The document outlines the fundamentals of Android, detailing its software stack, major components like activities, services, and content providers, and the use of APIs for app development. It explains user interface basics, including the structure of view and viewgroup objects, various layouts, as well as input events and application menus. Additionally, it covers hardware interactions such as sensors and Bluetooth management.

1. Android Fundamentals
Android Fundamentals

2. What is Android
What is Android
 Software stack for mobile devices
Software stack for mobile devices
 SDK provides tools and APIs to develop
SDK provides tools and APIs to develop
apps
apps

3. Major Components
Major Components
Image source: http://developer.android.com/guide/basics/what-is-android.html

4. Applications
Applications
 Ships with core set of apps, written in Java
Ships with core set of apps, written in Java
 Developers have access to core APIs
Developers have access to core APIs
Views used to build application
Views used to build application
Content providers – access data from other
Content providers – access data from other
apps
apps
Resource manager – access to local strings,
Resource manager – access to local strings,
graphics
graphics
Notification manager – display custom alerts
Notification manager – display custom alerts
Activity manager – manages app lifecycle
Activity manager – manages app lifecycle

5. Libraries
Libraries
 C/C++
C/C++
 Media libraries – A/V, images
Media libraries – A/V, images
 Surface manager – 2D/3D graphic layers
Surface manager – 2D/3D graphic layers
 LibWebCore – web browser engine
LibWebCore – web browser engine
 SGL – 2D graphics engine
SGL – 2D graphics engine
 3D – hardware or software acceleration
3D – hardware or software acceleration
 FreeType – BMP and vector fonts
FreeType – BMP and vector fonts
 SQLite – database engine
SQLite – database engine

6. Runtime and Kernel
Runtime and Kernel
 Includes core set of libraries
Includes core set of libraries
Provides most of core Java libraries
Provides most of core Java libraries
Each app runs in its own process
Each app runs in its own process
Own instance of the Dalvik Virtual Machine
Own instance of the Dalvik Virtual Machine
 Linux 2.6 is used for core system services
Linux 2.6 is used for core system services
Abstraction layer between HW & SW stacks
Abstraction layer between HW & SW stacks

7. Main Components of Android
Main Components of Android
 Activities
Activities
 Services
Services
 Content Providers
Content Providers
 Broadcast Receivers
Broadcast Receivers

8. Activity
Activity
 Single page user interface
Single page user interface
 Most apps have multiple activities
Most apps have multiple activities
 Callable from other apps (if you allow it)
Callable from other apps (if you allow it)

9. Service
Service
 No user interface
No user interface
 Runs in background
Runs in background
 Started and stopped by activities
Started and stopped by activities

10. Content Provider
Content Provider
 Manages shared set of application data
Manages shared set of application data
 Data may be shared between apps or be
Data may be shared between apps or be
private
private
 Performs data handling functions
Performs data handling functions

11. Broadcast Receiver
Broadcast Receiver
 Listens for system wide (intent) broadcasts
Listens for system wide (intent) broadcasts
 Intent filter limits which intents cared about
Intent filter limits which intents cared about
 Similar to an interrupt handler
Similar to an interrupt handler
Redirects to appropriate activity or service
Redirects to appropriate activity or service

12. Intents
Intents
 Allows an activity, service or broadcast
Allows an activity, service or broadcast
receiver to link to another
receiver to link to another
Within or between apps
Within or between apps
Allows apps to use components of others
Allows apps to use components of others
Image source: Mednieks, Dornin, Meike, Nakamura. Programming Android

13. User Interfaces
User Interfaces
Images from Android Design
http://developer.android.com/design/get-started/ui-overview.html

14. User Interface Basics
User Interface Basics
 Recall the basic unit of an Android application is an Activity
Recall the basic unit of an Android application is an Activity
 An Activity displays the user interface
An Activity displays the user interface
 User Interfaces are built from View and ViewGroup object instances of the
User Interfaces are built from View and ViewGroup object instances of the
View class
View class
 View objects are data structures that store content and layout parameters
View objects are data structures that store content and layout parameters
 controls a specific rectangular region of the screen
controls a specific rectangular region of the screen
 responsible for drawing itself
responsible for drawing itself
 handles events
handles events
 Subclass “widgets” provide user interface objects:
Subclass “widgets” provide user interface objects:
 text fields, buttons, labels
text fields, buttons, labels
 serves as means of interaction with user
serves as means of interaction with user
Images from Android Design
http://developer.android.com/design/building-blocks/index.html

