com.trolltech.qt.gui
Class QUndoGroup

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.core.QObject
                  extended by com.trolltech.qt.gui.QUndoGroup
All Implemented Interfaces:
QtJambiInterface

public class QUndoGroup
extends QObject

The QUndoGroup class is a group of QUndoStack objects. For an overview of the Qt's undo framework, see the overview.

An application often has multiple undo stacks, one for each opened document. At the same time, an application usually has one undo action and one redo action, which triggers undo or redo in the active document.

QUndoGroup is a group of QUndoStack objects, one of which may be active. It has an undo() and redo() slot, which calls QUndoStack::undo() and QUndoStack::redo() for the active stack. It also has the functions createUndoAction() and createRedoAction(). The actions returned by these functions behave in the same way as those returned by QUndoStack::createUndoAction() and QUndoStack::createRedoAction() of the active stack.

Stacks are added to a group with addStack() and removed with removeStack(). A stack is implicitly added to a group when it is created with the group as its parent QObject.

It is the programmer's responsibility to specify which stack is active by calling QUndoStack::setActive(), usually when the associated document window receives focus. The active stack may also be set with setActiveStack(), and is returned by activeStack().

When a stack is added to a group using addStack(), the group does not take ownership of the stack. This means the stack has to be deleted separately from the group. When a stack is deleted, it is automatically removed from a group. A stack may belong to only one group. Adding it to another group will cause it to be removed from the previous group.

A QUndoGroup is also useful in conjunction with QUndoView. If a QUndoView is set to watch a group using QUndoView::setGroup(), it will update itself to display the active stack.


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
 QSignalEmitter.Signal1 activeStackChanged
          This signal takes 1 generic argument(s).
 QSignalEmitter.Signal1 canRedoChanged
          This signal takes 1 generic argument(s).
 QSignalEmitter.Signal1 canUndoChanged
          This signal takes 1 generic argument(s).
 QSignalEmitter.Signal1 cleanChanged
          This signal takes 1 generic argument(s).
 QSignalEmitter.Signal1 indexChanged
          This signal takes 1 generic argument(s).
 QSignalEmitter.Signal1 redoTextChanged
          This signal takes 1 generic argument(s).
 QSignalEmitter.Signal1 undoTextChanged
          This signal takes 1 generic argument(s).
 
Fields inherited from class com.trolltech.qt.internal.QSignalEmitterInternal
currentSender
 
Constructor Summary
QUndoGroup()
          Creates an empty QUndoGroup object with parent parent.
QUndoGroup(QObject parent)
          Creates an empty QUndoGroup object with parent parent.
 
Method Summary
 QUndoStack activeStack()
          Returns the active stack of this group.
 void addStack(QUndoStack stack)
          Adds stack to this group.
 boolean canRedo()
          Returns the value of the active stack's QUndoStack::canRedo().
 boolean canUndo()
          Returns the value of the active stack's QUndoStack::canUndo().
 QAction createRedoAction(QObject parent)
          Creates an redo QAction object with parent parent.
 QAction createRedoAction(QObject parent, java.lang.String prefix)
          Creates an redo QAction object with parent parent.
 QAction createUndoAction(QObject parent)
          Creates an undo QAction object with parent parent.
 QAction createUndoAction(QObject parent, java.lang.String prefix)
          Creates an undo QAction object with parent parent.
 boolean isClean()
          Returns the value of the active stack's QUndoStack::isClean().
 void redo()
          Calls QUndoStack::redo() on the active stack.
 java.lang.String redoText()
          Returns the value of the active stack's QUndoStack::redoText().
 void removeStack(QUndoStack stack)
          Removes stack from this group.
 void setActiveStack(QUndoStack stack)
          Sets the active stack of this group to stack.
 java.util.List stacks()
          Returns a list of stacks in this group.
 void undo()
          Calls QUndoStack::undo() on the active stack.
 java.lang.String undoText()
          Returns the value of the active stack's QUndoStack::undoText().
 
