Using a Data Management Singleton
- by Dan Ray
Here's my singleton code (pretty much boilerplate):
@interface DataManager : NSObject {
NSMutableArray *eventList;
}
@property (nonatomic, retain) NSMutableArray *eventList;
+(DataManager*)sharedDataManager;
@end
And then the .m:
#import "DataManager.h"
static DataManager *singletonDataManager = nil;
@implementation DataManager
@synthesize eventList;
+(DataManager*)sharedDataManager {
@synchronized(self) {
if (!singletonDataManager) {
singletonDataManager = [[DataManager alloc] init];
}
}
NSLog(@"Pulling a copy of shared manager.");
return singletonDataManager;
}
So then in my AppDelegate, I load some stuff before launching my first view:
NSMutableArray *eventList = [DataManager sharedDataManager].eventList;
....
NSLog(@"Adding event %@ to eventList", event.title);
[eventList addObject:event];
NSLog(@"eventList now has %d members", [eventList count]);
[event release];
As you can see, I've peppered the code with NSLog love notes to myself. The output to the Log reads like:
2010-05-10 09:08:53.355 MyApp[2037:207] Adding event Woofstock Music Festival to eventList
2010-05-10 09:08:53.355 MyApp[2037:207] eventList now has 0 members
2010-05-10 09:08:53.411 MyApp[2037:207] Adding event Test Event for Staging to eventList
2010-05-10 09:08:53.411 MyApp[2037:207] eventList now has 0 members
2010-05-10 09:08:53.467 MyApp[2037:207] Adding event Montgomery Event to eventList
2010-05-10 09:08:53.467 MyApp[2037:207] eventList now has 0 members
2010-05-10 09:08:53.524 MyApp[2037:207] Adding event Alamance County Event For June to eventList
2010-05-10 09:08:53.524 MyApp[2037:207] eventList now has 0 members
... What gives? I have no errors getting to my eventList NSMutableArray. But I addObject: fails silently?
