First of a workshop series by EESTEC LC Athens for Android. Introduction to Java, OOP and Android

1. EESTEC Android
Workshops
101 - Introduction to OOP, Java and Android

2. What we’ll cover today
EESTEC, Android, it’s APP to you!
Introduction to OOP
Introduction to Java
Setting up the Android Environment
Running your first App

3. Android, it’s APP to you!

4. How do I apply?
Create a great team!
Find an outstanding
idea!
Complete a simple
form!

5. Let’s get to the point!
OOP, here we come!

6. Basic Concepts
Class - Blueprint, used to create instances of
itself
Object / Instance - Instances are class
occurrences
Method - Function / Procedure of an object
or class
Attribute - Fields with values (objects) in a
object

7. Pros
Code decoupling, enforces code reusability
Associates data structures with their related
methods
Makes real-world object representation
easier

8. Inheritance
Classes can extend
other classes
They inherit their
attributes and
methods
Can extend only
one class

9. name
Human surname
Walks, Sleeps sex
no of toys job position
Kid school grade Adult company
Plays, Cries no of friends Works vat no
Example

10. Example
public class Hello {
public static void main(String[] argv) {
System.out.println(getHelloString());
}
private static String getHelloString() {
return "Hello";
}
}
public class HelloWorld extends Hello {
@Override
private static String getHelloString() {
return "Hello, world!";
}
}

11. Interfaces
Make a class implement certain functionality
A class can implement more than one
interfaces

12. Fema
le Ad
ult
Example Kid
ale
Male Female M
Fe
Watch football Cook male
Snore Be grumpy for
Hu
no reason ma
n

13. Example
public class Human {
abstract void sayHi();
abstract void sayGoodBye();
}
public class Eestecer implements Human {
@Override
private static String sayHi() {
System.out.println("Hello guys!");
}
@Override
private static String sayGoodBye() {
System.out.println("Goodbye... Keep partying!");
}
}

14. OOP Languages
C++
Ruby
Python
C#
VB.NET
...And, wait for it...

15. Java-dive!
Let’s take a fast look

16. Java, at a glance
C-like syntax
Created in Sun Microsystems,
by James Gosling
Now acquired by Oracle

17. Hello, Java World!
public class HelloJava {
public static void main(String[] argv) {
System.out.println(“Hello, Java World!”);
}

18. Great Things about Java
Has a garbage collector, simply do not care
about memory leakage!
Your program fails, except exceptions!
Is platform-independent, runs in it’s own VM,
the JVM

19. Garbage Collector
Java objects leave in
a heap
When the Garbage
Collector needs to
release memory, it
starts removing
dangling objects
Slightly pauses the
application threads

20. Exceptions
Java gives you the chance to get a bit off
track, but then makes sure you can handle
unwanted situations
You can try something weird and if it turns
bad, you handle the exception

21. Example
try {
something that might destroy the universe
catch (EarlyDestructionExcpetion e) {
save the world
}

22. Say hello, to my Green
friend

23. The mystery, explained...
Complete software stack
Operating System
Middleware
Key Applications
Open Source Developed by the Open Handset
Alliance
Fastest growing market
Platform with the most devices activations

24. Android, bottoms up!

25. Setup a new project

26. Activity
Creates a window, so that the user can
interact with the app
Can communicate with the system
Controls the higher level of the user
interface

27. Activity, get a
life!
The lifecycle of an Activity is
really important.
Listen to Lifecycle events, in
order to save and reproduce
the state of the app

28. Tasks for next time
1. Create an application 3. When the button is
that asks for the user’s pressed, a clear button
name appears that resets
everything
2. Then, after hitting a
button, it populates a Hint: Check the
text view with a following classes:
personalized message TextView, EditText,
for the user Button and
OnClickListener