Android Middleware课件.ppt

Android Middleware Bo Pang Bpang@cc.hut.fi 精品文档 Android System Architecture Source: Google 精品文档 overview Linux Kernel: memory management, process management, networking, and other operating system services. Native Libraries: written in C or C++, including: Surface Manager, 2D and 3D graphics, Media codes, SQL database, Browser engine, etc. only to be called by higher level programs 精品文档 overview Android Runtime: including the Dalvik virtual machine and the core Java libraries. (not J2SE/J2ME) Application Framework: Activity manager, Content providers, Resource manager, Notification manager Applications and Widgets: the real programs display information and interact with users. 精品文档 Media Framework Android use OpenCore as core component of Media framework OpenCore supports MP3, AAC, AAC+, 3GPP, MPEG-4 and JPEG, 精品文档 Media Framework 精品文档 Media Framework Example: ? MediaPlayer mp = new MediaPlayer(); ? mp.setDataSource(PATH_TO_FILE); ?? mp.prepare(); ?? mp.start(); 精品文档 Media Framework OpenCore lib has a C/S Architecture. MediaPlayer invoke JNI to manipulate client. The client request to the server to control hardwares. 精品文档 Media Framework 精品文档 Media Framework 精品文档 Activity Manager each user interface screen is represented by an Activity class. Each activity has its own life cycle. Activity uses Intent object to jump between them. 精品文档 Life cycle of activity Source: Hello Adroid 精品文档 Intent and Intent filters Intent activates activities, services, and broadcast receivers. Intent can be used in explicit way or implicit way. The implicit way depends on parameters: Action, Data(url and MIME type) , Category 精品文档 Intent and Intent filters To receive other components request, components’ need to register filters at activities framework. When launch a intent object, framework will match and find the qualified components and leave them for users to choose which to run. 精品文档 Intent and Intent filters Example intent-filter? ? ? ? ? ? ? ? action android:n