What is the sequence of methods that gets called when we tap on the home button on iPhone, i.e. when an application is going in background.
Basically, I want to make a server call before my app goes in background. I am writing my server call code in applicationWillResignActive:, but sometimes it executes and sometimes it doesn't.
I need a solution for this.
From the app delegate file itself:
- (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, called instead of applicationWillTerminate: when the user quits.
Superclass implementation saves changes in the application's managed object context before the application terminates.
*/
[super applicationDidEnterBackground:application];
}
Try using this method.....
Related
I am creating a simple application which perform some task on main thread. I am printing process in NSLog so I can understand that my process is running or not.
Now when I press home button without starting the process (Process will be start when I tap on a button) application enters in background and my both of methods applicationDidEnterBackground & applicationWillResignActive are being called.
But when I first tap on my button and process starts on main thread after that if I press home button none of these two method being called. So my application can't know that app entered in background or not.
Even after that when I again active the app it shows me a black screen with status bar only.
Why this is happening?
Why app not entering in background?
Why apple's methods not being called?
Is there a way to solve it?
UPDATE
Here is my appdelegate class code
- (void)applicationWillResignActive:(UIApplication *)application
{
}
- (void)applicationDidEnterBackground:(UIApplication *)application
{
}
- (void)applicationWillEnterForeground:(UIApplication *)application
{
}
- (void)applicationDidBecomeActive:(UIApplication *)application
{
}
All methods have no implementation.
Thanks in advance.
I am creating a simple application which perform some task on main thread.
Don't perform long-running operations on the main thread.
The delegate callbacks happen on the main thread. If the main thread is busy, then the callbacks won't happen until you return to the "run loop".
When foregrounding your app, the OS actually displays a screenshot if available, falling back to the launch image (Default.png). The screenshot is taken after -applicationDidEnterBackground: returns, which allows you to customize what gets saved (you might want to do this for security reasons, or to hide UI elements which might not make sense to show when relaunching e.g. a countdown timer).
The black screen is probably because your app has no launch image. If your app takes more than about 10 seconds to enter the background (and it does, since the main thread is blocked), it gets killed. Except the debugger is attached and catches SIGKILL, so it's easy to miss unless you're watching Xcode.
there are some cases
if UIApplicationExitsOnSuspend key set to true in your app's Info.plist, the applicationWillResignActive method is not called when the user hits the home button. and may b some thing other. check keys here Apple keys and see if something new you added to plist. and there is no other case that you say your delegate method not calling. it may also some time due to project in appropriate behavior. try cleaning your project and rebuild.
this is going to sound strange but for those it helps. I had the same issue and cleaned my project and then it started working again.
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.
Let say someone is using my app and the change the settings in the settings bundle, when they come back to my app I would like my view to update (via my updating method) according to those settings. I've tried many different things but I just can't get it to work.
What is the best way to implement this kind of behavior for my iPhone app?
in your AppDelegate put these methods:
- (void)applicationWillEnterForeground:(UIApplication *)application {
/*
Called as part of transition from the background to the active state: here you can undo many of the changes made on entering the background.
*/
}
- (void)applicationDidBecomeActive:(UIApplication *)application {
/*
Restart any tasks that were paused (or not yet started) while the application was inactive. If the application was previously in the background, optionally refresh the user interface.
*/
}
Then you have hooks to do whatever you want.
It's worth noting that you're not limited to the AppDelegate; you can listen for these events from anywhere in your code with an NSNotification. See this answer for more details on how to listen for UIApplicationDidBecomeActiveNotification.
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.