Sprite

java.lang.Object
- com.google.appinventor.components.runtime.VisibleComponent
- - com.google.appinventor.components.runtime.Sprite

All Implemented Interfaces:

AlarmHandler, Component, Deleteable, OnDestroyListener

Direct Known Subclasses:

Ball, ImageSprite
```
public abstract class Sprite
extends VisibleComponent
implements AlarmHandler, OnDestroyListener, Deleteable
```
Superclass of sprites able to move and interact with other sprites. While the Simple programmer sees the x- and y-coordinates as integers, they are maintained internally as doubles so fractional changes (caused by multiplying the speed by a cosine or sine value) have the chance to add up.

Field Summary

Fields
Modifier and Type	Field and Description
`protected Canvas`	`canvas`
`protected double`	`heading` The angle, in degrees below the positive x-axis, specified by the user.
`protected double`	`headingCos`
`protected double`	`headingRadians`
`protected double`	`headingSin`
`protected boolean`	`initialized`
`protected int`	`interval`
`protected float`	`speed`
`protected double`	`userHeading` The angle, in degrees above the positive x-axis, specified by the user.
`protected boolean`	`visible`
`protected double`	`xLeft`
`protected double`	`yTop`
`protected double`	`zLayer`

Fields inherited from interface com.google.appinventor.components.runtime.Component
ACCELEROMETER_SENSITIVITY_MODERATE, ACCELEROMETER_SENSITIVITY_STRONG, ACCELEROMETER_SENSITIVITY_WEAK, ALIGNMENT_CENTER, ALIGNMENT_NORMAL, ALIGNMENT_OPPOSITE, ASSET_DIRECTORY, BUTTON_SHAPE_DEFAULT, BUTTON_SHAPE_OVAL, BUTTON_SHAPE_RECT, BUTTON_SHAPE_ROUNDED, COLOR_BLACK, COLOR_BLUE, COLOR_CYAN, COLOR_DEFAULT, COLOR_DKGRAY, COLOR_GRAY, COLOR_GREEN, COLOR_LTGRAY, COLOR_MAGENTA, COLOR_NONE, COLOR_ORANGE, COLOR_PINK, COLOR_RED, COLOR_WHITE, COLOR_YELLOW, DEFAULT_VALUE_COLOR_BLACK, DEFAULT_VALUE_COLOR_BLUE, DEFAULT_VALUE_COLOR_CYAN, DEFAULT_VALUE_COLOR_DEFAULT, DEFAULT_VALUE_COLOR_DKGRAY, DEFAULT_VALUE_COLOR_GRAY, DEFAULT_VALUE_COLOR_GREEN, DEFAULT_VALUE_COLOR_LTGRAY, DEFAULT_VALUE_COLOR_MAGENTA, DEFAULT_VALUE_COLOR_NONE, DEFAULT_VALUE_COLOR_ORANGE, DEFAULT_VALUE_COLOR_PINK, DEFAULT_VALUE_COLOR_RED, DEFAULT_VALUE_COLOR_WHITE, DEFAULT_VALUE_COLOR_YELLOW, DIRECTION_EAST, DIRECTION_MAX, DIRECTION_MIN, DIRECTION_NONE, DIRECTION_NORTH, DIRECTION_NORTHEAST, DIRECTION_NORTHWEST, DIRECTION_SOUTH, DIRECTION_SOUTHEAST, DIRECTION_SOUTHWEST, DIRECTION_WEST, FONT_DEFAULT_SIZE, LAYOUT_ORIENTATION_HORIZONTAL, LAYOUT_ORIENTATION_VERTICAL, LENGTH_FILL_PARENT, LENGTH_PREFERRED, LENGTH_UNKNOWN, SLIDER_MAX_VALUE, SLIDER_MIN_VALUE, SLIDER_THUMB_VALUE, TOAST_LENGTH_LONG, TOAST_LENGTH_SHORT, TYPEFACE_DEFAULT, TYPEFACE_MONOSPACE, TYPEFACE_SANSSERIF, TYPEFACE_SERIF

Constructor Summary

Constructors
Modifier	Constructor and Description
`protected`	`Sprite(ComponentContainer container)` Creates a new Sprite component.
`protected`	`Sprite(ComponentContainer container, android.os.Handler handler)` Creates a new Sprite component.

