I'm trying to get keyboard notifications to work in my app but somehow I keep running into this error. This is my code:
override func viewWillAppear(_ animated: Bool) {
NotificationCenter.default.addObserver(self, selector: Selector(("keyboardDidShow:")), name: .UIKeyboardDidShow, object: nil)
NotificationCenter.default.addObserver(self, selector: Selector(("keyboardWillHide:")), name: .UIKeyboardWillHide, object: nil)
}
override func viewWillDisappear(_ animated: Bool) {
NotificationCenter.default.removeObserver(self)
}
func keyboardDidShow(notification : Notification)
{
print("keyboard shown")
if let keyboardSize = (notification.userInfo?[UIKeyboardFrameBeginUserInfoKey] as? NSValue)?.cgRectValue.size
{
print(keyboardSize)
}
}
func keyboardWillHide(notification : Notification)
{
}
I honestly can't find where I'm going wrong. I keep getting the error as stated in the question statement.
Related
I have a problem with the moving of text input and button when the keyboard is open. I am using the following code
override func viewDidLoad() {
super.viewDidLoad()
NotificationCenter.default.addObserver(self, selector: #selector(keyboardWillChange(notification:)), name: UIResponder.keyboardWillShowNotification, object: nil)
NotificationCenter.default.addObserver(self, selector: #selector(keyboardWillChange(notification:)), name: UIResponder.keyboardWillChangeFrameNotification, object: nil)
NotificationCenter.default.addObserver(self, selector: #selector(keyboardWillChange(notification:)), name: UIResponder.keyboardWillHideNotification, object: nil)
}
deinit {
NotificationCenter.default.removeObserver(self, name: UIResponder.keyboardWillShowNotification, object: nil)
NotificationCenter.default.removeObserver(self, name: UIResponder.keyboardWillChangeFrameNotification, object: nil)
NotificationCenter.default.removeObserver(self, name: UIResponder.keyboardWillHideNotification, object: nil)
}
#objc func keyboardWillChange(notification: NSNotification) {
guard let keyboardSize = (notification.userInfo?[UIResponder.keyboardFrameEndUserInfoKey] as? NSValue)?.cgRectValue else {
return
}
if notification.name == UIResponder.keyboardWillShowNotification || notification.name == UIResponder.keyboardWillChangeFrameNotification {
view.frame.origin.y = -keyboardSize.height
} else {
view.frame.origin.y = 0
}
}
The problem occurs when I start typing in the text field, here are images before: https://imgur.com/a/cbQbJzW and after: https://imgur.com/a/f1Nakrs
I am sorry about the language it of files don't say anything spacial.
I want to know why this happens, is it possible to be because I am using CocoaPods - YoshikoTextField in the grey text field ?
Thank you!
import UIKit
class ViewController: UIViewController, UITextFieldDelegate {
#IBOutlet weak var backgroundScrollView: UIScrollView!
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)
// Do any additional setup after loading the view, typically from a nib.
}
#objc func keyboardWillShow(notification:NSNotification) {
adjustingHeight(true, notification: notification)
}
#objc func keyboardWillHide(notification:NSNotification) {
adjustingHeight(false, notification: notification)
}
func adjustingHeight(_ isShow:Bool, notification:NSNotification) {
let userInfo = notification.userInfo!
let keyboardFrame = (userInfo[UIResponder.keyboardFrameBeginUserInfoKey] as! NSValue).cgRectValue
let changeInHeight = (keyboardFrame.height + 20) * (isShow ? 1 : -1)
backgroundScrollView.contentInset.bottom += changeInHeight
backgroundScrollView.scrollIndicatorInsets.bottom += changeInHeight
}
func textFieldShouldReturn(_ textField: UITextField) -> Bool {
self.view.endEditing(true)
return true
}
override func didReceiveMemoryWarning() {
super.didReceiveMemoryWarning()
// Dispose of any resources that can be recreated.
}
}
I am trying to call a function from another class in Swift and NotificationCenter is an option to do that so I started with the addObserver.
override func viewDidLoad() {
super.viewDidLoad()
NotificationCenter.default.addObserver(self, selector: #selector(toggleSideMenu), name: NSNotification.Name("callToggleSideMenu"), object: nil)
}
#objc func toggleSideMenu(){
if isMenuOpen {
sideContainer.constant = -260
} else {
sideContainer.constant = 0
}
}
And in the other class I have added the (post):
#objc func clickOnButton(button: UIButton) {
NotificationCenter.default.post(name: NSNotification.Name("callToggleSideMenu"), object: nil)
}
Everything seems ok but I do not know why it is not working. I have seen a lot of the same issue here in stackoverflow but no answer solved my issue.
