iOS Is it right way to use Category?

[mikezang]

I am not sure if I can post this question here because it is about Objective-C.

I start to use Category for my special purpose, but I found many time I used '+' class, for example, I want to parse specific Table from HTML, I made a Category for that as below.

#import "Element.h"

@interface Element (ParseTables) 
+ (NSArray *)parseHtml:(NSString *)html forTable:(int)table;
@end

In fact, it doesn't return a Element or array of Element, it returns of array of NSString, I want to know if this is a right way to use Category, or it is better to let it as a standalone function?:

NSArray *parseHtml(NSString *html, int table);

 

[Comrade Yeti]

My personal opinion and style is that if the function has nothing to do with the class, it should not be in the class. It increases the likelyhood that when I look at it months later, I'll understand what it was doing.

I would make it a plain C function.

If you insist/want to use categories, I would make it a category of NSArray with a helper name like

+(NSArray*)arrayFromHTML:(NSString*)html andTable:(int)table

 

[mikezang]

My personal opinion and style is that if the function has nothing to do with the class, it should not be in the class
[/code]

I am still not sure which case I should use Category or not, do you have any samples for easy to understand?

 

[Comrade Yeti]

I am still not sure which case I should use Category or not, do you have any samples for easy to understand?

Use categories when you want to add functionality to existing classes. Its normally used to add functionality to the existing Cocoa classes, as sub-classing them can be a lot of work.