KViewStateSerializer

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KViewStateSerializer Class Referenceabstract

#include <KViewStateSerializer>

Inheritance diagram for KViewStateSerializer:

Public Member Functions

 KViewStateSerializer (QObject *parent=nullptr)
 
 ~KViewStateSerializer () override
 
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)
 
QBindable< QStringbindableObjectName ()
 
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 () const const
 
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 QRegularExpression &re, Qt::FindChildOptions options) const const
 
QList< T > findChildren (const QString &name, Qt::FindChildOptions options) const const
 
QList< T > findChildren (Qt::FindChildOptions options) const const
 
bool inherits (const char *className) const const
 
void installEventFilter (QObject *filterObj)
 
bool isQuickItemType () const const
 
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_EMIT Q_EMIT
 
 Q_ENUM (...)
 
 Q_ENUM_NS (...)
 
 Q_ENUMS (...)
 
 Q_FLAG (...)
 
 Q_FLAG_NS (...)
 
 Q_FLAGS (...)
 
 Q_GADGET Q_GADGET
 
 Q_GADGET_EXPORT (EXPORT_MACRO)
 
 Q_INTERFACES (...)
 
 Q_INVOKABLE Q_INVOKABLE
 
 Q_MOC_INCLUDE Q_MOC_INCLUDE
 
 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
 
qobject_cast (const QObject *object)
 
qobject_cast (QObject *object)
 
 QT_NO_NARROWING_CONVERSIONS_IN_CONNECT QT_NO_NARROWING_CONVERSIONS_IN_CONNECT
 
void removeEventFilter (QObject *obj)
 
void setObjectName (const QString &name)
 
void setObjectName (QAnyStringView name)
 
void setParent (QObject *parent)
 
bool setProperty (const char *name, const QVariant &value)
 
bool setProperty (const char *name, QVariant &&value)
 
bool signalsBlocked () const const
 
int startTimer (int interval, Qt::TimerType timerType)
 
int startTimer (std::chrono::milliseconds interval, 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 *context, Functor functor, 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)
 
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, const QMetaMethod &signal, const QObject *receiver, const QMetaMethod &method)
 
bool disconnect (const QObject *sender, PointerToMemberFunction signal, const QObject *receiver, PointerToMemberFunction method)
 
QString tr (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,
if (list.isEmpty()) {
return QModelIndex();
}
return list.first();
}
QString DynamicTreeStateSaver::indexToConfigString(const QModelIndex& index) const
{
return index.data(DynamicTreeModel::DynamicTreeModelId).toString();
}
virtual QModelIndex index(int row, int column, const QModelIndex &parent) const const=0
virtual QModelIndexList match(const QModelIndex &start, int role, const QVariant &value, int hits, Qt::MatchFlags flags) const const
T & first()
bool isEmpty() const const
QVariant data(int role) const const
int toInt(bool *ok, int base) const const
MatchRecursive
QString toString() const const

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 setView.

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)
{
...
m_view = new QTreeView(splitter);
m_view->setModel(model);
connect(model, &QAbstractItemModel::modelAboutToBeReset, this, [this]() { saveState(); });
connect(model, &QAbstractItemModel::modelReset, [this]() { restoreState(); });
connect(qApp, &QApplication::aboutToQuit, this, [this]() { saveState(); });
restoreState();
}
void StateSaverWidget::saveState()
{
ConcreteStateSaver saver;
saver.setView(m_view);
KConfigGroup cfg(KSharedConfig::openConfig(), "ExampleViewState");
saver.saveState(cfg);
cfg.sync();
}
void StateSaverWidget::restoreState()
{
// Will delete itself.
ConcreteTreeStateSaver *saver = new ConcreteStateSaver();
saver->setView(m_view);
KConfigGroup cfg(KSharedConfig::openConfig(), "ExampleViewState");
saver->restoreState(cfg);
}
static KSharedConfig::Ptr openConfig(const QString &fileName=QString(), OpenFlags mode=FullConfig, QStandardPaths::StandardLocation type=QStandardPaths::GenericConfigLocation)
void modelAboutToBeReset()
QObject * parent() const const
T qobject_cast(QObject *object)
QFuture< ArgsType< Signal > > connect(Sender *sender, Signal signal)

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.

