I found that my controller is out of the view hierarchy in this code andI call this in viewDidLoad:
if CLLocationManager.locationServicesEnabled() {
// code
} else {
let alertController = UIAlertController(...)
//
present(alertController)
}
If I wrap else clause in .async or .asyncAfter in the main queue I have my issue go away.
Why do this happen here?
Thank you!
based on your question you are tried to load UIAlertController before load the UIviewcontroller hierarchy, in here you can do it two ways,
you can forcefully load the UIAlertController in the main thread, so in here you need to use .async or .asyncAfter, but it's not suggested.
alternate suggestion but it will works fine, you need to wait for your initial UI view hierarchy, I mean you need to convert your code from viewDidLoad to viewDidAppear. for ref : Difference between viewDidLoad and viewDidAppear
Related
Since I updated to Xcode8/iOS10 & Swift 3 I have this weird issue on segmented controls used as navigation bar titles.. it takes some time to appear. Or I can touch the area (invisible at that time) and it will appear.
I believe the item as been loaded but just not be drawn and then it got either draw by touching the area or because of the event loop asking for view redraw.
UI is not blocked.
can't find a way to fix it.
PS: could not reproduce on fresh new project
Breaking with Debug View Hierarchy, it appears the UISegmentedControls lives but is not initialised with colors/texts.. then it will, few seconds later.
Ok this was due to threads.
My app on loading was initialising a core data stack. On the callback of it I was instantiating the right view controller using window.rootViewController = vc, this needs to be executed on the main thread, but the completion of the core data stack init was launch on a background one.
Something weird yet. I had implemented a UIWindow extension
extension UIWindow {
func setRootViewController(with viewController: UIViewController) {
DispatchQueue.main.async {
self.rootViewController = viewController
}
}
}
// beeing in background thread
self.window.setRootViewController(with: self.rootVC)
this will produce the issue below.
but the next will work
extension UIWindow {
func setRootViewController(with viewController: UIViewController) {
self.rootViewController = viewController
}
}
// beeing in background thread
DispatchQueue.main.async {
self.window.setRootViewController(with: self.rootVC)
}
don't know what's the difference.
I'm calling a method from another controller, but for some reason it does not work. The NSLog works fine but myButton is not showing up.
First controller .h:
-(void) buttonChange;
First controller .m
-(void)buttonChange {
myButton.hidden=NO; //this is not getting executed
NSLog(#"it's working");
}
- (void)viewDidLoad{
myButton.hidden=YES; //initially hidden
//....other codes
}
Second controller:
FirstController *theButtonInstance = [[FirstController alloc] init];
[theButtonInstance buttonChange]; //all works fine when I call this, but button is not showing up
Place this line myButton.hidden=YES; in init method of FirstController.
You're creating your instance of FirstController, but viewDidLoad hasn't run yet. Then immediately, you're setting hidden to NO. Later, viewDidLoad will be called, and it will set hidden back to YES before the view appears. You have to wait until viewDidLoad is called before you can correctly set hidden, and it won't get called right at the creation of the controller. You could do something like:
[self performSelector:#selector(buttonChange) withObject:nil afterDelay:3.0] ;
To see your button not appear then appear 3 seconds later.
If you want to create a new instance of your FirstController (what you currently do like Undo already mentioned) you don´t have to call [theButtonInstance buttonChange]; but set theButtonInstance.myButton.hidden = NO; after you created the new instance of FirstController
You can create a BOOL property in FirstViewController.h. And set that property to NO before pushing the controller. After that go to the viewDidLoad method in FirstViewController and write the if condition whether to hide or show the button based on that property. Hope that works for you. Let me know if you need code for this.
I have a class A which has delegates . The delegates are being implemented in another class B.
In B I have a text field , which I am trying to make hidden when the delegate is called.
- (void) didRecieveResponseDelegate : (BOOL) status{
textField.hidden = YES;
}
But the textField doesnt get hidden. I've noticed none of the view related changes work inside the delegate including removing of child view controllers. What's the problem and how do I fix it ?
EDIT : B is a child view controller of another view controller
Try this,
- (void) didRecieveResponseDelegate : (BOOL) status{
dispatch_async(dispatch_get_main_queue(), ^{
textField.hidden = YES;
});
}
Does the method get called? (Breakpoint or NSLog to prove it).
