gpdraw
Class SketchPad

java.lang.Object
  java.awt.Component
      java.awt.Container
          javax.swing.JComponent
              javax.swing.JPanel
                  gpdraw.SketchPad

All Implemented Interfaces:

java.awt.event.KeyListener, java.awt.event.MouseListener, java.awt.event.MouseMotionListener, java.awt.image.ImageObserver, java.awt.MenuContainer, java.awt.print.Printable, java.io.Serializable, java.util.EventListener, javax.accessibility.Accessible

public class SketchPad
extends javax.swing.JPanel
implements java.awt.event.MouseListener, java.awt.event.MouseMotionListener, java.awt.event.KeyListener, java.awt.print.Printable

A SketchPad is graphics componet that provides methods for a programmer to draw pictures by moving a drawing object (a "pen")around on the screen The center of the graphics window is at location 0,0. Positive X is to the right; positive Y is up. Headings (angles) are measured in degrees counterclockwise from the positive X axis.

Since:

JDK1.4

Version:

1.11, 08/12/06

Author:

George Peck

See Also:

Serialized Form

Nested Class Summary

Nested classes/interfaces inherited from class javax.swing.JComponent

javax.swing.JComponent.AccessibleJComponent

Field Summary

Fields inherited from class javax.swing.JComponent

TOOL_TIP_TEXT_KEY, UNDEFINED_CONDITION, WHEN_ANCESTOR_OF_FOCUSED_COMPONENT, WHEN_FOCUSED, WHEN_IN_FOCUSED_WINDOW

Fields inherited from class java.awt.Component

BOTTOM_ALIGNMENT, CENTER_ALIGNMENT, LEFT_ALIGNMENT, RIGHT_ALIGNMENT, TOP_ALIGNMENT

Fields inherited from interface java.awt.print.Printable

NO_SUCH_PAGE, PAGE_EXISTS

Fields inherited from interface java.awt.image.ImageObserver

ABORT, ALLBITS, ERROR, FRAMEBITS, HEIGHT, PROPERTIES, SOMEBITS, WIDTH

Constructor Summary

SketchPad(int width, int height)
Constructor.

