Powerpoint - CS4HS@Unitec 2014

Transcript Powerpoint - CS4HS@Unitec 2014

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

John Casey  Dr John Casey  Email: [email protected]

 Room 3008, building 183  Phone: 815-4321 ext. 6003

My Experience    Oracle Certified Java Programmer (OCJP) Programmer  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

Android Gremlins      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

First Steps  Work out whether you are running a 32-bit or 64-bit OS  Control Panel >System and Security->System

Do you have Java Installed?

 http://www.oracle.com/technetwork/java/javase/ downloads/index.html

Download 32-bit OR 64-bit Version

Java already installed?

 Drop to a Command Prompt

Download the ADT Bundle  https://developer.android.com/sdk/index.html

 The number of bits must match! for OS, Java and ADT Bundle

Download the ADT Bundle  Make a cup of tea / coffee while the ADT Bundle downloads  385 MB later .... Extract the ADT Bundle.

Extract the ADT Bundle  Extract files to c:\android-adt

Open the SDK Manager

Update the SDK   Be careful not to download the Google Glass packages Android 4.3.1 API 18 is a good stable version of Android

 More Coffee ...

Run Eclipse

Update Eclipse

Android Developer Toolkit  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

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

Starting Eclipse  Keep the default workspace:  C:\Program Files\Eclipse Android\Workspace  API19 only available on lab machines

New Android Project  Use the wizard ...

 File ->New -> Other -> Android ->Android Project

  Match up the version of Android with the version that you downloaded!

Minimum version should also point to Android 18

} 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 );

}

Android Structure  Source Code folder  Generated Code folder  Resource folder  Images  Layouts  Menus  Strings  AndroidManifest.xml

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" />

Android Manifest  Defines configuration of the project using XML  Defines project resources  Images and Icons  Layouts  Menus  Hardware needed  Etc.

 Defines the main activity for the Android Project

First Android Project – Stick Man  We will hard code everything to make it easier  Won’t be touching anything in the resources directory

Stick Man and House  Create a new View class

Stickman and House  Extend / inherit from android.view.View

 Set the package  Class name  Superclass  Tick create constructors from super class.

Stickman and House package com.example.test; import android.content.Context; import android.util.AttributeSet; import android.view.View; public class public StickmanHouse extends View { 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); } }

Drawing in Android  Can draw various graphical primitives in Android using a View classes onDraw(Canvas canvas) method  By default onDraw(Canvas canvas) does not do anything...

Drawing in Android  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

);

Stickman and House     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);

Link StickmanView to MainActivity package com.example.test; import import android.app.Activity; android.os.Bundle; public class MainActivity extends Activity { @Override protected void onCreate(Bundle savedInstanceState) { super .onCreate(savedInstanceState); setContentView( new StickmanHouse(

getApplicationContext()

)); } }

Setting up the Emulator  Choose the Java perspective  Window -> Open Perspective -> Java

Setting up the Emulator  Press the Android Virtual Device button  It looks like a little mobile phone

Setting up the Emulator  Press the new button

Create new Virtual Device  Set the following parameters  Keep the device screen smaller – larger devices are very slow  Select an x86 CPU  Press OK

Start the new Virtual Device  Takes about 5 – 10 minutes to start depending on your hardware

Emulator

Running your App – Right Click Project

Running your App  Right Click Project  Select Run As  Android Application  The application will run on your emulator (eventually) ...

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(200-10,115 8,200+10,115+8 ), 0, 180, true, paint);

What have we done?

 A lot on project setup  Create project  Create emulator  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

Bouncing Ball Animation  Declare global integer variables  Use global vars to specify co-ordinates of the circle  Use invalidate() method to force a screen redraw

Animation Code int int x y = 0; = 0; @Override protected void { onDraw(Canvas canvas) Paint paint = new Paint(); paint.setColor(Color.

RED );

canvas.drawCircle( x , y , 15, paint); x y = x = y +1; +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 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.