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KDE 4.9 PyKDE API Reference
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<h1>KViewStateSaver Class Reference</h1>
<code>from PyKDE4.kdeui import *</code>
<p>
Inherits: QObject<br />
<h2>Detailed Description</h2>
<p>Object for saving and restoring state in QTreeViews and QItemSelectionModels
</p>
<p>
Implement the indexFromConfigString and indexToConfigString methods to
handle the model in the view whose state is being saved. These implementations can be quite trivial:
</p>
<p>
<pre class="fragment">
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();
}
</pre>
</p>
<p>
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.
</p>
<p>
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.
</p>
<p>
The state of any QAbstractScrollArea can also be saved and restored.
</p>
<p>
A KViewStateSaver 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.
</p>
<p>
<pre class="fragment">
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()) );
restoreState();
}
void StateSaverWidget.saveState()
{
ConcreteStateSaver saver;
saver.setTreeView(m_view);
KConfigGroup cfg( KGlobal.config(), "ExampleViewState" );
saver.saveState( cfg );
cfg.sync();
}
void StateSaverWidget.restoreState()
{
// Will delete itself.
ConcreteTreeStateSaver *saver = new ConcreteStateSaver();
saver->setTreeView(m_view);
KConfigGroup cfg( KGlobal.config(), "ExampleViewState" );
saver->restoreState( cfg );
}
</pre>
</p>
<p>
After creating a saver, the state can be saved using a KConfigGroup.
</p>
<p>
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.
</p>
<p>
<pre class="fragment">
class DynamicTreeStateSaver : public KViewStateSaver
{
Q_OBJECT
public:
// ...
void selectItems(const QList<qint64> &items)
{
QStringList itemStrings;
foreach(qint64 item, items)
itemStrings << QString.number(item);
restoreSelection(itemStrings);
}
void expandItems(const QList<qint64> &items)
{
QStringList itemStrings;
foreach(qint64 item, items)
itemStrings << QString.number(item);
restoreSelection(itemStrings);
}
};
</pre>
</p>
<p>
Note that a single instance of this class should be used with only one widget. That is don't do this:
</p>
<p>
<pre class="fragment">
saver->setTreeView(treeView1);
saver->setSelectionModel(treeView2->selectionModel());
saver->setScrollArea(treeView3);
</pre>
</p>
<p>
To save the state of 3 different widgets, use three savers, even if they operate on the same root model.
</p>
<p>
<pre class="fragment">
saver1->setTreeView(treeView1);
saver2->setSelectionModel(treeView2->selectionModel());
saver3->setScrollArea(treeView3);
</pre>
</p>
<p>
<dl class="note" compact><dt><b>Note:</b></dt><dd> The KViewStateSaver does not take ownership of any widgets set on it.
</dd></dl> </p>
<p>
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.
</p>
<p>
<dl class="see" compact><dt><b>See also:</b></dt><dd> QAbstractItemModel.modelAboutToBeReset QAbstractItemModel.modelReset
</dd></dl> </p>
<p>
<dl class="author" compact><dt><b>Author:</b></dt><dd> Stephen Kelly <stephen@kdab.com> </dd></dl>
<dl class="since" compact><dt><b>Since:</b></dt><dd> 4.5
</dd></dl>
</p>
<table border="0" cellpadding="0" cellspacing="0"><tr><td colspan="2"><br><h2>Methods</h2></td></tr>
<tr><td class="memItemLeft" nowrap align="right" valign="top"> </td><td class="memItemRight" valign="bottom"><a class="el" href="#KViewStateSaver">__init__</a> (self, QObject parent=0)</td></tr>
<tr><td class="memItemLeft" nowrap align="right" valign="top">QString </td><td class="memItemRight" valign="bottom"><a class="el" href="#currentIndexKey">currentIndexKey</a> (self)</td></tr>
<tr><td class="memItemLeft" nowrap align="right" valign="top">QStringList </td><td class="memItemRight" valign="bottom"><a class="el" href="#expansionKeys">expansionKeys</a> (self)</td></tr>
<tr><td class="memItemLeft" nowrap align="right" valign="top">QModelIndex </td><td class="memItemRight" valign="bottom"><a class="el" href="#indexFromConfigString">indexFromConfigString</a> (self, QAbstractItemModel model, QString key)</td></tr>