Method Summary

void	addNotify() Called after native screen peer object exists
void	addSketchPadListener(SketchPadListener listener) Adds the specified SketchPad listener to receive mouse events, mouse motion events, and key events from this component.
void	backward(double distance) This drawing position is moved backward from current location by distance pixels from the old (previous) location.
void	clear() Clears the background to the current color
void	clear(java.awt.Color bg) Clears the background to specified Color
void	clear(int colorCode) Clears the background to the color specified by the given color code
java.awt.Color	codeToColor(int colorCode) Returns the Color indicated by the color code colorCode.
void	down() Sets drawing mode to true.
void	drawCircle(double r) If the object is in drawing mode, Draws a circle of radius radius around the current location using the current width and color.
void	drawImage(java.lang.String fileName) Loads and draws the image specified by the file name fileName.
void	drawImage(java.lang.String fileName, double w, double h) Loads and draws the image specified by the file name fileName.
void	drawOval(double w, double h) Draws the outline of an oval.
void	drawRect(double w, double h) Draws the outline of the specified rectangle.
void	drawString(java.lang.String s) Draw the string text at the current location using the current color and font.
void	fillCircle(double r) Fills the specified circle.
void	fillOff() Sets the drawing mode so that only the outline of all circle, oval and rectangle shapes are drawn..
void	fillOn() Sets the drawing mode so that all circle, oval and rectangle shapes are filled with the current color when drawn.
void	fillOval(double w, double h) Fills the specified oval.
void	fillRect(double w, double h) Fills the specified rectangle.
void	forward(double distance) This drawing position is moved forward from current location by distance pixels from the old (previous) location.
java.awt.Color	getBackgroundColor() Gets the background color of the SketchPad panel
java.awt.Color	getColor() Gets the color of the SketchPad foreground color
double	getDirection() Gets the current drawing orientation.
boolean	getFill() Get the state of the fill flag
int	getHeight() Get the height of the SketchPad panel
SketchPad	getPadPanel() Returns this SketchPadPanel object.
int	getPenWidth() Get the drawing width of the "pen"
java.awt.geom.Point2D.Double	getPosition() Gets the x and y coordinates of the current postion of the current drawing position.
boolean	getTranslate() Get the state of the translation flag
int	getWidth() Get the width of the SketchPad panel
double	getXPos() Gets the x coordinate of the current drawing postion
double	getYPos() Gets the y coordinate of the current drawing postion
void	home() The drawing location is set to the center of the SketchPad panel with the drawing direction set in the positive x-direction.
boolean	isDown() Get the drawing state of the SketchPad panel
void	keyPressed(java.awt.event.KeyEvent e)
void	keyReleased(java.awt.event.KeyEvent e)
void	keyTyped(java.awt.event.KeyEvent e)
void	mouseClicked(java.awt.event.MouseEvent e)
void	mouseDragged(java.awt.event.MouseEvent e)
void	mouseEntered(java.awt.event.MouseEvent e)
void	mouseExited(java.awt.event.MouseEvent e)
void	mouseMoved(java.awt.event.MouseEvent e)
void	mousePressed(java.awt.event.MouseEvent e)
void	mouseReleased(java.awt.event.MouseEvent e)
void	move(double d) This drawing position is moved in the current direction by distance pixels from the old (previous) location.
void	move(double x, double y) This drawing position is moved from the current position to the position specified by the coordinates x and y.
void	move(int x, int y)
void	pause(int delay) Pauses for delay milliseconds.
void	pixel(int x, int y) Plots a single pixel at the point (x, y) using the current drawing color.
void	play(java.lang.String fileName) Plays a wav or midi sound.
void	print() Prints the SketchPad panel area confirming from user with a print dialog
int	print(java.awt.Graphics g, java.awt.print.PageFormat pf, int pi)
void	rotate(double angle) Changes the current direction counterclockwise by angle degrees from the current direction
void	save(java.lang.String fileName) Write the SketchPad panel to a file.
void	setColor(java.awt.Color c) The foreground drawing color is set to c.
void	setColor(int colorCode) The foreground drawing color is set to the Color indicated by the colorCode.
void	setColorHSB(int h, int s, int b) The foreground drawing color is set using hue-saturation-brightness.
void	setColorRGB(int r, int g, int b) The foreground drawing color is set using red-green-blue.
void	setDirection(double d) Sets the direction to d degrees.
void	setWidth(int width) Sets the drawing width to width pixels.
java.lang.String	toString() Returns a string representation of this object.
void	translateOff() Sets the origin of the SketchPad panel to the lower left-hand corner of the window.
void	translateOn() Sets the origin of the SketchPad panel to the center of the window.
void	turn(double angle) Changes the current direction counterclockwise by angle degrees from the current direction
void	turnLeft(double degrees) Changes the current direction counterclockwise by degrees degrees from the current direction
void	turnRight(double degrees) Changes the current direction clockwise by degrees degrees from the current direction
void	up() Sets drawing mode to false (movement mode).

Methods inherited from class javax.swing.JPanel

getAccessibleContext, getUI, getUIClassID, setUI, updateUI

Methods inherited from class javax.swing.JComponent

addAncestorListener, addVetoableChangeListener, computeVisibleRect, contains, createToolTip, disable, enable, firePropertyChange, firePropertyChange, firePropertyChange, getActionForKeyStroke, getActionMap, getAlignmentX, getAlignmentY, getAncestorListeners, getAutoscrolls, getBorder, getBounds, getClientProperty, getComponentPopupMenu, getConditionForKeyStroke, getDebugGraphicsOptions, getDefaultLocale, getFontMetrics, getGraphics, getInheritsPopupMenu, getInputMap, getInputMap, getInputVerifier, getInsets, getInsets, getListeners, getLocation, getMaximumSize, getMinimumSize, getNextFocusableComponent, getPopupLocation, getPreferredSize, getRegisteredKeyStrokes, getRootPane, getSize, getToolTipLocation, getToolTipText, getToolTipText, getTopLevelAncestor, getTransferHandler, getVerifyInputWhenFocusTarget, getVetoableChangeListeners, getVisibleRect, getX, getY, grabFocus, isDoubleBuffered, isLightweightComponent, isManagingFocus, isOpaque, isOptimizedDrawingEnabled, isPaintingTile, isRequestFocusEnabled, isValidateRoot, paint, paintImmediately, paintImmediately, print, printAll, putClientProperty, registerKeyboardAction, registerKeyboardAction, removeAncestorListener, removeNotify, removeVetoableChangeListener, repaint, repaint, requestDefaultFocus, requestFocus, requestFocus, requestFocusInWindow, resetKeyboardActions, reshape, revalidate, scrollRectToVisible, setActionMap, setAlignmentX, setAlignmentY, setAutoscrolls, setBackground, setBorder, setComponentPopupMenu, setDebugGraphicsOptions, setDefaultLocale, setDoubleBuffered, setEnabled, setFocusTraversalKeys, setFont, setForeground, setInheritsPopupMenu, setInputMap, setInputVerifier, setMaximumSize, setMinimumSize, setNextFocusableComponent, setOpaque, setPreferredSize, setRequestFocusEnabled, setToolTipText, setTransferHandler, setVerifyInputWhenFocusTarget, setVisible, unregisterKeyboardAction, update

