I'm trying to trigger a save of my CoreData on a window close as its only a single window application.
I've got the following code in my viewDidLoad and viewDidAppear
override func viewDidLoad() {
super.viewDidLoad()
if windowShouldClose(self) {
saveValues()
}
}
override func viewDidAppear() {
super.viewDidAppear()
self.view.window?.delegate = self
}
however im still getting the following error
Use of unresolved identifier 'windowShouldClose'
Any advice as to why i'm still getting this error after declaring the window delegate as self?
Set the delegate in viewDidLoad
override func viewDidLoad() {
super.viewDidLoad()
self.view.window?.delegate = self
}
and implement the delegate method
func windowWillClose(notification: NSNotification) {
saveValues()
}
windowShouldClose is different. It asks for permission to close the window and expects a boolean return value.
Related
I've tried, without success, respond to events such as windowWillClose() and windowShouldClose() inside NSWindowController (yes conforming to NSWindowDelegate).
Later, to my surprise, I was able to receive those events if I make my contentViewController (NSViewController) conform to NSWindowDelegate.
Unfortunately, later on, found out that view.window?.windowController is nil inside windowWillClose() or windowShouldClose(), code:
override func viewDidAppear() {
super.viewDidAppear()
self.view.window?.delegate = self
self.view.window?.windowController // not nil!
}
func windowWillClose(_ notification: Notification) {
self.view.window?.windowController // nil!!
}
func windowShouldClose(_ sender: NSWindow) -> Bool {
self.view.window?.windowController // nil!!
return true
}
After realizing that view.window?.windowController is not nil inside viewDidAppear() the next thing I thought was that Swift garbage collected the controller, so I changed viewDidAppear() in a way that creates another reference of windowController thus preventing garbage collection on said object, code:
var windowController: NSWindowController?
override func viewDidAppear() {
super.viewDidAppear()
self.view.window?.delegate = self
windowController = view.window?.windowController
}
func windowWillClose(_ notification: Notification) {
self.view.window?.windowController // NOT nil
}
func windowShouldClose(_ sender: NSWindow) -> Bool {
self.view.window?.windowController // NOT nil
return true
}
My hypothesis turned out to be correct (I think).
Is this the same issue that is preventing me from receiving those events inside NSWindowController?
Is there another way I can achieve the same thing without creating more object references?
In order to post code, I use the Answer option even though it is more of a comment.
I added in NSViewController:
override func viewDidAppear() {
super.viewDidAppear()
parentWindowController = self.view.window!.windowController
self.view.window!.delegate = self.view.window!.windowController as! S1W2WC. // The NSWC class, which conforms to NSWindowDelegate
print(#function, "windowController", self.view.window!, self.view.window!.windowController)
}
I get print log:
viewDidAppear() windowController Optional()
and notification is passed.
But if I change to
override func viewDidAppear() {
super.viewDidAppear()
// parentWindowController = self.view.window!.windowController
self.view.window!.delegate = self.view.window!.windowController as! S1W2WC
print(#function, "windowController", self.view.window!, self.view.window!.windowController)
}
by commenting out parentWindowController, notification don't go anymore to the WindowController…
Edited: I declared in ViewController:
var parentWindowController: NSWindowController? // Helps keep a reference to the controller
The proposed solutions are, in my opinion, hacks that can cause serious problems with memory management by creating circular references. You definitely can make instances of NSWindowController work as the window’s delegate. The proper way is to wire it up correctly in either code or in Interface Builder in Xcode. An example of how to do it properly is offered here.
If the delegate methods are not called is because the wiring up is not done correctly.
Another thing that must be done in Swift is when you add the name of the NSWindowController subclass in Interface Builder in Xcode is to check the checkbox of Inherits from Module. If you fail to do this, none of your subclass methods will be called.
Here is the line of code causing the error
class ViewController: UIViewController, UITextFieldDelegate {
I'm following a tutorial so I can't imagine why this went wrong.
It was working just fine until I added this function into my code:
//Check if user is already logged in when opening app if so display dashboard page
override func viewDidAppear(animated: Bool){
if PFUser.currentUser() != nil{
if self.theUser.user_db_obj.email == "mike#chicagodrumlessons.com"{
self.performSegueWithIdentifier("adminLogin", sender: self) //dislay admin page
}
else{
self.performSegueWithIdentifier("userLogin", sender: self) //display user page
}
}
}
Here is the only lines of code where the delegate is referenced I believe
override func viewDidLoad() {
super.viewDidLoad()
self.email_tf.delegate = self
self.pass_tf.delegate = self
}
Any idea what caused this error and how to fix it?