<tr><td class="memItemLeft" nowrap align="right" valign="top">QString </td><td class="memItemRight" valign="bottom"><a class="el" href="#indexToConfigString">indexToConfigString</a> (self, QModelIndex index)</td></tr>
<tr><td class="memItemLeft" nowrap align="right" valign="top"> </td><td class="memItemRight" valign="bottom"><a class="el" href="#restoreCurrentItem">restoreCurrentItem</a> (self, QString indexString)</td></tr>
<tr><td class="memItemLeft" nowrap align="right" valign="top"> </td><td class="memItemRight" valign="bottom"><a class="el" href="#restoreExpanded">restoreExpanded</a> (self, QStringList indexStrings)</td></tr>
<tr><td class="memItemLeft" nowrap align="right" valign="top"> </td><td class="memItemRight" valign="bottom"><a class="el" href="#restoreScrollState">restoreScrollState</a> (self, int verticalScoll, int horizontalScroll)</td></tr>
<tr><td class="memItemLeft" nowrap align="right" valign="top"> </td><td class="memItemRight" valign="bottom"><a class="el" href="#restoreSelection">restoreSelection</a> (self, QStringList indexStrings)</td></tr>
<tr><td class="memItemLeft" nowrap align="right" valign="top"> </td><td class="memItemRight" valign="bottom"><a class="el" href="#restoreState">restoreState</a> (self, <a href="../kdecore/KConfigGroup.html">KConfigGroup</a> configGroup)</td></tr>
<tr><td class="memItemLeft" nowrap align="right" valign="top"> </td><td class="memItemRight" valign="bottom"><a class="el" href="#saveState">saveState</a> (self, <a href="../kdecore/KConfigGroup.html">KConfigGroup</a> configGroup)</td></tr>
<tr><td class="memItemLeft" nowrap align="right" valign="top">(int,int) </td><td class="memItemRight" valign="bottom"><a class="el" href="#scrollState">scrollState</a> (self)</td></tr>
<tr><td class="memItemLeft" nowrap align="right" valign="top">QStringList </td><td class="memItemRight" valign="bottom"><a class="el" href="#selectionKeys">selectionKeys</a> (self)</td></tr>
<tr><td class="memItemLeft" nowrap align="right" valign="top">QItemSelectionModel </td><td class="memItemRight" valign="bottom"><a class="el" href="#selectionModel">selectionModel</a> (self)</td></tr>
<tr><td class="memItemLeft" nowrap align="right" valign="top"> </td><td class="memItemRight" valign="bottom"><a class="el" href="#setSelectionModel">setSelectionModel</a> (self, QItemSelectionModel selectionModel)</td></tr>
<tr><td class="memItemLeft" nowrap align="right" valign="top"> </td><td class="memItemRight" valign="bottom"><a class="el" href="#setView">setView</a> (self, QAbstractItemView view)</td></tr>
<tr><td class="memItemLeft" nowrap align="right" valign="top">QAbstractItemView </td><td class="memItemRight" valign="bottom"><a class="el" href="#view">view</a> (self)</td></tr>
</table>
<hr><h2>Method Documentation</h2><a class="anchor" name="KViewStateSaver"></a>
<div class="memitem">
<div class="memproto">
<table class="memname"><tr>
<td class="memname">__init__</td>
<td>(</td>
<td class="paramtype"> <em>self</em>, </td>
<td class="paramname"></td>
</tr><tr>
<td class="memname"></td>
<td></td>
<td class="paramtype">QObject </td>
<td class="paramname"><em>parent=0</em></td>
</tr>
<tr>
<td></td>
<td>)</td>
<td></td>
<td></td>
<td width="100%"> </td>
</tr></table>
</div>
<div class="memdoc"><p>Constructor
</p><dl compact><dt><b>Parameters:</b></dt><dd>
<table border="0" cellspacing="2" cellpadding="0">
<tr><td></td><td valign="top"><em>parent</em> </td><td> standard parent object, but ignored since this object will delete itself
</td></tr>
</table></dl>
<p>
</p></div></div><a class="anchor" name="currentIndexKey"></a>
<div class="memitem">
<div class="memproto">
<table class="memname"><tr>
<td class="memname">QString currentIndexKey</td>
<td>(</td>
<td class="paramtype"> </td>
<td class="paramname"><em>self</em> )</td>
<td width="100%"> </td>
</tr>
</table>
</div>
<div class="memdoc"><p>Returns a QString describing the current index in the selection model.
