com.jmobilecore.ui.core
Class Component

java.lang.Object
  com.jmobilecore.ui.core.Component

Direct Known Subclasses:

ImageComponent, Label, SoftKeyBar, TextComponent, TextPane

public abstract class Component
extends java.lang.Object

A component is an object having a graphical representation that can be displayed on the screen and that can interact with the user. Examples of components are the buttons, checkboxes, and scrollbars of a typical graphical user interface.

The Component class is the abstract superclass of the User Interface components. Class Component can also be extended directly to create a custom component.

Author:

Greg Gridin

Field Summary

int	alignment The label's alignment.
int	background The background color for this component.
static int	CENTER Indicates that the component should be centered.
boolean	focusable
int	focusedBackground The background color for this component when it focused.
int	focusedForeground The foreground color for this component when it focused.
protected javax.microedition.lcdui.Font	font The font used by this component.
int	foreground The foreground color for this component.
protected int	height The height of the component.
protected boolean	isCompletelyVisible Indicated if component is completely visible on the screen
protected boolean	isFocused Indicated if component is focusable
protected boolean	isVisible Indicated if component is completely or partially visible on the screen
static int	LEFT Indicates that the component should be left justified.
protected ScreenCanvas	parentScreen The parent screen of the object.
static int	RIGHT Indicates that the component should be right justified.
protected int	screenY Vertical offset in pixels of current component from top of the window
protected boolean	valid Indicated if component should be repainted
int	width The width of the component.

Constructor Summary

Component()

Method Summary

void	destructor() Default destructor.
int	getBackground() Get background
javax.microedition.lcdui.Font	getFont() Get the component's font
int	getForeground() Get foreground
int	getHeight() Returns the current height of this component.
int	getWidth() Returns the current width of this component.
void	invalidate() Invalidates this component.
boolean	isFocusOwner() Returns true if this Component is the focus owner.
protected boolean	keyPressed(int keyCode) Processes a press of a key.
protected boolean	keyReleased(int keyCode) Processes a release of a key.
protected boolean	keyRepeated(int keyCode) Processes when a key is repeated (held down).
void	paint(javax.microedition.lcdui.Graphics g) Paints this component.
protected void	paintBackground(javax.microedition.lcdui.Graphics g) Paints background for the component
protected boolean	pointerDragged(int x, int y) Processes when a pointer is dragged (held down).
protected boolean	pointerPressed(int x, int y) Processes a press of a pointer.
protected boolean	pointerReleased(int x, int y) Processes a release of a pointer.
protected void	prepareForeground(javax.microedition.lcdui.Graphics g) Prepares foreground for painting
void	releaseFocus()
void	requestFocus() Sets the focusable state of this Component to the specified value.
void	setFont(javax.microedition.lcdui.Font font) Sets the font of this component.
protected void	setHeight() Calculates the component height

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Detail

alignment

public int alignment

The label's alignment. The default alignment is set to be left justified.

background

public int background

The background color for this component.

CENTER

public static final int CENTER

Indicates that the component should be centered.

See Also:

Constant Field Values

focusable

public boolean focusable

focusedBackground

public int focusedBackground

The background color for this component when it focused.

focusedForeground

public int focusedForeground

The foreground color for this component when it focused.

font

protected javax.microedition.lcdui.Font font

The font used by this component. The font can be null.

See Also:

setFont(javax.microedition.lcdui.Font)

foreground

public int foreground

The foreground color for this component.

height

protected int height

The height of the component.

isCompletelyVisible

protected boolean isCompletelyVisible

Indicated if component is completely visible on the screen

isFocused

protected boolean isFocused

Indicated if component is focusable

See Also:

isFocusOwner(), requestFocus(), releaseFocus()

isVisible

protected boolean isVisible

Indicated if component is completely or partially visible on the screen

LEFT

public static final int LEFT

Indicates that the component should be left justified.

See Also:

Constant Field Values

parentScreen

protected ScreenCanvas parentScreen

The parent screen of the object.

RIGHT

public static final int RIGHT

Indicates that the component should be right justified.

See Also:

Constant Field Values

screenY

protected int screenY

Vertical offset in pixels of current component from top of the window

valid

protected boolean valid

Indicated if component should be repainted

See Also:

invalidate()

width

public int width

The width of the component.

Constructor Detail

Component

public Component()

Method Detail

destructor

public void destructor()

Default destructor. Helps VM to perform garbage collection

getBackground

public int getBackground()

Get background

getFont

public javax.microedition.lcdui.Font getFont()

Get the component's font

Returns:

the current font

getForeground

public int getForeground()

Get foreground

getHeight

public int getHeight()

Returns the current height of this component.

Returns:

the current height of this component

getWidth

public int getWidth()

Returns the current width of this component.

Returns:

the current width of this component

invalidate

public void invalidate()

Invalidates this component.

isFocusOwner

public boolean isFocusOwner()

Returns true if this Component is the focus owner.

Returns:

true if this Component is the focus owner; false otherwise

keyPressed

protected boolean keyPressed(int keyCode)

Processes a press of a key.

keyReleased

protected boolean keyReleased(int keyCode)

Processes a release of a key.

keyRepeated

protected boolean keyRepeated(int keyCode)

Processes when a key is repeated (held down).

paint

public void paint(javax.microedition.lcdui.Graphics g)

Paints this component.

Parameters:

g - the graphics context to use for painting

paintBackground

protected void paintBackground(javax.microedition.lcdui.Graphics g)

Paints background for the component

Parameters:

g - the Graphics context

pointerDragged

protected boolean pointerDragged(int x,
                                 int y)

Processes when a pointer is dragged (held down).

pointerPressed

protected boolean pointerPressed(int x,
                                 int y)

Processes a press of a pointer.

pointerReleased

protected boolean pointerReleased(int x,
                                  int y)

Processes a release of a pointer.

prepareForeground

protected void prepareForeground(javax.microedition.lcdui.Graphics g)

Prepares foreground for painting

Parameters:

g - the Graphics context

releaseFocus

public void releaseFocus()

requestFocus

public void requestFocus()

Sets the focusable state of this Component to the specified value. If component is not focusable then focusable state won't be changed

See Also:

isFocusOwner(), releaseFocus()

setFont

public void setFont(javax.microedition.lcdui.Font font)

Sets the font of this component.

Parameters:

font - the font to become this component's font; if this parameter is null then this component font won't be changed

setHeight

protected void setHeight()

Calculates the component height