com.trolltech.qt.gui
Class QTextBlock

java.lang.Object
  extended by com.trolltech.qt.internal.QSignalEmitterInternal
      extended by com.trolltech.qt.QSignalEmitter
          extended by com.trolltech.qt.QtJambiObject
              extended by com.trolltech.qt.gui.QTextBlock
All Implemented Interfaces:
QtJambiInterface, java.lang.Cloneable, java.lang.Comparable

public class QTextBlock
extends QtJambiObject
implements java.lang.Comparable, java.lang.Cloneable

The QTextBlock class provides a container for text fragments in a QTextDocument. A text block encapsulates a block or paragraph of text in a QTextDocument. QTextBlock provides read-only access to the block/paragraph structure of QTextDocuments. It is mainly of use if you want to implement your own layouts for the visual representation of a QTextDocument, or if you want to iterate over a document and write out the contents in your own custom format.

Text blocks are created by their parent documents. If you need to create a new text block, or modify the contents of a document while examining its contents, use the cursor-based interface provided by QTextCursor instead.

Each text block is located at a specific position() in a document(). The contents of the block can be obtained by using the text() function. The length() function determines the block's size within the document (including formatting characters). The visual properties of the block are determined by its text layout(), its charFormat(), and its blockFormat().

The next() and previous() functions enable iteration over consecutive valid blocks in a document under the condition that the document is not modified by other means during the iteration process. Note that, although blocks are returned in sequence, adjacent blocks may come from different places in the document structure. The validity of a block can be determined by calling isValid().

QTextBlock provides comparison operators to make it easier to work with blocks: operator==() compares two block for equality, operator!=() compares two blocks for inequality, and operator<() determines whether a block precedes another in the same document.


See also:
QTextBlockFormat, QTextCharFormat, and QTextFragment.


Nested Class Summary
 
Nested classes/interfaces inherited from class com.trolltech.qt.QSignalEmitter
QSignalEmitter.AbstractSignal, QSignalEmitter.PrivateSignal0, QSignalEmitter.PrivateSignal1, QSignalEmitter.PrivateSignal2, QSignalEmitter.PrivateSignal3, QSignalEmitter.PrivateSignal4, QSignalEmitter.PrivateSignal5, QSignalEmitter.PrivateSignal6, QSignalEmitter.PrivateSignal7, QSignalEmitter.PrivateSignal8, QSignalEmitter.PrivateSignal9, QSignalEmitter.Signal0, QSignalEmitter.Signal1, QSignalEmitter.Signal2, QSignalEmitter.Signal3, QSignalEmitter.Signal4, QSignalEmitter.Signal5, QSignalEmitter.Signal6, QSignalEmitter.Signal7, QSignalEmitter.Signal8, QSignalEmitter.Signal9
 
Nested classes/interfaces inherited from class com.trolltech.qt.internal.QSignalEmitterInternal
com.trolltech.qt.internal.QSignalEmitterInternal.AbstractSignalInternal
 
Field Summary
 
Fields inherited from class com.trolltech.qt.internal.QSignalEmitterInternal
currentSender
 
Constructor Summary
QTextBlock(QTextBlock o)
          Copies the other text block's attributes to this text block.
 
Method Summary
 QTextBlock_iterator begin()
          Returns a text block iterator pointing to the beginning of the text block.
 QTextBlockFormat blockFormat()
          Returns the QTextBlockFormat that describes block-specific properties.
 int blockFormatIndex()
          Returns an index into the document's internal list of block formats for the text block's format.
 int blockNumber()
          Returns the number of this block, or -1 if the block is invalid.
 QTextCharFormat charFormat()
          Returns the QTextCharFormat that describes the block's character format.
 int charFormatIndex()
          Returns an index into the document's internal list of character formats for the text block's character format.
 void clearLayout()
          Clears the QTextLayout that is used to lay out and display the block's contents.
 QTextBlock clone()
          This method is reimplemented for internal reasons
 boolean contains(int position)
          Returns true if the given position is located within the text block; otherwise returns false.
 QTextDocument document()
          Returns the text document this text block belongs to, or 0 if the text block does not belong to any document.
 QTextBlock_iterator end()
          Returns a text block iterator pointing to the end of the text block.
 int firstLineNumber()
          Returns the first line number of this block, or -1 if the block is invalid.
 boolean isValid()
          Returns true if this text block is valid; otherwise returns false.
 boolean isVisible()
          Returns true if the block is visible; otherwise returns false.
 QTextLayout layout()
          Returns the QTextLayout that is used to lay out and display the block's contents.
 int length()
          Returns the length of the block in characters.
 int lineCount()
          Returns the line count.
 QTextBlock next()
          Returns the text block in the document after this block, or an empty text block if this is the last one.
 int position()
          Returns the index of the block's first character within the document.
 QTextBlock previous()
          Returns the text block in the document before this block, or an empty text block if this is the first one.
 int revision()
          Returns the blocks revision.
 void setLineCount(int count)
          Sets the line count to count.
 void setRevision(int rev)
          Sets a blocks revision to rev.
 void setUserData(QTextBlockUserData data)
          Attaches the given data object to the text block.
 void setUserState(int state)
          Stores the specified state integer value in the text block.
 void setVisible(boolean visible)
          Sets the block's visibility to visible.
 java.lang.String text()
          Returns the block's contents as plain text.
 QTextList textList()
          If the block represents a list item, returns the list that the item belongs to; otherwise returns 0.
 QTextBlockUserData userData()
          Returns a pointer to a QTextBlockUserData object if previously set with setUserData() or a null pointer.
 int userState()
          Returns the integer value previously set with setUserState() or -1.
 
