Question

Im new to Obj-C, and I have a class, with a variable of a class in it, and I have a function not in a class that I need to call a function of the variable of the first one from, when the first class calls the function. Thats written all wrong, but I dont know the right words so:

Root.h:

@interface Root {
    UITableView *tableview;
}
@property (nonatomic,retain) UITableView *tableview;
@end

I have a function(Root is a delagate, so it gets called, and calls another function, not in any class or anything:

void Search()
{
    //here I need to call a function, I dont know how.  If I was in Root.m, it would be
    //[self.tableview reloadData];

But here I dont know how to call it, ive tried passing Search a pointer to a function in Root.m that calls the function:

-(void) update {
    [self.tableview reloadData];
}
-(void) anotherFunction {
    Search(update);

or

    Search(self.update);

etc
but it always errors there, I also tried passing a pointer (self) to Search, and calling

[pointer.tableview reloadData];

but that errors when I run it:

unrecognized selector sent to instance 0x3detc

How Do I do it?

(sorry if this was very confusing)

Answer 1

So let me get this straight: you have a class Root and an instance of that class myRoot. In the class, there two functions -update and -anotherFunction. You also have a C function search(). When in -anotherFunction, you want to call search() and, from there, call back to -update in the original instance of root.

If that is all correct, let’s pretend you got into -anotherFunction by calling [myRoot anotherFunction];. We’ll also assume that everything is in the same file or that all files have been #imported or #included correctly.

You need to define search() as void search(id callback). In -anotherFunction call search() like this: search(self). Then, in search(), you can call [callback update]; to call -update from the class instance where you were originally executing -anotherFunction.

I think that answers your question. Please don’t hesitate to ask for clarifications.