Calling a function in another class that is not the App delegate nor a sngl

Question

Hi all-
OK- I have searched and read and searched, however I cannot figure out an easy way to call a function in another class if that class is not the app delegate (I have that down) nor a singleton (done that also- but too much code)
If you use the method Rick posted:
MainView *myMainView = [[MainView alloc] init];
[MyMainView goTell];
That works, however myMainView is a second instance of the class MainView- I want to talk to the instance/Class already instantiated.
Is there a way to do that without making the class a singleton?
Thanks!

Answer 1

I had some trouble wrapping my head around this stuff at first too.
I've gotten pretty good at letting my objects communicate with one another, however I don't think my method is the most efficient or organized way but I'll try to explain the basic idea.
When you want a class to be able to talk to another class that's initialized elsewhere, the class your making should just have a pointer in it to the class you want to communicate with. Then at some point (during your init function for example) you should set the pointer to the class you're trying to message.
for example in the app-delegate assume you have an instance of a MainView class
and the app-delegate also makes an instance of a class called WorkClass
If you want WorkClass to know about MainView just give it a pointer of MainView and set it when it's instantiated.
So WorkClass might be defined something like this
//WorkClass.h
@import "MainView.h"
@interface WorkClass : NSObject
MainView *myPointerToTheMainView;
@property (retain) myPointerToTheMainView;
-(void)tellMainViewHello;
@end
//WorkClass.m
@import "WorkClass.h"
@implementation WorkClass
@synthesize myPointerToTheMainView;//this makes getter and setter functions for
//the pointer and allows us to use the dot
//syntax to refrence it.
-(void)tellMainViewHello
[myPointerToTheMainView hello]; //sends a message to the main view
//assume the class MainView has defined a
//method -(void)hello
@end
now somewhere in the app delegate you would make the WorkClass instance and pass it a reference to the MainView class so that WorkClass would be able to call it's say hello method, and have the method go where you want (to the single instance of MainView owned by the app-delegate)
ex:
//somewhere in app-delegate's initialization
//assume MainView *theMainView exists and is instantiated.
WorkClass *myWorkClass = [[WorkClass alloc] init];
myWorkClass.myPointerToTheMainView = theMainView; //now myWorkClass can speak with
// the main view through it's
// reference to it
I hope that gets the basic idea across.
I'm pretty new to Obj-c myself so if I made any mistakes or if anyone has a better way to go about this please feel free to add
Message was edited by: kodafox