCurrentState(true)    VIEwUtil.changeVIEwFrame(vIEw: self.commentFormVIEw,yposition: self.vIEw.frame.size.height - (self.keyboardInfo["height"] as! CGfloat) - self.commentFormVIEw.frame.size.height)    VIEwUtil.removeShadowToVIEw(self.commentFormlauncherbutton)    UIVIEw.commitAnimations()}func moveCommentinputDown() {    print("Moving down... ",self.vIEw.frame.size.height)    UIVIEw.beginAnimations(nil,yposition: self.vIEw.frame.size.height)    VIEwUtil.addShadowToVIEw(commentFormlauncherbutton,position: CGSize(wIDth: 0,height: 5))    UIVIEw.commitAnimations()}

按钮的动作是

@IBAction func showCommentForm(_ sender: UIbutton) {    self.commentinput.becomeFirstResponder()}

日志(请参阅Gif)显示视图从568(屏幕底部)再次移动到568

// The numbers show the initial and the final value of the keyboard Y position// Click on button to focus the inputMoving up...  568.0  to  282.0// Tap anywhereMoving down...  282.0  to  568.0// Click again on button to focus the inputMoving up...  568.0  to  282.0///// Write "hhh". The vIEw is gone,I don't kNow why.// Tap anywhereMoving down...  568.0  to  568.0    // The vIEw seems to move from 568 to 568,hugh// Click on button to focus the inputMoving up...  568.0  to  282.0      // This dIDn't work apparently// Tap anywhereMoving down...  568.0  to  568.0    // 568 to 568 again

我错过了什么？

系统：iOS 9,Xcode 8,Swift 3

解决方法 好的,这是一个不需要CocoaPods的解决方案.

我的方法涉及在键盘出现和消失时设置textFIEld的底部约束的常量.这意味着您需要创建对textFIEld的底部约束的引用.

@IBOutlet weak var textFIEldBottomConstraint: NSLayoutConstraint!

我开始在vIEwDIDLoad中设置NSNotification.name.UIKeyboarDWillShow和UIKeyboarDWillHIDe上的观察者,而不是UIKeyboarDWillChangeFrame：

NotificationCenter.default.addobserver(self,selector: #selector(handleKeyboardNotification),name: NSNotification.name.UIKeyboarDWillShow,object: nil)NotificationCenter.default.addobserver(self,name: NSNotification.name.UIKeyboarDWillHIDe,object: nil)

接下来我设置选择器及其函数来设置textFIEld的底部约束的常量：

func handleKeyboardNotification(notification: NSNotification) {    if let userInfo = notification.userInfo {        let keyboardFrameValue = (userInfo[UIKeyboardFrameEndUserInfoKey] as? NSValue)        let keyboardFrame = keyboardFrameValue?.cgRectValue        let isKeyboardShowing = notification.name == NSNotification.name.UIKeyboarDWillShow        textFIEldBottomConstraint.constant = isKeyboardShowing ? keyboardFrame!.height + 4 : 4        self.vIEw.layoutIfNeeded()    }}

请注意,textFIEldBottomConstraint是底部约束的引用变量.

这样做会使textFIEld在键盘出现或消失时设置它的底部约束,并且不会遇到您遇到的奇怪故障.

希望这有所帮助,并毫不犹豫地要求澄清！

YouTuber的功劳让我们构建该应用程序！通过此视频提供解决方案：

https://www.youtube.com/watch?v=p8IaS5lmhuM

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