Methods inherited from class com.trolltech.qt.core.QObject
childEvent, children, connectSlotsByName, customEvent, disposeLater, dumpObjectInfo, dumpObjectTree, dynamicPropertyNames, event, eventFilter, findChild, findChild, findChild, findChildren, findChildren, findChildren, findChildren, indexOfProperty, installEventFilter, isWidgetType, killTimer, moveToThread, objectName, parent, properties, property, removeEventFilter, setObjectName, setParent, setProperty, startTimer, timerEvent, toString, userProperty
 
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
clone, getClass, hashCode, notify, notifyAll, wait, wait, wait
 
Methods inherited from interface com.trolltech.qt.QtJambiInterface
disableGarbageCollection, nativeId, nativePointer, reenableGarbageCollection, setJavaOwnership
 

Field Detail

activeStackChanged

public final QSignalEmitter.Signal1 activeStackChanged

This signal takes 1 generic argument(s). We list their type and the name they go by in the description of this signal. <com.trolltech.qt.gui.QUndoStack(named: stack)>:

This signal is emitted whenever the active stack of the group changes. This can happen when setActiveStack() or QUndoStack::setActive() is called, or when the active stack is removed form the group. stack is the new active stack. If no stack is active, stack is 0.

See also:
setActiveStack(), and QUndoStack::setActive().


canRedoChanged

public final QSignalEmitter.Signal1 canRedoChanged

This signal takes 1 generic argument(s). We list their type and the name they go by in the description of this signal. <java.lang.Boolean(named: canRedo)>:

This signal is emitted whenever the active stack emits QUndoStack::canRedoChanged() or the active stack changes.

canRedo is the new state, or false if the active stack is 0.

See also:
QUndoStack::canRedoChanged() , and setActiveStack().


canUndoChanged

public final QSignalEmitter.Signal1 canUndoChanged

This signal takes 1 generic argument(s). We list their type and the name they go by in the description of this signal. <java.lang.Boolean(named: canUndo)>:

This signal is emitted whenever the active stack emits QUndoStack::canUndoChanged() or the active stack changes.

canUndo is the new state, or false if the active stack is 0.

See also:
QUndoStack::canUndoChanged() , and setActiveStack().


cleanChanged

public final QSignalEmitter.Signal1 cleanChanged

This signal takes 1 generic argument(s). We list their type and the name they go by in the description of this signal. <java.lang.Boolean(named: clean)>:

This signal is emitted whenever the active stack emits QUndoStack::cleanChanged() or the active stack changes.

clean is the new state, or true if the active stack is 0.

See also:
QUndoStack::cleanChanged() , and setActiveStack().


indexChanged

public final QSignalEmitter.Signal1 indexChanged

This signal takes 1 generic argument(s). We list their type and the name they go by in the description of this signal. <java.lang.Integer(named: idx)>:

This signal is emitted whenever the active stack emits QUndoStack::indexChanged() or the active stack changes.

idx is the new current index, or 0 if the active stack is 0.

See also:
QUndoStack::indexChanged() , and setActiveStack().


redoTextChanged

public final QSignalEmitter.Signal1 redoTextChanged

This signal takes 1 generic argument(s). We list their type and the name they go by in the description of this signal. <java.lang.String(named: redoText)>:

This signal is emitted whenever the active stack emits QUndoStack::redoTextChanged() or the active stack changes.

redoText is the new state, or an empty string if the active stack is 0.

See also:
QUndoStack::redoTextChanged() , and setActiveStack().


undoTextChanged

public final QSignalEmitter.Signal1 undoTextChanged

This signal takes 1 generic argument(s). We list their type and the name they go by in the description of this signal. <java.lang.String(named: undoText)>:

This signal is emitted whenever the active stack emits QUndoStack::undoTextChanged() or the active stack changes.

undoText is the new state, or an empty string if the active stack is 0.

See also:
QUndoStack::undoTextChanged() , and setActiveStack().

Constructor Detail

QUndoGroup

public QUndoGroup()
Creates an empty QUndoGroup object with parent parent.

See also:
addStack().


QUndoGroup

public QUndoGroup(QObject parent)
Creates an empty QUndoGroup object with parent parent.

See also:
addStack().

Method Detail

activeStack

public final QUndoStack activeStack()
Returns the active stack of this group.

If none of the stacks are active, or if the group is empty, this function returns 0.

See also:
setActiveStack(), and QUndoStack::setActive().


addStack

public final void addStack(QUndoStack stack)
Adds stack to this group. The group does not take ownership of the stack. Another way of adding a stack to a group is by specifying the group as the stack's parent QObject in QUndoStack::QUndoStack(). In this case, the stack is deleted when the group is deleted, in the usual manner of QObjects.

