Design And Implementation Of Android Multi-window System

As a new intelligent terminal-operating system, the application fields of Android OS have continue to expand. It may installed on the smart phones, smart bracelet or car-based mobile devices. The Android operating system is designed to provide a better experience for end-user to use the smart mobile devices. But devices with a larger size screen become a new trend in the development of smart mobile devices, the single-window display mode of Android operating system is increasingly unable to meet this trend.Android operating system has a hierarchical system architecture, which is followed by the Linux kernel layer, the system runtime layer, the application framework layer and the application layer. To achieve multi-window display mode of Android, the Android application framework layer should be modified and the corresponding applications should be coded. The application framework layer of the Android OS consists of lots of modules,the Binder mechanism provide a way of communication among the modules. The Activity Manager Service module manages the changes of all the Activity's statuses. It manages Activities in different workspaces simultaneously by adding few Activity Stacks. The Window Manager Service module controls the displays of all the windows in the system,by adding new data structures and processes the module manages the windows in different workspaces. Displaying of the application UI interface is the responsibility of the View System module. Users can manage workspaces by the Workspace Manager and the Multi-Window Launcher provides a way to launch the applications.The results of the functional and performance tests show that the implementation of the Android multi-window system has the similar performance and stability in compare with the original Android system.