</p></div></div><a class="anchor" name="expansionKeys"></a>
<div class="memitem">
<div class="memproto">
<table class="memname"><tr>
<td class="memname">QStringList expansionKeys</td>
<td>(</td>
<td class="paramtype"> </td>
<td class="paramname"><em>self</em> )</td>
<td width="100%"> </td>
</tr>
</table>
</div>
<div class="memdoc"><p>Returns a QStringList representing the expanded indexes in the QTreeView.
</p></div></div><a class="anchor" name="indexFromConfigString"></a>
<div class="memitem">
<div class="memproto">
<table class="memname"><tr>
<td class="memname">QModelIndex indexFromConfigString</td>
<td>(</td>
<td class="paramtype"> <em>self</em>, </td>
<td class="paramname"></td>
</tr><tr>
<td class="memname"></td>
<td></td>
<td class="paramtype">QAbstractItemModel </td>
<td class="paramname"><em>model</em>, </td>
</tr>
<tr>
<td class="memname"></td>
<td></td>
<td class="paramtype">QString </td>
<td class="paramname"><em>key</em></td>
</tr>
<tr>
<td></td>
<td>)</td>
<td></td>
<td></td>
<td width="100%"> </td>
</tr></table>
</div>
<div class="memdoc"><dl compact><dt><b>Abstract method:</b></dt><dd>This method is abstract and can be overridden but not called directly.</dd></dl><p>Reimplement to return an index in the <b>model</b> described by the unique key <b>key</b>
</p></div></div><a class="anchor" name="indexToConfigString"></a>
<div class="memitem">
<div class="memproto">
<table class="memname"><tr>
<td class="memname">QString indexToConfigString</td>
<td>(</td>
<td class="paramtype"> <em>self</em>, </td>
<td class="paramname"></td>
</tr><tr>
<td class="memname"></td>
<td></td>
<td class="paramtype">QModelIndex </td>
<td class="paramname"><em>index</em></td>
</tr>
<tr>
<td></td>
<td>)</td>
<td></td>
<td></td>
<td width="100%"> </td>
</tr></table>
</div>
<div class="memdoc"><dl compact><dt><b>Abstract method:</b></dt><dd>This method is abstract and can be overridden but not called directly.</dd></dl><p>Reimplement to return a unique string for the <b>index.</b>
</p></div></div><a class="anchor" name="restoreCurrentItem"></a>
<div class="memitem">
<div class="memproto">
<table class="memname"><tr>
<td class="memname"> restoreCurrentItem</td>
<td>(</td>
<td class="paramtype"> <em>self</em>, </td>
<td class="paramname"></td>
</tr><tr>
<td class="memname"></td>
<td></td>
<td class="paramtype">QString </td>
<td class="paramname"><em>indexString</em></td>
</tr>
<tr>
<td></td>
<td>)</td>
<td></td>
<td></td>
<td width="100%"> </td>
</tr></table>
</div>
<div class="memdoc"><p>Make the index described by <b>indexString</b> the currentIndex in the selectionModel.
</p></div></div><a class="anchor" name="restoreExpanded"></a>
<div class="memitem">
<div class="memproto">
<table class="memname"><tr>
<td class="memname"> restoreExpanded</td>
<td>(</td>
<td class="paramtype"> <em>self</em>, </td>
<td class="paramname"></td>
</tr><tr>
<td class="memname"></td>
<td></td>
<td class="paramtype">QStringList </td>
<td class="paramname"><em>indexStrings</em></td>
</tr>
<tr>
<td></td>
<td>)</td>
<td></td>
<td></td>
<td width="100%"> </td>
</tr></table>
</div>
<div class="memdoc"><p>Expand the indexes described by <b>indexStrings</b> in the QTreeView.
