Question

If you have a class object is there a way to use it to call class methods of that class. For example, if you have class A with method + (void)foo defined how can you achieve something like the example below without the compiler warning that it can’t find the method foo:

A* object = [[A alloc] init];
id objectClass = [object class];
[objectClass foo]; // complains that the method is not found

Answer 1

Creating a class method in your .h:

MyClass.h

@interface MyClass : NSObject {    
}
+(void) test;

@end

MyClass.m

@implementation MyClass

-(id) init
{
    self = [super init];

    return self;
}

+(void) test
{
    NSLog(@"Test executed");
}

@end

You can then just call it like this:

MyClass* myClass = [[[MyClass alloc] init] autorelease];

[[myClass class] test];

Edit:

If the problem is the compiler warning, just create a @protocol that defines the foo method you want to call.
Instead of calling:

id objectClass = [object class]; 

Try this;

id<MyProtocol> myCastedObject = (id<MyProtocol>)object;
[myCastedObject class] foo];