如何解决为什么在 textViewDidBeginEditing 之前调用观察者 onKeyboardDisplayed
我的应用程序运行迅速。当我编辑 UITextField 时,有时键盘会隐藏该字段。所以我使用委托 textFieldDidBeginEditing 来设置“activeTextField”(和 textFieldDidEndEditing 将其重置为 nil)。然后在 viewDidLoad 上,我添加了一个链接到 onKeyboarddisplayed 函数的观察者,我在其中测试“activeTextField”的值,以便我可以在需要时向上滑动屏幕。而且效果很好:)
坏消息是我试图对 UITextView 做同样的事情,使用委托 textViewDidBeginEditing 来设置“activeTextView”。但与 UITextField 不同的是,委托是在 onKeyboarddisplayed 之后调用的,因此键盘仍然隐藏了我的 UITextView。
NotificationCenter.default.addobserver(self,selector: #selector(onKeyboarddisplayed(notification:)),name: UIResponder.keyboardWillShowNotification,object: nil)
@objc func onKeyboarddisplayed(notification: Notification) {
guard let keyboardRect = (notification.userInfo?[UIResponder.keyboardFrameEndUserInfoKey] as? NSValue)?.cgRectValue else {
return
}
var visibleRect : CGRect = self.view.frame
visibleRect.size.height -= keyboardRect.height
if (activeTextField != nil) {
// Get y position of active textField bottom.
let textFieldBottomPosition = activeTextField!.convert(CGPoint.zero,to: nil).y + activeTextField!.frame.height
if(textFieldBottomPosition > visibleRect.size.height) {
// swipe up
view.frame.origin.y = (visibleRect.size.height - textFieldBottomPosition - 6)
}
}
if (activeTextView != nil) {
// Get y position of active textView bottom.
let textViewBottomPosition = activeTextView!.convert(CGPoint.zero,to: nil).y + activeTextView!.frame.height
if(textViewBottomPosition > visibleRect.size.height) {
// swipe up
view.frame.origin.y = (visibleRect.size.height - textViewBottomPosition - 6)
}
}
}
解决方法
最后我在这里找到了解决方案:Keyboard events called before UITextView delegate events
我更改了 keyboardWillShowNotification
NotificationCenter.default.addObserver(self,selector: #selector(onKeyboardDisplayed(notification:)),name: UIResponder.keyboardWillShowNotification,object: nil)
通过keyboardDidShowNotification
NotificationCenter.default.addObserver(self,name: UIResponder.keyboardDidShowNotification,object: nil)
现在它运行良好:在委托 textViewDidBeginEditing 之后调用我的 onKeyboardDisplayed 函数
,处理键盘出现的标准方法是这样
在您的视图控制器中:
override func viewDidLoad() {
super.viewDidLoad()
NotificationCenter.default.addObserver(self,selector: #selector(handleKeyboardWillShow),name: UIControl.keyboardWillShowNotification,object: nil)
NotificationCenter.default.addObserver(self,selector: #selector(handleKeyboardWillHide),name: UIControl.keyboardWillHideNotification,object: nil)
}
@objc private func handleKeyboardWillShow(notification: NSNotification){
guard let keyboardSize = (notification.userInfo?[UIResponder.keyboardFrameEndUserInfoKey] as? NSValue)?.cgRectValue else{
return
}
self.view.frame.origin.y -= keyboardSize.height
}
@objc private func handleKeyboardWillHide(notification: NSNotification){
self.view.frame.origin.y = 0
}
这会根据键盘的高度上下移动视图框架。 如果我正确理解您的问题,我相信这可以帮助您
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