Methods inherited from class java.awt.Container

add, add, add, add, add, addContainerListener, addPropertyChangeListener, addPropertyChangeListener, applyComponentOrientation, areFocusTraversalKeysSet, countComponents, deliverEvent, doLayout, findComponentAt, findComponentAt, getComponent, getComponentAt, getComponentAt, getComponentCount, getComponents, getComponentZOrder, getContainerListeners, getFocusTraversalKeys, getFocusTraversalPolicy, getLayout, getMousePosition, insets, invalidate, isAncestorOf, isFocusCycleRoot, isFocusCycleRoot, isFocusTraversalPolicyProvider, isFocusTraversalPolicySet, layout, list, list, locate, minimumSize, paintComponents, preferredSize, printComponents, remove, remove, removeAll, removeContainerListener, setComponentZOrder, setFocusCycleRoot, setFocusTraversalPolicy, setFocusTraversalPolicyProvider, setLayout, transferFocusBackward, transferFocusDownCycle, validate

Methods inherited from class java.awt.Component

action, add, addComponentListener, addFocusListener, addHierarchyBoundsListener, addHierarchyListener, addInputMethodListener, addKeyListener, addMouseListener, addMouseMotionListener, addMouseWheelListener, bounds, checkImage, checkImage, contains, createImage, createImage, createVolatileImage, createVolatileImage, dispatchEvent, enable, enableInputMethods, firePropertyChange, firePropertyChange, firePropertyChange, firePropertyChange, firePropertyChange, getBackground, getBounds, getColorModel, getComponentListeners, getComponentOrientation, getCursor, getDropTarget, getFocusCycleRootAncestor, getFocusListeners, getFocusTraversalKeysEnabled, getFont, getForeground, getGraphicsConfiguration, getHierarchyBoundsListeners, getHierarchyListeners, getIgnoreRepaint, getInputContext, getInputMethodListeners, getInputMethodRequests, getKeyListeners, getLocale, getLocation, getLocationOnScreen, getMouseListeners, getMouseMotionListeners, getMousePosition, getMouseWheelListeners, getName, getParent, getPeer, getPropertyChangeListeners, getPropertyChangeListeners, getSize, getToolkit, getTreeLock, gotFocus, handleEvent, hasFocus, hide, imageUpdate, inside, isBackgroundSet, isCursorSet, isDisplayable, isEnabled, isFocusable, isFocusOwner, isFocusTraversable, isFontSet, isForegroundSet, isLightweight, isMaximumSizeSet, isMinimumSizeSet, isPreferredSizeSet, isShowing, isValid, isVisible, keyDown, keyUp, list, list, list, location, lostFocus, mouseDown, mouseDrag, mouseEnter, mouseExit, mouseMove, mouseUp, nextFocus, paintAll, postEvent, prepareImage, prepareImage, remove, removeComponentListener, removeFocusListener, removeHierarchyBoundsListener, removeHierarchyListener, removeInputMethodListener, removeKeyListener, removeMouseListener, removeMouseMotionListener, removeMouseWheelListener, removePropertyChangeListener, removePropertyChangeListener, repaint, repaint, repaint, resize, resize, setBounds, setBounds, setComponentOrientation, setCursor, setDropTarget, setFocusable, setFocusTraversalKeysEnabled, setIgnoreRepaint, setLocale, setLocation, setLocation, setName, setSize, setSize, show, show, size, transferFocus, transferFocusUpCycle

