How can I suspend my application or send a suspend message to my application?
I want to simulate pressing the home button.
There is a private instance method for UIApplication:
The following code would work, (tested in an iPhone 3GS):
UIApplication *app = [UIApplication sharedApplication];
[app performSelector:#selector(suspend)];
In swift:
UIControl().sendAction(#selector(NSURLSessionTask.suspend), to: UIApplication.sharedApplication(), forEvent: nil)
Edit Swift3:
UIControl().sendAction(#selector(URLSessionTask.suspend), to: UIApplication.shared, for: nil)
Quitting your application or sending it to the background programmatically is a violation of the iOS Human Interface Guidelines, which usually doesn't bode well for getting through the review process:
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.
The philosophical reason for this is explained earlier in that document:
People, not applications, should
initiate and control actions. Although
an application can suggest a course of
action or warn about dangerous
consequences, it’s usually a mistake
for the app to take decision-making
away from the user. The best apps find
the correct balance between giving
people the capabilities they need
while helping them avoid dangerous
outcomes.
Users feel more in control of an app
when behaviors and controls are
familiar and predictable. And, when
actions are simple and
straightforward, users can easily
understand and remember them.
People expect to have ample
opportunity to cancel an operation
before it begins, and they expect to
get a chance to confirm their
intention to perform a potentially
destructive action. Finally, people
expect to be able to gracefully stop
an operation that’s underway.
There should be no reason that you need to force your application into the background during its operation. It should remain fully functional when displayed onscreen and it should be up to the user when they want to switch away from your application.
You can't do this.
If you want to exit your app, don't fear rejection and love false positive crash report emails from users you could call exit(0);
Use :
sleep(15)
it will suspend your app for specific time
When the application is suspended, a UIApplicationWillResignActiveNotification notification is posted.
I would guess you could try to post this notification manually. Didn't try this myself though.
Related
Does anyone know if exit(0) is deprecated in iOS application? I know it is not a good decision to manually terminate the app, but does Apple ban the application if we use it in the code?
I got an app which was rejected because of a way of exit (via UIAlertView), doing an exit(5) when user click on the correct button.
I received that:
We found that your app includes a UI control for quitting the app.
This is not in compliance with the iOS Human Interface Guidelines, as
required by the App Store Review Guidelines.
Please refer to the attached screenshot/s for reference.
The iOS Human Interface Guidelines specify,
"Always Be Prepared to Stop iOS applications stop when people press
the Home button to open a different application or use a device
feature, such as the phone. In particular, people don’t tap an
application close button or select Quit from a menu. To provide a good
stopping experience, an iOS application should:
Save user data as soon as possible and as often as reasonable because an exit or terminate notification can arrive at any time.
Save the current state when stopping, at the finest level of detail possible so that people don’t lose their context when they start the
application again. For example, if your app displays scrolling data,
save the current scroll position."
It would be appropriate to remove any mechanisms for quitting your
app.
A "hidden" exit could be understood as a crash for the user, no?
No, Apple will not reject your app for using exit(0).
You are correct, it is not a great design choice, but it can be useful sometimes.
As Larme mentioned, if used incorrectly, it can be perceived as a crash and a crash will result in your app being rejected.
However, it can be very useful in applicationDidEnterBackground when (on a conditional basis ) you might want to force the app to start a fresh.
No, you must not call exit as your app SHOULD be rejected. This has been repeatedly discouraged by Apple and is known to cause serious bugs with iOS multitask switching. You should simply leave the user to use the home button themselves.
http://developer.apple.com/library/ios/#qa/qa1561/_index.html
"Additionally, data may not be saved, because -applicationWillTerminate: and similar UIApplicationDelegate methods will not be invoked if you call exit. If DURING DEVELOPMENT or TESTING it is necessary to terminate your application, the abort function, or assert macro is recommended."
2012-04-09
Updated to more strongly discourage the exit function, and include best practices for debugging.
2008-08-27
New document that discusses best practices for terminating an iOS application in code.
Straight from the iOS Human Interface Guidelines
http://developer.apple.com/library/ios/#documentation/UserExperience/Conceptual/MobileHIG/UEBestPractices/UEBestPractices.html#//apple_ref/doc/uid/TP40006556-CH20-SW27
"Don’t Quit Programmatically
Never quit an iOS app programmatically because people tend to interpret this as a crash. However, if external circumstances prevent your app 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 app 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 app. It puts users in control, letting them decide whether they want to take corrective action and continue using your app or press the Home button and open a different app
If only some of your app's features are unavailable, display either a screen or an alert when people use the feature. Display the alert only when people try to access the feature that isn’t functioning.