Method Summary

Methods
Modifier and Type	Method and Description
`void`	`alarm()` Moves and redraws sprite, registering changes.
`void`	`Bounce(int edge)` Makes this sprite bounce, as if off of a wall by changing the `heading` (unless the sprite is not traveling toward the specified direction).
`void`	`CollidedWith(Sprite other)` Handler for CollidedWith events, called when two sprites collide.
`static boolean`	`colliding(Sprite sprite1, Sprite sprite2)` Determines whether two sprites are in collision.
`boolean`	`CollidingWith(Sprite other)` Indicates whether a collision has been registered between this sprite and the passed sprite.
`boolean`	`containsPoint(double qx, double qy)` Indicates whether the specified point is contained by this sprite.
`void`	`Dragged(float startX, float startY, float prevX, float prevY, float currentX, float currentY)` Handler for Dragged events.
`void`	`EdgeReached(int edge)` Event handler called when the sprite reaches an edge of the screen.
`boolean`	`Enabled()` Enabled property getter method.
`void`	`Enabled(boolean enabled)` Enabled property setter method: starts or stops the timer.
`void`	`Flung(float x, float y, float speed, float heading, float xvel, float yvel)` When a fling gesture (quick swipe) is made on the sprite: provides the (x,y) position of the start of the fling, relative to the upper left of the canvas.
`BoundingBox`	`getBoundingBox(int border)` Provides the bounding box for this sprite.
`HandlesEventDispatching`	`getDispatchDelegate()` Returns the dispatch delegate that is responsible for dispatching events for this component.
`double`	`Heading()` Returns the heading of the sprite.
`void`	`Heading(double userHeading)` Sets heading in which sprite should move.
`protected int`	`hitEdge()` Specifies which edge of the canvas has been hit by the Sprite, if any, moving the sprite back in bounds.
`protected int`	`hitEdge(int canvasWidth, int canvasHeight)`
`void`	`Initialize()`
`boolean`	`intersectsWith(BoundingBox rect)` Determines whether this sprite intersects with the given rectangle.
`int`	`Interval()` Interval property getter method.
`void`	`Interval(int interval)` Interval property setter method: sets the interval between timer events.
`void`	`MoveIntoBounds()` Moves the sprite back in bounds if part of it extends out of bounds, having no effect otherwise.
`protected void`	`moveIntoBounds(int canvasWidth, int canvasHeight)` Moves the sprite back in bounds if part of it extends out of bounds, having no effect otherwise.
`void`	`MoveTo(double x, double y)` Moves sprite directly to specified point.
`void`	`NoLongerCollidingWith(Sprite other)` Handler for NoLongerCollidingWith events, called when a pair of sprites cease colliding.
`void`	`onDelete()`
`void`	`onDestroy()`
`protected abstract void`	`onDraw(android.graphics.Canvas canvas)` Draws the sprite on the given canvas
`void`	`PointInDirection(double x, double y)` Turns this sprite to point towards a given point.
`void`	`PointTowards(Sprite target)` Turns this sprite to point towards a given other sprite.
`protected void`	`postEvent(Sprite sprite, java.lang.String eventName, java.lang.Object... args)` Posts a dispatch for the specified event.
`protected void`	`registerChange()` Responds to a move or change of this sprite by redrawing the enclosing Canvas and checking for any consequences that need handling.
`float`	`Speed()` Gets the speed with which this sprite moves.
`void`	`Speed(float speed)` Sets the speed with which this sprite should move.
`void`	`TouchDown(float x, float y)` When the user begins touching the sprite (places finger on sprite and leaves it there): provides the (x,y) position of the touch, relative to the upper left of the canvas
`void`	`Touched(float x, float y)` When the user touches the sprite and then immediately lifts finger: provides the (x,y) position of the touch, relative to the upper left of the canvas
`void`	`TouchUp(float x, float y)` When the user stops touching the sprite (lifts finger after a TouchDown event): provides the (x,y) position of the touch, relative to the upper left of the canvas
`protected void`	`updateCoordinates()` Updates the x- and y-coordinates based on the heading and speed.
`boolean`	`Visible()` Gets whether sprite is visible.
`void`	`Visible(boolean visible)` Sets whether sprite should be visible.
`double`	`X()`
`void`	`X(double x)`
`double`	`Y()`
`void`	`Y(double y)`
`double`	`Z()`
`void`	`Z(double layer)` Sets the layer of the sprite, indicating whether it will appear in front of or behind other sprites.

