Download Powerpoint - CS4HS@Unitec 2015 workshop

Crash Course in Android
Development
Content

Installing the ADT
 Hardware
and OS requirements
 Java
 ADT



Bundle
Eclipse Project Setup
Drawing in Android
Animation in Android
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John Casey

Dr John Casey
 Email:
jcasey@unitec.ac.nz
 Room 3008, building 183
 Phone: 815-4321 ext. 6003
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My Experience


Oracle Certified Java Programmer (OCJP)
Programmer

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
P2P, Sockets, Distributed Systems, Information Retrieval
Motor Registry System – State of Tasmania
Fines and Infringement Notices Database – State of Tasmania
LifeLink - Births, Deaths and Marriages State of NSW
Mobile Research Projects
…
Educator


Deakin University, Melbourne
Unitec
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Android Gremlins

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SDK is very complicated
There are 4-5 separate components to install and
configure and something can go wrong at each
stage
The Android SDK has lots of bugs
Android can have weird interactions with the OS
and Hardware
Many give up after failing to install and configure
Java, Android and Eclipse
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First Steps


Work out whether
you are running a
32-bit or 64-bit OS
Control Panel>System and
Security->System
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Do you have Java Installed?

http://www.oracle.com/technetwork/java/javase/
downloads/index.html
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Download 32-bit OR 64-bit Version
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Java already installed?

Drop to a Command Prompt
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Download the ADT Bundle
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https://developer.android.com/sdk/index.html
The number of bits must match! for OS, Java and
ADT Bundle
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Download the ADT Bundle


Make a cup of tea / coffee while the ADT Bundle
downloads
385 MB later .... Extract the ADT Bundle.
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Extract the ADT Bundle

Extract files to c:\android-adt
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Open the SDK Manager
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Update the SDK

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Be careful not to download the Google Glass packages
Android 4.3.1 API 18 is a good stable version of Android
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
More Coffee ...
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Run Eclipse
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Update Eclipse
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Android Developer Toolkit

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Lots of steps where things can go wrong
Can alternatively build your own environment OR
you can also use Android Studio Beta
Follow the steps outlined above though and you
can’t go too far wrong
Haven’t even started coding yet :D
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Android Need to Know


Nice to know a general purpose programming
language like Java / C#
Nice to know a bit about Object Oriented
programming
 Variables
+ Functions
 Inheritance and Subclassing



Functions and parameters
A bit about XML
Have a lot of patience – Lots of bugs + Gotchas
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Starting Eclipse

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Keep the default
workspace:
C:\Program
Files\Eclipse
Android\Workspace
API19 only
available on lab
machines
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New Android Project

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Use the wizard ...
File ->New ->
Other -> Android
->Android Project
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
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Match up the version of Android with the version that you
downloaded!
Minimum version should also point to Android 18
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Android Projects

Main class file is the Activity
public class MainActivity extends Activity {
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
}
}
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Android Structure
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Source Code folder
Generated Code folder
Resource folder
 Images
 Layouts
 Menus
 Strings

AndroidManifest.xml
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Android Manifest
<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
package="com.example.test“ android:versionCode="1“ android:versionName="1.0"
>
<uses-sdk android:minSdkVersion="18“ android:targetSdkVersion="18" />
<application
android:allowBackup="true“ android:icon="@drawable/ic_launcher"
android:label="@string/app_name“ android:theme="@style/AppTheme" >
<activity
android:name=".MainActivity"
android:label="@string/app_name" >
<intent-filter>
<action android:name="android.intent.action.MAIN" />
<category android:name="android.intent.category.LAUNCHER" />
</intent-filter>
</activity>
</application>
</manifest>
Android Manifest
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Defines configuration of the project using XML
Defines project resources
 Images
and Icons
 Layouts
 Menus
 Hardware
needed
 Etc.

