I am wanting to save some app state data for when the user is quitting the app. I am thinking that I should be using the applicationWillTerminate method inside of my appDelegate, but when I try and do anything there, it's not doing anything:
- (void) applicationWillTerminate:(UIApplication *)application {
NSLog(#"test");
}
When I run my app, and do some stuff, and hit the home button to quit the app, nothing comes over the console...
Do I have to implement the applicationWillTerminate method in the appDelegate? The user of my app will most likely be in a Reader view when they leave, is there anyway to implement the app will close method there?
see this link iPhone simulator and applicationWillTerminate() for older iOS versions;
but remember the Home button does not necessarily terminate the application is ios4... you should use applicationDidEnterBackground but would suggest both places applicationWillTerminate and applicationDidEnterBackground
Adding the UIApplicationExitsOnSuspend key to your application’s Info.plist file and setting its value to YES will make you application quit when you hit the home button, even on iOS4
In iOS 4, the applicationWillTerminate: method is only called if you opt out of the background execution model. In the standard iOS 4 application lifecycle, applications are suspended (not terminated) when the home button is pressed. Your application delegate will receive an applicationWillResignActive: message followed by an applicationDidEnterBackground: message. The applicationDidEnterBackground: method is a good place to save user data.
Related
I have a method that I want to call not the first time the app launches from being not open at all, but whenever the app opens at all, whenever. So if the app is open, then the user closes it, but it is still running through multitasking, I want to the method to run when they resume the app as well.
applicationWillEnterForeground:
In iOS 4.0 and later, this method is called as part of the transition from the background to the active state. Specifically, it is not called when the application is launched for the first time -- which is what you are looking for.
- (void) applicationWillEnterForeground:(UIApplication *)application {
}
I had installed my app on ipad(ios 4) , and i was navigating through the pages of my app.whenever i close the app and re open the app it goes back to the recent page which i was working on.
But i want it to restart the app from first page,whenever i exit and reopen .As it is working on iphone(ios 3.1.3),Can any one suggest how to do that on ipad.
thanks in advance
I think you can do that easily. You need to set info.plist key "Application does not run in background" to YES and it will no longer to run in background.
When application enters background the delegate method appDidEnterBackground is called and when resumed the method willEnterForeGround will be called.
You can handle your application behaviour in these methods.
For more info you can refer to this link which explains the concepts beautifully.
On iOS 4 the app does not exit it goes to background. And when you tap on the icon the app resumes from where you left it.
If you want to reset something when it goes in background you need to implement custom code in appDelegate methods:
- (void)applicationDidEnterBackground:(UIApplication *)application
{
/*
Use this method to release shared resources, save user data, invalidate timers, and store enough application state information to restore your application to its current state in case it is terminated later.
If your application supports background execution, this method is called instead of applicationWillTerminate: when the user quits.
*/
}
- (void)applicationWillEnterForeground:(UIApplication *)application
{
/*
Called as part of the transition from the background to the inactive state; here you can undo many of the changes made on entering the background.
*/
}
You need to set UIApplicationExitsOnSuspend to yes in your info.plist
Which methods are called when user presses home button and double presses it again to return
here you can find answer to event on clicking on home button
interesting article
Find your info.plist file in resources and add the key:
"Application does not run in background" and set the value to 1.
How to know the termination of app?
I added this code in viewDidLoad
[[NSNotificationCenter defaultCenter] addObserver:self
selector:#selector(applicationWillTerminate:) name:UIApplicationWillTerminateNotification
object : nil];
and if the app ends, it will notify me of termination.
- (void)applicationWillTerminate:(NSNotification*) notif{
NSLog(#"program will end");
}
But it doesn't work...
I terminated the app, by clicking home button and pressing home button in 2sec, followed by clicking app icon's '-'button.
I want to be notified of the termination of app.
And also intereseted in what function to be called when the app terminates.(is it viewDidLoad?)
And the termination of app by clicking the '-'button is to send the app SIGKILL?
I terminated the app, by clicking home button and pressing home button in 2sec, followed by clicking app icon's '-'button.
