我有一个 UIView 在键盘出现时不能正常移动。我用来输入文本的 UIView 中有一个 UITextView。如果我选择 TextView 输入文本，键盘会出现，但 UIView 不会第一次移动。如果我点击背景并使键盘消失，然后再次点击 TextView，则 UIView 会正确向上移动。有谁知道这里发生了什么？
class ChatViewController: UIViewController, CNContactPickerDelegate, UISearchBarDelegate, UITableViewDelegate, UITableViewDataSource, UIToolbarDelegate, UITextFieldDelegate, UITextViewDelegate {
@IBOutlet weak var composeTextView: UITextView!
@IBOutlet weak var composeViewBottomConstraint: NSLayoutConstraint!
override func viewDidLoad() {
super.viewDidLoad()
composeTextView.delegate = self
}
func textViewDidBeginEditing(_ textView: UITextView) {
UIView.animate(withDuration: 0.5){
NotificationCenter.default.addObserver(self, selector: #selector(self.keyboardWillShow), name: .UIKeyboardWillShow, object: nil)
}
self.view.layoutIfNeeded()
}
@objc func keyboardWillShow(notification: Notification) {
let keyboardSize = (notification.userInfo?[UIKeyboardFrameEndUserInfoKey] as? NSValue)?.cgRectValue
let keyboardHeight = keyboardSize?.height
if #available(iOS 11.0, *){
self.composeViewBottomConstraint.constant = keyboardHeight! - view.safeAreaInsets.bottom
}
else {
self.composeViewBottomConstraint.constant = view.safeAreaInsets.bottom
}
self.view.layoutIfNeeded()
}
}
最佳答案
问题是第一次单击 textView 时 View 没有上升是在 beginEditing 中添加了 showKeyboard 观察者，所以这一行应该在 viewDidLoad 中
NotificationCenter.default.addObserver(self, selector: #selector(self.keyboardWillShow), name: .UIKeyboardWillShow, object: nil)
NotificationCenter.default.addObserver(self, selector: #selector(self.keyboardWillHide), name: .UIKeyboardWillHide, object: nil)
除了以下修复
func textViewDidBeginEditing(_ textView: UITextView) {
// I think no need for it
}
@objc func keyboardWillShow(notification: Notification) {
let keyboardSize = (notification.userInfo? [UIKeyboardFrameEndUserInfoKey] as? NSValue)?.cgRectValue
let keyboardHeight = keyboardSize?.height
if #available(iOS 11.0, *){
self.composeViewBottomConstraint.constant = keyboardHeight! - view.safeAreaInsets.bottom
}
else {
self.composeViewBottomConstraint.constant = view.safeAreaInsets.bottom
}
UIView.animate(withDuration: 0.5){
self.view.layoutIfNeeded()
}
}
@objc func keyboardWillHide(notification: Notification){
self.composeViewBottomConstraint.constant = 0 // or change according to your logic
UIView.animate(withDuration: 0.5){
self.view.layoutIfNeeded()
}
}
关于ios - 出现键盘时更改约束 - Swift，我们在Stack Overflow上找到一个类似的问题：https://stackoverflow.com/questions/49441226/