我正在尝试将此代码更新为Swift 3：
NSNotificationCenter.defaultCenter().addObserver(self, selector: Selector("keyboardWillShow:"), name: UIKeyboardWillShowNotification, object: nil)
NSNotificationCenter.defaultCenter().addObserver(self, selector: Selector("keyboardWillHide:"), name: UIKeyboardWillHideNotification, object: nil)`
到目前为止，我刚刚尝试了编译器给出的自动更正。这会导致这样的代码：
let notificationCenter = NotificationCenter.default()
notificationCenter.addObserver(self, selector: Selector(("keyboardWillShow:")), name: NSNotification.Name.UIKeyboardWillShow, object: nil)
notificationCenter.addObserver(self, selector: Selector(("keyboardWillHide:")), name: NSNotification.Name.UIKeyboardWillHide, object: nil)`
不幸的是，这并没有使我走得更远，导致了其他错误。
有人解决了这个问题吗？
请注意，我只是在尝试如何编写通知。我还没有试图修复通知功能。谢谢
swift 4.2 xcode 10（10l213o）
与Swift 3相比，主要更改在UIWindow.keyboardWillShowNotification和UIWindow.keyboardWillHideNotification
let notifier = NotificationCenter.default
notifier.addObserver(self,
selector: #selector(KeyboardLayoutConstraint.keyboardWillShowNotification(_:)),
name: UIWindow.keyboardWillShowNotification,
object: nil)
notifier.addObserver(self,
selector: #selector(KeyboardLayoutConstraint.keyboardWillHideNotification(_:)),
name: UIWindow.keyboardWillHideNotification,
object: nil)
@objc
func keyboardWillShowNotification(_ notification: NSNotification) {}
@objc
func keyboardWillHideNotification(_ notification: NSNotification) {}
swift 4
override func viewDidLoad() {
super.viewDidLoad()
NotificationCenter.default.addObserver(self, selector: #selector(keyboardWillShow), name: .UIKeyboardWillShow, object: nil)
NotificationCenter.default.addObserver(self, selector: #selector(self.keyboardWillHide), name: NSNotification.Name.UIKeyboardWillHide, object: nil)
}
func keyboardWillShow(notification: NSNotification) {
print("keyboardWillShow")
}
func keyboardWillHide(notification: NSNotification){
print("keyboardWillHide")
}
deinit {
NotificationCenter.default.removeObserver(self)
}
您还可以使用这些方法中的以下代码获取键盘信息。
NotificationCenter.default.addObserver(self, selector: #selector(keyboardWillChange), name: .UIKeyboardWillChangeFrame, object: nil) .
@objc func keyboardWillChange(notification: NSNotification) {
let duration = notification.userInfo![UIKeyboardAnimationDurationUserInfoKey] as! Double
let curve = notification.userInfo![UIKeyboardAnimationCurveUserInfoKey] as! UInt
let curFrame = (notification.userInfo![UIKeyboardFrameBeginUserInfoKey] as! NSValue).cgRectValue
let targetFrame = (notification.userInfo![UIKeyboardFrameEndUserInfoKey] as! NSValue).cgRectValue
let deltaY = targetFrame.origin.y - curFrame.origin.y
}
我通过编写类似的代码
来解决此问题NotificationCenter.default.addObserver(self, selector: #selector(keyboardWillShow), name: .UIKeyboardWillShow, object: nil)
swift 4.2 .UIKeyboardWillShow已更名为UIResponder.keyboardWillShowNotification和 .UIKeyboardWillHide被重命名为UIResponder.keyboardWillHideNotification
NotificationCenter.default.addObserver(self, selector: #selector(NameOfSelector), name: UIResponder.keyboardWillShowNotification , object: nil)
NotificationCenter.default.addObserver(self, selector: #selector(NameOfSelector), name: UIResponder.keyboardWillHideNotification , object: nil)
@objc func NameOfSelector() {
//Actions when notification is received
}
您可以用类型检查的#selector(Class.method)对替换不弃用的字符串字面的Selector：
