KViewStateSerializer

KViewStateSerializer Class Referenceabstract

#include <KViewStateSerializer>

Inheritance diagram for KViewStateSerializer:

Public Member Functions

 KViewStateSerializer (QObject *parent=nullptr)
 
 ~KViewStateSerializer ()
 
QString currentIndexKey () const
 
QStringList expansionKeys () const
 
void restoreCurrentItem (const QString &indexString)
 
void restoreExpanded (const QStringList &indexStrings)
 
void restoreScrollState (int verticalScoll, int horizontalScroll)
 
void restoreSelection (const QStringList &indexStrings)
 
QPair< int, int > scrollState () const
 
QStringList selectionKeys () const
 
QItemSelectionModelselectionModel () const
 
void setSelectionModel (QItemSelectionModel *selectionModel)
 
void setView (QAbstractItemView *view)
 
QAbstractItemViewview () const
 
- Public Member Functions inherited from QObject
 QObject (QObject *parent)
 
bool blockSignals (bool block)
 
const QObjectListchildren () const const
 
QMetaObject::Connection connect (const QObject *sender, const char *signal, const char *method, Qt::ConnectionType type) const const
 
void deleteLater ()
 
void destroyed (QObject *obj)
 
bool disconnect (const char *signal, const QObject *receiver, const char *method) const const
 
bool disconnect (const QObject *receiver, const char *method) const const
 
void dumpObjectInfo ()
 
void dumpObjectInfo () const const
 
void dumpObjectTree ()
 
void dumpObjectTree () const const
 
QList< QByteArraydynamicPropertyNames () const const
 
virtual bool event (QEvent *e)
 
virtual bool eventFilter (QObject *watched, QEvent *event)
 
findChild (const QString &name, Qt::FindChildOptions options) const const
 
QList< T > findChildren (const QString &name, Qt::FindChildOptions options) const const
 
QList< T > findChildren (const QRegExp &regExp, Qt::FindChildOptions options) const const
 
QList< T > findChildren (const QRegularExpression &re, Qt::FindChildOptions options) const const
 
bool inherits (const char *className) const const
 
void installEventFilter (QObject *filterObj)
 
bool isWidgetType () const const
 
bool isWindowType () const const
 
void killTimer (int id)
 
virtual const QMetaObjectmetaObject () const const
 
void moveToThread (QThread *targetThread)
 
QString objectName () const const
 
void objectNameChanged (const QString &objectName)
 
QObjectparent () const const
 
QVariant property (const char *name) const const
 
 Q_CLASSINFO (Name, Value)
 
 Q_DISABLE_COPY (Class)
 
 Q_DISABLE_COPY_MOVE (Class)
 
 Q_DISABLE_MOVE (Class)
 
 Q_EMIT Q_EMIT
 
 Q_ENUM (...)
 
 Q_ENUM_NS (...)
 
 Q_ENUMS (...)
 
 Q_FLAG (...)
 
 Q_FLAG_NS (...)
 
 Q_FLAGS (...)
 
 Q_GADGET Q_GADGET
 
 Q_INTERFACES (...)
 
 Q_INVOKABLE Q_INVOKABLE
 
 Q_NAMESPACE Q_NAMESPACE
 
 Q_NAMESPACE_EXPORT (EXPORT_MACRO)
 
 Q_OBJECT Q_OBJECT
 
 Q_PROPERTY (...)
 
 Q_REVISION Q_REVISION
 
 Q_SET_OBJECT_NAME (Object)
 
 Q_SIGNAL Q_SIGNAL
 
 Q_SIGNALS Q_SIGNALS
 
 Q_SLOT Q_SLOT
 
 Q_SLOTS Q_SLOTS
 
qFindChild (const QObject *obj, const QString &name)
 
QList< T > qFindChildren (const QObject *obj, const QRegExp &regExp)
 
QList< T > qFindChildren (const QObject *obj, const QString &name)
 
qobject_cast (QObject *object)
 
qobject_cast (const QObject *object)
 
 QT_NO_NARROWING_CONVERSIONS_IN_CONNECT QT_NO_NARROWING_CONVERSIONS_IN_CONNECT
 
void removeEventFilter (QObject *obj)
 
void setObjectName (const QString &name)
 
void setParent (QObject *parent)
 
bool setProperty (const char *name, const QVariant &value)
 
bool signalsBlocked () const const
 
int startTimer (int interval, Qt::TimerType timerType)
 
int startTimer (std::chrono::milliseconds time, Qt::TimerType timerType)
 
