So, I have an app that monitors significant location changes. I want to only record changes at most every 2 hours. The other times, I really don't want my app to startup at all. Does anyone know if I can terminate my app from within
- (BOOL) application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions
Will returning "False" cause my app not to be loaded (from the docs it seems that is only if it is trying to handle a URL).
You should not terminate the app as it lead to rejection by apple.As docs say
There is no API provided for gracefully terminating an iOS application.
You can show pop up to user for appropriate message.During development or testing you can call abort().But you should not ship your app with any of terminate api as apple strongly discourage this.
you can try exit(0); but Let me warn you apple may reject your app if you terminate your app willingly, what would be better is to show a dialogue box containing the reason and asking the user to close the app on thier own.
You really should not terminate your application, but should prompt the user that there's nothing to show at the moment and have them go to the home screen.
However, if you really want to, you can use abort().
From Apple's Developer Library (emphasis added):
In iOS, the user presses the Home button to close applications. Should your application have conditions in which it cannot provide its intended function, the recommended approach is to display an alert for the user that indicates the nature of the problem and possible actions the user could take — turning on WiFi, enabling Location Services, etc. Allow the user to terminate the application at their own discretion.
[...]
If during development or testing it is necessary to terminate your application, the abort function, or assert macro is recommended.
Related
At some point in my application I have done this exit(0) which crashes my app. But I haven't figured out what method gets called when this executes.
I've put messages in:
(void)applicationWillTerminate:(UIApplication *)application
(void)applicationDidEnterBackground:(UIApplication *)application
But none of this seem to get called! Any idea about what method is called when exit(0) is done?
From Apple's Human User Guidelines...
Don’t Quit Programmatically
Never quit an iOS application programmatically because people tend to
interpret this as a crash. However, if external circumstances prevent
your application from functioning as intended, you need to tell your
users about the situation and explain what they can do about it.
Depending on how severe the application malfunction is, you have two
choices.
Display an attractive screen that describes the problem and suggests a
correction. A screen provides feedback that reassures users that
there’s nothing wrong with your application. It puts users in control,
letting them decide whether they want to take corrective action and
continue using your application or press the Home button and open a
different application
If only some of your application's features are not working, display
either a screen or an alert when people activate the feature. Display
the alert only when people try to access the feature that isn’t
functioning.
If you've decided that you are going to quit programmatically anyway...
In C, exit(0) will halt execution of the application. This means that no delegate methods or exception handlers will be called. So, if the goal is to make sure that some code gets called when the closes, even on a forced close, there may be another option. In your AppDelegate implement a custom method called something like -(void)applicaitonIsgoingAway. Call this method from within anywhere you want your exiting code to be called:
applicationWillTerminate
applicationDidEnterBackground
onUncaughtException
The first two are ones that you already mentioned in your question. The third can be a catch-all of sorts. It's a global exception handler. This next bit comes from a question on that very topic.
This exception handler will get called for any unhanded exceptions (which would otherwise crash your app). From within this handler, you can call applicaitonIsgoingAway, just like in the other 2 cases. From the other question that I mentioned above, you can find an answer similar to this.
void onUncaughtException(NSException* exception)
{
[[AppDelegate sharedInstance] applicationIsgoingAway];
}
But in order for this to work, you need to set this method up as the exception handler like so...
- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions
{
NSSetUncaughtExceptionHandler(&onUncaughtException);
//There may already be more code in this method.
}
Now, you can quit the app programmatically by calling NSAssert(FALSE, #"Quitting the app programmatically."); As long as there is no other exception handler in place to catch this, your app will begin to crash, and your exception handler code will be called. in-turn calling applicationIsGoingAway.
When you call exit(0) you immediately terminate your application. 0 is a status code which means successful termination.
No other method is called, you application just dies. As a result end user may think app is just crashed.
Apple discourages you to call exit anywhere.
exit(0) is a C function that terminates your app's process therefore none of the application delegates methods will be called, the app will be killed immediately. Apple recommends strongly against your app quitting because it appears broken to the user.
There is no Apple-supported method to terminate your application programmatically. Calling exit is certainly out of the question. This causes all sorts of bugs (for example the multitasking switcher will break badly) as well as simply being wrong.
If you are trying to disable multitasking, you can do this with the UIApplicationExitsOnSuspend key in your Info.plist file (the title for the key is "Application does not run in background").
Other than that, it's up to your users to press the home button to close your application.
these methods will be called but you cannot use exit(0) you will need to press the back button to close your app then these methods will be called
At some point in my application I have done this exit(0) which crashes my app. But I haven't figured out what method gets called when this executes.
I've put messages in:
(void)applicationWillTerminate:(UIApplication *)application
(void)applicationDidEnterBackground:(UIApplication *)application
But none of this seem to get called! Any idea about what method is called when exit(0) is done?
