I am working on an app that requires my main view controller to receive notifications from its child view controller. To do this, I set up the observer in the viewDidLoad() method of the parent controller, and I am trying to call the postNotificationName() function when a button is pressed that is located in the child view controller.
When the postNotificationName() call is located in the #IBAction func buttonPressed(){ } function, the observer never gets the notification. However, when the same code is called from a different function in the same view controller, it works.
I thought this might be a thread issue, and unsuccessfully tried many of the solutions for that issue. I'm not very familiar with threading, though, so maybe I still missed it. Does anyone have any idea what the issue might be?
Thanks for the help!
ViewController
class GameController: UIViewController {
override func viewDidLoad() {
super.init()
NSNotificationCenter.defaultCenter().addObserver(self, selector: "attemptHumanMove:", name: Constants.NSNotificationKey.tilePressed, object: nil)
}
func attemptHumanMove(notification: NSNotification) {
print("test")
}
ChildViewController
#IBAction func tileTouched(sender: AnyObject) {
NSNotificationCenter.defaultCenter().postNotificationName(Constants.NSNotificationKey.tilePressed, object: nil, userInfo: ["a": 0])
}
Experimenting with the flow you have mentioned, the following code does receive the notification message from a child view controller.
ParentViewController
class ViewController: UIViewController {
#IBOutlet weak var notificationMsgLabel: UILabel!
override func viewDidLoad() {
super.viewDidLoad()
notificationMsgLabel.text = "Waiting for notification..."
NSNotificationCenter.defaultCenter().addObserver(self, selector: "attemptHumanMove:", name: "tilePressed", object: nil)
}
func attemptHumanMove(notification: NSNotification) {
print("Notification message received!")
notificationMsgLabel.text = "Notification received!!!"
}
}
ChildViewController
class ChildViewController: UIViewController {
override func viewDidLoad() {
super.viewDidLoad()
}
#IBAction func sendNotification() {
print("Sending notification message!!!")
NSNotificationCenter.defaultCenter().postNotificationName("tilePressed", object: nil, userInfo: ["a": 0])
}
}
Here you can find the screen shot of the storyboard:
Storyboard Snapshot
Related
Beneath is my code,
Currently, it isn't working and allowing me to connect a button to my swift file (main storyboard). Also, the timer function isn't working, would this be to do with the function not working as well?
unsure on how to fix this, let me know if you need any other screen shots.
Any help will be appreciated.
Thanks
import UIKit
class ViewController: UIViewController {
#IBOutlet weak var CounterLabel: UILabel!
var time = 30
var timer = Timer()
#IBAction func start(_ sender: UIButton)
{
timer = Timer.scheduledTimer(timeInterval: 1, target: self, selector: #selector(ViewController.action), userInfo: nil, repeats: true)
}
func action()
{
time += 1
}
//GIFS
override func viewDidLoad() {
super.viewDidLoad()
// Do any additional setup after loading the view, typically from a nib.
}
override func didReceiveMemoryWarning() {
super.didReceiveMemoryWarning()
// Dispose of any resources that can be recreated.
}
}
I am currently developing an iOS application with login and sign up forms. To make sure that the keyboard does not cover any UITextFields I've implemented the following solution provided by Apple and discussed in this issue.
To briefly sum it up, this solution uses a UIScrollView in which the different UI elements are placed and UIKeyboardDidShowNotification and UIKeyboardDidHideNotification to move the elements up and down when the keyboard appears/disappears so that the UITextFields aren't hidden.
This works like a charm except for one thing: for all my UIViewControllers I have to repeat the same code. To tackle my problem I have tried:
to create a base UIViewController, providing an implementation for the different functions, that can be subclasses by the other UIViewControllers;
to use a protocol and a protocol extension to provide a default implementation for the different functions and make my UIViewControllers conform to it.
Both solutions didn't solve my problem. For the first solution, I wasn't able to connect the UIScrollView of my base class through the Interface Builder although it was declared.
#IBOutlet weak var scrollView: UIScrollView!
When trying to implement the second solution, the UIViewController implementing my protocol somehow did not recognise the declared methods and their implementations.
