我正在尝试在键盘显示和消失时运行一个函数，并且有以下代码：
let notificationCenter = NotificationCenter.default
notificationCenter.addObserver(self, selector: #selector(ViewController.keyBoardUp(Notification :)), name: NSNotification.Name.UIKeyboardWillShow, object: nil)
以下是函数keyBoardUp的代码：
func keyBoardUp( Notification: NSNotification){
print("HELLO")
}
然而当键盘弹出时，该函数不会在控制台中打印任何内容。非常感谢您的帮助。
override func viewDidLoad() {
super.viewDidLoad()
NotificationCenter.default.addObserver(self, selector: #selector(ViewController.keyboardWillShow), name: Notification.Name.UIKeyboardWillShow, object: nil)
NotificationCenter.default.addObserver(self, selector: #selector(ViewController.keyboardWillHide), name: Notification.Name.UIKeyboardWillHide, object: nil)
}
func keyboardWillShow(notification: Notification) {
if let keyboardSize = (notification.userInfo?[UIKeyboardFrameBeginUserInfoKey] as? NSValue)?.cgRectValue {
print("notification: Keyboard will show")
if self.view.frame.origin.y == 0{
self.view.frame.origin.y -= keyboardSize.height
}
}
}
func keyboardWillHide(notification: Notification) {
if let keyboardSize = (notification.userInfo?[UIKeyboardFrameBeginUserInfoKey] as? NSValue)?.cgRectValue {
if self.view.frame.origin.y != 0 {
self.view.frame.origin.y += keyboardSize.height
}
}
}
NotificationCenter.default.addObserver(self, selector: #selector(keyboardWillShow), name: UIResponder.keyboardWillShowNotification, object: nil)
NotificationCenter.default.addObserver(self, selector: #selector(keyboardWillHide), name: UIResponder.keyboardWillHideNotification, object: nil)
@objc fileprivate func keyboardWillShow(notification: Notification) {
if let keyboardSize = (notification.userInfo?[UIResponder.keyboardFrameBeginUserInfoKey] as? NSValue)?.cgRectValue {
// Do something with size
}
}
@objc fileprivate func keyboardWillHide(notification: Notification) {
if let keyboardSize = (notification.userInfo?[UIResponder.keyboardFrameBeginUserInfoKey] as? NSValue)?.cgRectValue {
// Do something with size
}
}
Swift 4.2+
override func viewDidLoad() {
super.viewDidLoad()
NotificationCenter.default.addObserver(self, selector: #selector(ViewController.keyboardWillShow), name: UIResponder.keyboardWillShowNotification, object: nil)
NotificationCenter.default.addObserver(self, selector: #selector(ViewController.keyboardWillHide), name: UIResponder.keyboardWillHideNotification, object: nil)
}
@objc func keyboardWillShow(notification: Notification) {
if let keyboardSize = (notification.userInfo?[UIResponder.keyboardFrameEndUserInfoKey] as? NSValue)?.cgRectValue {
if self.view.frame.origin.y == 0{
self.view.frame.origin.y -= keyboardSize.height
}
}
}
@objc func keyboardWillHide(notification: Notification) {
if let keyboardSize = (notification.userInfo?[UIResponder.keyboardFrameEndUserInfoKey] as? NSValue)?.cgRectValue {
if self.view.frame.origin.y != 0 {
self.view.frame.origin.y += keyboardSize.height
}
}
}
@vandana的答案已更新以反映Swift 4.2中本地通知的更改。
override func viewDidLoad() {
super.viewDidLoad()
NotificationCenter.default.addObserver(self, selector: #selector(ViewController.keyboardWillShow), name: UIResponder.keyboardWillShowNotification, object: nil)
NotificationCenter.default.addObserver(self, selector: #selector(ViewController.keyboardWillHide), name: UIResponder.keyboardWillHideNotification, object: nil)
}
@objc func keyboardWillShow(notification: Notification) {
if let keyboardSize = (notification.userInfo?[UIResponder.keyboardFrameEndUserInfoKey] as? NSValue)?.cgRectValue {
if self.view.frame.origin.y == 0 {
self.view.frame.origin.y -= keyboardSize.height
}
}
}
@objc func keyboardWillHide(notification: Notification) {
if let keyboardSize = (notification.userInfo?[UIResponder.keyboardFrameEndUserInfoKey] as? NSValue)?.cgRectValue {
if self.view.frame.origin.y != 0 {
self.view.frame.origin.y += keyboardSize.height
}
}
}
另外，您需要使用UIKeyboardFrameEndUserInfoKey来考虑iOS 11引入的safeAreaInset更改。
在中设置键盘通知观察器
override func viewDidLoad() {
super.viewDidLoad()
// Do any additional setup after loading the view.