15. View & ViewGroup
View & ViewGroup
 ViewGroup objects act like containers for View objects
ViewGroup objects act like containers for View objects
 one or more Views are grouped together
one or more Views are grouped together
 Subclass “layouts” provide different layout architectures:
Subclass “layouts” provide different layout architectures:
 LinearLayout – displays Views in linear direction either horizontally or vertically
LinearLayout – displays Views in linear direction either horizontally or vertically
 default is horizontal
default is horizontal
 text field, two radio buttons, and button
text field, two radio buttons, and button
in a vertical orientation
in a vertical orientation
 RelativeLayout – displays Views in relative position to each other
RelativeLayout – displays Views in relative position to each other
 an id needs to be assigned to elements for
an id needs to be assigned to elements for
reference
reference
 text field, two radio buttons, and button
text field, two radio buttons, and button
in relative position
in relative position
Images from Android Basics & User Interfaces
http://www3.ntu.edu.sg/home/ehchua/programming/android/Android_BasicsUI.html

16. ViewGroup Layout
ViewGroup Layout
 TableLayout – displays Views in table form with rows and columns
TableLayout – displays Views in table form with rows and columns
 buttons for the calculator are in table form
buttons for the calculator are in table form
 Some other layouts from base class android.view.ViewGroup:
Some other layouts from base class android.view.ViewGroup:
 AbsoluteLayout
AbsoluteLayout
 FrameLayout
FrameLayout
 ScrollView
ScrollView
Image from Android Basics & User Interfaces
http://www3.ntu.edu.sg/home/ehchua/programming/android/Android_BasicsUI.html

17. Common Attributes
Common Attributes
 View and ViewGroup attributes:
View and ViewGroup attributes:
 layout_width
layout_width
 layout_height
layout_height
 layout_margintop
layout_margintop
 layout_marginbottom
layout_marginbottom
 layout_marginleft
layout_marginleft
 layout_marginright
layout_marginright
 layout_x
layout_x
 layout_y
layout_y
 LinearLayout and TableLayout attributes:
LinearLayout and TableLayout attributes:
 layout_gravity – specifies how child Views are positioned
layout_gravity – specifies how child Views are positioned
 layout_weight – specifies how much space is to be allocated, total
layout_weight – specifies how much space is to be allocated, total
must equal 1
must equal 1
Images from Understanding User Interface In Android
http://mobiforge.com/designing/story/understanding-user-interface-android-part-1-layouts

18. View Hierarchy
View Hierarchy
 Parent nodes contain and organize layout of child nodes
Parent nodes contain and organize layout of child nodes
 Child nodes are responsible for drawing themselves at the request of the parent
Child nodes are responsible for drawing themselves at the request of the parent
 control and respond to user input contained within their region of the display
control and respond to user input contained within their region of the display
 The Activity that displays a particular screen calls the setContentView() method to draw the screen
The Activity that displays a particular screen calls the setContentView() method to draw the screen
defined by the hierarchy
defined by the hierarchy
 XML layout files typically used for defining layouts and expressing view hierarchies
XML layout files typically used for defining layouts and expressing view hierarchies
 each element in XML is a View or ViewGroup object
each element in XML is a View or ViewGroup object
Image from Android Developers
http://developer.android.com/guide/topics/ui/index.html

19. Input Events
Input Events
 Define to inform the system of user interaction
Define to inform the system of user interaction
 Event listener is defined and registered with the View object
Event listener is defined and registered with the View object
 View class has a collection of On<SomeEvent>Listener:
View class has a collection of On<SomeEvent>Listener:
 View.OnClickListener
View.OnClickListener
 View.OnTouchListener
View.OnTouchListener
 View.OnKeyListener
View.OnKeyListener
 Example: OnTouch, when the user touches a defined View object on the
Example: OnTouch, when the user touches a defined View object on the
screen
screen
 define View.OnTouchListener
define View.OnTouchListener
 register the View object with setOnTouchListener()
register the View object with setOnTouchListener()

20. Application Menus
Application Menus
 Two types of menus
Two types of menus
 Options menu – typically when an application is running
Options menu – typically when an application is running
 accessed by pressing the MENU button on the device
accessed by pressing the MENU button on the device
 Context menu – typically used for displaying specific information about an item
Context menu – typically used for displaying specific information about an item
 accessed by pressing and hold down on an object
accessed by pressing and hold down on an object
Images from Android User Interfaces
http://eagle.phys.utk.edu/guidry/android/androidUserInterface.html

21. Application Menus
Application Menus
 Options menus allow users quick access to an application’s functions,
Options menus allow users quick access to an application’s functions,
preferences and settings
preferences and settings
 Structured using a View hierarchy
Structured using a View hierarchy
 define onCreateOptionsMenu()
define onCreateOptionsMenu()
 define onCreateContectMenu()
define onCreateContectMenu()
 Handle their own events, no need to register event listeners
Handle their own events, no need to register event listeners
 Selections handled by methods
Selections handled by methods
 onOptionsItemSelected()
onOptionsItemSelected()
 onContextItemSelected()
onContextItemSelected()
 Items for menus can be declared in an XML file like an application layout
Items for menus can be declared in an XML file like an application layout

