Ios listening app resumes from the background to the foreground

Under normal circumstances, the following two methods are implemented in AppDelegate to enable the listener to recover from the background to the foreground.

[Cpp]
-(Void) applicationDidEnterBackground :( UIApplication *) application
{
Log4info (@ "--- applicationDidEnterBackground ----");
// Enter the background
}
 
-(Void) applicationDidBecomeActive :( UIApplication *) application
{
 
NSLog (@ "--- applicationDidBecomeActive ----");
// Enter the front-end
 

}

-(Void) applicationDidEnterBackground :( UIApplication *) application
{
Log4info (@ "--- applicationDidEnterBackground ----");
// Enter the background
}

-(Void) applicationDidBecomeActive :( UIApplication *) application
{

NSLog (@ "--- applicationDidBecomeActive ----");
// Enter the front-end

}

 

 

But how can I monitor a single UIViewController?

In the-viewDidLoad method, add the code to listen to notification

[Cpp]
[[Nsicationcenter center defacenter center] addObserver: self
Selector: @ selector (someMethod :)
Name: UIApplicationDidBecomeActiveNotification object: nil];

[[Nsicationcenter center defacenter center] addObserver: self
Selector: @ selector (someMethod :)
Name: UIApplicationDidBecomeActiveNotification object: nil];
Don't forget to remove the listener in-dealloc:

[Cpp]
[[Nsicationcenter center defacenter center] removeObserver: self];

[[Nsicationcenter center defacenter center] removeObserver: self];