NotificationCenter.default.addObserver(self, selector: #selector(self.keyboardNotification(notification:)), name: NSNotification.Name.UIKeyboardDidShow, object: nil)
}
func keyboardNotification(notification: NSNotification) {
print("keyboard displayed!!")
}
希望这能对你有所帮助。
我喜欢这种内联、基于块的方法，它已经有很长时间了！你可以在这里了解有关addObserver(...)参数的更多信息。
这种方法的一些优点包括：
重要提示：在对象的
deinit中调用NotificationCenter.default.removeObserver(observer)，该对象是注册观察者的对象（通常是视图控制器）。
let center = NotificationCenter.default
let keyboardWillShowObserver: NSObjectProtocol = center.addObserver(forName: UIResponder.keyboardWillShowNotification, object: nil, queue: nil) { (notification) in
guard let value = notification.userInfo?[UIResponder.keyboardFrameEndUserInfoKey] as? NSValue else { return }
let height = value.cgRectValue.height
// use the height of the keyboard to layout your UI so the prt currently in
// foxus remains visible
}
let keyboardWillHideObserver: NSObjectProtocol = center.addObserver(forName: UIResponder.keyboardWillHideNotification, object: nil, queue: nil) { (notification) in
// restore the layout of your UI before the keyboard has been shown
}
更新至Swift：
// MARK:- Kyeboard hide/show methods
func keyboardWasShown(_ notification: Notification) {
if let keyboardSize = (notification.userInfo?[UIKeyboardFrameBeginUserInfoKey] as? NSValue)?.cgRectValue {
if self.view.frame.origin.y == 0{
self.view.frame.origin.y -= keyboardSize.height
}
}
}
func keyboardWillBeHidden(_ notification: Notification) {
if let keyboardSize = (notification.userInfo?[UIKeyboardFrameBeginUserInfoKey] as? NSValue)?.cgRectValue {
if self.view.frame.origin.y != 0{
self.view.frame.origin.y += keyboardSize.height
}
}
}
func registerForKeyboardNotifications(){
//Adding notifies on keyboard appearing
NotificationCenter.default.addObserver(self, selector: #selector(keyboardWasShown(_:)), name: NSNotification.Name.UIKeyboardWillShow, object: nil)
NotificationCenter.default.addObserver(self, selector: #selector(keyboardWillBeHidden(_:)), name: NSNotification.Name.UIKeyboardWillHide, object: nil)
}
func deregisterFromKeyboardNotifications(){
//Removing notifies on keyboard appearing
NotificationCenter.default.removeObserver(self, name: NSNotification.Name.UIKeyboardWillShow, object: nil)
NotificationCenter.default.removeObserver(self, name: NSNotification.Name.UIKeyboardWillHide, object: nil)
}
func textFieldDidBeginEditing(_ textField: UITextField) {
if textField == mEnterPasswordTextField || textField == mEnterConfirmPassword {
animateViewMoving(up: true, moveValue: 120)
}
}
func textFieldDidEndEditing(_ textField: UITextField) {
if textField == mEnterPasswordTextField || textField == mEnterConfirmPassword {
animateViewMoving(up: false, moveValue: 120)
}
}
func animateViewMoving (up:Bool, moveValue :CGFloat){
let movementDuration:TimeInterval = 0.3
let movement:CGFloat = ( up ? -moveValue : moveValue)
UIView.beginAnimations( "animateView", context: nil)
UIView.setAnimationBeginsFromCurrentState(true)
UIView.setAnimationDuration(movementDuration )
self.view.frame = self.view.frame.offsetBy(dx: 0, dy: movement)
UIView.commitAnimations()
}
// 在viewDidLoad()方法中
self.registerForKeyboardNotifications()
self.deregisterFromKeyboardNotifications()
class ViewController: UIViewController {
@IBOutlet weak var commentsTxt: UITextField!