Methods inherited from class com.google.appinventor.components.runtime.VisibleComponent
Height, Height, Width, Width

Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

- Field Detail
  - canvas
```
protected final Canvas canvas
```
  - initialized
```
protected boolean initialized
```
  - interval
```
protected int interval
```
  - visible
```
protected boolean visible
```
  - xLeft
```
protected double xLeft
```
  - yTop
```
protected double yTop
```
  - zLayer
```
protected double zLayer
```
  - speed
```
protected float speed
```
  - userHeading
```
protected double userHeading
```
    The angle, in degrees above the positive x-axis, specified by the user. This is private in order to enforce that changing it also changes heading, headingRadians, headingCos, and headingSin.
  - heading
```
protected double heading
```
    The angle, in degrees below the positive x-axis, specified by the user. We use this to compute new coordinates because, on Android, the y-coordinate increases "below" the x-axis.
  - headingRadians
```
protected double headingRadians
```
  - headingCos
```
protected double headingCos
```
  - headingSin
```
protected double headingSin
```
- Constructor Detail
  - Sprite
```
protected Sprite(ComponentContainer container,
      android.os.Handler handler)
```
    Creates a new Sprite component. This version exists to allow injection of a mock handler for testing.
    
    Parameters:
    container - where the component will be placed
    handler - a scheduler to which runnable events will be posted
  - Sprite
```
protected Sprite(ComponentContainer container)
```
    Creates a new Sprite component. This is called by the constructors of concrete subclasses, such as Ball and ImageSprite.
    
    Parameters:
    container - where the component will be placed
- Method Detail
  - Initialize
```
public void Initialize()
```
  - Enabled
```
public boolean Enabled()
```
    Enabled property getter method.
    
    Returns:
    true indicates a running timer, false a stopped timer
  - Enabled
```
public void Enabled(boolean enabled)
```
    Enabled property setter method: starts or stops the timer.
    
    Parameters:
    enabled - true starts the timer, false stops it
  - Heading
```
public void Heading(double userHeading)
```
    Sets heading in which sprite should move. In addition to changing the local variables userHeading and heading, this sets headingCos, headingSin, and headingRadians.
    
    Parameters:
    userHeading - degrees above the positive x-axis
  - Heading
```
public double Heading()
```
    Returns the heading of the sprite.
    
    Returns:
    degrees above the positive x-axis
  - Interval
```
public int Interval()
```
    Interval property getter method.
    
    Returns:
    timer interval in ms
  - Interval
```
public void Interval(int interval)
```
    Interval property setter method: sets the interval between timer events.
    
    Parameters:
    interval - timer interval in ms
  - Speed
```
public void Speed(float speed)
```
    Sets the speed with which this sprite should move.
    
    Parameters:
    speed - the magnitude (in pixels) to move every interval milliseconds
  - Speed
```
public float Speed()
```
    Gets the speed with which this sprite moves.
    
    Returns:
    the magnitude (in pixels) the sprite moves every interval milliseconds.
  - Visible
```
public boolean Visible()
```
    Gets whether sprite is visible.
    
    Returns:
    true if the sprite is visible, false otherwise
  - Visible
```
public void Visible(boolean visible)
```
    Sets whether sprite should be visible.
    
    Parameters:
    visible - true if the sprite should be visible; false otherwise.
  - X
```
public double X()
```
  - X
```
public void X(double x)
```
  - Y
```
public void Y(double y)
```
  - Y
```
public double Y()
```
  - Z
```
public void Z(double layer)
```
    Sets the layer of the sprite, indicating whether it will appear in front of or behind other sprites.
    
    Parameters:
    layer - higher numbers indicate that this sprite should appear in front of ones with lower numbers; if values are equal for sprites, either can go in front of the other
  - Z
```
public double Z()
```
  - postEvent
```
protected void postEvent(Sprite sprite,
             java.lang.String eventName,
             java.lang.Object... args)
```
    Posts a dispatch for the specified event. This guarantees that event handlers run with serial semantics, e.g., appear atomic relative to each other. This method is overridden in tests.
    
    Parameters:
    sprite - the instance on which the event takes place
    eventName - the name of the event
    args - the arguments to the event handler
  - CollidedWith
```
public void CollidedWith(Sprite other)
```
    Handler for CollidedWith events, called when two sprites collide. Note that checking for collisions with a rotated ImageSprite currently checks against the sprite's unrotated position. Therefore, collision checking will be inaccurate for tall narrow or short wide sprites that are rotated.
    
    Parameters:
    other - the other sprite in the collision
  - Dragged
```
public void Dragged(float startX,
           float startY,
           float prevX,
           float prevY,
           float currentX,
           float currentY)
```
    Handler for Dragged events. On all calls, the starting coordinates are where the screen was first touched, and the "current" coordinates describe the endpoint of the current line segment. On the first call within a given drag, the "previous" coordinates are the same as the starting coordinates; subsequently, they are the "current" coordinates from the prior call. Note that the Sprite won't actually move anywhere in response to the Dragged event unless MoveTo is specifically called.
    
