I'm trying to observe a property of my AppDelegate in order to update a tableview. It's a little complicated, so here's some of my code.
I want to update the content of a UITableView whenever an array is updated. I feel like there's a more efficient way to do this but can't seem to figure it out. I've read through Apple's documentation online and am kinda confused. Thanks ahead of time!! :)
//Game.h
@interface Game: NSObject
@property (strong,nonatomic) NSMutableArray *myArray;
@end
//AppDelegate.h
#import "Game.h"
@interface AppDelegate : UIResponder <UIApplicationDelegate>
@property (strong,nonatomic) Game *myGame;
@end
//ViewController.m
#import "AppDelegate.h"
@implementation ViewController
//...
- (void)viewDidLoad
{
[(AppDelegate*)[[UIApplication sharedApplication] delegate] addObserver:self forKeyPath:@"myGame" options:0 context:nil];
}
- (void)observeValueForKeyPath:(NSString *)keyPath ofObject:(id)object change:(NSDictionary *)change context:(void *)context
{
//THIS METHOD NEVER GETS CALLED
NSLog(@"change observed");
[self.tableView reloadData];
}
- (void)dealloc
{
[(AppDelegate*)[[UIApplication sharedApplication] delegate] removeObserver:self forKeyPath:@"myGame"];
}
//...
@end
UPDATE:
I would encourage you to make the view controller subscribe to the notification in the setter of the data model. It will conveniently keep subscriptions-unsubscriptions in one place:
- (void)setDataModel:(YourDataModelClass*)dataModel
{
[_dataModel removeObserver:self forKeyPath:@"myGame" context:nil];
_dataModel = dataModel; // I hope you use ARC, otherwise check if the pointers are different.
if (_dataModel != nil)
[_dataModel addObserver:self forKeyPath:@"myGame" options:0 context:nil];
}
- (void)dataModelDidUpdate
{
[self.tableView reloadData];
}
- (void)dealloc
{
self.dataModel = nil; //An easy way to unsubscribe
}
The owner of the view controller is responsible to set the proper data model on creation and when it changes.