Android Handheld Systems
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The document outlines the Android platform, discussing its multi-layered software stack for mobile applications, including the OS kernel, system libraries, and application frameworks. It describes the Android SDK, core components like the Dalvik virtual machine, and key functionalities such as the package and window managers. Additionally, it highlights the Android development environment, focusing on its emulation capabilities and limitations.
Android Handheld Systems
- 4. A multi-layered software stack for building and running mobile applications
- 5. A software stack for mobile devices: OS kernel, system libraries, application frameworks & key apps. Android Software Development Kit (SDK) for creating apps. Libraries & development tools.
- 8. Security Memory & process management File & network I/O Device drivers
- 9. Power management Android shared memory Low memory killer Inter process communication And much more
- 10. System C library ->Bionic libc Surface Mgr. ->Display management Media Framework ->Audio/ Video Webkit ->browser engine OpenGL ->Graphics engines SQLite ->Relational ->database engine
- 11. Two main components -> Core Java libraries -> Dalvik Virtual Machine
- 12. basic java classes -- java.*, javax.* app lifecycle -- android.* Internet/Web services -- org. * Unit testing -- junit.*
- 13. App written in java compiled to Java byte code files. DX converts java byte code files to a single dex byte code file (CLASSES.DEX). Dalvik executes DEX byte code file.
- 14. Designed for resource-constrained environments <>Slower CPU <>Less RAM <>Limited battery life
- 15. PACKAGE MANAGER Keeps track of App Packages on Device. WINDOW MANAGER Manages the Windows comprising an App.
- 18. Provides common user interface Elements. e.g., icons, text entry boxes, buttons and more.
- 19. Manages non- compiled resources, e.g. Strings, Graphics, and Layout files. ACTIVITY MANAGER Manages App Lifecycle and Navigation Stack.
- 20. Inter Application Data Sharing. LOCATION MANAGER Provides Location and Movement Information. NOTIFICATION MANAGER Place Notification Icons in the Status Bar when important events occur.
- 21. Notification
- 22. Standard apps include: Home – main screen Contacts – contacts database Phone – dial phone numbers Browser – view web pages Email reader –compose & read email messages.
- 24. Your workbench for writing Android applications
- 27. Runs virtual devices Can emulate many different device/ user characteristics, such as: Network speed/ latencies, Battery power, Location coordinates. Emulate incoming phone calls & SMS messages Can interconnect multiple emulators
- 29. Doesn’t require an actual phone Hardware is reconfigurable Changes are non-destructive
- 30. Can be very slow Some features unavailable e.g., no support for blue tooth or USB connections Performance / user experience can be misleading