let center = NotificationCenter.default
center.addObserver(self,
selector: #selector(keyboardWillShow(_:)),
name: .UIKeyboardWillShow,
object: nil)
center.addObserver(self,
selector: #selector(keyboardWillHide(_:)),
name: .UIKeyboardWillHide,
object: nil)
#selector语法要安全得多，因为Swift能够在编译时间检查指定方法实际上存在。
有关Swift Selectors的更多信息，请参见Rickster的详细答案。
swift 5.1 combine swiftui
@State var keyboardHeight: CGFloat = 0 // or @Published if one is in ViewModel: ObservableObject
private var cancellableSet: Set<AnyCancellable> = []
init() {
let notificationCenter = NotificationCenter.default
notificationCenter.publisher(for: UIWindow.keyboardWillShowNotification)
.map {
guard
let info = $0.userInfo,
let keyboardFrame = info[UIResponder.keyboardFrameEndUserInfoKey] as? CGRect
else { return 0 }
return keyboardFrame.height
}
.assign(to: .keyboardHeight, on: self)
.store(in: &cancellableSet)
notificationCenter.publisher(for: UIWindow.keyboardDidHideNotification)
.map { _ in 0 }
.assign(to: .keyboardHeight, on: self)
.store(in: &cancellableSet)
}
在Swift 3.0
中 override func viewDidLoad()
{
super.viewDidLoad()
NotificationCenter.default.addObserver(self, selector: #selector(self.keyboardWillShow), name: NSNotification.Name.UIKeyboardWillShow, object: nil)
NotificationCenter.default.addObserver(self, selector: #selector(self.keyboardWillHide), name: NSNotification.Name.UIKeyboardWillHide, object: nil)
}
keybord show和hide
func keyboardWillShow(notification: NSNotification)
{
// Your Code Here
}
func keyboardWillHide(notification: NSNotification)
{
//Your Code Here
}
您可以分别在两个版本的Swift上执行键盘通知。
添加objserver：
NotificationCenter.default.addObserver(self, selector: #selector(keyboardDidShow), name: .UIKeyboardWillShow, object: nil)
呼叫功能Swift 3
func keyboardDidShow() {
print("keyboardDidShow")
}
swift 4
中的呼叫功能@objc func keyboardDidShow() {
print("keyboardDidShow")
}
NotificationCenter.default.addObserver(self, selector: Selector(("keyboardWillShow:")), name:UIResponder.keyboardWillShowNotification, object: nil);
NotificationCenter.default.addObserver(self, selector: Selector(("keyboardWillHide:")), name:UIResponder.keyboardWillHideNotification, object: nil);
这是对我有用的最佳解决方案（从"让我们构建该应用程序" YouTube频道）
class ChatVC: UIViewController, UITableViewDelegate, UITableViewDataSource, UITextFieldDelegate {
// reference to your UIView with message TextField
@IBOutlet weak var ChatView: UIView!
// bottom constrain to your UIView (in my case ChatView)
var bottomConstraint: NSLayoutConstraint?
override func viewDidLoad() {
super.viewDidLoad()
// add some text in the placeholder if you want
messageField.placeholder = "Type your message.."
// here we add two notifications for showing and hiding the keyboard
NotificationCenter.default.addObserver(self, selector: #selector(handleKeyboardNotification), name: UIResponder.keyboardWillShowNotification, object: nil)
NotificationCenter.default.addObserver(self, selector: #selector(handleKeyboardNotification), name: UIResponder.keyboardWillHideNotification, object: nil)
// defines the start position for message textField that will be shown on the screen
bottomConstraint = NSLayoutConstraint(item: ChatViewField!, attribute: .bottom, relatedBy: .equal, toItem: view, attribute: .bottom, multiplier: 1, constant: -40)
view.addConstraint(bottomConstraint!)
