I need to invoke a method each time an event is occurred even if the application is in the background.
In my case -each time I get a picture from the server I want to present it,
and if the application is in the background I want it to reEnter the foreground and present the picture.
Is it possible? if not, what is the nearest alternative?
Thanks,
Asaf
i thnk this is not possible, but use notifications to do this that application will become active when it receive notification.
further see these threads
iPhone OS 4.0.x - transition from background to foreground
How to bring app to foreground programmatically
Related
I am building a word game and I want to hide the board when application is suspended?
the code looks fine however it givs a strange behaviour!!,
when I suspend the app nothing will happen but when i resume the application then the board will hide!!
local onSystem = function( event )
if event.type == "applicationSuspend" then
print("suspend")
board_group.alpha = 0
end
end
Runtime:addEventListener( "system", onSystem )
Note: you might wonder how do I know how the application looks when suspended?
the answer is: by pressing the home button twice.
example
SpellTower in normal state
https://dzwonsemrish7.cloudfront.net/items/430k0c0b0y0b413d0b42/Image%202012.11.12%208:08:24%20AM.png?v=4822f549
SpellTower after pressing the home button twice
https://dzwonsemrish7.cloudfront.net/items/280a1y0r2U3W321y1B2z/Image%202012.11.12%208:08:31%20AM.png?v=09c37567
you can see how they are hiding the letters, this is exactly what I want to do for my game, the only difference is i am using Corona SDK
When you do board_group.alpha = 0 you only has set a variable, the result will only take effect after a screen update.
But since the application is suspended... it won't update! So, changing any graphics on applicationSuspend don't work.
I believe the reason is because the application is not considered as suspended. In normal objective c programming it means that applicationWillResignActive is called when the user double clicks on the home button. So what you want to do is to add that code for this part.
Here is a flow of events:
http://www.cocoanetics.com/2010/07/understanding-ios-4-backgrounding-and-delegate-messaging/
Corona seems to have these events:
"applicationStart" occurs when the application is launched and all code
in main.lua is executed.
"applicationExit" occurs when the user quits the application.
"applicationSuspend" occurs when the device needs to suspend the application such as during a phone call or if the phone goes to sleep
from inactivity. In the simulator, this corresponds to the simulator
running in the background. During suspension, no events (not even
enterFrame events) are sent to the application while suspended, so if
you have code that depends on time, you should account for the time
lost to an application being suspended.
"applicationResume" occurs when the application resumes after a suspend. On the phone, this occurs if the application was suspended
because of a phone call. On the simulator, this occurs when the simulator was in the background and now is the foreground application.
So my guess is that you have to implement it outside of the corona API.
According to the corona documents you can implement them in the delegate:
You can intercept UIApplicationDelegate events via your implementation
of the CoronaDelegate protocol.
This protocol conforms to the UIApplicationDelegate protocol. Corona's
internal delegate will call your protocol's method if it is
implemented.
Please keep in mind the following:
Methods that Apple has deprecated will be ignored.
In most cases, your class' version will be invoked after Corona's corresponding version of the UIApplicationDelegate method. There is one situation in which your version will be called before.
In situations where the app is about to suspend or go to the background, your method will be called before Corona's version, e.g.
applicationWillResignActive: and applicationDidEnterBackground:.
http://docs.coronalabs.com/native/enterprise/ios/CoronaDelegate.html
But this is just a guess. Hope it helps!
Edit:
I was thinking, something really simple you could do is catch it outside and present a "pause" screen, then just hide it when the application enters foreground.
So if you can't do that (for now), one other option is to save application state when the application is about to terminate, and then set UIApplicationExitsOnSuspend = true in your plist file. This will cause the application to exit instead of suspending, which will avoid any screenshots, effectively "hiding" the board, etc. The downfall is, the app will have to read the session state when it launches again... this is only useful if your application can be designed to actually exit without losing your state, and is quite honestly, a little extreme. That said, it may be the only way to effectively do what you're trying to do.
Other ideas would be to see if you can add a large black layer to the screen, even though the application is suspending; perhaps this will somehow trigger an internal screen update by natively setting setNeedsDisplay. Also, instead of modifying the alpha, you might consider temporarily removing all of your layers and see if that has a similar effect.
On IOS 5, we now have the notification bar on top to put messages. I have seen that Local Notifications will only happen if the app is in the background (not sure when queued, and / or when the notification is to fire, assume the latter).
Is there any way to put notifications in the notification bar while the app is in the foreground?
From my understanding, your app will be notified of a local notification while the app is running in the application:didReceiveLocalNotification delegate method, but a banner will not be shown at the top of the device screen, not will an entry be put in Notification Center. Your app is notified however, and this is so you can show your own UI for the notification in the app, or choose to ignore it.
Notification Center is only for notifications that you're missed because the app is not in the foreground, and that's why they disappear when the app is opened.
Yes, local notifications work with the simulator. However, make sure you are implementing application:didreceiveLocalNotification in your app delegate if you want to see the nofication while your app is in the foreground (source)
further troubleshooting steps per our conversation in chat and based on the above.
Like i said there are only 2 possibilities of why its not working. placement (in app delegate vs another class) and the application variable. so if it works in the app delegate then im not sure how to resolve that other then making a public method that you can reach from the class you want the notification to come from. probably not the most elegant or proper way but i dont know what else to say.
If its the application variable then make sure you use the same one i posted, application from the applicationfinishloading arguments list vs [[shared application]
Is it possible to show NSLocalNotification when the app is running and in the foremost position? As the Apple document says when the app is in the foremost position the notification will not be shown (it shows in notification center though, just doesn't have the flipping animation on top), then what's the point for method presentLocalNotificationNow: ?
You have to use your own UI to present notifications when your app is active. Use UIApplicationDelegate's application:didReceiveLocalNotification: method to find out when a notification is posted.
Notifications are designed to be triggered when the app is no longer active. And by default, they are suppresed if your app is active. So if you tell it to trigger Now, it won't because it won't display any notifications. For something immediate while your app is active, you would use alerts. I don't believe you will be able to override this default behavior.
My App needs a Internet Connection which is checkt in the ViewDidLoad if there is no Internet connection I want to terminate the app when the Home Button is clickt so that the app start in its initial state next time but only in this case.
If there is a Internet connection from the start the homeButton should bring the app just to the background.
Apple does strongly discourages quitting from application programmatically.
I think you can handle your case without quitting application - when application goes to background(in applicationDidEnterBackground method of application delegate) save some flag indicating that you want to reinit it on resume, then when application comes back to foreground (applicationWillEnterForeground method in delegate) apply your initialization logic in case flag is set.
Programatically terminate an App is a behaviour that will be rejected to be published in the AppStore, as it seems that the application crashed.
If you don't mind that your application will never see the light at the AppStore, you can simply use exit(0).
When your app does not find an internet connection, switch to a view that exactly imitates your Default start-up image, then force that view to stay visible the usual amount of start-up time after any call to making your app active. You can also kill and recreate fresh all your other MVC objects during this time.
That way, no one will know that your app wasn't freshly started when brought back from the background.
Is there a way to determine if the screen has been shut off via the top Power button?
I just need to know if the screen has been somehow set to off to kill a loop that updates location.
Thanks
Your Application delegate will receive a applicationWillResignActive: message just before the screen is locked (or when the phone rings or another window pops up). This is an excellent time to kill any idle-time processes. After re-activating, you'll receive an applicationDidBecomeActive: message, in which you can restart all this stuff.