IOS delegate proxy mode observer mode communication between different views

delegate, ubiquitous in iOS, nsurlconnection (network requests have), TableView, Connectionview, and other systems comes with common agents. Even, when they write code, randomly beat out the protocol, according to demand, came out a delegate. In fact, it is the specific application of the observer pattern. Basic observer. The same idea is to create an abstract method that is implemented in a specific view controller. The most common practice is to create a singleton pattern, then invoke the object, set the proxy object, and write the specific implementation.

Nsnotification notification Signal Although can achieve the same effect, to achieve different views of the communication between the actual situation or to see business logic needs, for example, change the theme background color, it is best to nsnotification to achieve. (Refer to 4, 5 network source code is to do so).

Well, look at the source code more every day, not behind closed doors.

IOS delegate proxy mode observer mode communication between different views