@IBOutlet weak var keyboardBottom: NSLayoutConstraint!
override func viewWillAppear(_ animated: Bool) {
IQKeyboardManager.shared.enable = false
NotificationCenter.default.addObserver(
self,
selector: #selector(keyboardWillShow),
name: UIResponder.keyboardWillShowNotification,
object: nil
)
NotificationCenter.default.addObserver(
self,
selector: #selector(keyboarddidHide),
name: UIResponder.keyboardWillHideNotification,
object: nil
)
}
@objc func keyboardWillShow(_ notification: Notification) {
if let keyboardFrame: NSValue = notification.userInfo?[UIResponder.keyboardFrameEndUserInfoKey] as? NSValue {
let keyboardRectangle = keyboardFrame.cgRectValue
let keyboardHeight = keyboardRectangle.height
self.keyboardBottom.constant = keyboardHeight - self.bottomLayoutGuide.length
DispatchQueue.main.asyncAfter(deadline: .now()+0.1, execute: {
let bottomOffset = CGPoint(x: 0, y: self.scrlView.contentSize.height - self.scrlView.bounds.size.height)
self.scrlView.setContentOffset(bottomOffset, animated: true)
})
}
}
@objc func keyboarddidHide(_ notification: Notification) {
self.keyboardBottom.constant = 0
}
override func viewWillDisappear(_ animated: Bool) {
IQKeyboardManager.shared.enable = true
NotificationCenter.default.removeObserver(self, name: UIResponder.keyboardWillShowNotification, object: nil)
NotificationCenter.default.removeObserver(self, name: UIResponder.keyboardWillHideNotification, object: nil)
}
}
试试这个
override func viewDidLoad()
{
super.viewDidLoad()
NotificationCenter.default.addObserver(self, selector: #selector(self.keyboardWillShow(notification:)), name: NSNotification.Name.UIKeyboardDidShow, object: nil)
NotificationCenter.default.addObserver(self, selector: #selector(self.keyboardWillHide(notification:)), name: NSNotification.Name.UIKeyboardDidHide, object: nil)
}
@objc func keyboardWillShow(notification: NSNotification) {
if(messageCount > 0)
{
tableView.scrollToRow(at: IndexPath(item:messageCount - 1, section: 0), at: .bottom, animated: true)
}
}
@objc func keyboardWillHide(notification: NSNotification) {
if(messageCount > 0)
{
tableView.scrollToRow(at: IndexPath(item:0, section: 0), at: .top, animated: true)
}
}
Swift > 4.++
您可以使用协议和协议扩展。让我们创建KeyboardListener协议。
protocol KeyboardListener: class {
func registerKeyboardObserver()
func keyboardDidUpdate(keyboardHeight: CGFloat)
func removeObserver()
}
然后在UIViewController扩展中创建@objc函数
extension UIViewController {
@objc func adjustForKeyboard(notification: Notification) {
guard let keyboardValue = notification.userInfo?[UIResponder.keyboardFrameEndUserInfoKey] as? NSValue else { return }
let keyboardScreenEndFrame = keyboardValue.cgRectValue
let keyboardViewEndFrame = view.convert(keyboardScreenEndFrame, from: view.window)
if notification.name == UIResponder.keyboardWillHideNotification {
if let keyboardLister = self as? KeyboardListener {
keyboardLister.keyboardDidUpdate(keyboardHeight: .zero)
}
} else {
if let keyboardLister = self as? KeyboardListener {
keyboardLister.keyboardDidUpdate(keyboardHeight: keyboardViewEndFrame.height - view.safeAreaInsets.bottom)
}
}
}
}
然后，使用键盘监听器扩展来实现默认功能。extension KeyboardListener where Self: UIViewController {
func registerKeyboardObserver() {
let notificationCenter = NotificationCenter.default
notificationCenter.addObserver(self, selector: #selector(adjustForKeyboard), name: UIResponder.keyboardWillHideNotification, object: nil)
