Background Execution in Xcode

Question

I am asking if I can repeat a method in Xcode after home button pressed. Let's say every 30 minutes.

I have no idea to do it if it is possible.

Once that app is closed, so is your code. There is no way to run methods after it is closed — heinst, Apr 09 '15 at 17:10

score 1 · Accepted Answer · edited Jun 20 '20 at 09:12

I think your question is related to background execution by saying after home button pressed. First you need to address how to call the function in the background.

Here is what I recommend for you to follow:

First:

I recommend you to take a look at the apple official document.

https://developer.apple.com/library/ios/documentation/iPhone/Conceptual/iPhoneOSProgrammingGuide/BackgroundExecution/BackgroundExecution.html

Second:

There is a good tutorial:

http://pinkstone.co.uk/how-to-execute-a-method-on-a-background-thread-in-ios/

Third:

Here is what you are asking:

http://chrisrisner.com/31-Days-of-iOS--Day-23%E2%80%93Using-Background-Threads

Fourth:

If you want to explore the advanced material:

http://mobiforge.com/design-development/using-background-fetch-ios

score 0 · Answer 2 · answered Apr 09 '15 at 16:28

0

use NSTimer

[NSTimer scheduledTimerWithTimeInterval:"your time"
    target:self
    selector:@selector(your method:)
    userInfo:nil
    repeats:YES];

answered Apr 09 '15 at 16:28

Stephen Chen

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you mean the timer will run even when the home button pressed. – Ahmed.S.Alkaabi Apr 09 '15 at 16:31
if ur button action name homeAction:(id)sender then the code will be written inside the method `[NSTimer scheduledTimerWithTimeInterval:"your time" target:self selector:@selector(homeAction:) userInfo:nil repeats:YES];` – Stephen Chen Apr 09 '15 at 16:34
Thanks, but what I mean (after pressed home button) is after the app terminate. – Ahmed.S.Alkaabi Apr 09 '15 at 16:37
No, once the app is terminated you can't run any code. If you're trying to hack, stop. – user2320861 Apr 09 '15 at 18:19
sor. i just misunderstand ur question , i thought the home button is a instance variable – Stephen Chen Apr 10 '15 at 01:27

score 0 · Answer 3 · edited May 23 '17 at 11:43

There are Methods (like "viewDidLoad") that gets called for these cases. Here are some:

- (void)applicationWillResignActive:(UIApplication *)application
{
// Sent when the application is about to move from active to inactive state. This can occur for certain types of temporary interruptions (such as an incoming phone call or SMS message) or when the user quits the application and it begins the transition to the background state.
// Use this method to pause ongoing tasks, disable timers, and throttle down OpenGL ES frame rates. Games should use this method to pause the game.
}
- (void)applicationDidEnterBackground:(UIApplication *)application
{
// Use this method to release shared resources, save user data, invalidate timers, and store enough application state information to restore your application to its current state in case it is terminated later. 
// If your application supports background execution, this method is called instead of applicationWillTerminate: when the user quits.
}
- (void)applicationWillTerminate:(UIApplication *)application
{
// Called when the application is about to terminate. Save data if appropriate. See also applicationDidEnterBackground:.
}

you can place the NSTimer in one of these and anything else you want to do when the home button is pressed. Hope this helps.

Source: Detect when home button is pressed iOS

In iOS 6 above, the viewWillUnload and viewDidUnload methods of UIViewController are deprecated. — Mustafa Sait Demirci, Apr 09 '15 at 16:42

Background Execution in Xcode

3 Answers3