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

EESTEC Android Workshops

101 - Introduction to OOP, Java and Android

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

Android, it’s APP to you!

How do I apply?

Create a great team!

Find an outstanding idea!

Complete a simple form!

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

Basic ConceptsClass - 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

Pros

Code decoupling, enforces code reusability

Associates data structures with their related methods

Makes real-world object representation easier

Inheritance

Classes can extend other classes

They inherit their attributes and methods

Can extend only one class

Example

HumanWalks, Sleeps

namesurname

sex

AdultWorks

job positioncompanyvat no

KidPlays, Cries

no of toysschool gradeno of friends

Examplepublic 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!"; }}

Interfaces

Make a class implement certain functionality

A class can implement more than one interfaces

ExampleMale

Watch footballSnore

Female

CookBe grumpy for

no reason

Male Kid

Female Adult

Female Human

Examplepublic 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!"); } }

OOP Languages

C++

Ruby

Python

C#

VB.NET

...And, wait for it...

Java-dive!Let’s take a fast look

Java, at a glanceC-like syntax

Created in Sun Microsystems, by James Gosling

Now acquired by Oracle

Hello, Java World!

public class HelloJava { public static void main(String[] argv) {

System.out.println(“Hello, Java World!”);}

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

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

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

Example

try {

something that might destroy the universe

catch (EarlyDestructionExcpetion e) { save the world}

Say hello, to my Green friend

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

Android, bottoms up!

Setup a new project

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

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

Tasks for next time

1. Create an application that asks for the user’s name

2.Then, after hitting a button, it populates a text view with a personalized message for the user

3.When the button is pressed, a clear button appears that resets everything

Hint: Check the following classes: TextView, EditText, Button and OnClickListener