22. Hardware Systems/Sensors
Hardware Systems/Sensors
Images from Z-DeviceTest app
https://market.android.com/details?id=zausan.zdevicetest&hl=en

23. Sensors
Sensors
public class SensorActivity extends Activity, implements SensorEventListener {
public class SensorActivity extends Activity, implements SensorEventListener {
…
…
SensorManager mSensorManager = (SensorManager)getSystemService(SENSOR_SERVICE);
SensorManager mSensorManager = (SensorManager)getSystemService(SENSOR_SERVICE);
Sensor mAccelerometer =
Sensor mAccelerometer =
mSensorManager.getDefaultSensor(Sensor.TYPE_ACCELEROMETER);
mSensorManager.getDefaultSensor(Sensor.TYPE_ACCELEROMETER);
…
…
mSensorManager.registerListener(this, mAccelerometer,
mSensorManager.registerListener(this, mAccelerometer,
SensorManager.SENSOR_DELAY_NORMAL);
SensorManager.SENSOR_DELAY_NORMAL);
public void onSensorChanged(SensorEvent event) {
public void onSensorChanged(SensorEvent event) {
}
}
…
…}
}
Image from AndroSensor app
https://market.android.com/details?id=com.fivasim.androsensor&hl=en

24. Sensor Constants
Sensor Constants
 public static final float
public static final float GRAVITY_EARTH =
GRAVITY_EARTH = 9.80665
9.80665
 public static final float
public static final float LIGHT_FULLMOON =
LIGHT_FULLMOON = 0.25
0.25
 public static final float
public static final float MAGNETIC_FIELD_EARTH_MIN =
MAGNETIC_FIELD_EARTH_MIN = 30.0
30.0
 public static final float
public static final float PRESSURE_STANDARD_ATMOSPHERE =
PRESSURE_STANDARD_ATMOSPHERE = 1013.25
1013.25
 public static final float
public static final float GRAVITY_THE_ISLAND =
GRAVITY_THE_ISLAND = 4.815162
4.815162
 public static final float
public static final float GRAVITY_DEATH_STAR_I =
GRAVITY_DEATH_STAR_I = 3.5303614E-7
3.5303614E-7

25. Bluetooth
Bluetooth
BluetoothAdapter
BluetoothAdapter
Local radio state
Local radio state
Discover devices
Discover devices
BluetoothServerSocket
BluetoothServerSocket
Receives connection requests
Receives connection requests
Returns a BluetoothSocket when connected
Returns a BluetoothSocket when connected
BluetoothSocket
BluetoothSocket
InputStream object
InputStream object
OutputStream object
OutputStream object

26. Location
Location
LocationManager locman =
LocationManager locman =
(LocationManager) getSystemService(Context.LOCATION_SERVICE
(LocationManager) getSystemService(Context.LOCATION_SERVICE)
)
Location loc = locman.getLastKnownLocation(String provider)
Location loc = locman.getLastKnownLocation(String provider)
 NETWORK_PROVIDER
 GPS_PROVIDER

27. Location Listener
Location Listener
private class MyLocListener implements LocationListener
private class MyLocListener implements LocationListener
 onLocationChanged(Location location)
onLocationChanged(Location location)
requestLocationUpdates(long minTime, float
minDistance, Criteria criteria, PendingIntent intent)
)
public void addProximityAlert (double latitude, double longitude, float radius,
public void addProximityAlert (double latitude, double longitude, float radius,
long expiration, PendingIntent intent)
long expiration, PendingIntent intent)

28. References
References
 https://market.android.com/details?id=zausan.zdevicetest&hl=en
https://market.android.com/details?id=zausan.zdevicetest&hl=en
 https://market.android.com/details?
https://market.android.com/details?
id=com.fivasim.androsensor&hl=en
id=com.fivasim.androsensor&hl=en
 http://developer.android.com/reference
http://developer.android.com/reference
 Mednicks, Dornin, Meike, Nakamura,
Mednicks, Dornin, Meike, Nakamura, Programming Android
Programming Android
 http://developer.android.com
http://developer.android.com
 http://www3.ntu.edu.sg/home/ehchua/programming/android/
http://www3.ntu.edu.sg/home/ehchua/programming/android/
Android_BasicsUI.html
Android_BasicsUI.html
 http://phandroid.com/2011/05/11/10-tips-for-android-ui-design/
http://phandroid.com/2011/05/11/10-tips-for-android-ui-design/
 http://eagle.phys.utk.edu/guidry/android/androidUserInterface.html
http://eagle.phys.utk.edu/guidry/android/androidUserInterface.html
 Ableson, Sen, King, Ortiz: Android In Action – Third Edition
Ableson, Sen, King, Ortiz: Android In Action – Third Edition