How programmatically restart an iPhone app in iOS

Question

How programmatically restart an iPhone app in iOS?

I find this way http://writeitstudios.com/david/?p=54

But may be something simple.

Solution 1

The only way I know to do this is not ideal, but it works.

First, your app has to opt out of background execution (multitasking) The app has to quit when exited, not run as a background task. This is done with the plist key UIApplicationExitsOnSuspend.

Second, your app needs to register a custom URL scheme that can be used to launch the app.

Third, you need a web page hosted somewhere that when loaded will redirect to your app's custom URL scheme.

Forth, the user needs an active Internet connection.

To exit and restart, call UIApplication openURL on your hosted redirecting web page. Your app will exit and safari will launch and load your page. The page will redirect Safari to your custom URL scheme, prompting Safari to internally call openURL, causing iOS to launch your app.

Solution 2

my post that you linked to is referring to a Cocoa Application, not the iOS. On the iOS, you can quit an application (but Apple doesn't like this) by using exit(0); but I don't recommend that. You cannot restart iPhone apps though.

Comments

[Jonathan Sterling]

No. Don't do this. For the love of god.

[tc.]

And, of course, the real question: Why do you want to?

[Adrian Kosmaczewski]

I think Alexei refers to restarting the app, not the device. Of course, restarting the latter is more than out of the question.

[tc.]

Sure you can — you can call exit() or kill() or just return from main(), or various other things (like abort()). It's undistinguishable from a crash and will probably get your app rejected by Apple for that reason.

[tc.]

If you're feeling perverse, you can host the page from your app itself (you get about 10 seconds to exit in -applicationWillTerminate:; it might be easier to serve it in another thread, but you can equally just call socket(), bind(), listen(), accept(), write(), and close()). Let your app terminate after you've served the page and make the page launch your app with a delay (the "Refresh" or "Reload" header, I think).

[Andrei Eremchuk]

What means return from main()? I solve problem adding exit() button to app. I need it because measure first time and second time always different.

[tc.]

You don't even need to set UIApplicationExitsOnSuspend; you just have to call exit(). Wrapping the "server" in -beginBackgroundTaskWithExpirationHandler: ensures that your app gets enough CPU time to serve the thing, and then you can sleep for 500 ms (to "ensure" the data is sent) and exit(). The complicated bit is parsing the request, but you can fudge that by sleeping for 500 ms and reading into a largeish (8K) buffer, or (if you're feeling adventurous) select+read for 500 ms.

[Michael Behan]

I'm using exit() to quit an app, got past app store review no problem.

[samvermette]

@mbehan probably because the review team didn't stumble upon it. If they had they most likely would have rejected it.

[Michael Behan]

@samvermette They can't have failed to notice it - if you enter a dob that makes you less than 18 on the initial screen it exits (requirement from the drinks company whose app it is.) I wouldn't be surprised if I submitted the same app and have it rejected on that though. Rejections all seem a bit random!