The protocol declaration:
protocol ScrollViewProtocol {
var scrollView: UIScrollView! { get set }
var activeTextField: UITextField? { get set }
func addTapGestureRecognizer()
func singleTapGestureCaptured()
func registerForKeyboardNotifications()
func deregisterForKeyboardNotifications()
func keyboardWasShown(notification: NSNotification)
func keyboardWillBeHidden(notification: NSNotification)
func setActiveTextField(textField: UITextField)
func unsetActiveTextField()
}
The protocol extension implements all functions expect for the addTapGestureRecognizer() as I would like to avoid using #objc:
extension ScrollViewProtocol where Self: UIViewController {
// The implementation for the different functions
// as described in the provided links expect for the following method
func registerFromKeyboardNotifications() {
NSNotificationCenter.defaultCenter().addObserverForName(UIKeyboardDidShowNotification, object: nil, queue: nil, usingBlock: { notification in
self.keyboardWasShown(notification)
})
NSNotificationCenter.defaultCenter().addObserverForName(UIKeyboardDidHideNotification, object: nil, queue: nil, usingBlock: { notification in
self.keyboardWillBeHidden(notification)
})
}
}
Does anyone have a good solution to my problem, knowingly how could I avoid repeating the code related to moving the UITextFields up and down when the keyboard appears/disappears? Or does anyone know why my solutions did not work?
I found a solution. I'll post it in case someone once to do the same thing.
So, I ended up deleting the UIScrollView outlet in my base class and replacing it with a simple property that I set in my inheriting classes. The code for my base class look as follow:
import UIKit
class ScrollViewController: UIViewController, UITextFieldDelegate {
// MARK: Properties
var scrollView: UIScrollView!
var activeTextField: UITextField?
// MARK: View cycle
override func viewDidLoad() {
super.viewDidLoad()
let singleTap = UITapGestureRecognizer(target: self, action: #selector(singleTapGestureCaptured))
scrollView.addGestureRecognizer(singleTap)
}
override func viewWillAppear(animated: Bool) {
super.viewWillAppear(animated)
registerForKeyboardNotifications()
}
override func viewWillDisappear(animated: Bool) {
super.viewWillDisappear(animated)
deregisterFromKeyboardNotifications()
}
// MARK: Gesture recognizer
func singleTapGestureCaptured(sender: AnyObject) {
view.endEditing(true)
}
// MARK: Keyboard management
func registerForKeyboardNotifications() {
NSNotificationCenter.defaultCenter().addObserver(self, selector: #selector(keyboardWasShown), name: UIKeyboardWillShowNotification, object: nil)
NSNotificationCenter.defaultCenter().addObserver(self, selector: #selector(keyboardWillBeHidden), name: UIKeyboardWillHideNotification, object: nil)
}
func deregisterFromKeyboardNotifications() {
NSNotificationCenter.defaultCenter().removeObserver(self, name: UIKeyboardWillShowNotification, object: nil)
NSNotificationCenter.defaultCenter().removeObserver(self, name: UIKeyboardWillHideNotification, object: nil)
}
func keyboardWasShown(notification: NSNotification) {
scrollView.scrollEnabled = true
let info : NSDictionary = notification.userInfo!
let keyboardSize = (info[UIKeyboardFrameBeginUserInfoKey] as? NSValue)?.CGRectValue().size
let contentInsets : UIEdgeInsets = UIEdgeInsetsMake(0.0, 0.0, keyboardSize!.height, 0.0)
scrollView.contentInset = contentInsets
scrollView.scrollIndicatorInsets = contentInsets
var aRect : CGRect = self.view.frame
aRect.size.height -= keyboardSize!.height
if let activeFieldPresent = activeTextField {
if (!CGRectContainsPoint(aRect, activeFieldPresent.frame.origin)) {
scrollView.scrollRectToVisible(activeFieldPresent.frame, animated: true)
}
}
}
func keyboardWillBeHidden(notification: NSNotification) {
let info : NSDictionary = notification.userInfo!
