Android源码中所使用到的设计模式design patterns

最新推荐文章于 2025-02-10 18:50:48 发布

stefzeus

最新推荐文章于 2025-02-10 18:50:48 发布

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文章标签： android 设计模式 decorator behavior object string

本文链接：https://blog.youkuaiyun.com/stefzeus/article/details/7503749

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这篇博客探讨了Android源码中使用的设计模式，包括接口和抽象类、MVC架构、MVVM、组合模式、装饰模式、观察者模式以及工厂方法。文中详细解释了这些模式如何在Android系统中实现，例如，ViewGroup和View利用了组合模式，BroadcastReceiver体现了观察者模式，而工厂方法在创建对象时提供了灵活性。

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一、接口和抽线类

(1)抽象类abstract class

Object

Context

ContextWapper(抽象类)

| | |

Service Activity .......

(2)接口interface

public class Activity extends ContextThemeWrapper implements LayoutInflater.Factory, Window.Callback, KeyEvent.Callback, OnCreateContextMenuListener, ComponentCallbacks { ... }

区别: （未写）

关键字：层次，方法集，多继承

二、MVC

You define your user interface in various XML files by resolution/hardware etc.
You define your resources in various XML files by locale etc.
You extend clases like ListActivity, TabActivity and make use of the XML file by inflaters
You can create as many classes as you wish for your model
A lot of Utils have been already written for you. DatabaseUtils, Html

Model:data

View:UI

Cotrollor:logic

三、MVVM

四、组合模式Composite

Android 的ViewGroup 和View就是用了组合模式。

import java.util.List; import java.util.ArrayList; /** "Component" */ interface Graphic { //Prints the graphic. public void print(); } /** "Composite" */ class CompositeGraphic implements Graphic { //Collection of child graphics. private List<graphic> mChildGraphics = new ArrayList<graphic>(); //Prints the graphic. public void print() { for (Graphic graphic : mChildGraphics) { graphic.print(); } } //Adds the graphic to the composition. public void add(Graphic graphic) { mChildGraphics.add(graphic); } //Removes the graphic from the composition. public void remove(Graphic graphic) { mChildGraphics.remove(graphic); } } /** "Leaf" */ class Ellipse implements Graphic { //Prints the graphic. public void print() { System.out.println("Ellipse"); } } /** Client */ public class Program { public static void main(String[] args) { //Initialize four ellipses Ellipse ellipse1 = new Ellipse(); Ellipse ellipse2 = new Ellipse(); Ellipse ellipse3 = new Ellipse(); Ellipse ellipse4 = new Ellipse(); //Initialize three composite graphics CompositeGraphic graphic = new CompositeGraphic(); CompositeGraphic graphic1 = new CompositeGraphic(); CompositeGraphic graphic2 = new CompositeGraphic(); //Composes the graphics graphic1.add(ellipse1); graphic1.add(ellipse2); graphic1.add(ellipse3); graphic2.add(ellipse4); graphic.add(graphic1); graphic.add(graphic2); //Prints the complete graphic (four times the string "Ellipse"). graphic.print(); } } </graphic></graphic>

四、Decorator 装饰模式