1. Android OS
Kesav Kaliyaperumal

2. Yummy Desserts! Cupcake Donuts Éclair Frozen Yoghurt (Froyo)
Gingerbread
Honeycomb
What do these have in common?

3. Smartphone OS Symbian Windows Mobile RIM Blackberry OS Apple iOS
Google Android
Palm WebOS
Windows Phone 7

4. Android OS Fastest growing mobile OS
Over 300,000 Android activations a day
Android overtook iOS as the dominant OS in US during 2H 2010
First phone launched HTC G1 in 2008
Currently an OS of choice for Motorola, HTC, Samsung, Sony Ericsson, among others
Software updates every few months

5. Android – what is it? software stack for mobile devices
incl. OS, middleware and key applications
Open source – source code is open and contributions are welcome
application framework enabling reuse/replacement of apps
Dalvik virtual machine optimized for mobile
integrated browser based on webkit
Optimized graphics – 2D graphics library, 3D based on OPEN GL ES
SQLite for data storage
Media support (MPEG4, H.264, MP3, AAC, JPG, PNG,…)
Support for radio interfaces, Bluetooth, WiFi, Camera, GPS, accelerometer
Software Development Kit (SDK)
Preinstalled applications from Google (GMS)
Gmail, Maps, Search, Voice Search, Youtube

6. Software Stack Linux kernel Libraries Android run time
core libraries
Dalvik virtual machine
application layer
application protocol

7. Android Architecture

8. Android Google Maps and other GMS applications
Background services and applications
allows multi tasking of applications
Shared Data and interprocess communication
All applications are equal
does not discriminate between native and non-native applications
allows any applications to be enhanced/reused
p2p interdevice application messaging

9. Dalvik VM
All applications written in Java and converted to the dalvik executable .dex
Every android app runs its own process, with its own instance of the dalvik virtual machine
Not a traditional JVM, but a custom VM designed to run multiple instances efficiently on a single device
VM uses linux kernel to handle low-level functionality incl. security, threading, process and memory management

10. Application Framework
Rich, extensible set of Views
apps can inclused lists, grids, text boxes, buttons, web browser
Content Providers
allows data access from other applications or share own data
Resource Manager
access to localized strings, graphics, layout files
Notification Manager
enables custom alerts to be displayed in status bar
Activity Manager
Manages lifecycle of applications and provides navigation backstack

11. Application Fundamentals
Activities
application presentation layer
Services
invisible components, update data sources, visible activities, trigger notifications
perform regular processing even when app is not active or invisible
Content Providers
shareable data store
Intents
message passing framework
broadcase messages system wide, for an action to be performed
Broadcast receivers
consume intent broadcasts
lets app listen for intents matching a specific criteria like location
Notifications
Toast notification
Status Bar Notification
Dialog notification

12. Applications
All apps (native and 3rd party) are written using the same APIs and run on the same run time executable
All apps have APIs for hardware access, location-based services, support for background services, map-based activities, 2D and 3D graphics.
App Widgets are miniature app views that can be embedded in other apps like Home Screen

13. App Priority and Processes
Android apps do not have control over their own life cycles
Aggressively manages resources to ensure device responsiveness and kills process/apps when needed
Active Process – critical priority
Visible Process – high priority
Started Service Process
Background Process – low priority
Empty process

14. Client apps
Developed using the Android SDK and installed on user devices
Compiled Java code, with data and resource – bundled by Android Asset Packaging tool (AAPT) into Android package or .apk
All applications have Android Manifest file in its root directory
provides essential information about app
Could be installed directly on phone, but necessary to be distributed thru Market

15. Web Apps An alternative to standalone apps
Developed using web standards and accessed through browser – nothing to install on devices
Mixing client and web apps is also possible – Client apps can embed web pages using “Webview” in Android app

16. SDK Android APIs, Full Documentation and Sample code Development tools
Dalvik Debug Monitor Service (DDMS)
Android Debug Bridge (ADB)
Android Emulator
Online support and blog
Native Development Kit also available
allows developers to implement parts of apps in native-code languages like C/C++
Plug in available to use Eclipse integrated development environment
Developer forums and developer phones from Google, MOTO Dev studio from Motorola

17. Android Market Google Market - Part of GMS apps
3rd party apps submitted to Google, approved and distributed through Market
Both Free and Paid apps
Apps now limited to 50 MB; updates possible through Market
Monetization through ads available
Available in many countries, not all countries have support for paid apps
Other Market place applications available – Amazon has announced its own Android Market place
App searches filtered based on Manifest file (eg. if a device does not have trackball, apps using trackball will be filtered out)
Every app publishes a list of components the app will access and permissions need to be granted before installation
Apps installed on device and SD card (SD Card from Froyo)

18. Search Core feature in android
User should be able to search any data on device or internet
Usually one of the android buttons
Search suggestions based on recent queries
Provide custom search suggestions that match actual results in application data
system side Quick Search Box
Voice Search available and enhanced in recent releases

19. Locations & Maps Compelling and most popular apps for mobile devices
Google Maps provides free navigation
applications allowed access to location services supported by device
Google provides Maps external library
allows built-in downloading, rendering and caching of Maps tiles, and other display options and controls

20. Device Administration
Froyo introduces support for enterprise applications with Device Administraion API
allows to create security-aware applications to control employee devices
Apps might include
clients
remote wipe
device management services and apps

21. Android Software Updates
Android 1.0 – G1
1.5 – Cupcake
1.6 – Donuts (CDMA support)
2.0 – Éclair (Droid introduced with Éclair)
2.2 – Froyo
2.3 Gingerbread (SDK released 2 weeks ago and source will follow soon)
API Levels used by apps to identify software version on the device
Android apps are generally forward compatible with newer version, but not necessarily backwards compatible

22. Compatibility Why? Android compatibility is free and easy
Allow customizable devices
Create Common eco system
Android compatibility is free and easy
Obtain Android source code
Comply with Android Compatibility Definition (ACD) doc
List requirements that need to be met for devices to be compatible with a particular version on Android
Pass the Compatibility Test Suite (CTS)
Automated test harness running on desktop, manages test exectuion
Test cases written, packaged as .apk to run on actual device or emulator
Porting guide available for bringing up Android on custom HW

23. Other possibilities Google TV - a new platform based on Android
Tablets – Samsung Galaxy tab introduced in Oct 2010
eBook reader – Latest Barnes and Noble Nook is an Android tablet

24. Resources http://www.android.com
developers.blogspot.com