QThreadthread () const const
 

Protected Member Functions

virtual QModelIndex indexFromConfigString (const QAbstractItemModel *model, const QString &key) const =0
 
virtual QString indexToConfigString (const QModelIndex &index) const =0
 
void restoreState ()
 
- Protected Member Functions inherited from QObject
virtual void childEvent (QChildEvent *event)
 
virtual void connectNotify (const QMetaMethod &signal)
 
virtual void customEvent (QEvent *event)
 
virtual void disconnectNotify (const QMetaMethod &signal)
 
bool isSignalConnected (const QMetaMethod &signal) const const
 
int receivers (const char *signal) const const
 
QObjectsender () const const
 
int senderSignalIndex () const const
 
virtual void timerEvent (QTimerEvent *event)
 

Additional Inherited Members

- Properties inherited from QObject
 objectName
 
- Static Public Member Functions inherited from QObject
QMetaObject::Connection connect (const QObject *sender, const char *signal, const QObject *receiver, const char *method, Qt::ConnectionType type)
 
QMetaObject::Connection connect (const QObject *sender, const QMetaMethod &signal, const QObject *receiver, const QMetaMethod &method, Qt::ConnectionType type)
 
QMetaObject::Connection connect (const QObject *sender, PointerToMemberFunction signal, const QObject *receiver, PointerToMemberFunction method, Qt::ConnectionType type)
 
QMetaObject::Connection connect (const QObject *sender, PointerToMemberFunction signal, Functor functor)
 
QMetaObject::Connection connect (const QObject *sender, PointerToMemberFunction signal, const QObject *context, Functor functor, Qt::ConnectionType type)
 
bool disconnect (const QMetaObject::Connection &connection)
 
bool disconnect (const QObject *sender, const char *signal, const QObject *receiver, const char *method)
 
bool disconnect (const QObject *sender, PointerToMemberFunction signal, const QObject *receiver, PointerToMemberFunction method)
 
bool disconnect (const QObject *sender, const QMetaMethod &signal, const QObject *receiver, const QMetaMethod &method)
 
QString tr (const char *sourceText, const char *disambiguation, int n)
 
QString trUtf8 (const char *sourceText, const char *disambiguation, int n)
 
- Public Attributes inherited from QObject
typedef QObjectList
 

Detailed Description

Object for saving and restoring state in QTreeViews and QItemSelectionModels.

Implement the indexFromConfigString and indexToConfigString methods to handle the model in the view whose state is being saved. These implementations can be quite trivial:

QModelIndex DynamicTreeStateSaver::indexFromConfigString(const QAbstractItemModel* model, const QString& key) const
{
QModelIndexList list = model->match(model->index(0, 0), DynamicTreeModel::DynamicTreeModelId, key.toInt(), 1, Qt::MatchRecursive);
if (list.isEmpty())
return QModelIndex();
return list.first();
}
QString DynamicTreeStateSaver::indexToConfigString(const QModelIndex& index) const
{
return index.data(DynamicTreeModel::DynamicTreeModelId).toString();
}

It is possible to restore the state of a QTreeView (that is, the expanded state and selected state of all indexes as well as the horizontal and vertical scroll state) by using setTreeView.

If there is no tree view state to restore (for example if using QML), the selection state of a QItemSelectionModel can be saved or restored instead.

The state of any QAbstractScrollArea can also be saved and restored.

A KViewStateSerializer should be created on the stack when saving and on the heap when restoring. The model may be populated dynamically between several event loops, so it may not be immediate for the indexes that should be selected to be in the model. The saver should not be persisted as a member. The saver will destroy itself when it has completed the restoration specified in the config group, or a small amount of time has elapsed.

MyWidget::MyWidget(Qobject *parent)
: QWidget(parent)
{
...
m_view = new QTreeView(splitter);
m_view->setModel(model);
connect( model, SIGNAL(modelAboutToBeReset()), SLOT(saveState()) );
connect( model, SIGNAL(modelReset()), SLOT(restoreState()) );
connect( qApp, SIGNAL(aboutToQuit()), SLOT(saveState()) );
}
void StateSaverWidget::saveState()
{
ConcreteStateSaver saver;
saver.setTreeView(m_view);
KConfigGroup cfg( KSharedConfig::openConfig(), "ExampleViewState" );
saver.saveState( cfg );
cfg.sync();
}
void StateSaverWidget::restoreState()
{
// Will delete itself.
ConcreteTreeStateSaver *saver = new ConcreteStateSaver();
saver->setTreeView(m_view);
KConfigGroup cfg( KSharedConfig::openConfig(), "ExampleViewState" );
saver->restoreState( cfg );
}

After creating a saver, the state can be saved using a KConfigGroup.

