viewdidappear

问题 I'm trying to figure out from Apple's sketchy documentation which method is the best place to be initializing and adding my Views controls to the controller's view. With winforms it's fairly straightforward, as they're always initialized inside InitializeDesigner , called in the constructor. I'm trying to match the reliability of this pattern if possible. I'm working with UIViewControllers and UITableViewControllers inside a UINavigationController most of the time - if this effects it all.

问题 I'm trying to figure out from Apple's sketchy documentation which method is the best place to be initializing and adding my Views controls to the controller's view. With winforms it's fairly straightforward, as they're always initialized inside InitializeDesigner , called in the constructor. I'm trying to match the reliability of this pattern if possible. I'm working with UIViewControllers and UITableViewControllers inside a UINavigationController most of the time - if this effects it all.

问题 I want to check the pasteboard and show an alert if it contains specific values when the view appears. I can place the code into viewDidLoad to ensure it's only invoked once, but the problem is that the alert view shows too quickly. I know I can set a timer to defer the alert's appearance, but it's not a good work-around I think. I checked the question iOS 7 - Difference between viewDidLoad and viewDidAppear and found that there is one step for checking whether the view exists. So I wonder if

问题 This question already has answers here : Difference between viewDidLoad and viewDidAppear (2 answers) Closed last year . Bottom line is, I've been working on an app, and it seems that if I place a UIAlert in viewDidLoad , it gets called twice (from a delegate method of UIImagePickerController ). If I put it in viewDidAppear , it gets called once. I've looked through documentation but it just confuses me. 回答1: A UIView object can get loaded into memory and released multiple times without ever

问题 I want to change a UITableViewCell 's subview when it is being setup in the cellForRowAtIndexPath with the following code: cellSubView.center = CGPointZero Printing out the frame's coordinates shows, that the frame updates successfully, however the view is still displayed in the position that was given in the interface builder. Overriding the viewDidAppear function with the following code would resolve this issue: override func viewDidAppear(animated: Bool) { super.viewDidAppear(animated)

问题 I want to load some data when a button is pressed and show a "loading view" as a subview of my current view while it's loading. So I want to start loading only after the subview did appear. If not my UI gets stuck without a notice (and the subview only shows after the loading is done). Is there a way to use something like viewDidAppear for subviews? Doing the work right after the addSubview: like this doesn't work: - (void)doSomeWorkAndShowLoadingView { UIView *loadingView = [[[UIView alloc]

问题 I want to do something in the viewDidAppear method but this method not auto calling the SDK describe this method is Notifies the view controller that its view was added to a window. if means implement this method in my view controller can auto calling? - (void)viewDidAppear:(BOOL)animated { [super viewDidAppear:animated]; ... } 回答1: It depends on how you add your view to the view hierarchy. If you push your controller on an navigation stack for example, this method will be called

问题 The segue runs but the app crashes with the above error. Why do I get this no segue with identifier message? I defined the segue Identifier. Here is the viewDidAppear method - (void)viewDidAppear:(BOOL)animated { [self performSegueWithIdentifier:@"showAlerting" sender:self]; } - (void)prepareForSegue:(UIStoryboardSegue *)segue sender:(id)sender { if ([[segue identifier] isEqualToString:@"showAlerting"]) { NSLog(@"Logging showAlerting"); } } I got these log messages 2015-03-28 20:04:33.025

问题 I'm writing my own SplitViewController from scratch (i.e. by subclassing UIViewController and not UISplitViewController ). It has two sub-viewControllers (one for the left panel and one for the detail right panel), to which I need to send the appropriate messages ( viewWillAppear, viewDidAppear, viewWillDisapppear and viewDidDisappear ). I am already forwarding those messages when my custom SplitViewController receives them and it works fine. However I am struggling to figure out when to send

问题 I am using Specta to create some tests but I don't seem to be able to get this basic one to pass. The app itself works fine but this test won't pass. ViewController - (void)viewDidAppear:(BOOL)animated { [super viewDidAppear:animated]; [self showLogin]; } - (void)showLogin { [self presentViewController:[ETLoginVC new] animated:NO completion:nil]; NSLog(@"PresentedVC: %@", [self.presentedViewController class]); } This logs: PresentedVC: ETLoginVC Specs #import "Specs.h" #import "ETLoadingVC.h"