com.jmobilecore.ui.core
Class ScreenCanvas

java.lang.Object
  javax.microedition.lcdui.Displayable
      javax.microedition.lcdui.Canvas
          com.jmobilecore.ui.core.PlatformCanvas
              com.jmobilecore.ui.core.ScreenCanvas

Direct Known Subclasses:

ConfirmForm, ListScreen

public class ScreenCanvas
extends PlatformCanvas

A screen that contains Components.

Author:

Greg Gridin

Field Summary

protected boolean	adjustFocus Indicated if focus ajjustment is required
protected int	bodyOffset y-coordinate offset within the body of the first component to display.
protected static int	CANVAS_SCROLL_STEP Scrolling step
protected java.util.Vector	components Vector of GUI components
protected int	focusedIndex Currently focused component.
protected javax.microedition.lcdui.Image	offScreen Off the screen image for double buffer painting
protected int	paintAreaHeight Height of the scrollable area (of current screen) in pixels
protected Label	screenTitle Screen title
static int	SCROLL_DOWN Scrolling direction.
static int	SCROLL_UP Scrolling direction.
protected SoftKeyBar	softKeyBar SoftKeyBar for current screen this component is not in components vector
protected int	softKeyBarHeight Height of the scrollbar in pixels
protected int	titleHeight Height of the title in pixels

Fields inherited from class com.jmobilecore.ui.core.PlatformCanvas

DOUBLE_BUFFER, HEIGHT, KEY_CLEAR, KEY_DOWN, KEY_ENTER, KEY_FIRE, KEY_LEFT, KEY_PHONE_OFF, KEY_PHONE_ON, KEY_RIGHT, KEY_SOFT_LEFT, KEY_SOFT_RIGHT, KEY_UNDEFINED, KEY_UP, KEY_VOLUME_DOWN, KEY_VOLUME_UP, PLATFORM, PLATFORM_BARTEO, PLATFORM_LG, PLATFORM_MOTOROLA, PLATFORM_MOTOROLA_V, PLATFORM_NOKIA, PLATFORM_NOKIA_30, PLATFORM_SAMSUNG, PLATFORM_SIEMENS, PLATFORM_SONYERICSSON, PLATFORM_SUN_WTK, WIDTH

Fields inherited from class javax.microedition.lcdui.Canvas

DOWN, FIRE, GAME_A, GAME_B, GAME_C, GAME_D, KEY_NUM0, KEY_NUM1, KEY_NUM2, KEY_NUM3, KEY_NUM4, KEY_NUM5, KEY_NUM6, KEY_NUM7, KEY_NUM8, KEY_NUM9, KEY_POUND, KEY_STAR, LEFT, RIGHT, UP

Constructor Summary

ScreenCanvas()
Creates a new ScreenCanvas instance.

ScreenCanvas(Label title)
Creates a new ScreenCanvas instance.

ScreenCanvas(Label title, SoftKeyBar softKeyBar)
Creates a new ScreenCanvas instance.

Method Summary

void	add(Component component) Adds the component to the screen.
void	add(Component component, int index) Adds the component to the screen at the given position.
void	changeFocus(int newIndex) Moves the focus to the specified component.
void	destructor() Class destructor.
static void	drawTriangle(javax.microedition.lcdui.Graphics g, int tipX, int tipY, int maxHeight, int direction, int color) Support method for painting scroller
protected int	getComponentsHeight() Get height of all components
protected int	getFirstFocusable() Gets first focusable component
protected int	getLastFocusable() Gets the last focusable component
protected int	getNextFocusable() Gets next focusable component
protected int	getPreviousFocusable() Gets previous focusable component
protected int	getScrollDirections() Returns the directions the body can be scrolled in.
protected void	keyPressed(int keyCode) Processes a press of a key.
void	paint(javax.microedition.lcdui.Graphics g) Paints the screen's body, which is all of the components that have been added to the screen.
void	paintBody(javax.microedition.lcdui.Graphics g) Paints the screen's body, which is all of the components that have been added to the screen.
protected void	paintBodyBackground(javax.microedition.lcdui.Graphics g) Paints the screen's body background
protected void	paintScroller(javax.microedition.lcdui.Graphics g) Paint scrolling indicator(s) at the bottom of the screen to indicate that the display can scroll vertically.
protected void	recalcAdjustment()
void	refocus() Adjust the screen to make focused component visible
void	remove(Component component) Removes the specified component from this container.
void	remove(int index) Removes the component, specified by index from the screen
void	removeAll() Removes all the components from this container.
protected boolean	scrollDown() Scrolls CANVAS_SCROLL_STEP pixels down
protected void	scrollTop() Scrolls to the top of the screen and sets first focusable component to focused state
protected boolean	scrollUp() Scrolls CANVAS_SCROLL_STEP pixels up

Methods inherited from class javax.microedition.lcdui.Canvas

getGameAction, getHeight, getKeyCode, getKeyName, getWidth, hasPointerEvents, hasPointerMotionEvents, hasRepeatEvents, hideNotify, isDoubleBuffered, keyReleased, keyRepeated, pointerDragged, pointerPressed, pointerReleased, repaint, repaint, serviceRepaints, showNotify

Methods inherited from class javax.microedition.lcdui.Displayable

addCommand, isShown, removeCommand, setCommandListener

Methods inherited from class java.lang.Object

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

Field Detail

adjustFocus

protected boolean adjustFocus

Indicated if focus ajjustment is required

See Also:

recalcAdjustment(), refocus()

bodyOffset

protected int bodyOffset

y-coordinate offset within the body of the first component to display. For example, if the screen container contains more components than can be displayed at one time vertically, this offset will be adjusted to ensure that the screen is scrolled to always display the currently-focused component.

