How do you get and set a class property across multiple functions in Objective-C?
- by editor
Following up on this question about sharing objects between classes, I now need to figure out how to share the objects across various functions in a class.
First, the setup: In my App Delegate I load menu information from JSON into a NSMutableDictionary and message that through to a view controller using a function called initWithData. I need to use this dictionary to populate a new Table View, which has methods like numberOfRowsInSection and cellForRowAtIndexPath.
I'd like to use the dictionary count to return numberOfRowsInSection and info in the dictionary to populate each cell. Unfortunately, my code never gets beyond the init stage and the dictionary is empty so numberOfRowsInSection always returns zero.
I thought I could create a class property, synthesize it and then set it. But it doesn't seem to want to retain the property's value. What am I doing wrong here?
In the header .h:
@interface FirstViewController:UIViewController <UITableViewDataSource, UITableViewDelegate, UITabBarControllerDelegate> {
NSMutableDictionary *sectorDictionary;
NSInteger sectorCount;
}
@property (nonatomic, retain) NSMutableDictionary *sectorDictionary;
- (id)initWithData:(NSMutableDictionary*)data;
@end
in the implementation .m:
- (id) testFunction:(NSMutableDictionary*)dictionary {
NSLog(@"Count #1: %d", [dictionary count]);
return nil;
}
- (id)initWithData:(NSMutableDictionary *)data {
if (!(self=[super init])) {
return nil;
}
[self testFunction:data];
// this is where I'd like to set a retained property
self.sectorDictionary = data;
return nil;
}
- (NSInteger)tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)section {
NSLog(@"Count #2: %d", [self.sectorDictionary count]);
return [self.sectorDictionary count];
}
Output from NSLog:
2010-05-04 23:00:06.255 JSONApp[15890:207] Count #1: 9
2010-05-04 23:00:06.259 JSONApp[15890:207] Count #2: 0