Methods inherited from class com.trolltech.qt.QtJambiObject
dispose, disposed, equals, finalize, reassignNativeResources, tr, tr, tr
 
Methods inherited from class com.trolltech.qt.QSignalEmitter
blockSignals, disconnect, disconnect, signalsBlocked, signalSender, thread
 
Methods inherited from class com.trolltech.qt.internal.QSignalEmitterInternal
__qt_signalInitialization
 
Methods inherited from class java.lang.Object
getClass, hashCode, notify, notifyAll, toString, wait, wait, wait
 
Methods inherited from interface java.lang.Comparable
compareTo
 
Methods inherited from interface com.trolltech.qt.QtJambiInterface
disableGarbageCollection, nativeId, nativePointer, reenableGarbageCollection, setJavaOwnership
 

Constructor Detail

QTextBlock

public QTextBlock(QTextBlock o)
Copies the other text block's attributes to this text block.

Method Detail

begin

public final QTextBlock_iterator begin()
Returns a text block iterator pointing to the beginning of the text block.

See also:
end().


blockFormat

public final QTextBlockFormat blockFormat()
Returns the QTextBlockFormat that describes block-specific properties.

See also:
charFormat().


blockFormatIndex

public final int blockFormatIndex()
Returns an index into the document's internal list of block formats for the text block's format.

See also:
QTextDocument::allFormats().


blockNumber

public final int blockNumber()
Returns the number of this block, or -1 if the block is invalid.

See also:
QTextCursor::blockNumber().


charFormat

public final QTextCharFormat charFormat()
Returns the QTextCharFormat that describes the block's character format. The block's character format is used when inserting text into an empty block.

See also:
blockFormat().


charFormatIndex

public final int charFormatIndex()
Returns an index into the document's internal list of character formats for the text block's character format.

See also:
QTextDocument::allFormats().


clearLayout

public final void clearLayout()
Clears the QTextLayout that is used to lay out and display the block's contents.

See also:
layout().


contains

public final boolean contains(int position)
Returns true if the given position is located within the text block; otherwise returns false.


document

public final QTextDocument document()
Returns the text document this text block belongs to, or 0 if the text block does not belong to any document.


end

public final QTextBlock_iterator end()
Returns a text block iterator pointing to the end of the text block.

See also:
begin(), next(), and previous().


firstLineNumber

public final int firstLineNumber()
Returns the first line number of this block, or -1 if the block is invalid. Unless the layout supports it, the line number is identical to the block number.

See also:
QTextBlock::blockNumber().


isValid

public final boolean isValid()
Returns true if this text block is valid; otherwise returns false.


isVisible

public final boolean isVisible()
Returns true if the block is visible; otherwise returns false.

See also:
setVisible().


layout

public final QTextLayout layout()
Returns the QTextLayout that is used to lay out and display the block's contents.

Note that the returned QTextLayout object can only be modified from the documentChanged implementation of a QAbstractTextDocumentLayout subclass. Any changes applied from the outside cause undefined behavior.

See also:
clearLayout().


length

public final int length()
Returns the length of the block in characters.

Note: The length returned includes all formatting characters, for example, newline.

See also:
text(), charFormat(), and blockFormat().


lineCount

public final int lineCount()
Returns the line count. Not all document layouts support this feature.

See also:
setLineCount().


next

public final QTextBlock next()
Returns the text block in the document after this block, or an empty text block if this is the last one.

Note that the next block may be in a different frame or table to this block.

See also:
previous(), begin(), and end().


position

public final int position()
Returns the index of the block's first character within the document.


previous

public final QTextBlock previous()
Returns the text block in the document before this block, or an empty text block if this is the first one.

Note that the next block may be in a different frame or table to this block.

See also:
next(), begin(), and end().


revision

public final int revision()
Returns the blocks revision.

See also:
setRevision(), and QTextDocument::revision().


setLineCount

public final void setLineCount(int count)
Sets the line count to count.

/sa lineCount()

See also:
lineCount().


setRevision

public final void setRevision(int rev)
Sets a blocks revision to rev.

See also:
revision(), and QTextDocument::revision().


setUserData

public final void setUserData(QTextBlockUserData data)
Attaches the given data object to the text block.

QTextBlockUserData can be used to store custom settings. The ownership is passed to the underlying text document, i.e. the provided QTextBlockUserData object will be deleted if the corresponding text block gets deleted. The user data object is not stored in the undo history, so it will not be available after undoing the deletion of a text block.

For example, if you write a programming editor in an IDE, you may want to let your user set breakpoints visually in your code for an integrated debugger. In a programming editor a line of text usually corresponds to one QTextBlock. The QTextBlockUserData interface allows the developer to store data for each QTextBlock, like for example in which lines of the source code the user has a breakpoint set. Of course this could also be stored externally, but by storing it inside the QTextDocument, it will for example be automatically deleted when the user deletes the associated line. It's really just a way to store custom information in the QTextDocument without using custom properties in QTextFormat which would affect the undo/redo stack.

See also:
userData().


setUserState

public final void setUserState(int state)
Stores the specified state integer value in the text block. This may be useful for example in a syntax highlighter to store a text parsing state.

See also:
userState().


setVisible

public final void setVisible(boolean visible)
Sets the block's visibility to visible.

See also:
isVisible().


text

public final java.lang.String text()
Returns the block's contents as plain text.

See also:
length(), charFormat(), and blockFormat().


textList

public final QTextList textList()
If the block represents a list item, returns the list that the item belongs to; otherwise returns 0.


userData

public final QTextBlockUserData userData()
Returns a pointer to a QTextBlockUserData object if previously set with setUserData() or a null pointer.

See also:
setUserData().


userState

public final int userState()
Returns the integer value previously set with setUserState() or -1.

See also:
setUserState().


clone

public QTextBlock clone()
This method is reimplemented for internal reasons

Overrides:
clone in class java.lang.Object