1. CS5103 Software Engineering
Lecture 07
Android Development II

2. Last class 2 Projects Android Development I Process and Evaluation
Requirements
Calendar
SMS Messenger
Contact Manager
Book Shelf
Android Development I
Android system & Emulator
Environment Setup 2

3. Today’s class Basic Android Development 3
Structure of an android project
Basic UI Components
Activities and Lifecycle
Action bars 3

4. Set environment variables
Set Android_SDK_Home:
%Android_SDK_Home%/.android will be the place all virtual devices stored
You may set your sdk directory as Android_SDK_Home
Add dirs to PATH env variable
Your sdk directory/tools
Your sdk directory/platform-tools 4

5. Structure of an Android Project
Source code
Generated code
Manifest file
Resource files 5

6. Source code & generated code
The code you will work on
Activities
Typically mainly implementing system call backs
Generated code
The code generated by the system according to your resource files
R.java
Including references to all fields in resource files
Do not edit it 6

7. Main components of android apps
Activities
Services
Broadcast Receivers
They usually can be executed directly with intents
Intents
Messages sent and received between components
System intents 7

8. Activities Most important component of an android app 8
An activity is basically everything showed at one time on the screen
Like window or frame in the desktop UI applications
Explore an app by trigger different activities
An activity has its own resource files 8

9. Manifest file Package name Versions targeted at Activities
Intent filters
Permissions
Uses-permissions
Declare permissions 9

10. Permissions 10 System permissions User defined permissions
Network
Reading/Writing/Sending/Receiving sms
Making/Receiving calls
Reading/writing contacts
Reading/writing SD cards …
User defined permissions 10

11. Resource files 11 Source code Generated code The code you will work on
Activities
Typically mainly implementing system call backs
Generated code
The code generated by the system according to your resource files
R.java
Including references to all fields in resource files
Do not edit it 11

12. Resource files Drawable Layout Menu 12 Icons used in the app
An xml file describing the layout of an activity
Eclipse-ADT provides a graphics layout, and maintain the consistency
Menu
An xml file describing the menu of an activity 12

13. Resource files
Values
Dimensions
Strings
Styles (color, fonts, etc.)
A project usually has multiple value folders for different targeted devices
Dimensions for different device size
Strings for different languages 13

14. Today’s class Basic Android Development 14 Play with Emulator
Structure of an android project
Basic UI Components
Activities and Lifecycle
Action bars 14

15. Basic UI Components Views ViewGroup 15 Basic UI component
Button, Checkbox, MenuItem, etc.
ViewGroup
A invisible container that holds views
Determines how views are placed in the container
LinearLayout, GridLayout, AbsoluteLayout, etc. 15

16. Views and View Groups 16

17. Basic UI Components Views ViewGroup 17 Basic UI component
Button, Checkbox, MenuItem, etc.
ViewGroup
A invisible container that holds views
Determines how views are placed in the container
LinearLayout, RelativeLayout, GridView, ListView 17

18. Add views/viewgroups to a project
All views and view groups can be added by
Editing layout resource file of an activity (recommended)
Edit the graphics layout
Set main attributes
Height
Width
Text / hint 18

19. Layouts Linear layouts 19
Views are placed in a vertical or horizontal list
The default size of views are “wrap_content”
You may set weight for views to make them occupy more spaces 19

20. Layouts Relative layouts 20
Views are placed relative to their neighbors
Views are places from top-left corner by default
Avoid too much hierarchies 20

21. Layouts List Views 21 Bind to ListActivity
A vertical list of scrollable items
Use Adaptor to build and manage items 21

22. Layouts
Grid Views
Display items in a two-dimensional scrollable grid
Use adaptors to build view and manage items 22

23. An example of input and display messages23

24. Respond to UI components
Add the onclick attribute
The content of the attribute is the name of method to be executed
Access data in the current activity
Find view by id
Do not forget to set an id for the views you want to get data from 24

25. Respond to UI components
Requirement to the responding method
Public
Return type is void
Has a single parameter: android.view.View
Otherwise the system will not be able to call the responding method 25

26. Start another activity
Create a new activity
Add it to multiple places (done automatically by eclipse)
Source code
Manifest file
Resource files for the new activity
Generate an intent to start the activity 26

27. Activity life cycles 27 Create Start Pause: Resume Stop Destroy
The activity become fully visible to the user
Pause:
The activity is partially visible, e.g., pop-up window
Resume
The activity is fully visible again
Stop
The activity is hidden
Destroy 27

28. Activity life cycles 28

29. Menus Menus are by default in the project
Each activity has a menu resource file
A empty action called settings is listed in the menu
Since phone screens are quite small, menu provide a place to put extra buttons that cannot be put onto the screen 29

30. Add items to menus Add item to the resource file Add ids to each item
Implement the method:
onOptionsItemSelected(MenuItem item) 30

31. Today’s class Basic Android Development 31 Play with Emulator
Structure of an android project
Basic UI Components
Activities and Lifecycle
Action bars 31

32. Thanks! 32

33. Start an emulator In eclipse In command line 33 Go to device manager
Click Start
In command line
emulator –avd ‘virtual device name’ 33

34. On the emulator 34 Use your keyboard to input text Useful Shortcuts
Home -> Home
Esc -> back
F2 -> Menu
Ctrl + F12 -> change orientation
Manage Apps
Go to menu -> manage apps
Operating everything as on a phone 34

35. Adb interface 35 A very useful tool for controlling emulator
adb devices: show all running emulators
Install and uninstall apps
adb push & pull: transfer data between the host system and the emulator
adb logcat: print the system log of the emulator
adb shell: access the file system of the emulator
Manage files in the virtual device
adb shell pm: List all installed apps 35

36. Telnet interface 36 telnet localhost <port number>
Simulate a number of events
Phone calls
gsm call <number>
SMS
sms send <number> <“text”>
Power level
power status charging / not-charging,
power capacity <percentage>
Set GPS
geo fix <longitude> <latitude> 36

37. Today’s class Basic Android Development 37 Play with Emulator
Structure of an android project
Basic UI Components
Activities and Lifecycle
Action bars 37