android.world
Class VoidWorld

java.lang.Object
  android.world.VoidWorld

public abstract class VoidWorld
extends java.lang.Object

A Class representing an imperative World and the related methods for drawing the world and handling various events. In order to implement a functioning World you must extend this class, and implement an onDraw method. Other handler methods (tickRate, onTick, onMouse, onKey, onRelease, onOrientation, stopWhen, and lastScene) are optional, and can be overridden to add new functionality.

See the individual methods for detailed documentation.

Extending VoidWorld

Developing an Android application is a bit more work, since it requires the Android development kit for Eclipse. After that, you can create an Android Project and fill in all the parameters. The World/VoidWorld classes only require a simple hook to be added to the application's Activity.

Below is a simple example of a World that adds a new point at each mouse click. The world contains a Scene and a new Circle is placed for each "button-down" event received. The VoidWorld is created in the class that extends Activity.

   
        import android.app.Activity;
        import android.os.Bundle;
        import android.view.Display;
       
        import android.image.*;
        import android.world.VoidWorld;
       
        public class VoidMousePoints extends Activity{
            // Called when the activity is first created.
            public void onCreate(Bundle savedState) {
                super.onCreate(savedState);
               
                Display dis = getWindowManager().getDefaultDisplay();
                // Create and start the World 
                new MousePointsVoidWorld(dis.getWidth(), dis.getHeight()-50);
                       .bigBang(this);        
            }
        }
       
        public class MousePointsVoidWorld extends VoidWorld{
            int WIDTH;
            int HEIGHT
            Scene scene;
     
            MousePointsVoidWorld(int WIDTH, int HEIGHT){
                 this.WIDTH = WIDTH;
                 this.HEIGHT = HEIGHT;
                 this.scene = new EmptyScene(WIDTH, HEIGHT);
            }
            
            public Scene onDraw(){ return this.scene; }
     
            public void onMouse(int x, int y, String me){
                if(me.equals("button-down")){
                    this.scene = this.scene.placeImage(
                                     new Circle(20, "solid", "red")
                                           .overlay(new Circle(20, "outline", "black")), x, y);
                }
            }
        }
 

After a few finger-taps, the device will look something like this:

Field Summary

static double	DEFAULT_TICK_RATE Default Tick rate for the world: ~33 frames per second
static java.lang.String	KEY_ARROW_DOWN Key arrow-down event String
static java.lang.String	KEY_ARROW_LEFT Key arrow-left event String
static java.lang.String	KEY_ARROW_RIGHT Key arrow-right event String
static java.lang.String	KEY_ARROW_UP Key arrow-up event String
static java.lang.String	KEY_MENU Menu Key event String.
static java.lang.String	KEY_SEARCH Search Key event String
static java.lang.String	MOUSE_DOWN Mouse down (button-down) event String
static java.lang.String	MOUSE_DRAG Mouse down & move (drag) event String
static java.lang.String	MOUSE_MOVE Mouse motion (move) event String
static java.lang.String	MOUSE_UP Mouse up (button-up) event String

Constructor Summary

VoidWorld()

Method Summary

VoidWorld	bigBang(android.app.Activity act) Kick off the interaction/animation in PORTRATE mode.
VoidWorld	bigBangFullscreen(android.app.Activity act) Kick off the interaction/animation in FULLSCREEN/PORTRATE mode.
VoidWorld	bigBangLandscape(android.app.Activity act) Kick off the interaction/animation in LANDSCAPE mode.
VoidWorld	bigBangLandscapeFullscreen(android.app.Activity act) Kick off the interaction/animation in FULLSCREEN/LANDSCAPE mode.
boolean	equals(java.lang.Object o) Make sure that changes are redrawn every time
Scene	lastScene() Returns the Scene that should be displayed when the interaction/animation completes (stopWhen() returns true).
BigBang	makeBigBang() Get a bigbang instance for this VoidWorld
static void	noScreenShots() Use to Disable Screen Shots
abstract Scene	onDraw() Return a visualization of this World as a Scene.
void	onKey(java.lang.String event) Change this World when a key event is triggered.
void	onMouse(int x, int y, java.lang.String event) Change this World when a touch event is triggered.
void	onOrientation(double x, double y, double z) Change this World when a device orientation event is triggered.
void	onRelease(java.lang.String event) Change this World when a key is released.
void	onTick() Change this World based on the Tick of the clock.
void	pause() Use to temperarily disable onTick/interactions
boolean	stopWhen() Determine if the World/interaction/animation should be stopped.
double	tickRate() Return the tick rate for this World in seconds.
void	unpause() Use to renable onTick/interactions

Methods inherited from class java.lang.Object

getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Detail

DEFAULT_TICK_RATE

public static double DEFAULT_TICK_RATE

Default Tick rate for the world: ~33 frames per second

MOUSE_DOWN

public static java.lang.String MOUSE_DOWN

Mouse down (button-down) event String

MOUSE_UP

public static java.lang.String MOUSE_UP

Mouse up (button-up) event String

MOUSE_MOVE

public static java.lang.String MOUSE_MOVE

Mouse motion (move) event String

MOUSE_DRAG

public static java.lang.String MOUSE_DRAG

Mouse down & move (drag) event String

KEY_ARROW_UP

public static java.lang.String KEY_ARROW_UP

Key arrow-up event String

KEY_ARROW_DOWN

public static java.lang.String KEY_ARROW_DOWN

Key arrow-down event String

KEY_ARROW_LEFT

public static java.lang.String KEY_ARROW_LEFT

Key arrow-left event String

KEY_ARROW_RIGHT

public static java.lang.String KEY_ARROW_RIGHT

Key arrow-right event String

KEY_MENU

public static java.lang.String KEY_MENU

Menu Key event String. The menu key will usually be intercepted to open a save dialog to enable the capture of application/game screen-shots.