My guess is you declare non-optional properties and they aren't initialized when the object is. The compiler is telling you you need an init or two to provide the non-optional properties values before the object can be initialized (or make the properties optionals).
I have this hierarchy - UIViewController -> ChildUIViewController -> WKWebView.
I had an issue with the WKWebView message handler that leaked and prevented the child view controller from being released.
After some reading I found a way to fix the retain cycle by using this fix - WKWebView causes my view controller to leak
Now I can see that the child view controller is reaching deinit but right after that the WKWebView is crashing on deinit (No useful log from Xcode).
Any Idea or direction what could be the issue ?
Thanks
UPDATE
here is my code - Code Gist
Put this inside deinit method of child view controller:
webView.scrollView.delegate = nil
Don't forget to remove WKWebView's delegates you added:
deinit {
webView.navigationDelegate = nil
webView.scrollView.delegate = nil
}
Looks like WKWebView stores __unsafe_unretained pointer to your delegate. Sometimes when web view deallocated not immediate after view controller deallocation. This cause crash when web view tries to notify delegate something.
I tried with same way as you mentioned. It works perfectly for me. Code which i tried is,
class CustomWKWebView : WKWebView {
deinit {
print("CustomWKWebView - dealloc")
}
}
class LeakAvoider : NSObject, WKScriptMessageHandler {
weak var delegate : WKScriptMessageHandler?
init(delegate:WKScriptMessageHandler) {
self.delegate = delegate
super.init()
}
func userContentController(userContentController: WKUserContentController,
didReceiveScriptMessage message: WKScriptMessage) {
self.delegate?.userContentController(
userContentController, didReceiveScriptMessage: message)
}
deinit {
print("LeakAvoider - dealloc")
}
}
class ChildViewController: UIViewController , WKScriptMessageHandler{
var webView = CustomWKWebView()
override func viewDidLayoutSubviews() {
super.viewDidLayoutSubviews()
}
override func viewDidLoad() {
super.viewDidLoad()
view.addSubview(webView)
webView.frame = self.view.bounds;
}
override func viewDidAppear(animated: Bool) {
super.viewDidAppear(animated)
let url = NSURL(string: "https://appleid.apple.com")
webView.loadRequest(NSURLRequest(URL:url!))
webView.configuration.userContentController.addScriptMessageHandler(
LeakAvoider(delegate: self), name: "dummy")
}
func userContentController(userContentController: WKUserContentController, didReceiveScriptMessage message: WKScriptMessage)
{
}
deinit {
print("ChaildViewController- dealloc")
webView.stopLoading()
webView.configuration.userContentController.removeScriptMessageHandlerForName("dummy")
}
}
class ViewController: UIViewController {
override func viewDidLayoutSubviews() {
super.viewDidLayoutSubviews()
}
override func viewDidLoad() {
super.viewDidLoad()
}
deinit {
print("ViewController - dealloc")
}
}
Log after popping ViewController is:
ViewController - dealloc
ChaildViewController- dealloc
LeakAvoider - dealloc
CustomWKWebView - dealloc
UPDATE
Put below lines in your WebViewViewController's viewWillDisappear function.
webView.navigationDelegate = nil
webView.scrollView.delegate = nil
I tried by setting these two delegates in my code and it started crashing. Solved by putting above lines in viewWillDisappear of ChildViewController.
Remember, the reason might caused by weak reference to it.
I'm sure that you have instantiated local variable of wrapped class with WKWebView.
#IBAction func getNewPhotoAction(sender: AnyObject) {
println("getNewPhotoAction")
}
override func viewDidLoad() {
super.viewDidLoad()
self.getNewPhotoAction(sender: AnyObject) // Error
}
I just want to call the getNewPhotoAction IBAction method in viewDidLoad.
Which parameter to enter in this line -> self.getNewPhotoAction(?????) ?
I don't have any parameter. I just need to call.
I used in Objective-C style:
[self getNewPhotoAction:nil]
but I don't know Swift style.
The parameter sender indicates who are calling the action method.
When calling from viewDidLoad, just pass self to it.
override func viewDidLoad() {
super.viewDidLoad()
getNewPhotoAction(self)
}
By the way, if the sender parameter of the getNewPhotoAction method wasn’t used, the parameter name can be omitted.
#IBAction func getNewPhotoAction(AnyObject) {
println("getNewPhotoAction")
}
You could always create a separate func that you call on in your viewDidLoad or in your IBAction
override func viewDidLoad() {
super.viewDidLoad()
self.getNewPhoto()
}
func getNewPhoto(){
//do whatever you want here.
println("getnewphotoaction")
println("whatever you want")
}
#IBAction func getNewPhotoAction(sender: AnyObject) {
self.getNewPhoto()
}
Swift 4.2
#IBAction func getNewPhotoAction(sender: Any) {
println("getNewPhotoAction")
}
override func viewDidLoad() {
super.viewDidLoad()
self.getNewPhotoAction(AnyObject.self)
}
If you still need to reference the UIButton or whatever is sending the action and want to call it from code at the same time - you can do this too:
onNext(UIButton())
Wasteful, but less code.
