viewdidload | 易学教程

presentModalViewController in viewDidLoad on first launch

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问题 I've been searching around but unfortunately have had no luck. My app requires the user to sign in/sign up the first time he or she launches the app. I know how to determine first launch (using NSUserDefaults) but whenever I try to present the modal containing the sign in/ sign up controls, nothing happens. Here's what I have: -(void)viewDidLoad { [self showLogin]; [super viewDidLoad]; } -(void)showLogin { FlipsideViewController *controller = [[FlipsideViewController alloc] initWithNibName:@

perform segue in viewDidLoad() without navigation controller in Swift

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问题 I have three views (view 1 checks a server connection, view 2 shows the main content, view3 shows the support page) and I created them in the storyboard without coding. On starting my iOS app the view 1 shows a spinner while checking the server connection. If the connection check is passed then I want to go to view 2 and if it's failed then I want to go to view 3. The view 1 is only for the connection check and I don't want to go back to this view. So, I think I don't need a navigation

UIApplicationDidBecomeActive vs UIApplicationWillEnterForeground difference

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问题 I need to fire a method when the application become active again. I've found this useful question about the topic, but unfortunately it's not enough for me, I can't decide which one should I use in my case.. I have this method in the viewDidAppear: , and I would like to call it again everytime when the app become active again. - (void)viewDidLoad { [PubNub requestFullHistoryForChannel:x-channel withCompletionBlock:^(NSArray *msg, PNChannel *channel, PNDate *fromDate, PNDate *toDate, PNError

Does viewDidload method call again on going back to a screen in navigation controller?

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问题 I am using navigation controller. I have pushed two viewcontroller to navigation stack. When I am coming back to viewcontroller1 from viewcontroller2 using back button of navigation bar then viewdidload method of viewcontroller1 is called again.But as much as I know viewdidload is called only once at loading time. So why is this happening? Please tell me. Thanks!! 回答1: -(void)viewDidLoad called only when view controller is loaded but if you want to call any method then you can write code in -

instantiateViewControllerWithIdentifier seems to call viewdidload

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问题 I am trying to push a ViewController programmatically into a navigation controller, And I'm using my storyboard to create it. here is my code : + (void) pushViewController:(NSString *) identifier ForItems:(NSMutableArray *) items sender:(UIViewController *) sender { GenericViewController *viewController = (GenericViewController *)[sender.storyboard instantiateViewControllerWithIdentifier:identifier]; viewController.items = [[NSMutableArray alloc] init]; [viewController.items removeAllObjects]

iPhone - viewDidUnload/viewDidLoad called inconsistently

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I was doing some testing and debugging of my Iphone app today and encountered some strange behaviour. In my MainView I have two modal views and when showing one of these using presentModalViewController I noted that the viewDidUnload method of my MainView was called while it was not happening when showing the other. It was the same case for the viewDidLoad method (of MainView ) while closing the subviews. I inspected the two methods for opening and closing the subviews and the only difference I found was in the modalTransitionStyle . In the one which did activate viewDidUnload / viewDidLoad I

viewDidLoad called before an IBAction?

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问题 in my Xcode project I have a button, that does two things. First: call an IBAction Second: go to another view (segue) In the action linked to the button I set a variable to YES (global var), but in the viewDidLoad method in the linked view, its still NO. Its YES in viewDidAppear though. I wonder why the action is not called first. Can I change that? I'd prefer to use the viewDidLoad method, since it seems to load quicker. 回答1: You can use the prepareForSegue method to pass whatever data to

InitWithNibName and viewDidLoad? [duplicate]

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This question already has answers here : Closed 7 years ago . Possible Duplicate: initWithNibName VS viewDidLoad I'm new at iOS development. I would just like to know the main differences between these 2 functions ? Thanks for your help viewDidLoad Is called when the view loads and is initiated/Unarchived and loaded into the memory. This is a great customisation stop. initWithNibName: Is used for initializing a certain class ( it is an overriden init method) with a xib file's name, the bundle parameter specifies the location of the file, you would pass nil for the main bundle, which is the

How to add an animation to the UIView in viewDidAppear?

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问题 I tried to add a animation to viewDidLoad and viewDidAppear, but it doesn't work: - (void)viewDidAppear:(BOOL)animated{ [UIView beginAnimations:@"transition" context:NULL]; [UIView setAnimationTransition:110 forView:self.view cache:YES]; [UIView commitAnimations]; } Why? 回答1: I had the same problem and I think I found the solution on this SO question. When viewDidAppear gets called you still don't see anything on the screen (despite the name), but you are about to. You can then use a

init method vs. a viewDidLoad type method [duplicate]

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This question already has an answer here: iOS: What is the difference between -init and -viewLoad of a ViewController? 3 answers What is the general guideline for the difference between the types of code (object allocation, setting up ui elements, network calls, etc.) that should go in the init method vs. a viewDidLoad type method for a view controller? Init => call at/use for initialize your ViewController and Initialize only for UIViewController and not it's views ViewDidLoad => call at/use for load view , This method gest called after the nib is loaded system can unload views to save memory