Methods inherited from class java.lang.Object

equals, getClass, hashCode, notify, notifyAll, wait, wait, wait

Constructor Detail

SketchPad

public SketchPad(int width,
                 int height)

Constructor. create a new SketchPad graphics panel of given dimensions

Parameters:

width - width of this SketchPad

height - height of this SketchPad

Method Detail

addNotify

public void addNotify()

Called after native screen peer object exists

Overrides:

addNotify in class javax.swing.JComponent

See Also:

http://mindprod.com/jgloss/addnotify.html

getXPos

public double getXPos()

Gets the x coordinate of the current drawing postion

Returns:

x coordinate of the current drawing postion

getYPos

public double getYPos()

Gets the y coordinate of the current drawing postion

Returns:

y coordinate of the current drawing postion

getDirection

public double getDirection()

Gets the current drawing orientation.

Returns:

current drawing orientation in degrees

isDown

public boolean isDown()

Get the drawing state of the SketchPad panel

Returns:

true if in drawing mode (pen is down); false otherwise

getColor

public java.awt.Color getColor()

Gets the color of the SketchPad foreground color

Returns:

current SketchPad foreground color

getBackgroundColor

public java.awt.Color getBackgroundColor()

Gets the background color of the SketchPad panel

Returns:

current background color of SketchPad panel

getPosition

public java.awt.geom.Point2D.Double getPosition()

Gets the x and y coordinates of the current postion of the current drawing position.

Returns:

x and y coordinates of the current postion as a Point2D.Double.

getPenWidth

public int getPenWidth()

Get the drawing width of the "pen"

Returns:

current width of the "pen"

getWidth

public int getWidth()

Get the width of the SketchPad panel

Overrides:

getWidth in class javax.swing.JComponent

Returns:

current width of the DrawingTool SketchPad panel

getHeight

public int getHeight()

Get the height of the SketchPad panel

Overrides:

getHeight in class javax.swing.JComponent

Returns:

current height of the SketchPad panel

getFill

public boolean getFill()

Get the state of the fill flag

Returns:

true if in fill mode, false otherwise.

getTranslate

public boolean getTranslate()

Get the state of the translation flag

Returns:

true if in translation mode, false otherwise.

home

public void home()

The drawing location is set to the center of the SketchPad panel with the drawing direction set in the positive x-direction.

down

public void down()

Sets drawing mode to true.

up

public void up()

Sets drawing mode to false (movement mode).

translateOn

public void translateOn()

Sets the origin of the SketchPad panel to the center of the window. This is the default mode.

translateOff

public void translateOff()

Sets the origin of the SketchPad panel to the lower left-hand corner of the window.

fillOn

public void fillOn()

Sets the drawing mode so that all circle, oval and rectangle shapes are filled with the current color when drawn.

fillOff

public void fillOff()

Sets the drawing mode so that only the outline of all circle, oval and rectangle shapes are drawn..

setDirection

public void setDirection(double d)

Sets the direction to d degrees. The orientation is d degrees counterclockwise from the positive x-axis

Parameters:

d - degrees counterclockwise from the positive x-axis

setWidth

public void setWidth(int width)

Sets the drawing width to width pixels.

Parameters:

width - drawing width in pixels

Throws:

java.lang.RuntimeException - if width is < 1

clear

public void clear()

Clears the background to the current color

clear

public void clear(java.awt.Color bg)

Clears the background to specified Color

Parameters:

bg - Color of the resulting cleared background

clear

public void clear(int colorCode)

Clears the background to the color specified by the given color code

Parameters:

colorCode - code used to specify the color of the resulting cleared background

See Also:

codeToColor(int colorCode)

setColor

public void setColor(java.awt.Color c)

The foreground drawing color is set to c.

Parameters:

c - a valid Color object

setColorRGB

public void setColorRGB(int r,
                        int g,
                        int b)

The foreground drawing color is set using red-green-blue.

Parameters:

r - the red component

g - the green component

b - the blue component

setColorHSB

public void setColorHSB(int h,
                        int s,
                        int b)

The foreground drawing color is set using hue-saturation-brightness.

Parameters:

h - the hue component

s - the saturation of the color

b - the brightness of the color

codeToColor

public java.awt.Color codeToColor(int colorCode)

Returns the Color indicated by the color code colorCode.

