Java(TM) 2 Platform, Standard Edition, v1.2.2 API Specification: Class ParagraphView - JDK 5 Documentation v1.2.2, Java 2 SDK 英文文档

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javax.swing.text
Class ParagraphView

java.lang.Object
  |
  +--javax.swing.text.View
        |
        +--javax.swing.text.CompositeView
              |
              +--javax.swing.text.BoxView
                    |
                    +--javax.swing.text.ParagraphView

Direct Known Subclasses:: ParagraphView

public class ParagraphView
extends BoxView
implements TabExpander

View of a simple line-wrapping paragraph that supports multiple fonts, colors, components, icons, etc. It is basically a vertical box with a margin around it. The contents of the box are a bunch of rows which are special horizontal boxes. This view creates a collection of views that represent the child elements of the paragraph element. Each of these views are placed into a row directly if they will fit, otherwise the breakView method is called to try and carve the view into pieces that fit.

See Also:: View

Field Summary

protected int firstLineIndent
          Indentation for the first line, from the left inset.

Fields inherited from class javax.swing.text.View

BadBreakWeight, ExcellentBreakWeight, ForcedBreakWeight, GoodBreakWeight, X_AXIS, Y_AXIS

Constructor Summary

ParagraphView(Element elem)
          Constructs a ParagraphView for the given element.

Method Summary

protected void adjustRow(javax.swing.text.ParagraphView.Row r, int desiredSpan, int x)
          Adjusts the given row if possible to fit within the layout span.

View breakView(int axis, float len, Shape a)
          Breaks this view on the given axis at the given length.

protected SizeRequirements calculateMinorAxisRequirements(int axis, SizeRequirements r)


void changedUpdate(DocumentEvent changes, Shape a, ViewFactory f)
          Gives notification from the document that attributes were changed in a location that this view is responsible for.

protected int findOffsetToCharactersInString(char[] string, int start)
          Finds the next character in the document with a character in string, starting at offset start.

protected boolean flipEastAndWestAtEnds(int position, Position.Bias bias)
          Subclasses may wish to subclass this and conditionally return true based on the position.

float getAlignment(int axis)
          Determines the desired alignment for this view along an axis.

int getBreakWeight(int axis, float len)
          Gets the break weight for a given location.

protected int getClosestPositionTo(int pos, Position.Bias b, Shape a, int direction, Position.Bias[] biasRet, int rowIndex, int x)
          Returns the closest model position to x.

protected View getLayoutView(int index)
          The child views of the paragraph are rows which have been used to arrange pieces of the Views that represent the child elements.

protected int getLayoutViewCount()
          The child views of the paragraph are rows which have been used to arrange pieces of the Views that represent the child elements.

protected int getNextNorthSouthVisualPositionFrom(int pos, Position.Bias b, Shape a, int direction, Position.Bias[] biasRet)
          Overriden from CompositeView.

protected float getPartialSize(int startOffset, int endOffset)
          Returns the size used by the views between startOffset and endOffset.

protected float getTabBase()


protected TabSet getTabSet()
          Gets the Tabset to be used in calculating tabs.

protected View getViewAtPosition(int pos, Rectangle a)
          Fetches the child view that represents the given position in the model.

protected int getViewIndexAtPosition(int pos)
          Fetches the child view index representing the given position in the model.

void insertUpdate(DocumentEvent changes, Shape a, ViewFactory f)
          Gives notification that something was inserted into the document in a location that this view is responsible for.

protected void layout(int width, int height)
          Lays out the children.

protected void loadChildren(ViewFactory f)
          Loads all of the children to initialize the view.

float nextTabStop(float x, int tabOffset)
          Returns the next tab stop position given a reference position.

void paint(Graphics g, Shape a)
          Renders using the given rendering surface and area on that surface.

void removeUpdate(DocumentEvent changes, Shape a, ViewFactory f)
          Gives notification that something was removed from the document in a location that this view is responsible for.

protected void setFirstLineIndent(float fi)
          Set the indent on the first line

protected void setJustification(int j)
          Set the type of justification.

protected void setLineSpacing(float ls)
          Set the line spacing.

protected void setPropertiesFromAttributes()


Methods inherited from class javax.swing.text.BoxView

baselineLayout, baselineRequirements, calculateMajorAxisRequirements, childAllocation, getChildAllocation, getHeight, getMaximumSpan, getMinimumSpan, getOffset, getPreferredSpan, getResizeWeight, getSpan, getViewAtPoint, getWidth, isAfter, isAllocationValid, isBefore, layoutMajorAxis, layoutMinorAxis, modelToView, paintChild, preferenceChanged, replace, setSize, viewToModel

Methods inherited from class javax.swing.text.CompositeView

append, getBottomInset, getInsideAllocation, getLeftInset, getNextEastWestVisualPositionFrom, getNextVisualPositionFrom, getRightInset, getTopInset, getView, getViewCount, insert, modelToView, removeAll, setInsets, setParagraphInsets, setParent

Methods inherited from class javax.swing.text.View

breakView, createFragment, getAttributes, getBreakWeight, getContainer, getDocument, getElement, getEndOffset, getParent, getStartOffset, getViewFactory, isVisible, modelToView, viewToModel

Methods inherited from class java.lang.Object

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

Field Detail

firstLineIndent

protected int firstLineIndent

Indentation for the first line, from the left inset.