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Defines the main activity for the Android Project
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First Android Project – Stick Man
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We will hard code everything to make it easier
Won’t be touching anything in the resources
directory
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Stick Man and House
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Create a new View class
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Stickman and House
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Extend / inherit from
android.view.View
 Set
the package
 Class name
 Superclass

Tick create constructors
from super class.
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Stickman and House
package com.example.test;
import android.content.Context;
import android.util.AttributeSet;
import android.view.View;
public class StickmanHouse extends View {
public StickmanHouse(Context context) {
super(context);
}
public StickmanHouse(Context context, AttributeSet attrs) {
super(context, attrs);
}
public StickmanHouse(Context context, AttributeSet attrs, int
defStyleAttr) {
super(context, attrs, defStyleAttr);
}
}
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Drawing in Android

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Can draw various graphical primitives in Android
using a View classes onDraw(Canvas canvas)
method
By default onDraw(Canvas canvas) does not do
anything...
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Drawing in Android

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The Canvas co-ordinate system
starts at the top-left hand corner
of the screen
Paint objects are used to control
the size, style and colour of the
shapes drawn by the Canvas
object
paint.setColor(Color.RED);
canvas.drawCircle(left, top, 10, paint);
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Stickman and House
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By default the StickmanHouse view does not draw anything
The super classes onDraw(Canvas canvas) method does not do anything
You will need to import android.graphics.*;
Implement the onDraw method as follows
@Override
protected void onDraw(Canvas canvas) {
Paint paint = new Paint();
paint.setColor(Color.RED);
canvas.drawCircle(50, 50, 15, paint);
}
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Link StickmanView to MainActivity
package com.example.test;
import android.app.Activity;
import android.os.Bundle;
public class MainActivity extends Activity {
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(new StickmanHouse(getApplicationContext()));
}
}
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Setting up the Emulator

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Choose the Java perspective
Window -> Open Perspective -> Java
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Setting up the Emulator
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Press the Android Virtual Device button
 It
looks like a little mobile phone
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Setting up the Emulator
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Press the new button
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Create new Virtual Device
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Set the following
parameters
Keep the device screen
smaller – larger devices
are very slow
Select an x86 CPU
Press OK
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Start the new Virtual Device

Takes about
5 – 10
minutes to
start
depending
on your
hardware
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Emulator
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Running your App – Right Click Project
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Running your App


Right Click Project
Select Run As
 Android

Application
The application will
run on your
emulator
(eventually) ...
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Activity

Build a stickman figure in teams of 2 people, using
canvas methods such as:
 canvas.drawRect(25,
125, 150, 250, paint);
 canvas.drawLine(200,125,200,200,paint);
 canvas.drawCircle(200, 115, 15, paint);
 canvas.drawArc(new RectF(200-10,1158,200+10,115+8 ), 0, 180, true, paint);
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What have we done?

A lot on project setup
 Create
project
 Create emulator
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A bit on object oriented programming
A bit on object creation / allocation
A lot on drawing objects using the
canvas and paint objects
Basics of Java language
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Bouncing Ball Animation
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Declare global
integer variables
Use global vars to
specify co-ordinates
of the circle
Use invalidate()
method to force a
screen redraw
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Animation Code
int x = 0;
int y = 0;
@Override
protected void onDraw(Canvas canvas)
{
Paint paint = new Paint();
paint.setColor(Color.RED);
canvas.drawCircle(x,y, 15, paint);
x = x +1;
y = y +1;
invalidate();
}

We need some guard
conditions otherwise
the circle will cont. to
move to the right
forever.
Boundary Guards
int x = 150;
int y = 0;

int deltax = 1;
int deltay = 1;
@Override

protected void onDraw(Canvas canvas) {
Paint paint = new Paint();
paint.setColor(Color.RED);
canvas.drawCircle(x,y, 15, paint);
if(x > getWidth())
{
deltax = -1;
}
x = x +deltax;
y = y +deltay;
invalidate();
}

New delta variables
to control movement
New guard conditions
to reflect ball
movement on right
hand side
Your job implement
guard conditions for
the top, bottom and
left sides
Summary

Basic animation
 Global
variables
 Math operators
 Assignments operators
 If statements
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Challenge get more circles on screen using arrays
Get them to collide with each other
If you want to learn more take the Mobile class over
Summer / Sem 1, 2015.
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