1. Android Programming Tutorial
2019/2/19

2. Introduction to Android
Reference 01
Introduction to Android 02
Android environment set up 03
Android project layout 04
Application components 05
Examples 06

3. 1. Reference Online guide Book
You may need VPN to visit this website
Book
Android Tutorial (by tutorialspoint.com)
Android – a programmers guide (J.F. DiMarzio)
Andbook (Nicolas Gramlich)

4. 2. Introduction to Android
What is Android
A linux-based OS for mobile devices
Developed by Google
First Android phone in October 2008
Many companies produce Android phones(Samsung, Motorola, LG…)
Android logo
Android phone

5. Introduction to Android
Why android?
The first truly open and comprehensive platform for mobile devices
No licensing, distribution, or development fees
Development over many platform
How does Android manage Applications?
Multiple applications can run at same time
Only one instance of an App runs at a time
Typical buttons: Home, Back, Menu, Search

6. 3. Android environment set up
2GB RAM and 2GB disk space
JDK + Android Studio on your own computer
Guide is here:

7. Concepts JDK Java Development Kit
Provide a Java Virtual Machine to run java code
Includes a complete JRE plus tools for developing, debugging, and monitoring Java applications.
Android is based on java

8. Concepts Android Studio Android SDK
Android Studio provides the fastest tools for building apps on every type of Android device.
Android SDK
The bulk of the Android SDK, in number of files, consists of documentation, with programming APIs, tools, and samples comprising the rest.

9. 5. Application Components
Activity
An activity represents a single screen with
a user interface.
Service (Background)
E.g. Network communication
Intent
Inter-communication among activities or services
Notification
Signaling users: light, sound, icon, dialog
E.g. new message arrives

10. Activities
They dictate the UI and handle the user interaction to the smartphone screen
Life of Activity
If you have worked with C, C++ or Java programming language then you must have seen that your program starts from main() function. Very similar way, Android system initiates its program with in an Activity starting with a call on onCreate() callback method. There is a sequence of callback methods that start up an activity and a sequence of callback methods that tear down an activity as shown in the below Activity life cycle diagram:

11. Activities
Callback
Description
onCreate()
This is the first callback and called when the activity is first created.
onStart()
This callback is called when the activity becomes visible to the user.
onResume()
This is called when the user starts interacting with the application
onPause()
The paused activity does not receive user input and cannot execute any code and called when the current activity is being paused and the previous activity is being resumed.

12. Activities
Callback
Description
onStop()
This callback is called when the activity is no longer visible.
onDestroy()
This callback is called before the activity is destroyed by the system.
onRestart()
This callback is called when the activity restarts after stopping it.

13. Activities – java code

14. Intents
An Android Intent is an object carrying an intent ie. message from one component to another component with-in the application or outside the application
We can start a new activity using Intents.
An Android Intent is an abstract description of an operation to be performed. 

15. Examples – “Hello World”
Several steps: (1) Start Android Studio and New project (2) New activity (3) Design GUI layout (4) Write java code for the activity (5) Run the activity on the virtual machine or your own mobile phone

16. (1) New project
File -> New Project

17. New project

18. (2) New activity

19. New activity

20. 4. Android Studio 1 2 3
1 project files editor debug information

21. Project architecture Src:
This contains the .java source files for your project. By default, it includes an mainActivity.javasource file
having an activity class that runs when your app is launched using the app icon.

22. Project architecture 3. Res/layout
This is a directory for files that define your app's user interface.

23. (3) GUI design
MyActivity.java corresponds to activity_my.xml

24. GUI design

25. Layout and views

26. (5) Run it in a virtual device1 2

27. Create a virtual device
Set device name, type, android version, CPU type, memory size.
Android version of device should be higher than that of project.
RAM size should not be very large, otherwise your computer will be very slow

28. Start the virtual device

29. Start the virtual device

30. Run app on the virtual device
Choose the virtual device

31. Run the application on your physical device
You may need to install driver for your phone
Connect your phone to the computer
Turn on the developer options -> USB debugging mode
Run your application in Android Studio, and choose your phone as the device

32. Run the application on your physical device
developer options -> USB debugging mode

33. “Hello world~”

34. 6.2 examples - Add a Button
For the “hello world ” application, there is just a TextView.
We can add more Views and controls(e.g. Button)
We should tell the application what to do, when user click the button.

35. Steps Add Button View in the layout Set the properties of Button
Write java code in the src/*.java
Run the application

36. Add Button, set property

37. Properties

38. Write java code
Two variables
Get views
Set click listener
Change text

39. Run application
Click the button

40. 6.3 examples - Start a new activity
New the second activity
Edit the layout files
Write java code
Run the application

41. New the second activity

42. New the second activity

43. Activity layout
Activity 1
Activity 2

44. Write java code Button variables Get views Set click listener
Change text
This is the MainActivity class
I didn’t modify Test1 class

45. Start a new activity
Click “Start Activity”

46. 6.4 examples - Sensor 1. Motion Sensors 2. Position Sensors
Accelerometer (also: Gravity, Linear Accl)
Gyroscope
Rotation Vector
2. Position Sensors
Magnetic Field
Orientation
Proximity
3. Environmental Sensors
Temperature, Light, Pressure, Humidity
4. Others
GPS, Camera, Microphone, Network

47. Steps for getting sensor values
Get a sensor manager
Get sensor list with sensor manager
Register listener with sensor manager
Implement function “onSensorChanged” in a listener
Get values of sensors in the function

48. Java codes
SensorManager manager = (SensorManager) getSystemService( Context.SENSOR_SERVICE ); Sensor light = manager.getDefaultSensor( Sensor.TYPE_LIGHT ); manager.registerListener( this, light, SensorManager.SENSOR_DELAY_NORMAL); public void onSensorChanged( SensorEvent event ) { float lux = event.values[0]; }

49. Show sensor values in a TextView
This class should implements “SensorEventListener”

50. Result

51. 6.5 examples - ListView
ListView is a view group that displays a list of scrollable items
Put ListView in the activity layout
Define layout for each item of
ListView
Write code

52. Put a ListView in the screen

53. Layout for each item Define a layout for each item in the ListView
Right click
->new
->XML
->layout XML File

54. Layout for each item

55. ListView -- java code Get data for display Get ListView New an adapter
Connect data and item layout with adapter
ListView set adapter

56. ListView – java code
Prepare data
Set Adapter
Set adapter

57. ListView -- “getData()”
Data format
Key: value

58. ListView result

59. log The application programmer can write custom log messages.
Log.v(); // Verbose
Log.d(); // Debug
Log.i(); // Info
Log.w(); // Warning
Log.e(); // Error
This is very useful for debugging

60. Tips Alt + Enter : for importing package or fixing your code
Another way to install application in your mobile phone.
Find “ [your project folder] /app/build/outputs/app/*.apk ” file
Copy the file to your phone
Install the apk

61. Project requirements Show sensors on your mobile phone
Show the values of these sensors
Try your best to make the user interface beautiful and friendly
Do not copy codes of others

62. Thank You!