I have an application, and this application open an url in Safari. But if the user tap on the top left button to return to my app how can i catch this event?
For this case, the solution is to view controller register for the UIApplicationWillEnterForegroundNotification notification. When this notification is sent, you can do the stuff needed.
[[NSNotificationCenter defaultCenter] addObserver:self selector:#selector(doSomeStuff) name:UIApplicationWillEnterForegroundNotification object:nil];
-(void)doSomeStuff
{
//handle what you needed
}
Related
In my app, When I press the home button, I pop the application to rootviewcontroller login class. Now, in the previous class, if any alertview comes and without dismissing it I press home button, Problem appears. Next time I tap on app icon to bring it in fore ground, the login screen is there, but on top of it, previous class alertview is also there. How to remove the alertviews on applicationDidEnterBackground?
Have a global (AppDelegate property or singleton) where you simply store the pointer to the last alert view displayed (and clear it when done). If the pointer is non-nil, dismiss it in DidEnterBackground or wherever.
You can also use UIApplicationWillResignActiveNotification,UIApplicationWillEnterForegroundNotification to solve this issue
[[NSNotificationCenter defaultCenter] addObserver:self
selector:#selector(resignActive)
name:UIApplicationWillResignActiveNotification
object:nil];
[[NSNotificationCenter defaultCenter] addObserver:self
selector:#selector(enterForeground)
name:UIApplicationWillEnterForegroundNotification
object:nil];
In resignActive method you can remove the alertviews...
In my applicationWillEnterForeground, I check and send a notification if data refresh is necessary:
[[NSNotificationCenter defaultCenter] postNotificationName:#"refreshModelNotification" object:nil];
The only observer for that particular notification is a particular view controller:
[[NSNotificationCenter defaultCenter] addObserver:self selector:#selector(refreshData:) name:#"refreshModelNotification" object:nil];
That view controller is one of several inside a UITabBarController.
My question is: what happens if that view controller isn't the active tab when the notification is sent?
Thanks in advance.
If the observer is still set for the view controller the view controller will still receive the notification and behave normally except any visual changes to the view controller's view will not be seen
I have a split view based app, and would like to listen for some sort of notification for when the root menu is displayed. The reason I want to do this is because the keyboard overlaps the menu, so I would like to hide the keyboard when the menu is displayed.
[[NSNotificationCenter defaultCenter] addObserver:self
selector:#selector(keyboardWillHide:)
name:<Some Notification Here>
object:self.view.window];
I already have the method to hide the keyboard, I'm just looking for the appropriate notification.
Thanks!
you can post the notification yourself from the root menu. Just subclass it and post the notification on viewDidAppear or viewWillAppear.
The word of warning: if you are targeting iOS 5 and up you should kep in mind the viewWillAppear and viewDidAppear are deprecated in iOS6. use
willMoveToParentViewController or didMoveToParentViewController or -(void)viewWillLayoutSubviews
-(void)willMoveToParentViewController:(UIViewController *)parent{
if (!parent)
//post notification here
}
Also, you can provide nil as a notification name and listen to any possible notification, then NSLog it out, perhaps you can find a useful notification there, just make sure it is documented to futureproof your product.
[[NSNotificationCenter defaultCenter] addObserver:self selector:#selector(notificationReceived:) name:nil object:nil];
In applications like Foursquare when I click the Home button the application goes to background. Then when I click on its icon, it loads back the content on the screen.
When I send my app to background and then I recall it back, it doesn't load back the content to the screen. I have entered my code in the viewDidAppear method but it is not executed.
How is it possible to load the application content when it becomes active?
You need to respond to - (void)applicationDidBecomeActive:(UIApplication *)application or - (void)applicationWillEnterForeground:(UIApplication *)application or the equivalent UIApplication notifications. The UIViewController lifecycle calls like viewDidAppear aren't triggered by app lifecycle transitions.
smparkes suggestion is right. You could register for UIApplicationDidBecomeActiveNotification or UIApplicationWillEnterForegroundNotification. These notifications are called after those method (the ones smparkes wrote) are called. In the handler for this notification do what you want. For example in viewDidLoad for your controller register the following notification:
[[NSNotificationCenter defaultCenter] addObserver:self
selector:#selector(doUpdate:)
name:UIApplicationDidBecomeActiveNotification object:nil];
Do not forget to remove in dealloc:
[[NSNotificationCenter defaultCenter] removeObserver:self];
Finally, doUpdate method could be the following
-(void)doUpdate:(NSNotification*)note
{
// do your stuff here...
}
I suggest you to read UIApplicationDelegate class reference. In particular read about Monitoring Application State Changes.
Hope it helps.
Suppose you want to listen to UIApplicationDidBecomeActiveNotification,here is the ObjC code that might help you.
[[NSNotificationCenter defaultCenter] addObserverForName:UIApplicationDidBecomeActiveNotification
object:nil queue:[NSOperationQueue mainQueue] usingBlock:^(NSNotification *note) {
// custom code goes here.
}];
I'm currently showing a dailymotion url directly into a UIWebview.
When tapping on the thumbnail image, the video starts playing in fullscreen mode.
The problem is: when the video stops playing or the user tapps the "done" button, the original thumbnail has disapeared from the UIWebview, making it impossible to launch the video again.
I would like to control when the video has finished playing or the user has tapped the done button to reload the UIWebView.
I've been looking around and playing with the Notification center but I couldn't get any response, can you tell me what code I should use ?
loading the video
NSURLRequest *requestObject = [NSURLRequest requestWithURL:[NSURL URLWithString:#"http://www.dailymotion.com/embed/video/xh7cgv_cine-pocket-a-candidate_creation"]];
[self.webv loadRequest:requestObject];
notification catch
[[NSNotificationCenter defaultCenter] addObserver:self
selector:#selector(moviePlayerDidExitFullscreen:)
name:MPMoviePlayerDidExitFullscreenNotification
object:nil];
[[NSNotificationCenter defaultCenter] addObserver:self
selector:#selector(moviePlayerDidEnterFullscreenNotification:)
name:MPMoviePlayerDidEnterFullscreenNotification
object:nil];
[[NSNotificationCenter defaultCenter] addObserver:self
selector:#selector(playbackDidFinish:)
name:MPMoviePlayerPlaybackDidFinishNotification
object:nil];
thanks,
Louis
corresponding to this thread the MediaPlayer doesn't send out any notifications when started from within the UIWebView (no source given however). you could try these hacks: visible-hidden events hack, timed key window checking-hack, subview events-hack. If you had luck, please share some code!