Number	Color	Number	Color	Number	Color	Number	Color
0	black	4	red	8	brown	12	salmon
1	blue	5	magenta	9	tan	13	violet
2	green	6	yellow	10	forest	14	orange
3	cyan	7	white	11	aqua	15	grey

Parameters:

colorCode - a valid colorCode

Returns:

Color corresponding to the colorCode

setColor

public void setColor(int colorCode)

The foreground drawing color is set to the Color indicated by the colorCode.

Parameters:

colorCode - a valid colorCode

See Also:

codeToColor(int colorCode)

move

public void move(int x,
                 int y)

Overrides:

move in class java.awt.Component

move

public void move(double x,
                 double y)

This drawing position is moved from the current position to the position specified by the coordinates x and y. If this object is in drawing mode, a line segment is drawn from the old (previous) position to the absolute position specified by x and y. The direction is changed to the heading given by the move from the previous postion to the current position.

Parameters:

x - x coordinate of destination

y - y coordinate of destination

move

public void move(double d)

This drawing position is moved in the current direction by distance pixels from the old (previous) location. If this object is in drawing mode, a line segment is drawn across the distance path just traversed.

Parameters:

d - pixels to move from the current location

forward

public void forward(double distance)

This drawing position is moved forward from current location by distance pixels from the old (previous) location. If this object is in drawing mode, a line segment is drawn across the distance path just traversed. The direction is unchanged. A delay occurs following this methods execution.

Parameters:

distance - pixels to move forwards from the current location

backward

public void backward(double distance)

This drawing position is moved backward from current location by distance pixels from the old (previous) location. If this object is in drawing mode, a line segment is drawn across the distance path just traversed. The direction is unchanged. A delay occurs following this methods execution.

Parameters:

distance - pixels to move backwards from the current location

pixel

public void pixel(int x,
                  int y)

Plots a single pixel at the point (x, y) using the current drawing color.

Parameters:

x - x coordinate of the pixel to be drawn

y - y coordinate of the pixel to be drawn

fillRect

public void fillRect(double w,
                     double h)

Fills the specified rectangle. The rectangle is centered at the current drawing position. The left and right edges of the rectangle are at x - recWidth/2 and x + recWidth/2. The top and bottom edges are at y - recHeight/2 and y + recHeight/2. The rectangle is filled using the DrawingTool's current color.Degenerates to single pixel if the rectangle is too small.

Parameters:

w - width of the rectangle to be filled

h - height of the rectangle to be filled

drawRect

public void drawRect(double w,
                     double h)

Draws the outline of the specified rectangle. The rectangle is centered at the current drawing position. The left and right edges of the rectangle are at x - recWidth/2 and x + recWidth/2. The top and bottom edges are at y - recHeight/2 and y + recHeight/2. The rectangle is drawn using the DrawingTool's current color. Degenerates to single pixel if the rectangle is too small.

Parameters:

w - width of the rectangle to be drawn

h - height of the rectangle to be drawn

fillCircle

public void fillCircle(double r)

Fills the specified circle. The result is a filled circle of radius radiuscentered around the current drawing position The circle is drawn using the DrawingTool's current color. Degenerates to single pixel if the circle is too small.

Parameters:

r - radius of circle to be drawn

drawCircle

public void drawCircle(double r)

If the object is in drawing mode, Draws a circle of radius radius around the current location using the current width and color. Degenerates to single pixel if the circle is too small.

Parameters:

r - radius of circle to be drawn

fillOval

public void fillOval(double w,
                     double h)

Fills the specified oval. The result is a filled circle or ellipse that is centered around the current drawing position and fits in a rectangle specified by the width, and height arguments. The left and right edges of the bounding rectangle are at x - recWidth/2 and x + recWidth/2. The top and bottom edges are at y - recHeight/2 and y + recHeight/2. The oval is drawn using the DrawingTool's current color. Degenerates to single pixel if the oval is too small.

Parameters:

w - width of the oval to be filled

h - height of the oval to be filled

drawOval

public void drawOval(double w,
                     double h)

Draws the outline of an oval. The result is a circle or ellipse that is centered around the current drawing position and fits in a rectangle specified by the width, and height arguments. The left and right edges of the bounding rectangle are at x - recWidth/2 and x + recWidth/2. The top and bottom edges are at y - recHeight/2 and y + recHeight/2. The oval is drawn using the DrawingTool's current color. Degenerates to single pixel if the oval is too small.

