I wrote my first iPhone App, and managed to get it into the App store. I later discovered a bug that happens on a real device but not on my emulator. I have committed a fix (changed plist to prevent app running in background), but I don't really understand why it happened.
My App allows users to record a sound-byte, however while they are recording they can use the iPhone home button to move the app to the background, and then it can keep recording forever if they don't restart the phone or the app does not crash.
My impression from everything I have read, is that this should not happen as you have to ask for background audio specifically if you want to do this, but now it appears to me that you have to ask specifically to disable it.
Could anyone explain this to me?
The iOS App lifecycle is described in Apple's iOS App Programming Guide.
The App is given the opportunity to save data and otherwise stop things that don't need to be running, before being suspended. You can request extra time doing this by using beginBackgroundTaskWithExpirationHandler:.
If you want your app to stop doing its "normal thing" when it is put into the background then you need to detect the App state transition and stop it yourself.
Related
My app has to run for a long time (also) in the background, due to Location Services.
When a certain condition is met the app has to move to the foreground.
I was able to run my app in the background and bring it to the front manually.
Reading up on this issue I got confused on how to move my app to the foreground by code.
It has to be in an if statement but what to do from here?
No do not think this is possible. You will be able to spawn a UILocalNotification to show application state to the user, but it is my understanding that iOS prevents you from making your app take focus.
you can't do that without user interaction. You can present a UILocalNotification
-- you can't even be sure iOS leaves it running though!
on a jailbroken phone I guess it is possible
This is clearly not possible, as it would be a mess if any app could just take over control at any point in time. As mentioned, you have to post a notification, and then it is up to the user if he or she wants to launch the app. If you notification states a good reason why they should launch your app, they might very well do it :-) And remember, don't mix up the user's needs with your/your app's needs.
I am doing a tracking kind of application for internal use of an organization and do not wish to submit it to app store.
What I am doing in the application is I am tracking the phone calls, messages etc.
My app runs in background once I start the app manually and keeps on running in the background until I close the app or the phone is switched off.
The thing that I want to add to my app is, I want to load the app automatically when the phone is switched on again.
Any idea or guidance will help. Suggestion for use of private apis is also welcome.
In private api, in file SBApplication.h there are all methods that you need.
In particular:
[...]
-(BOOL) _shouldAutoLaunchOnBoot:(BOOL)boot;
-(void) autoLaunchIfNecessaryOnBoot:(BOOL)boot;
-(void) _cancelAutoRelaunch;
-(void) _relaunchAfterExit;
[...]
etc, etc...
hope this helps.
As far as I can understand you can do it by registering your app for significant location changes. If an app registers for significant location changes, as soon as your cellular phone moves to a new tower, app receives an update. If the application is suspended when an update occurs, the system wakes it up in the background to handle the update.
So if you close the app and turn of your phone, as soon as your phone will restart it should get an update and it will force your app to run in background mode.
For more info read iOS programming guide: http://developer.apple.com/library/ios/#documentation/iphone/conceptual/iphoneosprogrammingguide/BackgroundExecution/BackgroundExecution.html
Hope it helps
How can my app keep getting a call to its "accelerometer:didAccelerate:" method of UIAccelerometerDelegate IF another app interrupts my app, such as the iPhone user receiving a phone call?
My app measures motion, but stops if suspended by the user, or if interrupted by another app.
I know this has been difficult in the past, but maybe there is something new in iOS.
Thanks!
You can't, apple standards are to block the app when a proccess pops in, It freezes the app at the moment it was interrupted. If finishes the last proccess it started in the background then it freezes the app. If you find a way around it i'd love to know it. Here is something that might help you to find the solution stackoverflow post similar to your question
How can I quit iPhone4 app? When I use exit(0) the app goes in the background. I want to quit the app instead of sending it to the background.
iPhone apps shouldn't have a quit button. The user quits by pressing the main button.
From Apple's docs: (http://developer.apple.com/library/ios/documentation/UserExperience/Conceptual/MobileHIG/MobileHIG.pdf)
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
Set UIApplicationExitsOnSuspend in your application's plist. This will cause the app not to go into the background under iOS4 when the user switches to another app.
Then have your app send an openURL: message to Safari when your app wants to exit. When Safari launches, your app will be terminated (by honoring the UIApplicationExitsOnSuspend plist key).
If you point the Safari URL at a web page explaining why your app just stopped running, the user might be less likely to give it a 1-star rating.
Note that this procedure may or may not follow Apple's recommendations, but it does stay within legal public API use (e.g. even some of Apple's example apps launch Safari).
after that I put everything I had said I put this and it worked
- (Void) applicationDidEnterBackground: (UIApplication *) application
{
exit (0);
}
comes completely out of the application
in app delegate there is method call applicationDidEnterBackground
call the exit(0)
I can't seem to find a clear answer to this-- I'm spec'ing out an iPhone app that I'd like to have live in the background and notify the user at certain periods throughout the day. So the user would launch the app in the morning and then continue to use their phone, then every few hours the app would pop open a notification dialog.
Will my app ever be shut down (automatically) by the OS? Or will it just live forever, notifying user when it needs to?
thanks,
Eric
Basically there are three kinds of running in the background on iOS 4:
Running in the background to "finish" stuff (e.g. upload a posting or a picture, finish processing something etc.). You ask the OS to grant you extra time after the user switches to another app, and it will tell you how much time you got. You can't run in the background for an indefinite time.
Running in the background to do specific stuff: VoIP, tracking location (e.g. for GPS navigation), or playing audio. You can only do the stuff that you told the OS you would do in the background.
Local notifications (UILocalNotification). From your description, this is what you're looking for. You're not actually running, you just schedule notifications, and when it's time to notify the user, they'll be notified and can go to your app. If you need to notify the user dynamically (i.e. you don't know ahead at what times they need to be notified and it's not location or VoIP triggered), you might want to look into push notifications.
Apple has a good overview here:
https://developer.apple.com/documentation/uikit/app_and_environment/scenes/preparing_your_ui_to_run_in_the_background/about_the_background_execution_sequence