1.1 What is the plug-in？

      A game center, such as Lianzhong in China, supports hundreds of games such as Chess, Bridges, and Texas hold 'em poker. The game platform is made of all games which have hundreds of megabytes. It takes a long time to download them all, but users tend to play only one or two of them. It is improper for users to download hundreds of games that they do not play.

      In addition, any game update or release requires re-downloading hundreds of megabytes of installation packages, which is also a maddening event for users.

      Therefore, the game platform usually adopts plug-in technology.

      The common practice is to allow users to download only installation package with a dozen of megabyte, which includes the game center and the most popular games, such as Texas Hold 'em Poker. Users enter the game center, and get the game list, click on item named "Chess" to download Chess game plug-in, it is called "on-demand download".

      This is plug-in programming, and based on the game platform for the personal computer, such plug-in is an executable file with extension file name as ".exe" or ".dll".

      In the Android world, there is no such file as exe or dll. All files are compressed into an apk file and downloaded locally. App installation process of Android platform, in fact, just put the apk file into a local directory, then, use PMS to read the permission information and the information of four major components. So plug-in programming in the Android is not the same as that of software application on a computer.

      In fact, for the game in the Android world, the usage of the plug-in technology is not a real plug-in framework, it is just the dynamic delivery of the script from the server, according to the information in the script, modify the character attributes, add props and maps of the game.

      Android plug-in technology, mainly used in news, e-commerce, reading, traveling, video, music and other applications. For example, a traveling App, it involves the order and payment, and can be regarded as a branch of e-commerce, it can be split into independent plug-ins such as hotels, air tickets and train tickets, etc.