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.
Related
I have MainUIViewController(named withFlightSettingsContentViewController), that contain a container view, the container view is theUIPageViewController(named withFlightSettingContainer);
But the layout have to set a pageControl element on the MainUIViewController(FlightSettingsContentViewController), So I drag a page control on the MainUIViewController.
But when the container view(subview -FlightSettingContainer) load, I want to set the main viewcontroller's pageControlnumberOfPages.
I write below code on the subview-FlightSettingContainer.m to call parent viewcontroller pagecontrol page number .
#interface FlightSettingContainer()
{
FlightSettingMainViewController *parentFlightSetngVC;
}
#implementation FlightSettingContainer
- (void)viewDidLoad {
[super viewDidLoad];
parentFlightSetngVC = (FlightSettingMainViewController*) self.parentViewController;
[parentFlightSetngVC.pageControl setNumberOfPages:4];
}
But the pagecontrol dots not change to 4 dots on the main viewcontroller.
have anyone know where the problem? thank you very much.
I think as you are trying to access the parentViewController object in viewDidLoad method which will return you nil because till the FlightSettingContainer class(Child) view is loaded in memory it is not set as the child of FlightSettingMainViewController(parent). So use should use your code either in viewDidAppear or viewWillAppear and it will work because now it set as child of its parent.
Hope it will work Happy coding :)
You are calling your code too early, the relation is not set yet.
Put it in the viewDidAppear method
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.
This may sound silly, but read on...
I want to set the text of a UILabel from outside of a UIViewController that is instantiated by a storyboard. I need to make sure that the label property of the view controller is set when I set its text otherwise the label's text won't be set(because it won't be loaded yet to receive a text value).
Here's my current solution:
// Show pin entry
if (!self.pinViewController) {
// Load pin view controller
self.pinViewController = [self.storyboard instantiateViewControllerWithIdentifier:#"pinScreen"];
self.pinViewController.delegate = self;
if (!self.pinViewController.view) {
// Wait for pin screen to fully load
}
[self.pinViewController setMessageText:#"Set a pin for this device"];
}
Initially I had a while loop that looped until the value of view was not nil, But it seems the very act of checking the view loads it(as mentioned here: http://developer.apple.com/library/ios/documentation/UIKit/Reference/UIViewController_Class/Reference/Reference.html#//apple_ref/doc/uid/TP40006926-CH3-SW37)
I tried using the isViewLoaded method with no success. It just looped forever.
I've gone forward with the above code as my current solution, but it feels wrong.
Is there a better way ensure a UIView has loaded?
I want to propose an alternative way where you don't have to rely on the availability of the view.
If you need to wait for the view to load before you can call other methods on your viewController you break encapsulation, because the viewController that calls your PinViewController has to know about the inner workings of your PinViewController. That's usually not a good idea.
But you could save objects like NSStrings in the PinViewController instance, and when the view of the PinViewController will appear you set its views according to the properties you have set before.
If you need to change the text of an label from outside your viewController you can also create a custom setter that sets the label.text for you.
Your .h
#interface PinViewController : UIViewController
#property (copy, nonatomic) NSString *messageText;
// ...
#end
And your .m
#implementation PinViewController
- (void)viewWillAppear:(BOOL)animated {
[super viewWillAppear:animated];
self.messageLabel.text = self.messageText;
}
// optional, if you want to change the message text from another viewController:
- (void)setMessageText:(NSString *)messageText {
_messageText = messageText;
self.messageLabel.text = messageText;
}
// ...
#end
viewDidLoad should solve this I guess.
http://developer.apple.com/library/ios/#documentation/UIKit/Reference/UIViewController_Class/Reference/Reference.html
I would rather see you change your logic and do it the way that #MatthiasBauch shows in his answer. However, to answer your actual question, you can simply set a view property in order to force it to load:
self.pinViewController.view.hidden = NO;
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?