{
public:
// ...
void selectItems(const QList<qint64> &items)
{
for (qint64 item : items) {
}
restoreSelection(itemStrings);
}
void expandItems(const QList<qint64> &items)
{
for (qint64 item : items) {
}
restoreSelection(itemStrings);
}
};
Object for saving and restoring state in QTreeViews and QItemSelectionModels.
Q_OBJECTQ_OBJECT
QString number(double n, char format, int precision)

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

saver->setView(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->setView(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.nosp@m.en@k.nosp@m.dab.c.nosp@m.om
Since
4.5

Definition at line 168 of file kviewstateserializer.h.

Constructor & Destructor Documentation

◆ KViewStateSerializer()

KViewStateSerializer::KViewStateSerializer ( QObject * parent = nullptr)
explicit

Constructor.

Definition at line 96 of file kviewstateserializer.cpp.

◆ ~KViewStateSerializer()

KViewStateSerializer::~KViewStateSerializer ( )
overridedefault

Destructor.

Member Function Documentation

◆ currentIndexKey()

QString KViewStateSerializer::currentIndexKey ( ) const

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

Definition at line 307 of file kviewstateserializer.cpp.

◆ expansionKeys()

QStringList KViewStateSerializer::expansionKeys ( ) const

Returns a QStringList representing the expanded indexes in the QTreeView.

Definition at line 316 of file kviewstateserializer.cpp.

◆ indexFromConfigString()

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.

◆ indexToConfigString()

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

Reimplement to return a unique string for the index.

◆ restoreCurrentItem()

void KViewStateSerializer::restoreCurrentItem ( const QString & indexString)

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

Definition at line 202 of file kviewstateserializer.cpp.

◆ restoreExpanded()

void KViewStateSerializer::restoreExpanded ( const QStringList & indexStrings)

Expand the indexes described by indexStrings in the QTreeView.

Definition at line 236 of file kviewstateserializer.cpp.

◆ restoreScrollState()

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

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

Definition at line 255 of file kviewstateserializer.cpp.

◆ restoreSelection()

void KViewStateSerializer::restoreSelection ( const QStringList & indexStrings)

Select the indexes described by indexStrings.

Definition at line 287 of file kviewstateserializer.cpp.

◆ restoreState()

void KViewStateSerializer::restoreState ( )
protected

Definition at line 349 of file kviewstateserializer.cpp.

◆ scrollState()

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

Returns the vertical and horizontal scroll of the QAbstractScrollArea.

Definition at line 343 of file kviewstateserializer.cpp.

◆ selectionKeys()

QStringList KViewStateSerializer::selectionKeys ( ) const

Returns a QStringList describing the selection in the selectionModel.

Definition at line 326 of file kviewstateserializer.cpp.

◆ selectionModel()

QItemSelectionModel * KViewStateSerializer::selectionModel ( ) const

The QItemSelectionModel whose state is persisted.

Definition at line 126 of file kviewstateserializer.cpp.

◆ setSelectionModel()

void KViewStateSerializer::setSelectionModel ( QItemSelectionModel * selectionModel)

Sets the QItemSelectionModel whose state is persisted.

Definition at line 132 of file kviewstateserializer.cpp.

◆ setView()

void KViewStateSerializer::setView ( QAbstractItemView * view)

Sets the view whose state is persisted.

Definition at line 106 of file kviewstateserializer.cpp.

◆ view()

QAbstractItemView * KViewStateSerializer::view ( ) const

The view whose state is persisted.

Definition at line 120 of file kviewstateserializer.cpp.


The documentation for this class was generated from the following files:
This file is part of the KDE documentation.
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