试图创建一个字典(不知道是否应该NSDictionary
或NSMutableDictionary
)从NSString
到一个数组(不知道是否应该NSArray
或NSMutableArray
)。我如何初始化从NSString的字典来的NSArray
属性:
@property(nonatomic, readonly) NSMutableDictionary * categories;
实现:
@synthesize categories = _categories;
- (NSMutableDictionary *)categories{
if(! _categories) {
for(PFObject * each in self.products) {
NSString * currentcategory = [each valueForKey:@"subtitle"];
NSArray * currentlist = [_categories objectForKey:currentcategory];
if(! currentlist) {
currentlist = [[NSArray alloc] init];
}
NSMutableArray * newArray = [currentlist mutableCopy];
[newArray addObject:each];
NSArray * newlist = [NSArray arrayWithArray:newArray];
[_categories setObject:newlist forKey:currentcategory];
}
}
NSLog(@"After constructor the value of the dictionary is %d", [_categories count]);
return _categories;
}
从调试NSLog
我意识到是字典的施工后空。这里出了什么问题,我该如何改变它?
哎呀。谢谢! – Ra1nWarden