CANVAS_SCROLL_STEP

protected static final int CANVAS_SCROLL_STEP

Scrolling step

See Also:

Constant Field Values

components

protected java.util.Vector components

Vector of GUI components

focusedIndex

protected int focusedIndex

Currently focused component. Index points to components vector

offScreen

protected javax.microedition.lcdui.Image offScreen

Off the screen image for double buffer painting

paintAreaHeight

protected int paintAreaHeight

Height of the scrollable area (of current screen) in pixels

screenTitle

protected Label screenTitle

Screen title

SCROLL_DOWN

public static final int SCROLL_DOWN

Scrolling direction. Used with drawTriangle

See Also:

Constant Field Values

SCROLL_UP

public static final int SCROLL_UP

Scrolling direction. Used with drawTriangle

See Also:

Constant Field Values

softKeyBar

protected SoftKeyBar softKeyBar

SoftKeyBar for current screen this component is not in components vector

softKeyBarHeight

protected int softKeyBarHeight

Height of the scrollbar in pixels

titleHeight

protected int titleHeight

Height of the title in pixels

Constructor Detail

ScreenCanvas

public ScreenCanvas()

Creates a new ScreenCanvas instance.

ScreenCanvas

public ScreenCanvas(Label title)

Creates a new ScreenCanvas instance.

Parameters:

title - The screen title, one line text

ScreenCanvas

public ScreenCanvas(Label title,
                    SoftKeyBar softKeyBar)

Creates a new ScreenCanvas instance.

Parameters:

title - Title for current screen

softKeyBar - Container for soft keys for current screen

Method Detail

add

public void add(Component component)

Adds the component to the screen.

More presicely it adds a component to vector of components for current screen Components are displayed in order of components one component per line

Parameters:

component - the component to be added

add

public void add(Component component,
                int index)

Adds the component to the screen at the given position.

More presicely it adds a component to vector of components for current screen Components are displayed in order of components one component per line

Parameters:

component - the component to be added

index - the position at which to insert the component, or -1 to append the component to the end

changeFocus

public void changeFocus(int newIndex)

Moves the focus to the specified component.

Parameters:

newIndex - The index of component gaining focus

destructor

public void destructor()

Class destructor. Helps VM to perform garbage collection

drawTriangle

public static void drawTriangle(javax.microedition.lcdui.Graphics g,
                                int tipX,
                                int tipY,
                                int maxHeight,
                                int direction,
                                int color)

Support method for painting scroller

See Also:

paintScroller(javax.microedition.lcdui.Graphics)

getComponentsHeight

protected int getComponentsHeight()

Get height of all components

Returns:

height in pixes of all components in vector components for current screen

getFirstFocusable

protected int getFirstFocusable()

Gets first focusable component

Returns:

index of first focusable component, if there is no focusable components returns -1

getLastFocusable

protected int getLastFocusable()

Gets the last focusable component

Returns:

index of last focusable component, if there is no focusable components returns -1

getNextFocusable

protected int getNextFocusable()

Gets next focusable component

Returns:

index of next focusable component, if there is no focusable components returns -1

getPreviousFocusable

protected int getPreviousFocusable()

Gets previous focusable component

Returns:

index of previous focusable component, if there is no previous focusable components returns -1

getScrollDirections

protected int getScrollDirections()

Returns the directions the body can be scrolled in. This should be dynamic depending upon what portion of the body area is displayed.

Returns:

The directions that the body area can be scrolled. Should be 0 if all body elements can be displayed at once, but if not it should be an appropriate bitwise or of SCROLL_UP and/or SCROLL_DOWN

keyPressed

protected void keyPressed(int keyCode)

Processes a press of a key.

Overrides:

keyPressed in class javax.microedition.lcdui.Canvas

paint

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

Paints the screen's body, which is all of the components that have been added to the screen.

Specified by:

paint in class javax.microedition.lcdui.Canvas

Parameters:

g - Graphics context

paintBody

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

Paints the screen's body, which is all of the components that have been added to the screen.

Parameters:

g - The graphics object to draw to.

paintBodyBackground

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

Paints the screen's body background

Parameters:

g - Graphics context

paintScroller

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

Paint scrolling indicator(s) at the bottom of the screen to indicate that the display can scroll vertically.

Parameters:

g - Graphics context

recalcAdjustment

protected void recalcAdjustment()

refocus

public void refocus()

Adjust the screen to make focused component visible

remove

public void remove(Component component)

Removes the specified component from this container.

Parameters:

component - the component to be removed

remove

public void remove(int index)

Removes the component, specified by index from the screen

Parameters:

index - the index of the component to be removed.

removeAll

public void removeAll()

Removes all the components from this container.

scrollDown

protected boolean scrollDown()

Scrolls CANVAS_SCROLL_STEP pixels down

Returns:

true if scrolling is possible, false otherwise

scrollTop

protected void scrollTop()

Scrolls to the top of the screen and sets first focusable component to focused state

scrollUp

protected boolean scrollUp()

Scrolls CANVAS_SCROLL_STEP pixels up

Returns:

true if scrolling is possible, false otherwise