Constructor Detail

ParagraphView

public ParagraphView(Element elem)

Constructs a ParagraphView for the given element.

Parameters:: elem - the element that this view is responsible for

Method Detail

setJustification

protected void setJustification(int j)

Set the type of justification.

setLineSpacing

protected void setLineSpacing(float ls)

Set the line spacing.

Parameters:: ls - the value in points

setFirstLineIndent

protected void setFirstLineIndent(float fi)

Set the indent on the first line

Parameters:: ls - the value in points

setPropertiesFromAttributes

protected void setPropertiesFromAttributes()

getLayoutViewCount

protected int getLayoutViewCount()

The child views of the paragraph are rows which have been used to arrange pieces of the Views that represent the child elements. This is the number of views that have been tiled in two dimensions, and should be equivalent to the number of child elements to the element this view is responsible for.

getLayoutView

protected View getLayoutView(int index)

The child views of the paragraph are rows which have been used to arrange pieces of the Views that represent the child elements. This methods returns the view responsible for the child element index (prior to breaking). These are the Views that were produced from a factory (to represent the child elements) and used for layout.

loadChildren

protected void loadChildren(ViewFactory f)

Loads all of the children to initialize the view. This is called by the setParent method. This is reimplemented to not load any children directly (as they are created in the process of formatting). This does create views to represent the child elements, but they are placed into a pool that is used in the process of formatting.

Overrides:: loadChildren in class CompositeView

Parameters:: f - the view factory

getViewAtPosition

protected View getViewAtPosition(int pos,
                                 Rectangle a)

Fetches the child view that represents the given position in the model. This is implemented to walk through the children looking for a range that contains the given position. In this view the children do not have a one to one mapping with the child elements (i.e. the children are actually rows that represent a portion of the element this view represents).

Overrides:: getViewAtPosition in class CompositeView

Parameters:: pos - the search position >= 0; a - the allocation to the box on entry, and the allocation of the view containing the position on exit

getViewIndexAtPosition

protected int getViewIndexAtPosition(int pos)

Fetches the child view index representing the given position in the model.

Overrides:: getViewIndexAtPosition in class CompositeView

Parameters:: pos - the position >= 0

layout

protected void layout(int width,
                      int height)

Lays out the children. If the layout span has changed, the rows are rebuilt. The superclass functionality is called after checking and possibly rebuilding the rows. If the height has changed, the preferenceChanged method is called on the parent since the vertical preference is rigid.

Overrides:: layout in class BoxView

Parameters:: width - the width to lay out against >= 0. This is the width inside of the inset area.; height - the height to lay out against >= 0 (not used by paragraph, but used by the superclass). This is the height inside of the inset area.

adjustRow

protected void adjustRow(javax.swing.text.ParagraphView.Row r,
                         int desiredSpan,
                         int x)

Adjusts the given row if possible to fit within the layout span. By default this will try to find the highest break weight possible nearest the end of the row. If a forced break is encountered, the break will be positioned there.

Parameters:: r - the row to adjust to the current layout span.; desiredSpan - the current layout span >= 0; x - the location r starts at.

nextTabStop

public float nextTabStop(float x,
                         int tabOffset)

Returns the next tab stop position given a reference position. This view implements the tab coordinate system, and calls getTabbedSpan on the logical children in the process of layout to determine the desired span of the children. The logical children can delegate their tab expansion upward to the paragraph which knows how to expand tabs. LabelView is an example of a view that delegates its tab expansion needs upward to the paragraph.

This is implemented to try and locate a TabSet in the paragraph element's attribute set. If one can be found, its settings will be used, otherwise a default expansion will be provided. The base location for for tab expansion is the left inset from the paragraphs most recent allocation (which is what the layout of the children is based upon).

Specified by:: nextTabStop in interface TabExpander

Parameters:: x - the X reference position; tabOffset - the position within the text stream that the tab occurred at >= 0.
Returns:: the trailing end of the tab expansion >= 0
See Also:: TabSet, TabStop, LabelView

getTabSet

protected TabSet getTabSet()

Gets the Tabset to be used in calculating tabs.

Returns:: the TabSet

getPartialSize

protected float getPartialSize(int startOffset,
                               int endOffset)

Returns the size used by the views between startOffset and endOffset. This uses getPartialView to calculate the size if the child view implements the TabableView interface. If a size is needed and a View does not implement the TabableView interface, the preferredSpan will be used.

