Question

I have an interface that allows users to select a type of childObject. These objects all inherit from the same parentObject. Is there a way to dynamically generate this list of childObjects given a parentObject? Currently, when I create a new child, I then have to add it to the TVC’s list of children to display.

Edit:
Here’s an example:

Class A (child of NSObject)
->Class A1 (child of Class A)
->Class A2 (child of Class A)

I’d like to ask Class A: “What are your children?”

Answer 1

You can use reflection:

// find out the superclass of a class or object
Class parent = [[theObject class] superclass];

// get all classes loaded
unsigned n_classes = objc_getClassList(NULL, 0);
Class *classes;
classes = malloc(sizeof(*classes) * n_classes);
objc_getClassList(classes, n_classes);

// Filter the classes so that only child classes of the
// particular parent class are present
NSMutableArray *children = [NSMutableArray array];
int i;
for (i = 0; i < n_classes; i++) {
    if ([classes[i] isKindOfClass:parent]) {
        [children addObject:classes[i]]; // Yes, classes temselves are objects
    }
}

free(classes);

Here ‘children’ will contain the descandants of parent.