Delegate and IBAction

Question

他们似乎在目标C中完成了同样的事情。没有其他人，他们能做什么？

Answer 1

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).