Parameters:: startOffset - the starting document offset >= 0; endOffset - the ending document offset >= startOffset
Returns:: the size >= 0

findOffsetToCharactersInString

protected int findOffsetToCharactersInString(char[] string,
                                             int start)

Finds the next character in the document with a character in string, starting at offset start. If there are no characters found, -1 will be returned.

Parameters:: string - the string of characters; start - where to start in the model >= 0
Returns:: the document offset or -1

getTabBase

protected float getTabBase()

Returns:: where tabs are calculated from.

flipEastAndWestAtEnds

protected boolean flipEastAndWestAtEnds(int position,
                                        Position.Bias bias)

Description copied from class: CompositeView

Subclasses may wish to subclass this and conditionally return true based on the position. A return value of true indicates that when a View returns -1 from getNextVisualPositionFrom the next view for east should be the current index offset by -1, and for west it means offset by 1. The normal direction (for left to right text) is to offset east by 1 and west by -1.

Overrides:: flipEastAndWestAtEnds in class BoxView

Tags copied from class: CompositeView

Returns:: false

paint

public void paint(Graphics g,
                  Shape a)

Renders using the given rendering surface and area on that surface. This is implemented to delgate to the superclass after stashing the base coordinate for tab calculations.

Overrides:: paint in class BoxView

Parameters:: g - the rendering surface to use; a - the allocated region to render into
See Also:: View.paint(java.awt.Graphics, java.awt.Shape)

calculateMinorAxisRequirements

protected SizeRequirements calculateMinorAxisRequirements(int axis,
                                                          SizeRequirements r)

Overrides:: calculateMinorAxisRequirements in class BoxView

getAlignment

public float getAlignment(int axis)

Determines the desired alignment for this view along an axis. This is implemented to give the alignment to the center of the first row along the y axis, and the default along the x axis.

Overrides:: getAlignment in class BoxView

Parameters:: axis - may be either View.X_AXIS or View.Y_AXIS

breakView

public View breakView(int axis,
                      float len,
                      Shape a)

Breaks this view on the given axis at the given length.

ParagraphView instances are breakable along the Y_AXIS only, and only if len is after the first line.

Parameters:: axis - may be either View.X_AXIS or View.Y_AXIS; len - specifies where a potential break is desired along the given axis >= 0; a - the current allocation of the view
Returns:: the fragment of the view that represents the given span, if the view can be broken. If the view doesn't support breaking behavior, the view itself is returned.
See Also:: View.breakView(int, int, float, float)

getBreakWeight

public int getBreakWeight(int axis,
                          float len)

Gets the break weight for a given location. ParagraphView instances are breakable along the Y_AXIS only, and only if len is after the first row. If the length is less than one row, a value of BadBreakWeight is returned.

Parameters:: axis - may be either View.X_AXIS or View.Y_AXIS; len - specifies where a potential break is desired >= 0
Returns:: a value indicating the attractiveness of breaking here
See Also:: View.getBreakWeight(int, float, float)

insertUpdate

public void insertUpdate(DocumentEvent changes,
                         Shape a,
                         ViewFactory f)

Gives notification that something was inserted into the document in a location that this view is responsible for.

Overrides:: insertUpdate in class CompositeView

Parameters:: changes - the change information from the associated document; a - the current allocation of the view; f - the factory to use to rebuild if the view has children
See Also:: View.insertUpdate(javax.swing.event.DocumentEvent, java.awt.Shape, javax.swing.text.ViewFactory)

removeUpdate

public void removeUpdate(DocumentEvent changes,
                         Shape a,
                         ViewFactory f)

Gives notification that something was removed from the document in a location that this view is responsible for.

Overrides:: removeUpdate in class CompositeView

Parameters:: changes - the change information from the associated document; a - the current allocation of the view; f - the factory to use to rebuild if the view has children
See Also:: View.removeUpdate(javax.swing.event.DocumentEvent, java.awt.Shape, javax.swing.text.ViewFactory)

changedUpdate

public void changedUpdate(DocumentEvent changes,
                          Shape a,
                          ViewFactory f)

Gives notification from the document that attributes were changed in a location that this view is responsible for.

Overrides:: changedUpdate in class CompositeView

Parameters:: changes - the change information from the associated document; a - the current allocation of the view; f - the factory to use to rebuild if the view has children
See Also:: View.changedUpdate(javax.swing.event.DocumentEvent, java.awt.Shape, javax.swing.text.ViewFactory)

getNextNorthSouthVisualPositionFrom

protected int getNextNorthSouthVisualPositionFrom(int pos,
                                                  Position.Bias b,
                                                  Shape a,
                                                  int direction,
                                                  Position.Bias[] biasRet)
                                           throws BadLocationException

Overriden from CompositeView.

Overrides:: getNextNorthSouthVisualPositionFrom in class CompositeView