    Parameters:
    startX - the starting x-coordinate
    startY - the starting y-coordinate
    prevX - the previous x-coordinate (possibly equal to startX)
    prevY - the previous y-coordinate (possibly equal to startY)
    currentX - the current x-coordinate
    currentY - the current y-coordinate
  - EdgeReached
```
public void EdgeReached(int edge)
```
    Event handler called when the sprite reaches an edge of the screen. If Bounce is then called with that edge, the sprite will appear to bounce off of the edge it reached.
  - NoLongerCollidingWith
```
public void NoLongerCollidingWith(Sprite other)
```
    Handler for NoLongerCollidingWith events, called when a pair of sprites cease colliding. This also registers the removal of the collision to a private variable registeredCollisions so that CollidedWith(Sprite) and this event are only raised once per beginning and ending of a collision.
    
    Parameters:
    other - the sprite formerly colliding with this sprite
  - Touched
```
public void Touched(float x,
           float y)
```
    When the user touches the sprite and then immediately lifts finger: provides the (x,y) position of the touch, relative to the upper left of the canvas
    
    Parameters:
    x - x-coordinate of touched point
    y - y-coordinate of touched point
  - Flung
```
public void Flung(float x,
         float y,
         float speed,
         float heading,
         float xvel,
         float yvel)
```
    When a fling gesture (quick swipe) is made on the sprite: provides the (x,y) position of the start of the fling, relative to the upper left of the canvas. Also provides the speed (pixels per millisecond) and heading (0-360 degrees) of the fling, as well as the x velocity and y velocity components of the fling's vector.
    
    Parameters:
    x - x-coordinate of touched point
    y - y-coordinate of touched point * @param speed the speed of the fling sqrt(xspeed^2 + yspeed^2)
    heading - the heading of the fling
    xvel - the speed in x-direction of the fling
    yvel - the speed in y-direction of the fling
  - TouchUp
```
public void TouchUp(float x,
           float y)
```
    When the user stops touching the sprite (lifts finger after a TouchDown event): provides the (x,y) position of the touch, relative to the upper left of the canvas
    
    Parameters:
    x - x-coordinate of touched point
    y - y-coordinate of touched point
  - TouchDown
```
public void TouchDown(float x,
             float y)
```
    When the user begins touching the sprite (places finger on sprite and leaves it there): provides the (x,y) position of the touch, relative to the upper left of the canvas
    
    Parameters:
    x - x-coordinate of touched point
    y - y-coordinate of touched point
  - Bounce
```
public void Bounce(int edge)
```
    Makes this sprite bounce, as if off of a wall by changing the heading (unless the sprite is not traveling toward the specified direction). This also calls MoveIntoBounds() in case the sprite is out of bounds.
    
    Parameters:
    edge - the direction of the object (real or imaginary) to bounce off of; this should be one of Component.DIRECTION_NORTH, Component.DIRECTION_NORTHEAST, Component.DIRECTION_EAST, Component.DIRECTION_SOUTHEAST, Component.DIRECTION_SOUTH, Component.DIRECTION_SOUTHWEST, Component.DIRECTION_WEST, or Component.DIRECTION_NORTHWEST.
  - CollidingWith
```
public boolean CollidingWith(Sprite other)
```
    Indicates whether a collision has been registered between this sprite and the passed sprite.
    
    Parameters:
    other - the sprite to check for collision with this sprite
    
    Returns:
    true if a collision event has been raised for the pair of sprites and they still are in collision, false otherwise.
  - MoveIntoBounds
```
public void MoveIntoBounds()
```
    Moves the sprite back in bounds if part of it extends out of bounds, having no effect otherwise. If the sprite is too wide to fit on the canvas, this aligns the left side of the sprite with the left side of the canvas. If the sprite is too tall to fit on the canvas, this aligns the top side of the sprite with the top side of the canvas.
  - MoveTo
```
public void MoveTo(double x,
          double y)
```
    Moves sprite directly to specified point.
    
    Parameters:
    x - the x-coordinate
    y - the y-coordinate
  - PointTowards
```
public void PointTowards(Sprite target)
```
    Turns this sprite to point towards a given other sprite.
    
    Parameters:
    target - the other sprite to point towards
  - PointInDirection
```
public void PointInDirection(double x,
                    double y)
```
    Turns this sprite to point towards a given point.
    