It is also possible to save and restore state directly by using the restoreSelection, restoreExpanded etc methods. Note that the implementation of these methods should return strings that the indexFromConfigString implementation can handle.

class DynamicTreeStateSaver : public KViewStateSerializer
{
public:
// ...
void selectItems(const QList<qint64> &items)
{
QStringList itemStrings;
for (qint64 item : items)
itemStrings << QString::number(item);
restoreSelection(itemStrings);
}
void expandItems(const QList<qint64> &items)
{
QStringList itemStrings;
for (qint64 item : items)
itemStrings << QString::number(item);
restoreSelection(itemStrings);
}
};

Note that a single instance of this class should be used with only one widget. That is don't do this:

saver->setTreeView(treeView1);
saver->setSelectionModel(treeView2->selectionModel());
saver->setScrollArea(treeView3);

To save the state of 3 different widgets, use three savers, even if they operate on the same root model.

saver1->setTreeView(treeView1);
saver2->setSelectionModel(treeView2->selectionModel());
saver3->setScrollArea(treeView3);
Note
The KViewStateSerializer does not take ownership of any widgets set on it.

It is recommended to restore the state on application startup and after the model has been reset, and to save the state on application close and before the model has been reset.

See also
QAbstractItemModel::modelAboutToBeReset QAbstractItemModel::modelReset
Author
Stephen Kelly steph[email protected][email protected][email protected]dab.c[email protected]om
Since
4.5

Definition at line 154 of file kviewstateserializer.h.

Constructor & Destructor Documentation

KViewStateSerializer::KViewStateSerializer ( QObject parent = nullptr)
explicit

Constructor.

Definition at line 97 of file kviewstateserializer.cpp.

KViewStateSerializer::~KViewStateSerializer ( )

Destructor.

Definition at line 104 of file kviewstateserializer.cpp.

Member Function Documentation

QString KViewStateSerializer::currentIndexKey ( ) const

Returns a QString describing the current index in the selection model.

Definition at line 316 of file kviewstateserializer.cpp.

QStringList KViewStateSerializer::expansionKeys ( ) const

Returns a QStringList representing the expanded indexes in the QTreeView.

Definition at line 325 of file kviewstateserializer.cpp.

virtual QModelIndex KViewStateSerializer::indexFromConfigString ( const QAbstractItemModel model,
const QString key 
) const
protectedpure virtual

Reimplement to return an index in the model described by the unique key key.

virtual QString KViewStateSerializer::indexToConfigString ( const QModelIndex index) const
protectedpure virtual

Reimplement to return a unique string for the index.

void KViewStateSerializer::restoreCurrentItem ( const QString indexString)

Make the index described by indexString the currentIndex in the selectionModel.

Definition at line 205 of file kviewstateserializer.cpp.

void KViewStateSerializer::restoreExpanded ( const QStringList indexStrings)

Expand the indexes described by indexStrings in the QTreeView.

Definition at line 239 of file kviewstateserializer.cpp.

void KViewStateSerializer::restoreScrollState ( int  verticalScoll,
int  horizontalScroll 
)

Restores the scroll state of the QAbstractScrollArea to the verticalScoll and horizontalScroll.

Definition at line 262 of file kviewstateserializer.cpp.

void KViewStateSerializer::restoreSelection ( const QStringList indexStrings)

Select the indexes described by indexStrings.

Definition at line 292 of file kviewstateserializer.cpp.

QPair< int, int > KViewStateSerializer::scrollState ( ) const

Returns the vertical and horizontal scroll of the QAbstractScrollArea.

Definition at line 352 of file kviewstateserializer.cpp.

QStringList KViewStateSerializer::selectionKeys ( ) const

Returns a QStringList describing the selection in the selectionModel.

Definition at line 335 of file kviewstateserializer.cpp.

QItemSelectionModel * KViewStateSerializer::selectionModel ( ) const

The QItemSelectionModel whose state is persisted.

Definition at line 129 of file kviewstateserializer.cpp.

void KViewStateSerializer::setSelectionModel ( QItemSelectionModel selectionModel)

Sets the QItemSelectionModel whose state is persisted.

Definition at line 135 of file kviewstateserializer.cpp.

void KViewStateSerializer::setView ( QAbstractItemView view)

Sets the view whose state is persisted.

Definition at line 109 of file kviewstateserializer.cpp.

QAbstractItemView * KViewStateSerializer::view ( ) const

The view whose state is persisted.

Definition at line 123 of file kviewstateserializer.cpp.


The documentation for this class was generated from the following files:
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