iphone - iPhone 中 NSMutableArray 的排序

Question

我正在解析 XML 并将所有数据以字典的形式存储在 NSMutableArray 中。

NSMutableArray * stories;   

// a temporary item; added to the "stories" array one at a time,
// and cleared for the next one
NSMutableDictionary * item;

- (void)parser:(NSXMLParser *)parser
 didEndElement:(NSString *)elementName
  namespaceURI:(NSString *)namespaceURI 
 qualifiedName:(NSString *)qName
{       
    if ([elementName isEqualToString:@"item"])
    {
        // save values to an item, then store that item into the array...
        [item setObject:currentTitle forKey:@"title"];
        [item setObject:currentLink forKey:@"link"];
        [item setObject:currentSummary forKey:@"summary"];
        [item setObject:currentDate forKey:@"date"];

        //Numeric value for sorting
        [item setObject:rates forKey:@"rates"];

        [stories addObject:[item copy]];    
    }
}

完成解析后，我需要按数字字段的“费率”对数组进行排序。请提出建议。

Answer 1

假设 rates 键包含 NSNumbers:

NSSortDescriptor *sortDescriptor = [[NSSortDescriptor alloc] initWithKey: @"rates" ascending: YES];
[stories sortUsingDescriptors: [NSArray arrayWithObject: sortDescriptor]];
[sortDescriptor release];

在相关说明中，这行代码存在泄漏:

[stories addObject:[item copy]];

我认为你的意思是这样的:

[stories addObject:[[item copy] autorelease]];