iOS Accessing views data from delegate without allocating a new view - iphone

Question

I need to change a data (a label) from the app's delegate method ApplicationDidEnterForeground without allocating a new view. The view is called "Reminder", so I imported it into the delegate and I can access its data only if I allocate it (Reminder *anything = [Reminder alloc...etc), but since I want to change the current view loaded I need to have direct access to the view that's already loaded.
How would I do to change the main view's label from the delegate as soon as my application enters foreground?
obs: I know I can do it on -(void)ViewDidLoad or -(void)ViewWillAppear but it won't solve my problem, since it won't change the label if, for example, the user opens the app through a notification box (slide icon when phone is locked). In that case, none of the above methods are called if the app was open in background.
I don't know if I was clear, hope I was. Thank you in advance.

Answer 1

IF you are using storyboards, you can do this to access the current view being seen
- (void)applicationDidEnterBackground:(UIApplication *)application
{
UINavigationController *a=_window.rootViewController;
Reminder *rem = a.topViewController;
rem.label.text=#"test";
}
IF not using story boards
When I create views that I need to access later, I define them as a property, like this
on AppDelegate.h
//#interface SIMCAppDelegate : UIResponder <..........>
//{
//Some variables here
//}
//Properties here
#property (strong, nonatomic) Reminder *reminder;
//Some method declaration here
//eg: -(void) showSomething;
on AppDelegate.m
//#implementation AppDelegate
#synthesize reminder;
so when I alloc/init the view like this
- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions
{
//codes before here
self.reminder = [[Reminder alloc] init];
self.reminder.label.text = #"OLD LABEL";
//codes after here
}
I will be able to access it again after allocation on other methods, like this
- (void)applicationWillEnterForeground:(UIApplication *)application
{
self.reminder.label.text = #"NEW LABEL";
}

Answer 2

just send a notification from your ApplicationDidEnterForeground: method and receive it on that class where you want to update the label... Like this..
//Your ApplicationDidEnterForeground:
[[NSNotificationCenter defaultCenter] postNotificationWithName:#"UpdateLabel" withObject:nill];
and add observer in it viewDidLoad: of that controller where you want to update label
[[NSNotificationCenter defaultCenter] addObserver:self
selector:#selector(updateLabel:)
name:#"UpdateLabel"
object:nil];
made your method in same class ...
- (void)updateLabel:(NSNotification *)notification{
update label
}

Answer 3

Might be you can try following code -
NSMutableArray *activeControllerArray = [self.navigationController.viewControllers mutableCopy];
for (int i = 0; i< [activeControllerArray count]; i++) {
if ([[activeControllerArray objectAtIndex:i] isKindOfClass:[Reminder Class]) {
Reminder *object = [activeControllerArray objectAtIndex:i];
//Perform all the task here which you want.
break; //Once found break the loop to do further processing.
}
}