Parameters:

w - width of the oval to be drawn

h - height of the oval to be drawn

drawImage

public void drawImage(java.lang.String fileName)

Loads and draws the image specified by the file name fileName. The image is centered at the current drawing location.

Parameters:

fileName - file name of image to load and draw

drawImage

public void drawImage(java.lang.String fileName,
                      double w,
                      double h)

Loads and draws the image specified by the file name fileName. The image is centered at the current drawing location and scaled of size w-by-h.

Parameters:

fileName - file name of image to load and draw

w - width of bounding box in which the image is drawn

h - height of bounding box in which the image is drawn

rotate

public void rotate(double angle)

Changes the current direction counterclockwise by angle degrees from the current direction

Parameters:

angle - degrees counterclockwise from the current direction

turn

public void turn(double angle)

Changes the current direction counterclockwise by angle degrees from the current direction

Parameters:

angle - degrees counterclockwise from the current direction

turnLeft

public void turnLeft(double degrees)

Changes the current direction counterclockwise by degrees degrees from the current direction

Parameters:

degrees - degrees counterclockwise from the current direction

turnRight

public void turnRight(double degrees)

Changes the current direction clockwise by degrees degrees from the current direction

Parameters:

degrees - degrees clockwise from the current direction

toString

public java.lang.String toString()

Returns a string representation of this object.

Overrides:

toString in class java.awt.Component

Returns:

a string representation of this object

drawString

public void drawString(java.lang.String s)

Draw the string text at the current location using the current color and font.

Parameters:

s - string to be drawn

pause

public void pause(int delay)

Pauses for delay milliseconds. Also invokes a repaint of the display area.

Parameters:

delay - number of ms to delay

getPadPanel

public SketchPad getPadPanel()

Returns this SketchPadPanel object.

Returns:

Returns the SketchPadPanel property

play

public void play(java.lang.String fileName)

Plays a wav or midi sound.

Parameters:

fileName - name of the sound file

save

public void save(java.lang.String fileName)

Write the SketchPad panel to a file. The suffix of the file name can be png, jpg, or gif and will determine the format of the graphics file that is written.

Parameters:

fileName - Name of file to be written

print

public int print(java.awt.Graphics g,
                 java.awt.print.PageFormat pf,
                 int pi)
          throws java.awt.print.PrinterException

Specified by:

print in interface java.awt.print.Printable

Throws:

java.awt.print.PrinterException

print

public void print()

Prints the SketchPad panel area confirming from user with a print dialog

addSketchPadListener

public void addSketchPadListener(SketchPadListener listener)

Adds the specified SketchPad listener to receive mouse events, mouse motion events, and key events from this component. Can only have one listener

Parameters:

listener - the SketchPad listener

keyPressed

public void keyPressed(java.awt.event.KeyEvent e)

Specified by:

keyPressed in interface java.awt.event.KeyListener

keyReleased

public void keyReleased(java.awt.event.KeyEvent e)

Specified by:

keyReleased in interface java.awt.event.KeyListener

keyTyped

public void keyTyped(java.awt.event.KeyEvent e)

Specified by:

keyTyped in interface java.awt.event.KeyListener

mouseClicked

public void mouseClicked(java.awt.event.MouseEvent e)

Specified by:

mouseClicked in interface java.awt.event.MouseListener

mouseDragged

public void mouseDragged(java.awt.event.MouseEvent e)

Specified by:

mouseDragged in interface java.awt.event.MouseMotionListener

mouseMoved

public void mouseMoved(java.awt.event.MouseEvent e)

Specified by:

mouseMoved in interface java.awt.event.MouseMotionListener

mouseEntered

public void mouseEntered(java.awt.event.MouseEvent e)

Specified by:

mouseEntered in interface java.awt.event.MouseListener

mouseExited

public void mouseExited(java.awt.event.MouseEvent e)

Specified by:

mouseExited in interface java.awt.event.MouseListener

mousePressed

public void mousePressed(java.awt.event.MouseEvent e)

Specified by:

mousePressed in interface java.awt.event.MouseListener

mouseReleased

public void mouseReleased(java.awt.event.MouseEvent e)

Specified by:

mouseReleased in interface java.awt.event.MouseListener