Check if Bool Value Changed - ios

Question

I want to hide my button in my Popover class, whenever my bool value in the other class is false, but the Problem is i don't get the "TRUE" value.
My First Class
-(void) hideButton{
finished = _secondVC.finished;
BOOL isRunning = !finished;
if(isRunning){
_deleteButton.hidden = YES;
}else if(finished){
_deleteButton.hidden = NO;
}
}
I call the method of hideButton in my ViewWillAppear function.
My Second Class
-(void) someAction{
if(something){
self.finished = YES;
}
EDIT:
Now, if i load the Popover and the NSNotification gets fired the button is enabled, but the Problem is, if i close and open the popover, my delete button is still disabled.
My PopOver Class
- (void)viewWillAppear:(BOOL)animated {
[super viewWillAppear:animated];
if(syncFinished){
_deleteButton.enabled = YES;
}else if(!syncFinished){
_deleteButton.enabled = NO;
}
}
- (void)viewDidLoad {
[super viewDidLoad];
[[NSNotificationCenter defaultCenter] addObserver:self
selector:#selector(showButton)
name:#"syncFinish"
object:nil];
}
- (void) showButton{
syncFinished = YES;
_deleteButton.enabled = YES;
}
My Second Class
-(void) someAction{
if(something){
[[NSNotificationCenter defaultCenter] postNotificationName:#"syncFinish"
object:self];
}

Answer 1

you can't directly observe the value.
you could send a NSNotification when the action starts/finishes and observe for that in your first class to show/hide the button.

Answer 2

I solved This Problem with the NSUserDefaults. so I can set the bool if someAction is happening. And in every other class i can read the bool.
so in my Second Class:
-(void) someAction{
if(something){
[[NSUserDefaults standardUserDefaults] setBool:YES forKey:#"syncFinish"];
} else {
[[NSUserDefaults standardUserDefaults] setBool:NO forKey:#"syncFinish"];
}
In My Popover Class i say
- (void)viewWillAppear:(BOOL)animated {
[super viewWillAppear:animated];
if(![[NSUserDefaults standardUserDefaults] boolForKey:#"syncFinish"]) {
_deleteButton.enabled = NO;
} else {
_deleteButton.enabled = YES;
}
}