Is it possible to logout when the iPhone Home button is pressed?
In the current iPhone API, it is impossible to "hijack" any of the hardware presses. You will be notified of certain events however. If you are wishing to call some function (logout) when the user exits the app by pressing the home button, you can implement the
- (void)applicationWillTerminate:(UIApplication *)application {
....
}
method in your Application Delegate. This method is called when the app is about to terminate through a phone-call, manual exit, or any other reason. You should be advised, however, that anything here better be very short execution and non-essential, as Apple does not guarantee that it will run through the whole method before terminating the application
For iOS 4.0 + however you will have to implement logout in this method as well
- (void)applicationDidEnterBackground:(UIApplication *)application
Related
I need to close some resources I am using when the App is minimized by clicking on Home Button.
Attention, I don't want to intercept the Home button, I know it is not allowed by Apple
thanks
Use the delegate method - (void)applicationDidEnterBackground:(UIApplication *)application which is in appdelegate class. Whenever user taps the home button, this method will be called. for more details, check apple documentation. You can use applicationWillResignActive: in case you want to detect an incoming phone call or sms as well along with app minimizing.
You want to look at the UIApplicationDelegate (reference). Specifically, applicationWillResignActive and applicationDidEnterBackground should be what you want.
From the Apple docs, this also goes into more detail with examples - App States and Multitasking.
How can I know whether app is terminated by user?
(Double-clicking Home button and press red minus '-' button)
I need sample or pseudo code...
Sometimes you do get the UIApplicationWillTerminateNotification (you can also implement the applicationWillTerminate: method in your app delegate), but it's not guaranteed that you do get any notification at all in this case. So don't rely on it.
You won't receive the notification if your app is "suspended", that is it is in background but not running. In the suspended case you simply get killed with the non-catchable SIGKILL. Same for when you get killed due to out-of-memory.
From the documentation for applicationWillTerminate: (emphasis mine):
For applications that do not support background execution or are linked against iOS 3.x or earlier, this method is always called when the user quits the application. For applications that support background execution, this method is generally not called when the user quits the application because the application simply moves to the background in that case. However, this method may be called in situations where the application is running in the background (not suspended) and the system needs to terminate it for some reason.
When user kills the app:
- (void)applicationWillTerminate:(UIApplication *)application{
}
Application will enter inactive state:
- (void)applicationWillResignActive:(UIApplication *)application
{
NSLog(#"Application Did Resign Active");
}
User pushes Home button:
- (void)applicationDidEnterBackground:(UIApplication *)application
{
NSLog(#"Application Did Enter Background");
}
Try this:
- (void)applicationWillTerminate:(UIApplication *)application
{
/*
Called when the application is about to terminate.
Save data if appropriate.
See also applicationDidEnterBackground:.
*/
}
You should implement the method above in your class that implements UIApplicationDelegate
Some more notes: that method won't be called if you are stopping your app via Xcode (stop debug button). So be patient when testing.
Also there is this:
- (void)applicationDidEnterBackground:(UIApplication *)application {
}
Could be helpful if you want to know did it enter background ;)
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.
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.