Slide อบรม Introduction to Android

1. 12/1/2011
Mobile Application
Development
with ANDROID
Piya Sankhati ( Jenk )
Agenda
Mobile Application Development (MAD)
Intro to Android platform
Platform architecture
Application building blocks
Development tools
Hello Android
Resources
Present at Business Computer @Sci North
Chiang Mai 1

2. 12/1/2011
Mobile Applications
Mobile Apps are apps or services that can be pushed to a
mobile device or downloaded and installed locally.
Classification
• Browser-based: apps/services developed in a markup language
• Native: compiled applications (device has a runtime
environment). Interactive apps such as downloadable games.
• Hybrid: the best of both worlds (a browser is needed for
discovery)
What is Android
Android is an open source operating system, created by Google
specifically for use on mobile devices (cell phones and tablets)
Linux based (2.6 kernel)
Can be programmed in C/C++ but most app development is
done in Java (Java access to C Libraries via JNI (Java Native
Interface))
Supports Bluetooth, Wi-Fi, and 3G and 4G networking
Present at Business Computer @Sci North
Chiang Mai 2

3. 12/1/2011
Why Android?
Open source
Lots of samples
Popular
Free to develop
JAVA based
Easily shared
The Android Software Stack
Present at Business Computer @Sci North
Chiang Mai 3

4. 12/1/2011
Linux Kernel
• Works as a HAL
• Device drivers
• Memory management
• Process management
• Networking
Libraries
• C/C++ libraries
• Interface through Java
• Surface manager – Handling UI Windows
• 2D and 3D graphics
• Media codecs, SQLite, Browser engine
Present at Business Computer @Sci North
Chiang Mai 4

5. 12/1/2011
Android Runtime
• Dalvik VM
– Dex files
– Compact and efficient than class files
– Limited memory and battery power
• Core Libraries
– Java 5 Std edition
– Collections, I/O etc…
Application Framework
• API interface
• Activity manager – manages application life
cycle.
Present at Business Computer @Sci North
Chiang Mai 5

6. 12/1/2011
Applications
• Built in and user apps
• Can replace built in apps
Android Application
Development
Android
Eclipse IDE
SDK
Android
Android
Mobile
Emulator
Device
Present at Business Computer @Sci North
Chiang Mai 6

7. 12/1/2011
Android development
Java Source
Android
Manifest
Generated Java .dex Dalvik
Class Compiler File VM
Resource
XML
Android
Libraries
Android Application Types
Foreground applications
need cool UIs (sudoku)
Background services & intent receivers
little to no user input (back-up assistant)
Intermittent applications
combination of visible & invisible (music)
Widgets
dynamic data displays (date/time)
Present at Business Computer @Sci North
Chiang Mai 7

8. 12/1/2011
Foreground applications
Background Service
Present at Business Computer @Sci North
Chiang Mai 8

9. 12/1/2011
Intermittent applications
Home Screen Widget
Present at Business Computer @Sci North
Chiang Mai 9

10. 12/1/2011
Pre-installRequirements
JDK 5 or JDK 6 (JAVA DevelopementKit)
http://www.oracle.com/technetwork/java/javase/downloads/in
dex.html
Eclipse 3.3 orlater
http://www.eclipse.org/downloads/
ADT Plugin for Eclipse
http://developer.android.com/sdk/eclipse-adt.html
Android SDK
http://developer.android.com/sdk/index.html
EmulatororAndroiddevice
Introduction (cont.)
Design Considerations:
Low processing speed
Optimize code to run quick and efficiently
Limited storage and memory
Minimize size of applications; reuse and share data
Limited bandwidth and high latency
Design your application to be responsive to a slow (sometimes non-
existent), intermittent network connection
Limited battery life
Avoid expensive operations
Low resolution, small screen size
“Compress” the data you want to display
Present at Business Computer @Sci North
Chiang Mai 10

11. 12/1/2011
Application Components and Lifecycle
Components of your application:
Activities
Presentation layer for the application you are building
For each screen you have, their will be a matching Activity
An Activity uses Views to build the user interface
Services
Components that run in the background
Do not interact with the user
Can update your data sources and Activities, and trigger specific
notifications
Android Application Overview (cont.)
Components of your application:
Content Providers
Manage and share application databases
Intents
Specify what intentions you have in terms of a specific action being
performed
Broadcast Receivers
Listen for broadcast Intents that match some defined filter criteria
Can automatically start your application as a response to an intent
Present at Business Computer @Sci North
Chiang Mai 11