From Apple's Human User Guidelines...
Don’t Quit Programmatically
Never quit an iOS application programmatically because people tend to
interpret this as a crash. However, if external circumstances prevent
your application from functioning as intended, you need to tell your
users about the situation and explain what they can do about it.
Depending on how severe the application malfunction is, you have two
choices.
Display an attractive screen that describes the problem and suggests a
correction. A screen provides feedback that reassures users that
there’s nothing wrong with your application. It puts users in control,
letting them decide whether they want to take corrective action and
continue using your application or press the Home button and open a
different application
If only some of your application's features are not working, display
either a screen or an alert when people activate the feature. Display
the alert only when people try to access the feature that isn’t
functioning.
If you've decided that you are going to quit programmatically anyway...
In C, exit(0) will halt execution of the application. This means that no delegate methods or exception handlers will be called. So, if the goal is to make sure that some code gets called when the closes, even on a forced close, there may be another option. In your AppDelegate implement a custom method called something like -(void)applicaitonIsgoingAway. Call this method from within anywhere you want your exiting code to be called:
applicationWillTerminate
applicationDidEnterBackground
onUncaughtException
The first two are ones that you already mentioned in your question. The third can be a catch-all of sorts. It's a global exception handler. This next bit comes from a question on that very topic.
This exception handler will get called for any unhanded exceptions (which would otherwise crash your app). From within this handler, you can call applicaitonIsgoingAway, just like in the other 2 cases. From the other question that I mentioned above, you can find an answer similar to this.
void onUncaughtException(NSException* exception)
{
[[AppDelegate sharedInstance] applicationIsgoingAway];
}
But in order for this to work, you need to set this method up as the exception handler like so...
- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions
{
NSSetUncaughtExceptionHandler(&onUncaughtException);
//There may already be more code in this method.
}
Now, you can quit the app programmatically by calling NSAssert(FALSE, #"Quitting the app programmatically."); As long as there is no other exception handler in place to catch this, your app will begin to crash, and your exception handler code will be called. in-turn calling applicationIsGoingAway.
When you call exit(0) you immediately terminate your application. 0 is a status code which means successful termination.
No other method is called, you application just dies. As a result end user may think app is just crashed.
Apple discourages you to call exit anywhere.
exit(0) is a C function that terminates your app's process therefore none of the application delegates methods will be called, the app will be killed immediately. Apple recommends strongly against your app quitting because it appears broken to the user.
There is no Apple-supported method to terminate your application programmatically. Calling exit is certainly out of the question. This causes all sorts of bugs (for example the multitasking switcher will break badly) as well as simply being wrong.
If you are trying to disable multitasking, you can do this with the UIApplicationExitsOnSuspend key in your Info.plist file (the title for the key is "Application does not run in background").
Other than that, it's up to your users to press the home button to close your application.
these methods will be called but you cannot use exit(0) you will need to press the back button to close your app then these methods will be called
I have an iOS app and for several reasons I need to close it when the user clicks the home button of the device. I can't support background.
I now there is an option called Application does not run in background, but I can't use it because there is a bug from Facebook sdk that makes impossible to authenticate with Facebook when this option is in use. Here is the bug report at Facebook.
So I don't know what to do, how can I restart it? An [[NSThread mainThread] exit] in applicationDidEnterBackground?
Is there a workaround for this?
The legal (Apple will approve the app) way is set or create the key UIApplicationExitsOnSuspend to YES in the Info.plist.
To get this as action you would need exit(0) or [[NSThread mainThread] exit], but this is against the Human Interface Guidelines from Apple
So what you could also do is just design all your views in a manner that they have a reset function . Then when applicationDidEnterBackground store that you need to reset on next startup or directly call reset on all active views in applicationWillEnterBackground
So your App didn't really restart, but all your views look like this. To give you an advice, I would design my app in a manner that it doesn't shutdown itself when i quit. This is no good user experience.. Once clicked the home button and all your data is away, same when you receive a call.
Plain old stdlib.h exit() will terminate the app, though it violates apple guidelines (see "Don't Quit Programmatically").
Your app won't perform any background actions if you don't initiate any.
I want to exit my application programatically, I googled, some people suggesting to use exit(1), but apple is not supporting that I guess. If it is the case, How do I exit my application programatically. Any helps appreciated.
exit(0); will work but don't use it
You shouldn't force close an app as the standard way to terminate an application is to press the home button (or use the multitasking bar)
Don’t Quit Programmatically
Never quit an iOS application programmatically because people tend to
interpret this as a crash. However, if external circumstances prevent
your application from functioning as intended, you need to tell your
users about the situation and explain what they can do about it.