#IBAction func getNewPhotoAction(sender: AnyObject?){
......
}
**AnyObject** means that you have to pass kind of Object which you are using, nil is not a AnyObject.
But **AnyObject?**, that is to say AnyObject is Optional, nil is a valid value.
meaning the absence of a object.
self .getNewPhotoAction(nil)
You actually don't need to pass any object at all. If you have no need to use the sender, then declare the function without it like this:
#IBAction func getNewPhotoAction() { ... }
And use it like this:
self.getNewPhotoAction()
You may need to re-connect the outlet in interface builder when you make this change (remove it and then add it back) if this method is connected to an event in interface builder.
#IBAction func getNewPhotoAction(sender: AnyObject? = nil) {
print("getNewPhotoAction")
}
override func viewDidLoad() {
super.viewDidLoad()
self.getNewPhotoAction(nil)
}
Since you don't have any sender, hand over nil.
self.getNewPhotoAction(nil)
I tried to implement ADBannerView with the old way like Objective C but unsuccessfull. Everythings work but the advertisments didn't show up, it stays a blank field.
func bannerViewDidLoadAd(banner: ADBannerView!) {
UIView.beginAnimations(nil, context: nil)
UIView.setAnimationDuration(1)
banner.alpha = 1
UIView.commitAnimations()
}
func bannerView(banner: ADBannerView!, didFailToReceiveAdWithError error: NSError!) {
UIView.beginAnimations(nil, context: nil)
UIView.setAnimationDuration(1)
banner.alpha = 0
UIView.commitAnimations()
}
Anyone who already tried iAd on Swift?
I've found a solution, how to implement it. (You can use inside each method "banner.alpha 1.0" or other things, too.)
//import ... your normal imports as UIKit etc.
import iAd
class YourClassViewController: UIViewController, ADBannerViewDelegate {
#IBOutlet var adBannerView: ADBannerView //connect in IB connection inspector with your ADBannerView
override func viewDidLoad() {
super.viewDidLoad()
self.canDisplayBannerAds = true
self.adBannerView.delegate = self
self.adBannerView.hidden = true //hide until ad loaded
}
func bannerViewWillLoadAd(banner: ADBannerView!) {
NSLog("bannerViewWillLoadAd")
}
func bannerViewDidLoadAd(banner: ADBannerView!) {
NSLog("bannerViewDidLoadAd")
self.adBannerView.hidden = false //now show banner as ad is loaded
}
func bannerViewActionDidFinish(banner: ADBannerView!) {
NSLog("bannerViewDidLoadAd")
//optional resume paused game code
}
func bannerViewActionShouldBegin(banner: ADBannerView!, willLeaveApplication willLeave: Bool) -> Bool {
NSLog("bannerViewActionShouldBegin")
//optional pause game code
return true
}
func bannerView(banner: ADBannerView!, didFailToReceiveAdWithError error: NSError!) {
NSLog("bannerView")
}
//... your class implementation code
}
See the following answer, on how to do it without IBBuilder!
If you are using iOS 7, extension methods and properties have been added to UIViewController to support handling of iAd:
See
https://developer.apple.com/library/prerelease/ios/documentation/iAd/Reference/UIViewController_iAd_Additions/index.html
To show an iAd you first need to add the iAd framework, go to the projects properties, general tab, add the iAd.framework in the Linked framework and libraries section.
In your view controller, import iAd to access the iAd extensions. And finally in viewDidLoad, set self.canDisplayBannerAds = true.
To remove ads, set canDisplayBannerAds to false
Note there is no need to create an AdBannerView in the story board or programmatically and there is no need for your view controller to implement the AdViewDelegate.
import UIKit
import iAd
class ViewController : UIViewController
{
override func viewDidLoad()
{
super.viewDidLoad()
//That's it
self.canDisplayBannerAds = true
}
}
Mr. T answer contains a lot of useless code.
All you need is this part to show ads in your controller:
override func viewDidLoad() {
super.viewDidLoad()
canDisplayBannerAds = true
}
And when you don't need ads, you canDisplayBannerAds = false.
What it does — wrapping your controller into another controller with ad banner at the bottom. This feature is available since iOS7.
It's not possible to get delegate messages with it, so if you need it — you should replace it with ADBannerView instance variable.