If you press the home button, your app will be sent to the background. When you then kill it (by pressing the - button), it likely does not get the notification because it is not running anymore.
applicationWillTerminate is called on iOS < 4.0, when no multitasking (background) is available or when UIApplicationExitsOnSuspend is set in the info.plist file.
On iOS 4.x, when your app is sent to the background, it receives applicationWillEnterForeground:. Look at the UIApplicationDelegate Protocol Reference for more info:
You should use this method to release shared resources, save user data, invalidate timers, and store enough application state information to restore your application to its current state in case it is terminated later.
Keep in mind that you need to do this both in applicationWillEnterForeground and applicationWillTerminate if you also support iOS < 4
Have a look also at this post from S.O.
That should work, did you try adding logging into the application delegate method applicationWillTerminate: method too?
Edit:
For iOS 4+ devices, you need to do whatever work for shutdown in applicationWillEnterBackground instead... that always gets called as you are being suspended and is the right time to do final work.
you should implement applicationDidEnterBackground and do any preparation for termination there. If your app is terminated in the background, you will receive no other notification.
The applicationWillTerminate delegate method is not getting called in iOS 4.0
When I hit the Home button I am seeing the applicationWillResignActive and applicationDidEnterBackground delegate methods getting called.
- (void)applicationWillResignActive:(UIApplication *)application
{
NSLog(#"Application Did Resign Active");
}
- (void)applicationDidEnterBackground:(UIApplication *)application
{
NSLog(#"Application Did Enter Background");
}
And when I double Tap the Home button and again launch the Application the i find the applicationWillEnterForeground and applicationDidBecomeActive delegate methods are getting called.
- (void)applicationWillEnterForeground:(UIApplication *)application
{
NSLog(#"Application Will Enter Foreground");
}
- (void)applicationDidBecomeActive:(UIApplication *)application
{
NSLog(#"Application Did Become Active");
}
But I want to know when the applicationWillTerminate delegate method will be called , where I do some DB/file backup routines.
- (void)applicationWillTerminate:(UIApplication *)application{
}
I even tried to hit the minus sign and deleted the App running in the Background , but still it did not call any delegate method.
Any Ideas ???
From the iPhone Application Programming Guide:
Even if you develop your application using iPhone SDK 4 and later, you must still be prepared for your application to be terminated. If memory becomes constrained, the system might remove applications from memory in order to make more room. If your application is currently suspended, the system removes your application from memory without any notice. However, if your application is currently running in the background, the system does call the applicationWillTerminate: method of the application delegate. Your application cannot request additional background execution time from this method.
So yes, applicationWillTerminate: will generally not be called very often in iOS 4. If you have to save data, you should do so in both applicationWillTerminate: and applicationDidEnterBackground:.
The WWDC 2010 Session Adopting Multitasking on iPhone OS (Part 2) explains the application state transitions extremely well.
I got one solution for terminating apps when user hits the Home button in iOS4.
This will call the applicationWillTerminate delegate method instead of entering into background process.
Open your info.plist file
Add The Key UIApplicationExitsOnSuspend
Set the new key to YES
Actually you can also use this step to do so.
Open your info.plist file
Add The Key -> Application does not run in background
Set this key value to YES
When my app is run in the iPhone simulator, the delegate method
- (void)applicationWillTerminate:(UIApplication *)application
is only called the first time I hit the iPhone simulator's home button.
After the home button is pressed and the app is launched again, hitting the home button does not call the delegate method.
What is going on here? Am I misunderstanding something fundamental?
I suspect that it is being called, but that you are getting confused because after you hit the Home button in the Simulator, you've ended the current session in Xcode. You probably have an NSLog in your applicationWillTerminate: method, yes? Once you hit the Home button, NSLogs no longer show up in Xcode's run console. If you open /Applications/Console.app I expect they'll show up there.
- (void)applicationWillTerminate:(UIApplication *)application
is called when the application "terminates".
If you are using iOS then the app will NOT terminate when the home button is pressed, unless you have disabled multi-tasking for your app or the user does not have a "multi-tasking supported" device.
- (void)applicationDidEnterBackground {
is now used when the user presses the home button. Unless (as I previously said) you have disabled multi-tasking for your app or the user does not have a "multi-tasking supported" device.