de.enough.polish.ui
Class ScrollBar

java.lang.Object
  de.enough.polish.ui.Item
      de.enough.polish.ui.ScrollBar

public class ScrollBar
extends Item

Realizes a scrollbar for any J2ME Polish screens.

The scrollbar needs to be activated using the "polish.useScrollBar" variable:

    <variable name="polish.useScrollBar" value="true" />
    

Design the scrollbar using the predefined "scrollbar" style. You can also specify a screen specific style by defining the "scrollbar-style" CSS attribute.
Scrollbars support following additional attributes (apart from the background etc):

• scrollbar-slider-width: The width of the slider in pixels, is ignored when a slider-image is defined.
• scrollbar-slider-color: The color of the slider, is ignored when a slider-image is defined.
• scrollbar-slider-image: The image used for the slider.
• scrollbar-slider-image-repeat: Either "true" or "false". When "true" is given, the slider image is repeated vertically, if necessary.
• scrollbar-slider-mode: The mode of the slider, either "area", "item" or "page". In the "area" mode the slider represents the position of the current selection relativ to the complete width and height. In the "item" mode the index of currently selected item is taken into account relative to the number of items. In the "page" mode the position and height of the currently visible area is shown relative to the complete height of that screen. The default mode is "page".
• scrollbar-position: either "left" or "right" (not yet supported).
• :

You can exchange the default implementation with the "polish.classes.ScrollBar" variable.

Copyright Enough Software 2006 - 2008

 history
        22-Feb-2006 - rob creation
 

Author:

Robert Virkus, j2mepolish@enough.de

Field Summary

protected boolean	hideSlider
protected boolean	overlap
protected boolean	repeatSliderImage
protected int	repeatSliderNumber
protected int	scrollBarHeight
protected int	sliderColor
protected int	sliderHeight
protected javax.microedition.lcdui.Image	sliderImage
protected int	sliderMode
protected int	sliderWidth
protected int	sliderY

Fields inherited from class de.enough.polish.ui.Item

_bbField, _bbFieldAdded, appearanceMode, background, backgroundHeight, backgroundWidth, backgroundYOffset, border, borderWidth, BUTTON, colSpan, commands, completeBackground, completeBackgroundPadding, completeBorder, contentHeight, contentWidth, contentX, contentY, cssSelector, defaultCommand, focusedStyle, HORIZONTAL, HYPERLINK, includeLabel, INTERACTIVE, internalHeight, internalWidth, internalX, internalY, isFocused, isInitialized, isInvisible, isLayoutCenter, isLayoutExpand, isLayoutRight, isPressed, isShown, isStyleInitialised, itemCommandListener, itemHeight, itemWidth, label, labelStyle, layout, LAYOUT_2, LAYOUT_BOTTOM, LAYOUT_CENTER, LAYOUT_DEFAULT, LAYOUT_EXPAND, LAYOUT_LEFT, LAYOUT_NEWLINE_AFTER, LAYOUT_NEWLINE_BEFORE, LAYOUT_RIGHT, LAYOUT_SHRINK, LAYOUT_TOP, LAYOUT_VCENTER, LAYOUT_VEXPAND, LAYOUT_VSHRINK, marginBottom, marginLeft, marginRight, marginTop, maximumHeight, maximumWidth, minimumHeight, minimumWidth, NO_POSITION_SET, opacity, opacityPaintNormally, opacityRgbData, paddingBottom, paddingHorizontal, paddingLeft, paddingRight, paddingTop, paddingVertical, parent, PLAIN, preferredHeight, preferredWidth, preserveViewType, relativeX, relativeY, rowSpan, screen, style, TRANSPARENT, useSingleRow, VERTICAL, view