12. 12/1/2011
Android Application Overview (cont.)
Application Lifecycle
To free up resources, processes are being killed based on their
priority:
Critical Priority: foreground (active) processes
Foreground activities; components that execute an onReceive event
handler; services that are executing an onStart, onCreate, or
onDestroy event handler.
High Priority: visible (inactive) processes and started service
processes
Partially obscured activity (lost focus); services started.
Low Priority: background processes
Activities that are not visible; activities with no started service
Application Components and Lifecycle (cont.)
Activity Lifecycle:
Activities are managed as an activity stack (LIFO collection)
Activity has four states:
Running: activity is in the foreground
Paused: activity has lost focus but it is still visible
Stopped: activity is not visible (completely obscured by another
activity)
Inactive: activity has not been launched yet or has been killed.
Present at Business Computer @Sci North
Chiang Mai 12

13. 12/1/2011
Application Components and Lifecycle (cont.)
Source: http://code.google.com/android/reference/android/app/Activity.html#ActivityLifecycle
Activity Lifecycle
public class Activity extends ApplicationContext {
// full lifetime
protected void onCreate(BundlesavedInstanceState);
// visible lifetime
protected void onStart();
protected void onRestart();
// active lifetime
protected void onResume();
protected void onPause();
protected void onStop();
protected void onDestroy();
}
Present at Business Computer @Sci North
Chiang Mai 13

14. 12/1/2011
IntentReceivers
Components that respond to broadcast ‘Intents’
Way to respond to external notification or alarms
Apps can invent and broadcast their own Intent
Intents
Think of Intents as a verb and object; a description of
what you want done
E.g. VIEW, CALL, PLAY etc..
System matches Intent with Activity that can best
provide the service
Activities and IntentReceivers describe what Intents
they can service
Present at Business Computer @Sci North
Chiang Mai 14

15. 12/1/2011
Intents
Home
Picasa
Photo Gallery
Contacts
“Pick photo”
GMail
Client component makes a
Chat System picks best component
request for a specific action
New components can use
for that action
Blogger
Blogger
existing functionality
Services
Faceless components that run in the background
E.g. music player, network download etc…
Present at Business Computer @Sci North
Chiang Mai 15

16. 12/1/2011
ContentProviders
Enables sharing of data across applications
E.g. address book, photo gallery
Provides uniform APIs for:
querying
delete, update and insert.
Content is represented by URI and MIME type
Fundamental Coding Concepts
interface vs. processing
separation is key!!!
android app interface: res files
○ layout *.xml to define views
○ values *.xml to define strings, menus
○ drawable *.png to define images
android app processing: src *.java
event based programming
javascript example?
Present at Business Computer @Sci North
Chiang Mai 16

17. 12/1/2011
Application Manifest
master .xml file
declares all the components of the application
declares intent filters for each component
declares external app info: name, icon, version,
SDK levels, permissions, required configurations
and device features, etc.
http://developer.android.com/guide/topics/manif
est/manifest-intro.html
Day 4
Creating a New Application I
Create Project
File -> New -> Project -> Android -> Android
Project
New Project Wizard to specify
project name – file folder
check/change location
choose lowest level build target
application name – friendly description
package name – 2 part java namespace
create activity – main activity component
min SDK – lowest level that app will run on
Day 4
Present at Business Computer @Sci North
Chiang Mai 17

18. 12/1/2011
Creating a New Application II
Create Launch Configuration
project and activity to launch
virtual device and emulator options
input/output settings
Day 4
Creating a New Application
Run, Edit, Debug
III
debug & run default Hello World activity
cmd-shift-O to import necessary classes in Eclipse
select project, right click, Android Tools -> Fix
Project Properties
edit the starting activity
implement new components and behaviors
(borrow from samples)
select the project and then
Run -> Run As -> Android Application
Day 4
Present at Business Computer @Sci North
Chiang Mai 18

19. 12/1/2011
User Interfaces
GOOD BAD
intuitive overcrowding
clean too complicated
simple poor aesthetics
elegant lack of response, feedback
right level of information pop-ups
fast physically unwieldy
Day 1
HCI, UX, UI, oh my!
HCI: human computer interaction
UI: User Interface
GUI: Graphical User Interface
UX: User Experience
Day 1
Present at Business Computer @Sci North
Chiang Mai 19

20. 12/1/2011
Reference
http://developer.android.com
http://sites.google.com/site/io
http://www.github.com
Present at Business Computer @Sci North
Chiang Mai 20