Android Internals: The Quickest Overview

1. Android Application Development
Android Internals: A Quick Overview
Ahsanul Karim
ahsanul.karim@sentinelbd.com
Workshop: Day 1 Part 2 Sentinel Solutions Ltd.
http://www.sentinelbd.com
http://androidstream.wordpress.com

2. What is Android?
An Open Platform for Mobile Development
Google’s Andy Rubin describes Android as:
The first truly open and comprehensive platform for mobile devices,
all of the software to run a mobile phone but without the
proprietary obstacles that have hindered mobile innovation
Android is a software stack for wide range of devices
including mobiles, tablets and televisions that includes an
Operating System
Middleware
Key Applications.

3. The Stack

4. The Stack: Linux Kernel
Android runs of Linux
Linux provides:
1. Hardware Abstraction
Layer
2. Memory Management
3. Process Management
4. Networking
Users never see Linux sub-
system
(adb shell commands opens
Linux shell we’ll see later)

5. The Stack: Linux Kernel
Android runs of Linux
Linux provides:
1. Hardware Abstraction
Layer
2. Memory Management
3. Process Management
4. Networking
Users never see Linux sub-
system
(adb shell commands opens
Linux shell we’ll see later)

6. The Stack: Native Libraries
Bionic, a super fast and small
GPL-based libc library optimized
for embedded use.
Surface Manager for composing
window manager with off-
screen buffering.
2D and 3D graphics hardware
support or software simulation.
Media codecs offer support for
major audio/video codecs
SQLite database
WebKit library for fast HTML
rendering

7. The Stack: Android Runtime
Dalvik VM
Every Android app runs in its own process,
with its own instance of the Dalvik VM.
Why Dalvik VM?
1. Optimized
2. Small memory footprints
3. Register based architecture
4. Security
5. Or may be Google’s trick to
avoid SUN’s lawsuit

8. The Stack: Application Framework
Activity Manager controls the life
cycle of the app
Resource Manager manages
everything that is not the code
Location Manager figures out the
location of the phone (GPS, GSM,
WiFi)
Notification Manager for events
such as arriving messages,
appointments, etc

9. The Stack: Applications
Shipped Apps:
an email client,
SMS program,
calendar, maps,
browser, contacts etc.
Third Party Apps
This is where we
are

10. What is Android SDK
Provides all necessary tools to develop Android applications. This includes
1. a compiler,
2. debugger
3. a device emulator,
4. Own virtual machine to run Android programs.
background processing rich user interface library
OpenGL libraries access to the file system
embedded SQLite database

11. Android SDK Features
Features/APIs
Connectivity+Telephony GSM, EDGE, 3G, 4G, and LTE data transfer+calls+SMS
Location API APIs for GPS and Network based location detection
MAP Controls Full support for map integration+controls
Multimedia Full Multimedia hardware control
(camera+recorder+audio+video+still images)
Sensors APIs for using sensor hardware including
accelerometer, compasses, barometers etc.
Bluetooth & NFC Peer to peer communication
C2DM Cloud to Device Messaging (Push Notification)

12. Android SDK Features
Features/APIs
Shared Data Stores Shared Data Stores, APIs for contacts, social networks,
calendar and multimedia
Background Services Background Services and processes
Home Screen Widgets+ Live
Wallpaper
HTML5 Web-kit browser
Localization Framework
Reuse of Application
component
SQLite Data storage

13. Android Features (Cont.)
Accelerometer GPS
Thermal Sensor
Your App
+ With logic to
Actuate
=
Gyroscope
Light Sensor TTS
Voice Search
Magnetic Sensor