notificationCenter.addObserver(self, selector: #selector(adjustForKeyboard), name: UIResponder.keyboardWillChangeFrameNotification, object: nil)
}
func removeObserver() {
NotificationCenter.default.removeObserver(self)
}
}
最后，我们可以从我们的ViewController类中使用它。extension EditProfileVC: KeyboardListener {
func keyboardDidUpdate(keyboardHeight: CGFloat) {
//update view when keyboard appear,
}
}
在viewWillAppear中调用register方法，而在deinit中移除观察者。
override func viewWillAppear(_ animated: Bool) {
super.viewWillAppear(animated)
registerKeyboardObserver()
}
deinit {
removeObserver()
}
这个版本适用于iPhone 5和iPhone X。如果您在约束设置期间遵守安全区域，它将非常有效。
override func viewDidLoad() {
super.viewDidLoad()
NotificationCenter.default.addObserver(self, selector: #selector(keyboardWillShow), name: UIResponder.keyboardWillShowNotification, object: nil)
NotificationCenter.default.addObserver(self, selector: #selector(keyboardWillHide), name: UIResponder.keyboardWillHideNotification, object: nil)
}
@objc func keyboardWillShow(notification: NSNotification) {
if let _ = (notification.userInfo?[UIResponder.keyboardFrameBeginUserInfoKey] as? NSValue)?.cgRectValue {
self.view.frame.origin.y = self.navigationController!.navigationBar.frame.size.height + UIApplication.shared.statusBarFrame.size.height
if self.emailTextField.isFirstResponder {
self.view.frame.origin.y -= 100
} else if self.passwordTextField.isFirstResponder {
self.view.frame.origin.y -= 150
} else if self.passwordConfirmTextField.isFirstResponder {
self.view.frame.origin.y -= 200
}
}
}
@objc func keyboardWillHide(notification: NSNotification) {
if self.view.frame.origin.y != 0 {
self.view.frame.origin.y = self.navigationController!.navigationBar.frame.size.height + UIApplication.shared.statusBarFrame.size.height
}
}
NotificationCenter.default.addObserver(self, selector: #selector(didReceiveKeyboardNotificationObserver(_:)), name: UIResponder.keyboardWillShowNotification, object: nil)
NotificationCenter.default.addObserver(self, selector: #selector(didReceiveKeyboardNotificationObserver(_:)), name: UIResponder.keyboardWillHideNotification, object: nil)
@objc func didReceiveKeyboardNotificationObserver(_ notification: Notification) {
let userInfo = notification.userInfo
let keyboardBounds = (userInfo!["UIKeyboardBoundsUserInfoKey"] as! NSValue).cgRectValue
let keyboardFrame = (userInfo!["UIKeyboardFrameEndUserInfoKey"] as! NSValue).cgRectValue
let duration = userInfo!["UIKeyboardAnimationDurationUserInfoKey"] as! Double
let curve = userInfo!["UIKeyboardAnimationCurveUserInfoKey"] as! Int
let frameBegin = (userInfo!["UIKeyboardFrameBeginUserInfoKey"] as! NSValue).cgRectValue
let centerBegin = (userInfo!["UIKeyboardCenterBeginUserInfoKey"] as! NSValue).cgPointValue
let center = (userInfo!["UIKeyboardCenterEndUserInfoKey"] as! NSValue).cgPointValue
let location = userInfo!["UIKeyboardIsLocalUserInfoKey"] as! Int
println("keyboardBounds: \(keyboardBounds) \nkeyboardFrame: \(keyboardFrame) \nduration: \(duration) \ncurve: \(curve) \nframeBegin:\(frameBegin) \ncenterBegin:\(centerBegin)\ncenter:\(center)\nlocation:\(location)")
switch notification.name {
case UIResponder.keyboardWillShowNotification:
// keyboardWillShowNotification
case UIResponder.keyboardWillHideNotification:
// keyboardWillHideNotification
default:
break
}
}
#selector(ViewController.keyBoardUp(notification:))，并将函数更改为func keyBoardUp(notification: Notification){ print("HELLO") }。 - Nirav D