let keyboardSize = (info[UIKeyboardFrameBeginUserInfoKey] as? NSValue)?.CGRectValue().size
let contentInsets : UIEdgeInsets = UIEdgeInsetsMake(0.0, 0.0, -keyboardSize!.height, 0.0)
scrollView.contentInset = contentInsets
scrollView.scrollIndicatorInsets = contentInsets
view.endEditing(true)
scrollView.scrollEnabled = false
}
// MARK: Text field management
func textFieldDidBeginEditing(textField: UITextField) {
activeTextField = textField
}
func textFieldDidEndEditing(textField: UITextField) {
activeTextField = nil
}
}
And here is the inheriting class code:
class ViewController: ScrollViewController {
#IBOutlet weak var scrollViewOutlet: UIScrollView! {
didSet {
self.scrollView = self.scrollViewOutlet
}
}
// Your view controller functions
}
I hope this will help!
I am new to Mac OSX and with Apple promoting the fact that the bodies of code are becoming similar decided to tell the folk I am writing code for we should be able to do a Mac OSX version. iPhone and iPad versions are all good and about to release second version so no issues there.
So I am subclassing NSWindowController to get access to the Toolbar and worked out how to remove and add items on the toolbar, but for the life of me I can not get one NSViewController (firstViewController) to dismiss and bring up the second NSViewController (secondViewController) in the same NSWindowController.
So the 2 issues are that
1. I want to be able to performSegueWithIdentifier from the first NSViewController in code and
2. bring up the second NSViewController by replacing the first NSViewController in the same NSWindowController.
If I add a button to the firstViewController and put a segue to the secondViewController then when I select the button the secondViewController comes up just fine but in a seperate window not the same NSWindowController that I want it to and the firstViewController does not get replaced but stays in the NSWindowController.
So I know the segue idea will work but its not working in code and when I do insert the segue from a button it works but into a seperate NSViewController that is not part of the NSWindowController.
I am trying to find some programming guide from Apple on the issue but no luck so far.
Here is an overview from my Storyboard:
Here is my NSWindowController subclassed and the func loginToMe2Team is trigger from the NSToolBar and its working just find as the print statements show up on the console.
import Cocoa
class me2teamWindowsController: NSWindowController {
#IBOutlet var mySignUp : NSToolbarItem!
#IBOutlet var myToolbar : NSToolbar!
let controller = ViewController()
override func windowDidLoad() {
super.windowDidLoad()
print("window loaded")
}
override func windowWillLoad() {
print("window will load")
}
#IBAction func logInToMe2Team(sender: AnyObject){
controller.LogIn() //THIS IS THE FUNC I AM TESTING WITH
}
#IBAction func signUpToMe2Team(sender: AnyObject){
controller.signUp()
}
Here is my NSViewController subclassed with the func LogIn. Its getting selected just fine but the performSegueWithIdentifier is not. And I did cut and past the Identifier to make absolutely sure it was the same.
import Cocoa
import WebKit
class ViewController: NSViewController {
#IBOutlet weak var theWebPage: WebView!
#IBOutlet weak var progressIndicator: NSProgressIndicator!
override func viewDidLoad() {
super.viewDidLoad()
let urlString = "https://thewebpage.com.au"
self.theWebPage.mainFrame.loadRequest(NSURLRequest(URL: NSURL(string: urlString)!))
}
override func viewDidAppear() {
}
func LogIn() {
print("I logged in")
self.performSegueWithIdentifier("goToTeamPage", sender: self)
//THIS IS THE BIT THATS NOT WORKING
}
func signUp() {
print("I have to sign up now")
}
override var representedObject: AnyObject? {
didSet {
}
}
func webView(sender: WebView!, didStartProvisionalLoadForFrame frame: WebFrame!)
{
self.progressIndicator.startAnimation(self)
}
func webView(sender: WebView!, didFinishLoadForFrame frame: WebFrame!)
