android design patterns book

Generally speaking, the following eight kinds of design patterns are commonly used: single example, factory, observer, Agent, command, adapter, synthesis, visitor Single case mode: The goal is to have only one calling object in the system, the disadvantage of which is that it makes other programs rely too much on it, and that different single cases run in different processes, making maintenance difficult;

In general, there are 8 common Android design patterns: Singleton, factory, observer, Agent, command, adapter, composition, visitor.Singleton mode: In order to make the system only one call object, the disadvantage is that the singleton makes the other program rely on it excessively, and the different singleton runs in the different process, makes the maintenance

Design Patterns in Android development-a detailed explanation of the singleton pattern:1. Characteristics of the singleton mode:(1). Ensure that there is only one instance of a class(2). Provides a global access point that can be accessed to him.(3). The constructor is declared private, thereby preventing the creation of objects outside the class2. Type:(1). A hu

static function to obtain the singleton Single case using volatile modifiers Using synchronized for synchronous processing, and double-judging whether it is null, we see that synchronized (Singleton.class) is also null-judged, because one thread enters the code, and if another thread waits , when the previous thread has created an instance, and the other thread gets the lock into the synchronization code, the instance already exists and there is no need to create it again, so the decisi

Android and design patterns-Composite mode and androidcomposite Definition(GoF design patterns): combines objects into a tree structure to represent a "partial whole" hierarchy. The combination mode ensures consistency between the use of a single object and a composite obje

Msteeringwheel; public Engine Mengine; public Abstractfactory mfactory; public SMALLSUV () {Mfactory=new SUVFactory2 (); Mtyre=mfactory.createtyre (); Msteeringwheel=mfactory.createsteeringwheel (); Mengine=mfactory.createenginen (); } public void show () {mtyre.roll (); Msteeringwheel.turn (); Mengine.roar (); }}Test classpublicclass Host { publicstaticvoidmain(String[] args) { SmallSUV mSUV=new SmallSUV(); mSUV.show();

-transparency. However, leaves do not have child classes. Therefore, some declared methods are not applicable to leaves. This also brings about some security issues. Another method is to declare all methods used to manage subclass objects in composite. In this way, the security of the previous method is avoided, but because the leaves and branches have different interfaces, the transparency is lost. Design Pattern