I know this question has been asked many times and we have gotten this link as an answer from Apple:
http://developer.apple.com/library/ios/#qa/qa1561/
However, recently, I met with this case below. I don't see any other options except using 'exit(0)' directly.
I have an app which can collect digital data from camera or microphone of my iPhone.
Then I designed a button which reads 'Save and Exit', because this is a very common scenario of my app.
Without the capability to exit my app programatically, I can only have a stupid 'Save' button. Then my users have to click twice ( 1. the 'Save' button, and then 2. the 'Home' button ) to get the same result - a.k.a these two actions in sequence together.
Then I realized, maybe, this is a flaw of my design. Hence I changed it this way.
I removed the 'Save the Exit' button and, instead, added a note in the bottom says 'Use HOME button to SAVE & EXIT'. I tried to catch the quitting signal from users' action and then do the SAVE in prior.
By doing this, user can simply use the native HOME button to do the 'SAVE and EXIT'.
However, this solution is not perfect.
If my app takes too long to save the data, there's still a chance for iOS to kill my app after user hits the 'HOME' button. Then user can lost their data without notice!
If I can exit programmatically, I can try to 'SAVE' first. If 'SAVE' fails, I have plenty of time to inform my user or do all the remediation work needed.
Do you think this is a valid justification to use 'exit(0)' in my app without being rejected?
No, I very much doubt that Apple will let you have a "save and exit" button. It goes completely against the platform conventions and directly contradicts Apple's HIG.
Under which circumstances do you think you'll have data that can't be saved in the amount of time iOS gives an app to clean up? Have you actually measured this and found it to be a problem?
Why don't you try just saving automatically all the time? You could save to a temp directory and then at exit do a file move operation. This would probably be much faster than your current save operation which sometimes fails.
Related
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).
As you may have seen in some apps an alert pops up asking the user to rate the app in itunes and usually the alternatives you get to choose from is something like: Sure which opens the rate page for the app. The second option is No Thanks which closes the alert and the third option usually is maybe later which displays the alert later.
I was wondering how to do this.
I want the alert to be displayed after say the app has launched 20 times if that would be possible.
And how can I create an maybe later alternative which displays the alert maybe 15 launches of the app later?
And a final question is there a special link for the apps rate page? So when you click the sure button or whatever it will take your directly to the rate page.
I've used this: https://github.com/arashpayan/appirater. You can look at my fork as well for a specific mod I needed.
[EDIT: comment re NSUserDefaults]
I suggested this link because it is a full, working implementation of what you describe that is easily integrated into existing apps. I've used (and modified) it myself. NSUserDefaults is a general purpose mechanism for persisting app state. I agree with the others that it's a very useful thing to learn and use, it's just not a full answer to your question. If you choose to roll your own implementation of a rating system (nothing wrong with that) you will most likely use NSUserDefaults to store the relevant info.
Check out my answer for this similar question. I provide two different links you can use for taking the user to the "rate this app" screen in the App Store.
Direct "rate in iTunes" link in my app?
You can use NSUserDefaults to save the launch count (increment it in application:didFinishLaunchingWithOptions:), then save the user's choice another preference key. If the user says later, you could reset the counter back to zero.
I don't think there is a special rating link, but you can link to your app's specific App Store page. This was incorrect, as TomSwift points out; see Direct "rate in iTunes" link in my app?
I wrote a library for doing this with minimal effort on your part:
https://github.com/nicklockwood/iRate
I'd recommend using a library rather than rolling your own solution. It may seem like a simple problem but the library takes care of a whole bunch of extra stuff, like ensuring that the user is prompted for each new installed version, that they are reminded after a certain time if they decline, that they aren't prompted to go to the app store unless they have a network connection, etc.
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.