Function definition is not correct. It should be :
#objc func toggleSideMenu(_ notification: Notification){
if isMenuOpen {
sideContainer.constant = -260
} else {
sideContainer.constant = 0
}
}
Call it using :
NotificationCenter.default.addObserver(self, selector: #selector(toggleSideMenu(_:)), name: NSNotification.Name("callToggleSideMenu"), object: nil)
I have mainViewController and inside have scrollView and I have secondViewController I want to change scrollView offset to top from secondViewController when I want to try it with NSNotificationCenter gives me ;
: unrecognized selector sent to instance 0x7ff83e024200'
How can I fix it ?
My codes under below.
mainViewController
override func viewDidLoad() {
super.viewDidLoad()
NotificationCenter.default.addObserver(self, selector: "gotop:", name: NSNotification.Name(rawValue: "gotop"), object: nil)
}
func gotop(){
scrollView.setContentOffset(CGPoint(x:0, y:0), animated: false)
}
secondViewController
#IBAction func goButton (sender : UIButton){
NotificationCenter.default.post(name: NSNotification.Name(rawValue: "gotop"), object: nil)
}
check your addObserver code, selector should have below signature
NotificationCenter.default.addObserver(self, selector: #selector(MainViewController.goTop(notification:)), name: Notification.Name("gotop"), object: nil)
Method handler for received Notification:
func goTop(notification: Notification){
scrollView.setContentOffset(CGPoint(x:0, y:0), animated: false)
}
For posting notification
NotificationCenter.default.post(name: Notification.Name("gotop"), object: nil)
Remove Notification in denit
deinit {
NotificationCenter.default.removeObserver((self, name: Notification.Name("gotop"), object: nil)
}
I have used below code in my project to add notification :
NotificationCenter.default.addObserver(self, selector: #selector(YourViewController.gotop), name: NSNotification.Name(rawValue: "gotop"), object: nil)
Try if it works in your scenario.
the definition of your "goTop" func is wrong :
instead of
func gotop(){
//do your stuff
}
try this :
func gotop(notification : NSNotification){
//do your stuff
}
let me know if this solve your problem.
I have two controllers
class CtrlA: UIViewController {
override func viewWillAppear(_ animated: Bool) {
super.viewWillAppear(animated)
NotificationCenter.default.addObserver(CtrlB.self, selector: #selector(CtrlB.badge(notification:)), name: NSNotification.Name(rawValue: "badge"), object: nil)
}
override func viewWillDisappear(_ animated: Bool) {
super.viewWillDisappear(animated)
NotificationCenter.default.removeObserver(CtrlB.self, name: NSNotification.Name(rawValue: "badge"), object: nil)
}
}
class CtrlB: UIViewController {
static func badge (notification: NSNotification) {
// blah blah
}
}
Whats the correct way to unregister the notification listener above?
I'm not certain this is correct:
NotificationCenter.default.removeObserver(CtrlB.self, name: NSNotification.Name(rawValue: "badge"), object: nil)
I don't think I can use self either, since it was registered on CtrlB.self
So the best way to implement the notification in your project is create one class called NotificationManager inside that declare one dictionary in which you can always update the observers
class NotificationManager {
var observers = [String: AnyObject]()
}
Create addObserver method, post notification method and remove
observer method inside the same class.
func postNotification(_ name: String, userInfo: [AnyHashable: Any]? = nil) {
NotificationCenter.default.post(name: name, object: nil, userInfo: userInfo)
}
func addObserver(_ name: String, block: #escaping (Notification) -> Void) {
//if observer is already in place for this name, remove it
removeObserverForName(name)
let observer = NotificationCenter.default.addObserver(forName: name), object: nil, queue: OperationQueue.main, using: block)
self.observers[name] = observer
}
func removeObserver(_ name: name) {
guard let observer = self.observers[name] else { return }
NotificationCenter.default.removeObserver(observer)
self.observers.removeValue(forKey: name)
}
//Removes all observers
func removeAllObservers() {
for observer in self.observers.values {
NotificationCenter.default.removeObserver(observer)
}self.observers = [:]
}
So access the above method in any of your class wherever its required and it will take care of everything. This will also prevent crash in your code. If try to remove the same observer more than one time.
