Question

I have an object Person and a protocol PersonDelegate
Person has a @property (assign) id<PersonDelegate> delegate;

somewhere in my code I do:

Person *newPerson = [[Person alloc] init]; 
newPerson.delegate = theDelegate;  
...  
[theDelegate release]; // and dealloc

...

now Person has some new information for the delegate, so I call in Person
[self.delegate doSomething];

But then I’m getting EXC_BAD_ACCESS

Is this because the delegate was already dealloc? How can Person know that his delegate is dealloc?

Answer 1

Your delegate property is not set to retain so it will go bad as soon as you do [theDelegate release];

Normally a delegate is set to assign though to avoid a circular reference. But in that case the delegate itself is normally already keeping a reference to the object it is delegated from.

ie.

Person *newPerson = [[Person alloc] init]; 
[self.people addObject:newPerson];
newPerson.delegate = self;
[newPerson release];

So self.people is retaining all the persons which are created and those persons all point back to self as their delegate