Programmer Group

5. Structural mode Structural pattern describes how to form a larger structure of columns or objects according to a certain layout. It is divided into class structure pattern and object structure pattern. The former uses inheritance mechanism to organize interfaces and classes, and the latter uses composition or aggregation to combine objects. ...

Visitor mode brief introduction The purpose of visitor pattern is to encapsulate some operations imposed on some data structure element. Once these operations need to be modified, the data structure that accepts the operation can remain unchanged. Intent: mainly separate data structure from data operation. It mainly solves the problems of s ...

If A class wants to call the method of another class, for example, A wants to call the method of B. Method 1: Reference The simplest way is that A holds A reference to class B, that is, A has A member object of B. Mode 2: design mode (intermediary mode) Or a and B belong to the same Object C and call each other through Object C (mediator mode), ...

This article is excerpted from "design patterns should be learned this way"1 definition of specification modeSpecification Pattern can be considered as an extension of composite pattern. Many times, some conditions in the program determine the business logic. These conditions can be extracted and combined in a certain relationship (an ...

This article is excerpted from "design patterns should be learned this way"1. Application scenario of intermediary modeIn real life, the existence of intermediaries is indispensable. Without intermediaries, we can't communicate with distant friends. Each colleague object will reference each other. If each object interacts with multipl ...

Strategy mode brief introduction The policy pattern is the packaging of the algorithm. It separates the responsibility of using the algorithm from the algorithm itself and delegates it to different objects for management. Policy patterns usually package a series of algorithms into a series of policy classes as subclasses of an abstract policy ...

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Here, we can learn: 1. Compose is a declarative UI, not a traditional command UI. Instead of holding View to setXXX(), it uses functions to describe a UI state. 2. Compose adopts the idea of attribute refinement and behavior isolation. For example, in the demo, text is the direct attribute of text, and background is an attribute of modifier. ...

This article is excerpted from "design patterns should be learned this way" 1. Scenario of KPI assessment using visitor mode At the end of each year, the management will begin to evaluate the work performance of employees for one year. Employees are divided into engineers and managers; The management includes CEO and CTO. CTO pays at ...

Recommended by Haowen: Author: Ricardo mjiang preface At the end of July this year, Google officially released the 1.0 stable version of Jetpack Compose, which shows that Google believes that Compose can be used in the production environment. I believe that the wide application of Compose is in the near future. Now should be a better time t ...