Simple understanding of cocoa Delegation

When we need the help of others, we usually say that entrusting you to do something for me is here we are the delegate. The person who serves you is called the delegate ), in cocoa, the delegate is called the object of the publish delegate, and the delegate is called the delegate object (for short, the delegate object). After the publish delegate object receives the message, instead of processing the message, the message is forwarded to the delegate object for message processing. Therefore, the delegate is generally the observer who publishes the notification sent by the delegate object and serves as the observer, always prepare to receive and process messages from the delegate. Weak reference of the delegate held by the publish delegate object'

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