Constructor Summary

ScrollBar()
Creates a new default scrollbar

ScrollBar(Style style)
Creates a new styled scrollbar

Method Summary

boolean	animate() Animates this item.
protected java.lang.String	createCssSelector() Retrieves the CSS selector for this item.
protected boolean	handlePointerDragged(int x, int y) Allows to drag the scroll handle.
protected boolean	handlePointerPressed(int relX, int relY) Handles the event when a pointer has been pressed at the specified position.
protected boolean	handlePointerReleased(int relX, int relY) Handles the event when a pointer has been released at the specified position.
protected void	initContent(int firstLineWidth, int lineWidth) Initialises this item.
int	initScrollBar(int screenWidth, int screenAvailableHeight, int screenContentHeight, int contentYOffset, int selectionStart, int selectionHeight, int focusedIndex, int numberOfItems) Initializes this scrollbar.
void	paint(int x, int y, int leftBorder, int rightBorder, javax.microedition.lcdui.Graphics g) Paints this item on the screen.
protected void	paintContent(int x, int y, int leftBorder, int rightBorder, javax.microedition.lcdui.Graphics g) Paints the content of this item.
void	resetAnimation() Resets the animation status - when the opcaity is defined, it will be set to the start opacity again
void	setStyle(Style style) Sets the style of this item.

Methods inherited from class de.enough.polish.ui.Item

addCommand, addCommand, addCommands, addRelativeToBackgroundRegion, addRelativeToBackgroundRegion, addRelativeToContentRegion, animate, containsCommand, defocus, focus, getAbsoluteX, getAbsoluteY, getAppearanceMode, getAttribute, getAttributes, getBackgroundHeight, getBackgroundWidth, getBackgroundX, getBackgroundY, getContentHeight, getContentWidth, getContentX, getContentY, getDefaultCommand, getFocusedStyle, getItemAt, getItemCommandListener, getItemCommands, getItemHeight, getItemStateListener, getItemWidth, getLabel, getLabelItem, getLayout, getMinimumHeight, getMinimumWidth, getParent, getPreferredHeight, getPreferredWidth, getScreen, getStyle, handleCommand, handleKeyPressed, handleKeyReleased, handleKeyRepeated, hideNotify, init, initStyle, isInContentArea, isInItemArea, isInItemArea, isInitialized, isVisible, notifyItemPressedEnd, notifyItemPressedStart, notifyStateChanged, paintBackground, paintBackgroundAndBorder, paintBorder, releaseResources, removeCommand, repaint, repaint, repaintFully, requestInit, setAppearanceMode, setAttribute, setDefaultCommand, setItemCommandListener, setItemCommandListener, setItemStateListener, setLabel, setLayout, setParent, setParent, setPreferredSize, setVisible, show, showCommands, showNotify, toString

Methods inherited from class java.lang.Object

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

Field Detail

sliderColor

protected int sliderColor

sliderWidth

protected int sliderWidth

sliderImage

protected javax.microedition.lcdui.Image sliderImage

repeatSliderImage

protected boolean repeatSliderImage

repeatSliderNumber

protected int repeatSliderNumber

sliderMode

protected int sliderMode

hideSlider

protected boolean hideSlider

sliderY

protected int sliderY

sliderHeight

protected int sliderHeight

scrollBarHeight

protected int scrollBarHeight

overlap

protected boolean overlap

Constructor Detail

ScrollBar

public ScrollBar()

Creates a new default scrollbar

ScrollBar

public ScrollBar(Style style)

Creates a new styled scrollbar

Parameters:

style - the style

Method Detail

initScrollBar

public int initScrollBar(int screenWidth,
                         int screenAvailableHeight,
                         int screenContentHeight,
                         int contentYOffset,
                         int selectionStart,
                         int selectionHeight,
                         int focusedIndex,
                         int numberOfItems)

Initializes this scrollbar.

Parameters:

screenWidth - the width of the screen

screenAvailableHeight - the height available for the content within the screen

screenContentHeight - the height of the content area of the screen

contentYOffset - the y offset for the content in the range of [-(screenContentHeight-screenAvailableHeight)...0]

selectionStart - the start of the selection relative to the screenContentHeight

selectionHeight - the height of the current selection

focusedIndex - the index of currently focused item

numberOfItems - the number of available items

Returns:

the item width of the scroll bar.

resetAnimation

public void resetAnimation()

Resets the animation status - when the opcaity is defined, it will be set to the start opacity again

animate

public boolean animate()

Description copied from class: Item

Animates this item. Subclasses can override this method to create animations. The default implementation returns false

Overrides:

animate in class Item

Returns:

true when this item has been animated.

See Also:

Item.animate(long, ClippingRegion)

initContent

protected void initContent(int firstLineWidth,
                           int lineWidth)

Description copied from class: Item

Initialises this item. The implementation needs to calculate and set the contentWidth and contentHeight fields. The implementation should take the fields preferredWidth and preferredHeight into account.