    Parameters:
    x - parameter of the point to turn to
    y - parameter of the point to turn to
  - registerChange
```
protected void registerChange()
```
    Responds to a move or change of this sprite by redrawing the enclosing Canvas and checking for any consequences that need handling. Specifically, this (1) notifies the Canvas of a change so it can detect any collisions, etc., and (2) raises the EdgeReached(int) event if the Sprite has reached the edge of the Canvas.
  - hitEdge
```
protected int hitEdge()
```
    Specifies which edge of the canvas has been hit by the Sprite, if any, moving the sprite back in bounds.
    
    Returns:
    Component.DIRECTION_NONE if no edge has been hit, or a direction (e.g., Component.DIRECTION_NORTHEAST) if that edge of the canvas has been hit
  - moveIntoBounds
```
protected final void moveIntoBounds(int canvasWidth,
                  int canvasHeight)
```
    Moves the sprite back in bounds if part of it extends out of bounds, having no effect otherwise. If the sprite is too wide to fit on the canvas, this aligns the left side of the sprite with the left side of the canvas. If the sprite is too tall to fit on the canvas, this aligns the top side of the sprite with the top side of the canvas.
  - updateCoordinates
```
protected void updateCoordinates()
```
    Updates the x- and y-coordinates based on the heading and speed. The caller is responsible for calling registerChange().
  - hitEdge
```
protected int hitEdge(int canvasWidth,
          int canvasHeight)
```
  - getBoundingBox
```
public BoundingBox getBoundingBox(int border)
```
    Provides the bounding box for this sprite. Modifying the returned value does not affect the sprite.
    
    Parameters:
    border - the number of pixels outside the sprite to include in the bounding box
    
    Returns:
    the bounding box for this sprite
  - colliding
```
public static boolean colliding(Sprite sprite1,
                Sprite sprite2)
```
    Determines whether two sprites are in collision. Note that we cannot merely see whether the rectangular regions around each intersect, since some types of sprite, such as BallSprite, are not rectangular.
    
    Parameters:
    sprite1 - one sprite
    sprite2 - another sprite
    
    Returns:
    true if they are in collision, false otherwise
  - intersectsWith
```
public boolean intersectsWith(BoundingBox rect)
```
    Determines whether this sprite intersects with the given rectangle.
    
    Parameters:
    rect - the rectangle
    
    Returns:
    true if they intersect, false otherwise
  - containsPoint
```
public boolean containsPoint(double qx,
                    double qy)
```
    Indicates whether the specified point is contained by this sprite. Subclasses of Sprite that are not rectangular should override this method.
    
    Parameters:
    qx - the x-coordinate
    qy - the y-coordinate
    
    Returns:
    whether (qx, qy) falls within this sprite
  - alarm
```
public void alarm()
```
    Moves and redraws sprite, registering changes.
    
    Specified by:
    
    alarm in interface AlarmHandler
  - getDispatchDelegate
```
public HandlesEventDispatching getDispatchDelegate()
```
    Description copied from interface: Component
    
    Returns the dispatch delegate that is responsible for dispatching events for this component.
    
    Specified by:
    
    getDispatchDelegate in interface Component
  - onDestroy
```
public void onDestroy()
```
    Specified by:
    
    onDestroy in interface OnDestroyListener
  - onDelete
```
public void onDelete()
```
    Specified by:
    
    onDelete in interface Deleteable
  - onDraw
```
protected abstract void onDraw(android.graphics.Canvas canvas)
```
    Draws the sprite on the given canvas
    
    Parameters:
    canvas - the canvas on which to draw

Class Sprite

Field Summary

Fields inherited from interface com.google.appinventor.components.runtime.Component

Constructor Summary

Method Summary

Methods inherited from class com.google.appinventor.components.runtime.VisibleComponent

Methods inherited from class java.lang.Object

Field Detail

canvas

initialized

interval

visible

xLeft

yTop

zLayer

speed

userHeading

heading

headingRadians

headingCos

headingSin

Constructor Detail

Sprite

Sprite

Method Detail

Initialize

Enabled

Enabled

Heading

Heading

Interval

Interval

Speed

Speed

Visible

Visible

X

X

Y

Y

Z

Z

postEvent

CollidedWith

Dragged

EdgeReached

NoLongerCollidingWith

Touched

Flung

TouchUp

TouchDown

Bounce

CollidingWith

MoveIntoBounds

MoveTo

PointTowards

PointInDirection

registerChange

hitEdge

moveIntoBounds

updateCoordinates

hitEdge

getBoundingBox

colliding

intersectsWith

containsPoint

alarm

getDispatchDelegate

onDestroy

onDelete

onDraw