I would like to make 3 things and I don't know how :(
Make an automatic refresh every 5 minutes on my View Controllers
Add a reload button on my NavigationBar
Automatically close my app when passing in Background.
Is there any functions to initialiaze a refresh for example, a kind of countdown from the launch of the app ?
Thanks for all !
The methods [myView setNeedsDisplay]; and [myTableView reloadData]; could help. You could start a timer at application launch and call those methods every 5 Minutes. But when you ask me... This doesn't make sense. Nobody is using an app longer than 1 or 2 Minutes most of the time.
Related
In my project I show an Alert to the user to indicate an 'empty list'.
Right now, I show it in AppDelegate>applicationDidBecomeActive.
I'm doing this because I want the alert to show if the list is empty
at app startup and when coming out of the background (iOS 4.2 through 5.x).
EDIT:
I use a method in the AppDelegate, and call it with a slight delay, and I still get this notice.
[self performSelector:#selector(checkForNoMessages) withObject:nil afterDelay:1.0];
However, this causes a "wait_fences" notice in the debugger and I'd prefer not to submit to Apple with this notice.
Where is the proper place to put a popup Alert so that it appears:
1) At App startup
AND
2) When the App is coming out of the background?
Do I need the Alert in more than one place?
I recommend writing a method in your AppDelegate or better in your root view controller which shows the message. Maybe with some arguments, so you can reuse it but that's up to you.
If you are following the MVC architecture ask your model about existing entries and trigger the Alert message if necessary. But encapsulate this behavior in a controller as well.
application:didFinishLaunchingWithOptions: and applicationDidBecomeActive: are the places where you want to delegate this task to your controller.
More about iOS Multitasking: https://developer.apple.com/library/ios/#documentation/iphone/conceptual/iphoneosprogrammingguide/ManagingYourApplicationsFlow/ManagingYourApplicationsFlow.html
Edit:
Don't forget that you have to call the methods from the main thread.
And do all startup stuff first.
OK - the problem wasn't where I called the alert, it was because it was in a method. Once I moved the code from a method into applicationDidBecomeActive, all is well.
After some research on the web without success, I come here to ask you the question about my warning.
Actually, I have a view V1 with a navigation controller and I want to push a modal view V2 when V1 has finished loading.
So I use the performSegueWithIdentifier method (I'm using storyboard).
Here is my code:
[self performSegueWithIdentifier:#"showConnexionViewSegue" sender:self];
And when I compile, I got this warning:
Unbalanced calls to begin/end appearance transitions for <UINavigationController: 0x6849b30>
Can anyone help me?
It sounds like you may be performing the segue in -viewWillAppear: thus generating two -viewWillAppear: messages without 2 corresponding -viewDidAppear messages.
Try performing the segue in -viewDidAppear.
I had this problem, but what I had done is on a UIViewController I had linked a Segue from a UIButton and also coded it into a nextBtnPressed: function, so I was actually pushing two new UIViewControllers on the one button press. Limiting it to just the one segue fixed it. But it took some investigating to see that I had done this double up.
'Unbalanced calls to begin/end appearance transitions for '
Says an animation is started before the last related animation isnt done.
So, are you popping any view controller before pushing the new one ?
Or may be popping to root ? if yes try doing so without animation
i.e. [self.navigationController popToRootViewControllerAnimated:NO];
And see if this resolves the issue, In my case this did the trick.
The reasons for this are manifold and are very specific to the context and the programming. For example, what I was doing was
initialising a sound file, playing it (asynchronously) for 1.4 seconds,
making an image move across the screen using animation timed to last 1.4 seconds and,
with a timer set to 1.4 seconds after step 2, pushing a viewcontroller.
What i discovered is that if I DO NOT have the instructions for these 3 steps one after the other (if I mix them up), then I get the error "Unbalanced calls...". Also, if I time the push of the viewcontroller to less than 1.4 seconds, I get the message as well.
So, check that the sequence and timing of your program instructions are correct.
In my application, I have pushed from oneviewcontroller to anotherviewcontroller. In that page I have started a timer and updated UITableview for every 1 sec (using UITableview reloaddata).
I have start the timer in viewwillappear function and invalidate timer in viewwilldisappear.
