Objective C - delegation question?

Question

I need to create a class that gets a delegate does some calculation and then calls the delegate.

• Where am i suppose to release the object I allocated?
• Is it possible to init the MyClass object without allocating it, so that way I don't have to release it.

• What is the best practice to do such a thing? (I am trying to create a web service class which reads data, and as soon as it's done it sends back the data to the delegate and it destroys itself)?

  -(void)viewDidLoad { MyClass *class = [[MyClass alloc] initWithDelegate:self]; }

  -(void) MyClassRespond :(NSData*)data { //use data and populate on screen }

Answer 1

The class can't destroy itself, and you can't init a class object without allocating it (one of the issues being where exactly do the fields get stored without some stuff.

I am not sure why it needs to destroy itself, but the usual method to do this would be to have a variable of type MyClass* _class in the class with the viewDidLoad method. You would then do the equivalent of

-(void)viewDidLoad { _class = [[MyClass alloc] initWithDelegate:self]; }

-(void) MyClassRespond :(NSData*)data { 
      [_class release];
      //use data and populate on screen }

You could of course also do something where you pass MyClass back to the delegate method, so something like

-(void)viewDidLoad {MyClass *class = [[MyClass alloc] initWithDelegate:self]; }

-(void) MyClassRespond :(NSData*)data fromClass: (MyClass*)class { 
      [class release];
      //use data and populate on screen }

In this case your delegate would call MyClassResponds as

[delegate MyClassRespond:data fromClass:self];

It might also make sense to try and make MyClass reusable so you don't need to dispose it quite as quickly, but I understand there are cases where this doesn't work.