When checking through the time profiler, there is a gap in between Launching and Foreground - Active. I assume this to be the post main time that the app takes to launch.
So, I moved functions that do not need to be triggered until launch from my AppDelegate to the viewWillAppear of the rootViewController of my app. And still, this code contributes to the post main time of the app.
Where should I place such code so that it doesn't affect the post main time of my app?
Try moving those initializations from viewWillAppear to viewDidLoad. That way, they won't start up until the initial view is visible.
Related
I'm having an issue with this code (I have it in didFinishLaunchingWithOptions). I need it to finish executing the code inside before the app continues because it sets up some critical things in core data. It sends this to the background though and starts running the rest of the app and it doesn't finish quick enough for the data to be usable.
DataManager.getDataWithSuccess { (data) -> Void in
//code to execute here
}
How can I force the app to wait for this code to finish before moving on?
You shouldn't block the didFinishLaunchingWithOptions method from returning so that it can wait on an asynchronous task. It's crucially important to note that iOS applications are only given a limited amount of time to complete launching before the application is killed by the operating system.
An approach I have used in the past when waiting on asynchronous things to happen that need to happen before I really launch my app is to create a LaunchViewController. The interface for this view controller matches perfectly to the app's splash screen. From an end-user perspective, you can't even tell we've left the splash screen.
Here, we do any set up code such as asking your DataManager to get data. Then, when it (and any other set up actions) completes, you simply present the next view controller in much the same way you'd move between any other view controllers.
A huge positive side effect here is that you can have much nice looking animations from your splash screen into the first screen of your application.
Background
When the app is backgrounded I want to have a lock screen that forces the user to log in again. I have implemented this in the OnResignActivation method in AppDelegate.
Functionally this works fine, however, when backgrounded the lock screen tries to slide in but doesn't have time to complete. When the app opens again this animation completes.
Question
How can I get the animation to complete or not use the animation at all so that when ever the app is opened again the lock screen is there and not half way across?
Solution
The solution was in fact in implement the lock screen logic in DidEnterBackground instead of OnResignActivation in AppDelegate.
As the code was running to soon in the life cycle I was getting half an animation behaviour. Putting it in DidEnterBackground resolves this.
These SO answers helped me arrive at this solution.
https://stackoverflow.com/a/12416131/1593273
https://stackoverflow.com/a/25985478/1593273
I've come across a strange error while programming my iPhone application. Basically when I leave my application in the background and then access it after a long time (i.e. the entire night while I'm sleeping), the viewDidLoad method seems to be called again even though I did not exit the app (I only double tapped the Home button or I tapped the Home button once) but still left the app in the background. However, if I leave the app on for a short period of time (anytime between a few minutes to a few hours), the viewDidLoad method is not called again and everything is as it should be. After doing some research, I found that it is because the viewDidUnload method is called (after the OS finds that the app is suspended for a long time), which calls viewDidLoad again when we bring the app back up. I found this out through this link: view seems to reload itself but it doesn't seem that there's a way to prevent viewDidLoad from being called when the viewDidUnload is called. Is there any way to prevent this viewDidUnload method from being called again? The thing is I want my app to be running for a long time in the background (i.e. a few days in the background) to collect data. Or, is there no way around this? Any help would be appreciated. Thanks!
EDIT: I have realized that after iOS 5, viewDidUnload is deprecated but this phenomenon still occurs. Any ideas on how to fix it? Thanks!
If you want to do stuff in the background you should look into background tasks.
I have application with lot of view controllers and on every time when app comes from background I have to make some request to server and reinitialise some global variables. At the moment I am doing this by repeating code in every view controller in didViewLoad but I wonder is there way to this in delegate to avoid repeating on 10 places ? ( I check didFinishLuanchingWithOptions in delegate but it is called only first time not when app comes from background ).
I think you want to look at these two:
applicationDidBecomeActive
And
applicationWillEnterForeground
Check out the documentation for more details.
I have a timer in my app, and I want it to appear to be running while my app is on the background. I'd like that if the user presses the home button when the timer shows, for instant "01:11:11" and then goes back to the app and it becomes visible to him 10 minutes later, to see the timer as "01:01:11", however I get a split second where it shows the last state when the app went to the background ("01:11:11") before it starts updating from the correct time.
I assumed that I could correct this by updating the state of my timer in "applicationDidBecomeActive" and it did work on my simulator in Xcode but not on my Ipad.
I'm using cocos2d for my drawing and this is what I'm doing in my applicationDidBecomeActive:
CCScene *s=[director_ runningScene];
GameLayer *l=[(GameLayer*)[s getChildByTag:GAME_LAYER_TAG];
if (l!=nil) [l myUpdate];
I don't think it's relevant to the problem though because myUpdate does get called but I still have that split second glitch on my Ipad, as if it starts back from its last state no matter what.
In apples clock app, in applicationDidEnterBackground it hides the timer text, so that when the app comes into the foreground you see a blank UI for the split second where your app is loading the new timer data in the UI. Also, you may want to call some of your applicationDidBecomeActive code in applicationWillEnterForeground, which is called first. But keep in mind, applicationWillEnterForeground is not called when the app first launches.
There will always be a delay between when your app comes into the foreground, and when the UI updates. Theres no way to fix that, so you might as well use what apple uses to get around the issue.
Well I tried to hide my UI in both applicationWillResignActive and applicationDidEnterBackground. Since applicationWillResignActive is called first and before going into preview (double click on HOME) it causes a "not so pretty" preview but I thought at least it would solve my original problem. It didn't (not, on my IPad). It looks like the system takes the screen shot even before applicationWillResignActive.
I checked the timer in the official clock app and I see the clock is updating even when the app is in the background (in preview), so they "cheat" anyway...