{
self.progressIndicator.stopAnimation(self)
}
}
You need to use a custom segue class (or possibly NSTabViewController if it’s enough for your needs). Set the segue’s type to Custom, with your class name specified:
…and implement it. With no animation, it’s simple:
class ReplaceSegue: NSStoryboardSegue {
override func perform() {
if let src = self.sourceController as? NSViewController,
let dest = self.destinationController as? NSViewController,
let window = src.view.window {
// this updates the content and adjusts window size
window.contentViewController = dest
}
}
}
In my case, I was using a sheet and wanted to transition to a different sheet with a different size, so I needed to do more:
class ReplaceSheetSegue: NSStoryboardSegue {
override func perform() {
if let src = self.sourceController as? NSViewController,
let dest = self.destinationController as? NSViewController,
let window = src.view.window {
// calculate new frame:
var rect = window.frameRectForContentRect(dest.view.frame)
rect.origin.x += (src.view.frame.width - dest.view.frame.width) / 2
rect.origin.y += src.view.frame.height - dest.view.frame.height
// don’t shrink visible content, prevent minsize from intervening:
window.contentViewController = nil
// animate resizing (TODO: crossover blending):
window.setFrame(window.convertRectToScreen(rect), display: true, animate: true)
// set new controller
window.contentViewController = dest
}
}
}
I am creating a program and I would like the UI to change based on the size of the window. I'm looking for some method that is called when the window has been resized. I went to the documentation for windowDidResize, but I cannot get it to work when the window is resized.
import SpriteKit
import AppKit
class GameScene: SKScene , SKPhysicsContactDelegate ,NSWindowDelegate{
**** bunch of code ****
func windowDidResize (notification: NSNotification) {
HUDComp.updatePosition(size)
println("Screen has been resized")
}
}
Any info would be greatly appreciated.
Swift 5 macOS 11+
Updated for Xcode 12.2 and macOS Big Sur.
This will call windowDidResize when the window's dimensions have changed.
class ViewController: NSViewController, NSWindowDelegate {
override func viewDidLoad() {
super.viewDidLoad()
NotificationCenter.default.addObserver(self, selector: #selector(NSWindowDelegate.windowDidResize(_:)), name: NSWindow.didResizeNotification, object: nil)
}
func windowDidResize(_ notification: Notification) {
print(view.window?.frame.size as Any)
}
}
If you inherit NSWindowDelegate, the only thing you should do is add observer onto NSNotificationCenter.
Code is here.
NSNotificationCenter.defaultCenter().addObserver(self, selector: Selector("windowDidResize:"), name: NSWindowDidResizeNotification, object: nil)
my two cents for swift 5. (showing both delegate and notification, choose one..)
import Cocoa
class ViewController: BaseController, NSWindowDelegate {
override func viewDidLoad() {
super.viewDidLoad()
self.makeItListenZoom()
}
override func viewDidAppear() {
self.view.window?.delegate = self
}
private final func makeItListenZoom(){
NotificationCenter.default.addObserver(forName: NSWindow.didResizeNotification, object: nil, queue: OperationQueue.main) { (n: Notification) in
print("didresize---")
}
}
func windowDidResize(_ notification: Notification){
print("windowDidResize")
}
}
This is driving me crazy. I am trying to un-hide a hidden UIView on button click but its not working. Here is the code
import UIKit
class DownloadViewController: UIViewController {
#IBOutlet var activityView: UIView!
override func viewDidLoad() {
super.viewDidLoad()
// Do any additional setup after loading the view, typically from a nib.
self.activityView.hidden = true
}
override func didReceiveMemoryWarning() {
super.didReceiveMemoryWarning()
// Dispose of any resources that can be recreated.
}
#IBAction func downloadAction(sender: AnyObject) {
self.activityView.hidden = false
}
}
Please help me. This is driving me nuts, that its not doing such a simple thing.
Make sure that your outlet is connected to the correct button in Interface Builder, try connecting it again by ctrl-dragging from the button in IB to the #IBOutlet code.
This code works, are you getting an error or does the button not do anything?
Swift 3
import UIKit
class DownloadViewController: UIViewController {
#IBOutlet var activityView: UIView!
override func viewDidLoad() {
super.viewDidLoad()
// Do any additional setup after loading the view, typically from a nib.
self.activityView.isHidden = true
}
override func didReceiveMemoryWarning() {
super.didReceiveMemoryWarning()
// Dispose of any resources that can be recreated.
}
#IBAction func downloadAction(sender: AnyObject) {
self.activityView.isHidden = false
}
}