Depending on how severe the application malfunction is, you have two
choices.
Display an attractive screen that describes the problem and suggests a
correction. A screen provides feedback that reassures users that
there’s nothing wrong with your application. It puts users in control,
letting them decide whether they want to take corrective action and
continue using your application or press the Home button and open a
different application
If only some of your application's features are not working, display
either a screen or an alert when people activate the feature. Display
the alert only when people try to access the feature that isn’t
functioning.
Source
I believe u are not reading the comment properly thus posting the answer for ur question here:
"Simply Don't do that. as apple does not allow application to crash like that."
look at here. How do I exit my iOS app gracefully after handling a Local Notification and here Exit application in iOS 4.0 there are fare discussion over here.
After the release of iOS4, multitasking(new feature) was added by APPLE. This feature enabled the users to keep the app into suspended state in the background if in between he has to do some other activity(e.g. picking up phone call). So Apple considers your app should be maintained in the background until the user deletes the application from the background. And after this if you want to exit use exit(0);, using this would further lead to rejection from AppStore
Here's a wrong way to accomplished exit function in your app. This is coming to mind when I read your question, never applied anywhere, so be careful if you'll gonna implement this!
- (void) exitApp
{
NSArray *array = [[[NSArray alloc] init] autorelease];
NSLog(#"%#",[array objectAtIndex:10]); //will crash here, looks like exit.
}
P.S. You can put this code inside your UIAlertView asking exit confirmation like Do you really want to exit?. In YES button pressed you can call [self exitApp]; User think that he'll exit from the app.
At some point in my application I have done this exit(0) which crashes my app. But I haven't figured out what method gets called when this executes.
I've put messages in:
(void)applicationWillTerminate:(UIApplication *)application
(void)applicationDidEnterBackground:(UIApplication *)application
But none of this seem to get called! Any idea about what method is called when exit(0) is done?
From Apple's Human User Guidelines...
Don’t Quit Programmatically
Never quit an iOS application programmatically because people tend to
interpret this as a crash. However, if external circumstances prevent
your application from functioning as intended, you need to tell your
users about the situation and explain what they can do about it.
Depending on how severe the application malfunction is, you have two
choices.
Display an attractive screen that describes the problem and suggests a
correction. A screen provides feedback that reassures users that
there’s nothing wrong with your application. It puts users in control,
letting them decide whether they want to take corrective action and
continue using your application or press the Home button and open a
different application
If only some of your application's features are not working, display
either a screen or an alert when people activate the feature. Display
the alert only when people try to access the feature that isn’t
functioning.
If you've decided that you are going to quit programmatically anyway...
In C, exit(0) will halt execution of the application. This means that no delegate methods or exception handlers will be called. So, if the goal is to make sure that some code gets called when the closes, even on a forced close, there may be another option. In your AppDelegate implement a custom method called something like -(void)applicaitonIsgoingAway. Call this method from within anywhere you want your exiting code to be called:
applicationWillTerminate
applicationDidEnterBackground
onUncaughtException
The first two are ones that you already mentioned in your question. The third can be a catch-all of sorts. It's a global exception handler. This next bit comes from a question on that very topic.
This exception handler will get called for any unhanded exceptions (which would otherwise crash your app). From within this handler, you can call applicaitonIsgoingAway, just like in the other 2 cases. From the other question that I mentioned above, you can find an answer similar to this.
void onUncaughtException(NSException* exception)
{
[[AppDelegate sharedInstance] applicationIsgoingAway];
}
But in order for this to work, you need to set this method up as the exception handler like so...
- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions
{
NSSetUncaughtExceptionHandler(&onUncaughtException);
//There may already be more code in this method.
}
Now, you can quit the app programmatically by calling NSAssert(FALSE, #"Quitting the app programmatically."); As long as there is no other exception handler in place to catch this, your app will begin to crash, and your exception handler code will be called. in-turn calling applicationIsGoingAway.
When you call exit(0) you immediately terminate your application. 0 is a status code which means successful termination.
No other method is called, you application just dies. As a result end user may think app is just crashed.
Apple discourages you to call exit anywhere.
exit(0) is a C function that terminates your app's process therefore none of the application delegates methods will be called, the app will be killed immediately. Apple recommends strongly against your app quitting because it appears broken to the user.
There is no Apple-supported method to terminate your application programmatically. Calling exit is certainly out of the question. This causes all sorts of bugs (for example the multitasking switcher will break badly) as well as simply being wrong.
If you are trying to disable multitasking, you can do this with the UIApplicationExitsOnSuspend key in your Info.plist file (the title for the key is "Application does not run in background").
Other than that, it's up to your users to press the home button to close your application.
these methods will be called but you cannot use exit(0) you will need to press the back button to close your app then these methods will be called