If Necessary, Display a License Agreement or Disclaimer
If you provide an end-user license agreement (or EULA) with your iOS app, the App Store displays it so that people can read it before they get your app.
If possible, avoid requiring users to indicate their agreement to your EULA when they first start your app. Without an agreement displayed, users can enjoy your app without delay. However, even though this is the preferred user experience, it might not be feasible in all cases. If you must display a license agreement within your app, do so in a way that harmonizes with your user interface and causes the least inconvenience to users.
If possible, provide a disclaimer within your app description or EULA. Users can then view the disclaimer in the App Store, and you can balance business requirements with user experience needs."
We don't want the user enter our app if the app is out-dated.
Is that is possible to quit a iOS app when we do some date check BEFORE the app launch?
Or it is possible to quit the application after the main view is loaded?
Before the app launches: no. The launch animation is already in progress when the OS calls main.
After some time (1-2 sec): yes. You can use one of
[[UIApplication sharedApplication] terminateWithSuccess];
exit(0);
abort();
assert(0);
pthread_kill(pthread_self());
so many ways, but neither will go through AppStpre - you're not supposed to close your app programmatically. You're supposed to notify the user via an UIAlertView about the outdated app and disable interaction with the app.
According to Apple you cannot exit(quit) your application through code. i.e if you use exit(0). Your application will be rejected for that. Although you can use exit(1) and delay the exit time of your application. Or you may like to use local notification which is quite handy.
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 want to send my Application to background simply clicking on Button inside my Application.
Is there any way to call applicationdidenterbackground manually or any other way ?
iOS Human Interface Guidelines says "Don't Quit Programmatically", whereby quitting must be understood as including "suspending":
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 really want to exit your app programmatically, then you can call exit(0);, but I doubt that you app will pass the Apple review.
Unfortunately There is no any officialy way to force app to background state(Pause state).
I would like to close an iPad application as a result of clicking on a UIButton. However, I have not seen how to do this in the Apple documentation.
What call needs to be made to close an app?
Thanks.
You can call exit(0) to terminate the app. But Apple don't like this as this gives the user a feeling of sudden crash. If you still want to have an exit function (with a potential risk of rejection) then you should also send your app delegate the applicationWillTerminate message (if you have anything important there) before performing the exit.
It says:
Don’t Quit Programmatically
Never quit an iOS app programmatically because people tend to
interpret this as a crash. However, if external circumstances prevent
your app 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 app 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 app. It puts users in control, letting
them decide whether they want to take corrective action and continue
using your app or press the Home button and open a different app
If only some of your app's features are unavailable, display either a
screen or an alert when people use the feature. Display the alert only
when people try to access the feature that isn’t functioning.
The only way for a user to exit an application is by pressing the Home button. You can't do it in your app, at least not in a way that Apple would accept.
You can try to use command:
exit(0);
What is the proper way of ending an application on the iPhone when you are finished with it?
thanks,
anton
Jaanus is referring to this paragraph in the Apple iPhone Human Interface Guidelines
Stopping
People quit an iPhone application by opening a different application. In particular, note that people don’t tap an application close button or choose Quit from a menu. In iOS 4.0 and later, and on certain devices, the quitting application moves to a suspended state in the background. All iPhone applications should:
Be prepared to quit at any time. Therefore, save user data as soon as possible and as often as reasonable.
Save the current state when stopping, at the finest level of detail possible. For example, if your application displays scrolling data, save the current scroll position.
iPhone applications should never quit programmatically because doing so looks like a crash to the user. There may be times, however, when external circumstances prevent your application from functioning as intended. The best way to handle this is to display an attractive screen that describes the problem and suggests how users can correct it. This helps users in two ways:
It 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 certain circumstances prevent only some of your application's features from working, you can display either a screen or an alert when users activate the feature. Although an alert doesn't allow much flexibility in design, it can be a good choice if you can:
Describe the situation very succinctly
Supply a button that performs a corrective action
Display the alert only when users try to access the feature that isn’t functioning
As with all alerts, the less users see them, the more effective they are. For more information about creating alerts, see “Using Alerts.”
There is no way for an iPhone application to quit/terminate itself. Apple actively advises against it in their Human Interface and/or programming guides (can't remember which exactly) because it would look like a crash to the user.
An app should not terminate by itself.
Also, avoid showing an "exit screen" that prompts the user to quit the app manually as in iOS4, the app might stay open in the background and your user would be stuck in that exit state.