Specified by:

initContent in class Item

Parameters:

firstLineWidth - the maximum width of the first line

lineWidth - the maximum width of any following lines

See Also:

Item.contentWidth, Item.contentHeight, Item.preferredWidth, Item.preferredHeight

paint

public void paint(int x,
                  int y,
                  int leftBorder,
                  int rightBorder,
                  javax.microedition.lcdui.Graphics g)

Description copied from class: Item

Paints this item on the screen. This method should normally not be overriden. Override it only when you know what you are doing!

Overrides:

paint in class Item

Parameters:

x - the left start position of this item.

y - the top start position of this item.

leftBorder - the left border, nothing must be painted left of this position

rightBorder - the right border, nothing must be painted right of this position, rightBorder > x >= leftBorder

g - the Graphics on which this item should be painted.

paintContent

protected void paintContent(int x,
                            int y,
                            int leftBorder,
                            int rightBorder,
                            javax.microedition.lcdui.Graphics g)

Description copied from class: Item

Paints the content of this item. The background has already been painted and the border will be added after this method returns.

Specified by:

paintContent in class Item

Parameters:

x - the left start position

y - the upper start position

leftBorder - the left border, nothing must be painted left of this position

rightBorder - the right border, nothing must be painted right of this position

g - the Graphics on which this item should be painted.

createCssSelector

protected java.lang.String createCssSelector()

Description copied from class: Item

Retrieves the CSS selector for this item. The CSS selector is used for the dynamic assignment of styles - that is the styles are assigned by the usage of the item and not by a predefined style-name. With the #style preprocessing command styles are set fix, this method yields in a faster GUI and is recommended. When in a style-sheet dynamic styles are used, e.g. "Form>p", than the selector of the item is needed.
This abstract method needs only be implemented, when dynamic styles are used: #ifdef polish.useDynamicStyles
The returned selector needs to be in lower case.

Specified by:

createCssSelector in class Item

Returns:

the appropriate CSS selector for this item. The selector needs to be in lower case.

setStyle

public void setStyle(Style style)

Description copied from class: Item

Sets the style of this item.

Overrides:

setStyle in class Item

Parameters:

style - the new style for this item.

handlePointerPressed

protected boolean handlePointerPressed(int relX,
                                       int relY)

Handles the event when a pointer has been pressed at the specified position. The default method discards this event when relX/relY is outside of the item's area. When the event took place inside of the content area, the pointer-event is translated into an artificial FIRE game-action keyPressed event, which is subsequently handled bu the handleKeyPressed(-1, Canvas.FIRE) method. This method needs should be overwritten only when the "polish.hasPointerEvents" preprocessing symbol is defined: "//#ifdef polish.hasPointerEvents".

Overrides:

handlePointerPressed in class Item

Parameters:

relX - the x position of the pointer pressing relative to this item's left position

relY - the y position of the pointer pressing relative to this item's top position

Returns:

true when the pressing of the pointer was actually handled by this item.

See Also:

this method is used for determining whether the event belongs to this item, for a helper method for determining whether the event took place into the actual content area, Item.handleKeyPressed(int, int)

handlePointerReleased

protected boolean handlePointerReleased(int relX,
                                        int relY)

Handles the event when a pointer has been released at the specified position. The default method discards this event when relX/relY is outside of the item's area. When the event took place inside of the content area, the pointer-event is translated into an artificial FIRE game-action keyPressed event, which is subsequently handled bu the handleKeyPressed(-1, Canvas.FIRE) method. This method needs should be overwritten only when the "polish.hasPointerEvents" preprocessing symbol is defined: "//#ifdef polish.hasPointerEvents".

Overrides:

handlePointerReleased in class Item

Parameters:

relX - the x position of the pointer pressing relative to this item's left position

relY - the y position of the pointer pressing relative to this item's top position

Returns:

true when the pressing of the pointer was actually handled by this item.

See Also:

this method is used for determining whether the event belongs to this item, for a helper method for determining whether the event took place into the actual content area, Item.handleKeyPressed(int, int)

handlePointerDragged

protected boolean handlePointerDragged(int x,
                                       int y)

Allows to drag the scroll handle.

Parameters:

x - relative x offset

y - relative y offset

Returns:

true when the dragged event was handled