KEY_SEARCH

public static java.lang.String KEY_SEARCH

Search Key event String

Constructor Detail

VoidWorld

public VoidWorld()

Method Detail

onDraw

public abstract Scene onDraw()

Return a visualization of this World as a Scene. See EmptyScene, Scene.placeImage(android.image.Image, int, int), and Scene.addLine(int, int, int, int, String) for documentation on constructing Scenes

tickRate

public double tickRate()

Return the tick rate for this World in seconds. For example, 0.5 means two tick. The rate is only accessed when bigBang() is initially called and the window is created.

onTick

public void onTick()

Change this World based on the Tick of the clock. This method is called to get the update the World on each clock tick.

onMouse

public void onMouse(int x,
                    int y,
                    java.lang.String event)

Change this World when a touch event is triggered. x and y are the location of the event on the device screen, and event is a String that describes what kind of event occurred.

In addition to the normal World events (button-down/up) Android devices include a "long-button-down" event, for when the the user does a long press (touch and hold).

Possible Mouse Events

"button-down" :	The user presses the touch screen of the device
"long-button-down" :	The user presses and holds on the touch screen of the device
"button-up" :	The user releases the touch screen of the device
"move" :	The user moves the mouse in the World window
"drag" :	The user touches and moves on the touch screen of the device

onKey

public void onKey(java.lang.String event)

Change this World when a key event is triggered. The given event is a String that describes which key was pressed.

Special Key

"up" :	The user presses the up-arrow key
"down" :	The user presses the down-arrow key
"left" :	The user presses the left-arrow key
"right" :	The user presses the right-arrow key

Other keys generate a single character String that represents the key pressed. For example, Pressing the B key on the keyboard generates "b" as an event. If the shift key is held while pressing B then "B" is generated.

onRelease

public void onRelease(java.lang.String event)

Change this World when a key is released. The given event is a String that describes which key was released.

Special Keys

"up" :	The user presses the up-arrow key
"down" :	The user presses the down-arrow key
"left" :	The user presses the left-arrow key
"right" :	The user presses the right-arrow key

Other keys generate a single character String that represents the key released. For example, Pressing then releasing the B key on the keyboard generates "b" as an onKey event and again as an onRelease event. If the shift key is held while pressing/releasing B then "B" is generated.

onOrientation

public void onOrientation(double x,
                          double y,
                          double z)

Change this World when a device orientation event is triggered. x, y, and z make-up the new orientation vector for the device. When the device is resting on a flat, level surface the orientation should be entirely in the z direction (typically straight out the the back of the device).

If you are only concerned with the "down" angle (direction of down with respect to the screen) you can calculate it with a method as follows:

      double down(double x, double y, double z){
         double ang = Math.acos(x/Math.sqrt(x*x + y*y))+Math.PI;
         if(y < 0)return 2*Math.PI-ang;
         return ang;
      }
   

stopWhen

public boolean stopWhen()

Determine if the World/interaction/animation should be stopped. Returning a value of true discontinues all events (mouse, key, ticks) and causes lastScene() to be used to draw the final Scene.

lastScene

public Scene lastScene()

Returns the Scene that should be displayed when the interaction/animation completes (stopWhen() returns true).

bigBang

public VoidWorld bigBang(android.app.Activity act)

Kick off the interaction/animation in PORTRATE mode. This method returns the final state of the world after the user closes the World window.

bigBangLandscape

public VoidWorld bigBangLandscape(android.app.Activity act)

Kick off the interaction/animation in LANDSCAPE mode.

bigBangFullscreen

public VoidWorld bigBangFullscreen(android.app.Activity act)

Kick off the interaction/animation in FULLSCREEN/PORTRATE mode. This method returns the final state of the world after the user closes the World window.

bigBangLandscapeFullscreen

public VoidWorld bigBangLandscapeFullscreen(android.app.Activity act)

Kick off the interaction/animation in FULLSCREEN/LANDSCAPE mode.

makeBigBang

public BigBang makeBigBang()

Get a bigbang instance for this VoidWorld

noScreenShots

public static void noScreenShots()

Use to Disable Screen Shots

pause

public void pause()

Use to temperarily disable onTick/interactions

unpause

public void unpause()

Use to renable onTick/interactions

equals

public boolean equals(java.lang.Object o)

Make sure that changes are redrawn every time

Overrides:

equals in class java.lang.Object