}
// handles notifications for both cases when keyboard pops up and disappears
@objc func handleKeyboardNotification(notification: NSNotification){
if let userInfo = notification.userInfo {
let keyboardFrame = (userInfo[UIResponder.keyboardFrameEndUserInfoKey] as! NSValue).cgRectValue
print(keyboardFrame)
let isKeyboardShowing = notification.name == UIResponder.keyboardWillShowNotification
bottomConstraint?.constant = isKeyboardShowing ? -keyboardFrame.height : -40
// makes animation at the same time as the keyboard
UIView.animate(withDuration: 0, delay: 0, options: UIView.AnimationOptions.curveEaseOut, animations: {
self.view.layoutIfNeeded()
}) { (completed) in
}
}
}
您可以创建具有此逻辑的协议，并且您的UiviewController实现了它，在viewDidLoad中，您调用config方法绑定它。
我在底部使用约束来移动与键盘相同的动画的整个视图。
在这里您有一个使用Zafar007的答案的示例：
protocol ViewControllerKeyboardType {
var bottomConstraint: NSLayoutConstraint! { get set }
func configKeyboardNotification()
func keyboardWillChangeHandler(notification: NSNotification)
}
extension ViewControllerKeyboardType where Self: UIViewController {
func keyboardWillChangeHandler(notification: NSNotification) {
let duration = notification.userInfo?[UIResponder.keyboardAnimationDurationUserInfoKey] as? Double ?? 0.0
let curve = notification.userInfo?[UIResponder.keyboardAnimationCurveUserInfoKey] as? UInt ?? UIView.AnimationOptions.curveLinear.rawValue
let curFrame = (notification.userInfo![UIResponder.keyboardFrameBeginUserInfoKey] as! NSValue).cgRectValue
let targetFrame = (notification.userInfo![UIResponder.keyboardFrameEndUserInfoKey] as! NSValue).cgRectValue
let deltaY = targetFrame.origin.y - curFrame.origin.y
UIView.animate(withDuration: duration, delay: 0, options: UIView.AnimationOptions(rawValue: curve)) {
self.bottomConstraint.constant = self.bottomConstraint.constant - deltaY
self.view.layoutIfNeeded()
}
}
func configKeyboardNotification() {
NotificationCenter.default.addObserver(forName: UIResponder.keyboardWillChangeFrameNotification, object: nil, queue: nil) { [weak self] (notification) in
self?.keyboardWillChangeHandler(notification: notification as NSNotification)
}
}
}
用法：
class MyViewController: UIViewController, ViewControllerKeyboardType {
@IBOutlet weak var bottomConstraint: NSLayoutConstraint!
override func viewDidLoad() {
super.viewDidLoad()
self.configKeyboardNotification()
}
}
如果您是像我这样的白痴，而花哨的Combine：
UIViewController的简单扩展：
import UIKit
import Combine
extension Notification {
var keyboardHeight: CGFloat {
return (userInfo?[UIResponder.keyboardFrameEndUserInfoKey] as? CGRect)?.height ?? 0
}
}
enum KeyboardState {
case willShow
case willHide
}
struct KeyboardObject: Equatable {
var state: KeyboardState
var height: CGFloat
}
extension UIViewController {
private var keyboardWillShowPublisher: AnyPublisher<KeyboardObject, Never> {
NotificationCenter.default.publisher(for: UIResponder.keyboardWillShowNotification,object: nil)
.compactMap {
return KeyboardObject(state: .willShow, height: $0.keyboardHeight)
}.eraseToAnyPublisher()
}
private var keyboardWillHidePublisher: AnyPublisher<KeyboardObject, Never> {
NotificationCenter.default
.publisher(for: UIResponder.keyboardWillHideNotification,object: nil)
.compactMap { _ in
return KeyboardObject(state: .willHide, height: 0.0)
}.eraseToAnyPublisher()
}
func keyboardListener() -> AnyPublisher<KeyboardObject, Never> {
Publishers.Merge(keyboardWillShowPublisher, keyboardWillHidePublisher)
.removeDuplicates()
.eraseToAnyPublisher()
}
}
在您的UIViewController中：
import UIKit
import Combine
final class SomeVC: UIViewController {
var keyboardPublisher: AnyCancellable?
private var flowLayoutConstraint: NSLayoutConstraint!
private let defaults = UserDefaults.standard
override func viewWillAppear(_ animated: Bool) {
keyboardPublisher = self.keyboardListener()
.sink(receiveValue: { [unowned self] keyboard in
switch keyboard.state {
case .willShow:
manageKeyboardChange(value: keyboard.height)
case .willHide:
// I used a value saved in my userDefaults, but just set it back to the original constraint for that view without the keyboard
manageKeyboardChange(value: defaults.double(forKey: "opaqueHeight"))
}
})
}
override func viewWillDisappear(_ animated: Bool) {
keyboardPublisher?.cancel()
}
func manageKeyboardChange(value: CGFloat) {
self.flowLayoutConstraint.constant = value
UIView.animate(withDuration: 0.5, delay: 0, usingSpringWithDamping: 1, initialSpringVelocity: 1, options: .curveEaseOut, animations: { [weak self] in
self?.view.layoutIfNeeded()
}, completion: nil)
print("CHANGE")
}
}