Why are you using instance variables with leading underscore? That leads to bugs and confusion as well as distrust in your code.
Is textField actually set or is it nil? NSLog to prove it.
Fix spelling errors in method names. Quite possible that didReceiveResponseDelegate is called instead of didRecieveResponseDelegate.
Make sure you don't make UI calls from a background thread.
I have a UIActivity subclass that creates its own activityViewController:
- (UIViewController *)activityViewController {
WSLInProgressViewController* progressView = [[[WSLInProgressViewController alloc] init] autorelease];
progressView.message = [NSString stringWithFormat:NSLocalizedString(#"Posting to %#...",#"Posting to..."),
self.activityType];
return progressView;
}
I've add a full repro on GitHub.
According to the documentation, you aren't supposed to dismiss this manually. Instead, the OS does that when you call activityDidFinish:. This works fine when ran on an iPhone.
When I say "works," this is the sequence of events that I'm expecting (and see on the iPhone):
Display the UIActivityViewController
User presses my custom activity
My view controller appears
I call activityDidFinish:
My custom view controller is dismissed
The UIActivityViewController is also dismissed
However, when I run this same code on the iPad Simulator -- the only difference being that I put the UIActivityViewController in a popup, as the documentation says you should -- the activityViewController never dismisses.
As I say, this is code wo/the popUP works on the iPhone and I have stepped through the code so I know that activityDidFinish: is getting called.
I found this Radar talking about the same problem in iOS6 beta 3, but it seems such fundamental functionality that I suspect a bug in my code rather than OS (also note that it works correctly with the Twitter and Facebook functionality!).
Am I missing something? Do I need to do something special in the activityViewController when it's run in a UIPopoverViewController? Is the "flow" supposed to be different on the iPad?
The automatic dismissal only appears to happen when your 'activity' controller is directly presented, not wrapped in anything. So just before showing the popup it's wrapped in, add a completion handler
activity.completionHandler = ^(NSString *activityType, BOOL completed){
[self.popup dismissPopoverAnimated:YES];
};
and you'll be good.
I see the question is quite old, but we've been debugging the same view-controller-not-dismissing issue here and I hope my answer will provide some additional details and a better solution than calling up -dismissPopoverAnimated: manually.
The documentation on the UIActivity is quite sparse and while it hints on the way an implementation should be structured, the question shows it's not so obvious as it could be.
The first thing you should notice is the documentation states you should not be dismissing the view controller manually in anyway. This actually holds true.
What the documentation doesn't say, and what comes as an observable thing when you come across debugging the non-dissmissing-view-controller issue, is iOS will call your -activityViewController method when it needs a reference to the subject view controller. As it turns out, probably only on iPad, iOS doesn't actually store the returned view controller instance anywhere in it's structures and then, when it wants to dismiss the view controller, it merely asks your -activityViewController for the object and then dismisses it. The view controller instantiated in the first call to the method (when it was shown) is thus never dismissed. Ouch. This is the cause of the issue.
How do we properly fix this?
Skimming the UIActivity docs further one may stumble accross the -prepareWithActivityItems: method. The particular hint lies along the following text:
If the implementation of your service requires displaying additional UI to the user, you can use this method to prepare your view controller object and make it available from the activityViewController method.
So, the idea is to instantiate your view controller in the -prepareWithActivityItems: method and tackle it into an instance variable. Then merely return the same instance from your -activityViewController method.
Given this, the view controller will be properly hidden after you call the -activityDidFinish: method w/o any further manual intervention.
Bingo.
NB! Digging this a bit further, the -prepareWithActivityItems: should not instantiate a new view controller each time it's called. If you have previously created one, you should merely re-use it. In our case it happily crashed if we didn't.
I hope this helps someone. :)
I had the same problem. It solved for me saving activityViewController as member and return stored controller. Activity return new object and dismiss invoked on new one.
- (UIViewController *)activityViewController {
if (!self.detaisController) {
// create detailsController
}
return self.detailsController;
}
I pass through the UIActivity to another view then call the following...
