Over adapter mode

Problem scenario ：1、 I bought the Japanese version iPhone Telecom cards cannot be used in China , There was no signal , At this time, I need a card sticker , Card stickers are similar adapters that we are going to talk about today 2、 On the client side , A certain interface is displayed in red , And red is a binary value returned by the server , One day the server developer changed , He changed the binary value into 255 Bit rgb The number , Or some day it is changed into other forms , At this time, the idea of using adapter mode can better solve the problem .

The adapter pattern is generally divided into three roles ： Adapter     Adaptee     agreement

Adapter ： An object of active adaptation

Adaptee ： An adapted object

agreement ： To implement a set of behavioral agreements （iOS It usually appears in the form of agency agreement ）

Process definition ： The adapter executes a set of behavioral protocols , To solve the problems caused by compatibility

There are two adapter modes ： Class adapter and object adapter （iOS Medium class adapters are used more ）

The class adapter ： The adapter inherits the Adaptee , The adapter executes a set of behavioral protocols , Adapters and adaptees ​​ The mate belongs to the inheritance relationship

Object adapter ： The adapter applies the Adaptee through Association , The adapter executes a set of behavioral protocols , Adapters and adaptees ​​ The partner belongs to the relationship

Use different scenarios ： When the Adaptee is many subclasses of a class , Using object adapters is more appropriate .

Be careful ： Any design pattern adds files to the added code , In the process of actual use, it must be used according to the specific situation , Blindly pursuing design patterns is just asking for trouble , such as ： If you have a project , It is only the modification of a field returned by the server , You can make judgments in the method of obtaining this field. Generally speaking , Large enough projects should focus on the convenience brought by design patterns , Easy ： maintain , test , modify .