objective c - Multiple methods named "count" found with mismatched result, parameter type or attributes

Question

Since the update to Xcode 5.1 I can't archive my project any more. Xcode always says "Multiple methods named "count" found with mismatched result, parameter type or attributes. This problem is new and simulator and running on device works fine. Here is the code:

    for ( int i = 0; i<[parseJSONArray count];i++){
        for (int j = 0; j<[JSON[@"data"][@"menu"][i][@"item"] count];j++){
            [pictureURL addObject:JSON[@"data"][@"menu"][i][@"item"][j][@"image"]];
        }
    }

Xcode shows the error at this point : [JSON[@"data"][@"menu"][i][@"item"] count] JSON is a NSDictionary. Whats wrong with this?

Answer 1

Ask yourself: What is the type of JSON[@"data"][@"menu"][i][@"item"] ? It is "id". The compiler doesn't know which method this object responds to. You send a "count" message. The compiler goes through all the count methods of all classes that it knows about. If there are more than two different ones, it has to complain.

You could write

NSDictionary* data = JSON [@"data"];
NSArray* menu = data [@"menu"];
NSDictionary* menuI = menu [i];
NSArray* item = menuI [@"item"];

for (NSDictionary* picture in item)
    [pictureURL addObject:picture [@"image"];

More readable, easier to follow, runs faster, and easier to debug.

Of course you can also write

for (NSUInteger j = 0; j < item.count; ++j)
{
    NSDictionary* picture = item [i];
    [pictureURL addObject:picture [@"image"];
}