I am not sure why you are registering/unregistering to notifications with a class and not an instance. 'CtrlB.self' - will not give you an instance of the CtrlB class, in fact it will return a class itself.
Instead you should use something like this:
class CtrlA {
let ctrlBInstance = CtrlB()
override func viewWillAppear(_ animated: Bool) {
super.viewWillAppear(animated)
NotificationCenter.default.addObserver(ctrlBInstance, selector: #selector(CtrlB.badge(notification:)), name: NSNotification.Name(rawValue: "badge"), object: nil)
}
override func viewWillDisappear(_ animated: Bool) {
super.viewWillDisappear(animated)
NotificationCenter.default.removeObserver(ctrlBInstance, name: NSNotification.Name(rawValue: "badge"), object: nil)
}
}
And your ClassB should look like this in this case:
class CtrlB {
func badge (notification: NSNotification) {
// blah blah
}
}
You need to get the instance of the observer,which you haven't declared...
for instance you need to set class variable secondA...
class CtrlA: UIViewController {
var secondController: CtrlB?
override func viewDidLoad()
{
super.viewDidLoad()
if let unwrappedController = storyboard.instantiateViewController(withIdentifier: "someViewController") as? CtrlB
{
secondController = unwrappedController
}
}
override func viewWillAppear(_ animated: Bool) {
super.viewWillAppear(animated)
if let secondController = secondController
{
NotificationCenter.default.addObserver(CtrlB.self, selector: #selector(CtrlB.badge(notification:)), name: NSNotification.Name(rawValue: "badge"), object: nil)
}
}
override func viewWillDisappear(_ animated: Bool) {
super.viewWillDisappear(animated)
if let secondController = secondController
{
NotificationCenter.default.removeObserver(CtrlB.self, name: NSNotification.Name(rawValue: "badge"), object: nil)
}
}
//Also don't forget to remove listening on deinit
deinit
{
if let secondController = secondController
{
NotificationCenter.default.removeObserver(secondController, name: NSNotification.Name(rawValue: "badge"), object: nil)
}
}
}
class CtrlB: UIViewController {
//Here you go with notification...
static func badge (notification: NSNotification) {
// blah blah
}
}
Currently following a tutorial, however, some of the syntax is outdated. Basically the code should show and hide the user keyboard. I get some syntax errors with the addObserver method and Swift wants me to use key path instead, however, if i use the auto 'fix-it' i get even more errors. Can anyone help me out with this? Thanks!
NSNotification.addObserver(self, selector: #selector(keyboardwillShow), name: .UIKeyboardWillShow, nil)
NSNotification.addObserver(self, selector: #selector(keyboardwillHide), name: .UIKeyboardWillHide, nil)
func keyboardwillShow(_notification:NSNotification) {
keyboard = (_notification.userInfo![UIKeyboardFrameEndUserInfoKey]! as AnyObject).cgRectValue
UIView.animate(withDuration: 0.4) {
self.scrolledView.frame.size.height = self.scrollViewHeight - self.keyboard.height
}
}
func keyboardwillHide(_notification:NSNotification) {
UIView.animate(withDuration: 0.5) {
self.scrolledView.frame.size.height = self.view.frame.height
}
}
I get the debug message: "Incorrect argument labels in call(have _selector:name, expected _forKeyPath:options:context"
Your function has argument, That is missing when you add it in observer
And you have to use NotificationCenter.default.addObserver not NotificationCenter.addObserver
let selectorForKeyBoardWillShow: Selector = #selector(ViewController.keyboardWillShow(_:))
let selectorForKeyBoardWillHide: Selector = #selector(ViewController.keyboardWillHide(_:))
// MARK: - Functions
override func viewDidLoad() {
super.viewDidLoad()
NotificationCenter.default.addObserver(self, selector: selectorForKeyBoardWillShow, name: NSNotification.Name.UIKeyboardWillShow, object: nil)
NotificationCenter.default.addObserver(self, selector: selectorForKeyBoardWillHide, name: NSNotification.Name.UIKeyboardWillHide, object: nil)
}
// MARK: Keyboard Observer
func keyboardWillShow(_ notification: Notification) {
}
func keyboardWillHide(_ notification: Notification) {
}