See also:
removeStack(), stacks(), and QUndoStack::QUndoStack().


canRedo

public final boolean canRedo()
Returns the value of the active stack's QUndoStack::canRedo().

If none of the stacks are active, or if the group is empty, this function returns false.

See also:
canUndo(), and setActiveStack().


canUndo

public final boolean canUndo()
Returns the value of the active stack's QUndoStack::canUndo().

If none of the stacks are active, or if the group is empty, this function returns false.

See also:
canRedo(), and setActiveStack().


createRedoAction

public final QAction createRedoAction(QObject parent)
Creates an redo QAction object with parent parent.

Triggering this action will cause a call to QUndoStack::redo() on the active stack. The text of this action will always be the text of the command which will be redone in the next call to redo(), prefixed by prefix. If there is no command available for redo, if the group is empty or if none of the stacks are active, this action will be disabled.

If prefix is empty, the default prefix "Undo" is used.

See also:
createUndoAction(), canRedo(), and QUndoCommand::text().


createRedoAction

public final QAction createRedoAction(QObject parent,
                                      java.lang.String prefix)
Creates an redo QAction object with parent parent.

Triggering this action will cause a call to QUndoStack::redo() on the active stack. The text of this action will always be the text of the command which will be redone in the next call to redo(), prefixed by prefix. If there is no command available for redo, if the group is empty or if none of the stacks are active, this action will be disabled.

If prefix is empty, the default prefix "Undo" is used.

See also:
createUndoAction(), canRedo(), and QUndoCommand::text().


createUndoAction

public final QAction createUndoAction(QObject parent)
Creates an undo QAction object with parent parent.

Triggering this action will cause a call to QUndoStack::undo() on the active stack. The text of this action will always be the text of the command which will be undone in the next call to undo(), prefixed by prefix. If there is no command available for undo, if the group is empty or if none of the stacks are active, this action will be disabled.

If prefix is empty, the default prefix "Undo" is used.

See also:
createRedoAction(), canUndo(), and QUndoCommand::text().


createUndoAction

public final QAction createUndoAction(QObject parent,
                                      java.lang.String prefix)
Creates an undo QAction object with parent parent.

Triggering this action will cause a call to QUndoStack::undo() on the active stack. The text of this action will always be the text of the command which will be undone in the next call to undo(), prefixed by prefix. If there is no command available for undo, if the group is empty or if none of the stacks are active, this action will be disabled.

If prefix is empty, the default prefix "Undo" is used.

See also:
createRedoAction(), canUndo(), and QUndoCommand::text().


isClean

public final boolean isClean()
Returns the value of the active stack's QUndoStack::isClean().

If none of the stacks are active, or if the group is empty, this function returns true.

See also:
setActiveStack().


redo

public final void redo()
Calls QUndoStack::redo() on the active stack.

If none of the stacks are active, or if the group is empty, this function does nothing.

See also:
undo(), canRedo(), and setActiveStack().


redoText

public final java.lang.String redoText()
Returns the value of the active stack's QUndoStack::redoText().

If none of the stacks are active, or if the group is empty, this function returns an empty string.

See also:
undoText(), and setActiveStack().


removeStack

public final void removeStack(QUndoStack stack)
Removes stack from this group. If the stack was the active stack in the group, the active stack becomes 0.

See also:
addStack(), stacks(), and QUndoStack::~QUndoStack().


setActiveStack

public final void setActiveStack(QUndoStack stack)
Sets the active stack of this group to stack.

If the stack is not a member of this group, this function does nothing.

Synonymous with calling QUndoStack::setActive() on stack.

The actions returned by createUndoAction() and createRedoAction() will now behave in the same way as those returned by stack's QUndoStack::createUndoAction() and QUndoStack::createRedoAction().

See also:
QUndoStack::setActive(), and activeStack().


stacks

public final java.util.List stacks()
Returns a list of stacks in this group.

See also:
addStack(), and removeStack().


undo

public final void undo()
Calls QUndoStack::undo() on the active stack.

If none of the stacks are active, or if the group is empty, this function does nothing.

See also:
redo(), canUndo(), and setActiveStack().


undoText

public final java.lang.String undoText()
Returns the value of the active stack's QUndoStack::undoText().

If none of the stacks are active, or if the group is empty, this function returns an empty string.

See also:
redoText(), and setActiveStack().