Android Programming made easy

Android Programming made easy
I have always wished that my computer would be as easy to use as my telephone. My wish has come true. I no longer know how to use my telephone
- BjarneStronstrup

About me – Lars Vogel
(Twitter: @vogella)
Independently active in the OpenSource Community, e.g. Eclipse and Android
Working for SAP AG as Product Manager
Maintains http://www.vogella.de Java, Eclipse and Android related Tutorials with ~15 000 visitors per
Received the Eclipse Top Contributor Award 2010

The next 58 minutes
Android overview
Android Tool chain
Demos
Android Programming Constructs
Q&A

What is Android?
– operating system based on Linux
– middleware
– key applications
– set of APIs
Open Source
Developed officially by the Open Handset Alliance lead by Google

4 Software layers

Dalvik – town in iceland
Android Programming
You use the Java programming language but Android does not run Java Bytecode
Tool dx converts Java Bytecode into Dalvik Executable Code (.dex)

Android Programming
You use the Java programming language but Android does not run Java Bytecode

Calls
Uses

Developer Toolchain

Android Development Tools (ADT) for Eclipse
Not OpenSource 
Eclipse based tooling
Provide the emulator
Wizard for creating new project
Additional Tooling

Emulator
QEMU-based ARM emulator runs same image as a device
Use same toolchain to work with device or emulatorInital startup is slooooowwwwww.....

Your first Android app in < 60 secs
Timer check Application

Command lineadb – Android Debugging Bridgetelnet

Android programming
constructs

Main Android programming constructs
Activity
Views
Intents
Broadcast Receiver
Services
ContentProvider

Activity – screen in the Android application
Layout – Defines UI elements and their arrangements.

Life Cyle of an Activity
void onCreate(Bundle savedInstanceState) void onStart() void onRestart() void onResume() void onPause() void onStop() void onDestroy()
Android may destroy you!

Noteworthy:- ADT maintains the ID‘s automatically in R.java- Resources can be defined via xml

I had only the best intents....

Intents
Allow modular architecture
Two types
Explicit: Asking someone to do something
Implicit: Asking the system who can do something
Intent

Services
© Lars Vogel and others, Licensed under Creative Commons by-nc-nd-3.0 (de)

Services
Android provides a multitude of system services
NotificationService
VibratorService
LocationService
AlarmService
....
Access via context.getSystemService(Context.CONST);
You can define your own service.

Broadcast Receiver – Listen to system events
Example:
BATTERY_LOW, ACTION_BOOT_COMPLETED
Defined statically in manifest or temporary via code

Timer check ApplicationLets alert!

Security

Android Application requires explicit permissions, e.g. for
DB access
Phone access
Contacts
Internet
System messages

Security is an inherent part of the system and not a layer the programmer needs to handle

There is more....

Android Connectivity
I can talk and hear
Internet (java.net, Apache HttpClient,...)
Bluetooth
Email
SMS
I have feelings
Camera API
Motion Detection
Location API (GIS)
Heat Sensor
Accelerator

Storage
File System (device or SD card)
Preferences
Database (SQLightDatabase)

Beyond Android – Google API‘s

Performance?

Performance Sins
Avoid creating objects
Static rules
Avoid to use internal setters and getter (within the same class)
Static final for constants
Learn on giants (use the libraries)
Details: http://developer.android.com/guide/practices/design/performance.html

Be fast!
Avoid ApplicationNotResponding Error
Threads not allowed to modify the UI directly
Use handler or AsyncTask to update the UI after Thread is done

Summary
Android powerful and well-designed development platform
Power to the developer

Picture Credit
All pictures are from http://www.sxc.hu/ to get them add the number to http://www.sxc.hu/photo/
Agenda 1089869
Dalvik 1269657
Software Layer / Tomatos 832159
616474
Thinking guy 324541
Smiling Boy 812138
Toolchain 1197009
Stopwatch http://www.sxc.hu/photo/634598
Timer / Watches 1062014
Next guy 986700
Sad Lady 232738
Funny guy 1173019
Waiter / Services http://www.sxc.hu/photo/157966
Security 695054
There is more 702367
Performance rabbits 786444
Performance snail 1181451
Performance Running man 377100
Hang-man 620961
Summary http://www.sxc.hu/photo/1184807
Question http://www.sxc.hu/photo/418215
Reading material http://www.sxc.hu/photo/406547
Thank you http://www.sxc.hu/photo/986313

Android: Where to go from here:
Android Tutorial
http://www.vogella.de/articles/Android/article.html
Or Google for: ~1 rank
“android development tutorial”

Thank you
For further questions:
Lars.Vogel@gmail.com
http://www.vogella.de
http://www.twitter.com/vogella

License & Acknowledgements
This work is licensed under the Creative Commons Attribution-Noncommercial-No Derivative Works 3.0 Germany License
See http://creativecommons.org/licenses/by-nc-nd/3.0/de/deed.en_US

Android Programming made easy

by Lars Vogel on Sep 07, 2010

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