Delegate and IBAction

Question

They seem to accomplish the same thing in Objective C. What can one do without the other?

score 3 · Accepted Answer · answered Apr 25 '11 at 08:26

3

For example:

Delegate methods can have return values.
There can be multiple targets for the same action, but usually only one delegate.
The target-action mechanism is (semantically, not strictly) bound to predefined control events such as "value changed", "touch up", etc. Delegate methods can be anything.
Delegate methods can have arbitrary arguments. Action methods always have the same arguments (sender and event, both optional).

answered Apr 25 '11 at 08:26

Ole Begemann

Then why need IBAction at all? Why not always use delegate, like VB.net? Hmm... vb.net sort of only have IBAction isn't it? – user4951 Apr 25 '11 at 14:44
It's not a question of "need", it's a question of semantics. The target-action pattern fits better for predefined events (as mentioned above); the delegate pattern fits better for more complex relationships. – Ole Begemann Apr 25 '11 at 14:47

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