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
I’m trying to make a focus timer app like Forest, that detects if you leave the app, either by going to the home screen, switching to another app or by first locking the phone and later proceeding to a different app through notifications, widgets, camera etc..
What I can’t figure out is how to monitor such state changes even after the phone has been locked for a while. There are no “background modes” covering this use case, so I would expect the app to get suspended after a while in the background. Nevertheless, apps like Forest do this successfully. Do I need a workaround to keep the app awake, or am I missing some approach that doesn’t require background execution at all?
Help much appreciated!
If I had to guess, it's probably a combination of a few things:
Use the normal app delegate callbacks for app state transitions to determine if the app is still able to execute code. That's the easy part.
You could do something with string and regex processing of console logs to detect when other apps open, close, etc. and other activity which would allow you to detect activity on the device coming from places other than your app.
You need to use some sort of framework that Apple says can get data even in background state. One such framework is Core Motion. There may be others as well that suit your app's specific needs better.
See Execution States for Apps.
See Background Execution.
See Cocoanetics: Accessing the iOS System Log.
See Keep iOS App Awake To Monitor Movement.
See Apple System Log Facility.
I am working on an app that, among other things, provides alarms in emergencies. Users can toggle a setting to have alarms be put through even if their iPhone is muted, but this service has another hurdle to leap: when the app has been force quit, it cannot receive (content-available) notifications until the app is relaunched by the user.
There is a geofencing event in place which buys me some processing time even if the app has been force quit, and in that time, I would like to check if such a block is in place, and if so, request the user to open their app again, and not aggressively force-quit in the future. (Many people still think it's just a way to keep things clean, even though it actually costs you battery life to not just leave apps in the background)
SO THE CORE OF THE PROBLEM: I need an (API call? Something else?) that will tell me whether the app is in such a 'force quit, cannot receive notifications' state, assuming that I do have processing time to do this check.
Anything is welcome, I have not been able to find proper Apple documentation on the notifications block.
Thank you very much.
While there is no API I am aware of to find state after, you can infer the state just before the application is terminated, and record that.
Code
applicationDidEnterBackground
will be called when an app has received a terminate signal.
More Info
This question describes what lifecycle functions to use, and
I have an iPhone app that I need to send to the background automatically. The app is defined with the VOIP key in its background modes so it should continue running when in background. I specifically need the app to keep running so calling exit(0) is no good.
The app will not be distributed via app store so using a private API is ok.
I have read about UIApplication terminate and UIApplication terminateWithSuccess but they don't seem to be available anymore
Already answered quite well here:
Suspend the application
As that poster wrote:
Quitting your application or sending it to the background programmatically is a violation of the [iOS Human Interface Guidelines][1], 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.
In Swift 3 Use below code, working charm
DispatchQueue.main.asyncAfter(deadline: .now()) {
UIApplication.shared.perform(#selector(NSXPCConnection.suspend))
}
While I agree with the other answer that you "shouldn't" exit programatically. There is a way to exit programatically.
*disclaimer - You shouldn't do this.
exit(0);
There is no way to put the application into the background without pressing the home button. If there is, you might want to add the jailbreak flag to your question and ask them.
For more, check this duplicate question, Proper way to exit application.
I have a volume control app in the iOS store, but one problem that my users have frequently is that the device kicks it for memory control. Is there any way to either force it to stay active (by permission) or to at least alert the user when its no longer active or in danger?
All the answers are under Background Execution in the iOS Developer Library.
Of course, here's the philosophy:
Always try to avoid doing any background work unless doing so improves
the overall user experience.
See Table 3-1 for the types of background execution. There's a category for audio but it requires audio to be played from the app. It does not sound like your app fits in here. So you'll want to look at notifying the user.
You could send a notification to the user when the app falls to background with applicationDidEnterBackground(), or just before it quits with applicationWillTerminate(), supposedly time-permitting.
Running in the background is permitted. I have an app that does it and while the rules have changed and adapting to it has been gut wrenching at times, it is pretty straightforward. In your case, I would think that you could setup to be notified and then just disappear, no? waking from a notification is part of the state changing protocol and you should be able to do that.
As a point of comparison, in Android, background operations like yours would be implemented as services and would have no fear of being terminated. The strangest thing about the way ios chooses to allow background activity is that you are applying for status one time. In Android, I was able to indicate that a single activity should be kept alive when the app is backgrounded, all others could be terminated. There is no way to do that in ios.
I take it my disappear and wait for notifications is probably not going to work for you because there is no way to be notified of volume changes. You must be polling? In which case, you probably are going to have to ask to be kept alive. Would be nice if you could just piggyback on other services, e.g. keep me alive while music is playing.
To answer your other question, yes you will get notified if/when you really are going to get termed, so you could send a notification at that point.
I have an iPhone app that I need to send to the background automatically. The app is defined with the VOIP key in its background modes so it should continue running when in background. I specifically need the app to keep running so calling exit(0) is no good.
The app will not be distributed via app store so using a private API is ok.
I have read about UIApplication terminate and UIApplication terminateWithSuccess but they don't seem to be available anymore
Already answered quite well here:
Suspend the application
As that poster wrote:
Quitting your application or sending it to the background programmatically is a violation of the [iOS Human Interface Guidelines][1], 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.
In Swift 3 Use below code, working charm
DispatchQueue.main.asyncAfter(deadline: .now()) {
UIApplication.shared.perform(#selector(NSXPCConnection.suspend))
}
While I agree with the other answer that you "shouldn't" exit programatically. There is a way to exit programatically.
*disclaimer - You shouldn't do this.
exit(0);
There is no way to put the application into the background without pressing the home button. If there is, you might want to add the jailbreak flag to your question and ask them.
For more, check this duplicate question, Proper way to exit application.