But when timer is running, when I came back to my viewcontroller my application crashed rapidly.
Please help me? Thanks in advance...
My guess is when i push back to viewcontroller that time tablereloads in previous viewcontroller that time it make crashes. I am using try catch but nothing makes any difference. Can we stop tableview reloads when we are not in that page?
The main reason of your app crashing is that, when-ever u come back form anotherViewController to oneViewController, your table view got release in between your timer still alive which is trying to update tableView and when you accessing the release object then app will get crashed. So u need to before stop your timer properly and nil it if timer isValid.
I hope mine answer will help you.
You strongly need to send invalidate message to all you timers at dealloc method of your class
- (void)dealloc
{
if ([_someTimer isValid]) [_someTimer invalidate];
}
I have traced a problem in my iPhone app code to the viewDidAppear method not always firing. When you start the app the event fires as expected. However if I close the app using a phone capable of multitasking and reopen in. My viewDidAppear events no longer fire.
My views are loaded from Nibs and I use viewDidUnload to clean up (release and nil all outlets). My views are nested in side and tab bar then navigation controllers. I looks like the events aren't wired up properly when the nibs reload. Any idea on what I'm doing wrong/missing and how I can fix this?
Thanks in advance.
UPDATE I do not mean the event is not fired when the app first comes into the foreground. I mean the event never fires again. Even when changing between tabs or moving though the navigation views.
Example:
- (void)viewDidAppear:(BOOL)animated {
[super viewDidAppear:animated];
NSLog(#"viewDidAppear called");
}
This code is placed in two views, each on different tabs. Each time I swap between tabs "viewDidAppear called" is written to the log. When I close and reopen the app and swap between tabs this no longer happens. Other button events fire normally.
Btw, the viewDidUnload method is really badly named btw -- it's not an 'opposite' to viewDidLoad, it's only called if there was a low memory situation and the view for that controller was unloaded due to not being visible at that time.
(ORIGINAL, NOT SO RELEVANT ANSWER:)
Please see my answer to this similar question:
Why does viewWillAppear not get called when an app comes back from the background?
Basically, viewDidAppear gets called after your UIViewController's view was added to the application's UIWindow heirarchy. Backgrounding then restoring the app doesn't change your view in that respect, so viewDidAppear doesn't get called -- it's correct behaviour, and not a bug. Check out the API docs for UIViewController.
Found it.
While not new to programming I am new to iPhone development. On researching this problem I found it was not recommended to call the viewWillAppear and viewWillDisappear methods manually.
My viewWillDisappear methods resign any keyboards if shown, when my app enters the background it loads a splash screen ready for when the app re-enters the foreground (there is some logic I need to do to work out what the user is shown on restarting the app and I can do this under the splash screen).
As viewWillDisappear is not called when the app goes into the background to make sure no keyboards appeared over my splash screen I was calling viewWillDisapper in the applicationDidEnterBackground method. I guess this also un-registers my events.
By adding viewWillAppear to my applicationDidEnterForeground method my events started firing again. Lesson learned, I will refactor this so I don't call these events manually.
Thanks for the help.
I have an old app which did many UI initialization work in viewDidLoad of various views. In iOS4 home button just put the app in background so viewDidLoad won't get called when re-launching the app.
I don't want to put those initialization procedures in viewWillAppear as it is unnecessary to re-initialize the data every time the view appear.
How can I completely quit my app when user press the home button? or any simple way to reload the view controllers that sit inside a tabBarController?
thanks.
There is a key in your app's Info.plist file called UIApplicationExitsOnSuspend, set it to the boolean YES, which will essentially revert the home button's functionality to pre-iOS4 and completely exit your app when the home button is tapped.
Try disabling backgrounding. Apple has this in their documentation
Try to check.
UIApplicationExitsOnSuspend
http://developer.apple.com/iphone/library/documentation/UIKit/Reference/UIApplicationDelegate_Protocol/Reference/Reference.html
you have to look up to the UIApplicationDidBecomeActiveNotification i think, but in the uiapplicationdelegate-protocol, there are even some other interesting things for you
or perfectly for you:
UIApplicationWillEnterForegroundNotification as a new notification in ios4 for this problem