iosiphoneobjective-cswizzling

How to swizzle a class method on iOS?


Method swizzling works great for instance methods. Now, I need to swizzle a class method. Any idea how to do it?

Tried this but it doesn't work:

void SwizzleClassMethod(Class c, SEL orig, SEL new) {

Method origMethod = class_getClassMethod(c, orig);
Method newMethod = class_getClassMethod(c, new);

if(class_addMethod(c, orig, method_getImplementation(newMethod), method_getTypeEncoding(newMethod)))
    class_replaceMethod(c, new, method_getImplementation(origMethod), method_getTypeEncoding(origMethod));
else
    method_exchangeImplementations(origMethod, newMethod);
}

Solution

  • Turns out, I wasn't far away. This implementation works for me:

    void SwizzleClassMethod(Class c, SEL orig, SEL new) {
    
        Method origMethod = class_getClassMethod(c, orig);
        Method newMethod = class_getClassMethod(c, new);
    
        c = object_getClass((id)c);
    
        if(class_addMethod(c, orig, method_getImplementation(newMethod), method_getTypeEncoding(newMethod)))
            class_replaceMethod(c, new, method_getImplementation(origMethod), method_getTypeEncoding(origMethod));
        else
            method_exchangeImplementations(origMethod, newMethod);
    }