Swift language Essentials-talking about proxy mode (Delegate)

In iOS programming, we often talk about proxy agents, which is delegate, so what is a proxy?

Let's take a look at Cocoa's description of it:

Delegation is Cocoa's term for passing off some responsibilities of a object to another

Name implies:

An agent is the transfer of responsibility from one object to another.

In fact, if you have written a Java or C # program friends should know that we are in the design of the use of the interface and combination, the same truth.

Take a look at the following code:

First, we define a protocol

Protocol Savemediadelegate {    func save ()}

Then, we combine this protocol into our business logic class.

class MyComputer {    delegate : Savemediadelegate?         Func Saveinfo () {    　　//  Check to see if the delegate are there, then call it    DELEGATE? . Save ()    }}　　

Then, we implement different forms of the Protocol

class savetodisk:savemediadelegate {    func save () {        println ("saving to disk ... "     }}}class  savetousb:savemediadelegate {    func save () {        println ("  saving to usb ... " )    }}

Then we inject our protocol implementation class into our business Class (Di-dependency injection)

Let MyComputer =//  does= savetodisk () myComputer. delegate =//  prints "Saving to disk ..."= savetousb () myComputer. delegate =//  prints "Saving to usb ..."

It's simple, it's that simple!

Swift language Essentials-talking about proxy mode (Delegate)