[myActivity activityDidFinish:YES];
This works on my device as well as in the simulator. Make sure you're not overriding the activityDidFinish method in your UIActivity .m file as I was doing previously. You can see the code i'm using here.
a workaround is to ask the calling ViewController to perform segue to your destination ViewController via - (void)performActivity although Apple does not recommend to do so.
For example:
- (void)performActivity
{
if (UI_USER_INTERFACE_IDIOM() == UIUserInterfaceIdiomPad)
{
[self.delegate performSomething]; // (delegate is the calling VC)
[self activityDidFinish: YES];
}
}
- (UIViewController *)activityViewController
{
if (UI_USER_INTERFACE_IDIOM() == UIUserInterfaceIdiomPhone)
{
UIViewController* vc=XXX;
return vc;
}
else
{
return nil;
}
}
Do you use storyboards? Maybe in your iPad storyboard, the UIActivityIndicatorView doesn't have a check on "Hides When Stopped"?
Hope it helps!
So I had the same problem, I had a custom UIActivity with a custom activityViewController and when it was presented modally it would not dismiss not matter what I tried. The work around I choose to go with so that the experience remained the same to the user was to still use a custom UIActivity but give that activity a delegate. So in my UIActiviy subclass I have the following:
- (void)performActivity
{
if ([self.delegate respondsToSelector:#selector(showViewController)]) {
[self.delegate showViewController];
}
[self activityDidFinish:YES];
}
- (UIViewController *)activityViewController
{
return nil;
}
Then I make the view controller that shows the UIActivityViewController the delegate and it shows the view controller that you would otherwise show in activityViewController in the delegate method.
what about releasing at the end? Using non-arc project!
[progressView release];
Many Users have the same problem as u do! Another solution is:
UIActivityIndicatorView *progress= [[UIActivityIndicatorView alloc] initWithFrame:CGRectMake(125, 50, 30, 30)];
progress.activityIndicatorViewStyle = UIActivityIndicatorViewStyleWhiteLarge;
[alert addSubview:progress];
[progress startAnimating];
If you are using storyboard be sure that when u click on the activityind. "Hides When Stopped" is clicked!
Hope that helped...
To some this may sound like a daft question. I've searched around, and found little, mostly because I cannot find the appropriate search terms.
Here what I want to do is:
The application begins at view A.
View A launches view B, and view B launches view C.
Is their a way for view C to return directly back to A without dismissing itself and thus exposing B. For example a main menu button.
You can call popToRootViewControllerAnimated: if you have a UINavigationController. If you specify NO to animate it, then it will just jump back to the root without showing B first.
I have discovered a solution to my problem. Its a bit dirty, (and I''ll probably get shot down in flames for it) but works very well under tests and is very quick to implement. Here's how I did it.
In my app I have a Singleton class called GlobalVars (I use this for storing various global settings). This class holds a boolean called home_pressed and associated accessors (via synthesise). You could also store this value in the application delegate if you wish.
In every view controller with a main menu button, I wire the button to the homePressed IBAction method as follows. First setting the global homePressed boolean to YES, then dismissing the view controller in the usual way, but with NO animation.
-(IBAction) homePressed: (id) sender
{
[GlobalVars _instance].homePressed = YES;
[self dismissModalViewControllerAnimated: NO];
}//end homePressed
In every view controller except the main menu I implement the viewDidAppear method (which gets called when a view re-appears) as follows.
-(void) viewDidAppear: (Bool) animated
{
if ([GlobalVars _instance].homePressed == YES)
{
[self dismissModalViewController: NO];
}
else
{
//put normal view did appear code here/
}
}//end viewDidAppead
In the mainMenu view controller which is the root of the app, I set the global homePressed boolean to NO in its view did appear method as follows
-(void) viewDidAppear: (Bool) animated
{
if ([GlobalVars _instance].homePressed == YES)
{
[GlobalVars _instance].homePressed == NO;
}
else
{
//put normal view did appear code here/
}
}//end viewDidAppear
There, this enables me to go back to the root main menu of my app from any view further down the chain.
I was hoping to avoid this method, but its better than re-implementing my app which is what I'd have to do if I wanted use the UINavigationController solution.
Simple, took me 10 minutes to code in my 9 view app. :)
One final question I do have, would my solution be OK with the HIG?