</p></div></div><a class="anchor" name="restoreScrollState"></a>
<div class="memitem">
<div class="memproto">
<table class="memname"><tr>
<td class="memname"> restoreScrollState</td>
<td>(</td>
<td class="paramtype"> <em>self</em>, </td>
<td class="paramname"></td>
</tr><tr>
<td class="memname"></td>
<td></td>
<td class="paramtype">int </td>
<td class="paramname"><em>verticalScoll</em>, </td>
</tr>
<tr>
<td class="memname"></td>
<td></td>
<td class="paramtype">int </td>
<td class="paramname"><em>horizontalScroll</em></td>
</tr>
<tr>
<td></td>
<td>)</td>
<td></td>
<td></td>
<td width="100%"> </td>
</tr></table>
</div>
<div class="memdoc"><p>Restores the scroll state of the QAbstractScrollArea to the <b>verticalScoll</b>
and <b>horizontalScroll</b>
</p></div></div><a class="anchor" name="restoreSelection"></a>
<div class="memitem">
<div class="memproto">
<table class="memname"><tr>
<td class="memname"> restoreSelection</td>
<td>(</td>
<td class="paramtype"> <em>self</em>, </td>
<td class="paramname"></td>
</tr><tr>
<td class="memname"></td>
<td></td>
<td class="paramtype">QStringList </td>
<td class="paramname"><em>indexStrings</em></td>
</tr>
<tr>
<td></td>
<td>)</td>
<td></td>
<td></td>
<td width="100%"> </td>
</tr></table>
</div>
<div class="memdoc"><p>Select the indexes described by <b>indexStrings</b>
</p></div></div><a class="anchor" name="restoreState"></a>
<div class="memitem">
<div class="memproto">
<table class="memname"><tr>
<td class="memname"> restoreState</td>
<td>(</td>
<td class="paramtype"> <em>self</em>, </td>
<td class="paramname"></td>
</tr><tr>
<td class="memname"></td>
<td></td>
<td class="paramtype"><a href="../kdecore/KConfigGroup.html">KConfigGroup</a> </td>
<td class="paramname"><em>configGroup</em></td>
</tr>
<tr>
<td></td>
<td>)</td>
<td></td>
<td></td>
<td width="100%"> </td>
</tr></table>
</div>
<div class="memdoc"><p>Restores the state from the <b>configGroup</b>
</p></div></div><a class="anchor" name="saveState"></a>
<div class="memitem">
<div class="memproto">
<table class="memname"><tr>
<td class="memname"> saveState</td>
<td>(</td>
<td class="paramtype"> <em>self</em>, </td>
<td class="paramname"></td>
</tr><tr>
<td class="memname"></td>
<td></td>
<td class="paramtype"><a href="../kdecore/KConfigGroup.html">KConfigGroup</a> </td>
<td class="paramname"><em>configGroup</em></td>
</tr>
<tr>
<td></td>
<td>)</td>
<td></td>
<td></td>
<td width="100%"> </td>
</tr></table>
</div>
<div class="memdoc"><p>Saves the state to the <b>configGroup</b>
</p></div></div><a class="anchor" name="scrollState"></a>
<div class="memitem">
<div class="memproto">
<table class="memname"><tr>
<td class="memname">(int,int) scrollState</td>
<td>(</td>
<td class="paramtype"> </td>
<td class="paramname"><em>self</em> )</td>
<td width="100%"> </td>
</tr>
</table>
</div>
<div class="memdoc"><p>Returns the vertical and horizontal scroll of the QAbstractScrollArea.
</p></div></div><a class="anchor" name="selectionKeys"></a>
<div class="memitem">
<div class="memproto">
<table class="memname"><tr>
<td class="memname">QStringList selectionKeys</td>
<td>(</td>
<td class="paramtype"> </td>
<td class="paramname"><em>self</em> )</td>
<td width="100%"> </td>
</tr>
</table>
</div>
<div class="memdoc"><p>Returns a QStringList describing the selection in the selectionModel.
</p></div></div><a class="anchor" name="selectionModel"></a>
<div class="memitem">
<div class="memproto">
<table class="memname"><tr>
<td class="memname">QItemSelectionModel selectionModel</td>
<td>(</td>
<td class="paramtype"> </td>
<td class="paramname"><em>self</em> )</td>
<td width="100%"> </td>
</tr>
</table>
</div>
<div class="memdoc"><p>The QItemSelectionModel whose state is persisted.
</p></div></div><a class="anchor" name="setSelectionModel"></a>
<div class="memitem">
<div class="memproto">
<table class="memname"><tr>
<td class="memname"> setSelectionModel</td>
<td>(</td>
<td class="paramtype"> <em>self</em>, </td>
<td class="paramname"></td>
</tr><tr>
<td class="memname"></td>
<td></td>
<td class="paramtype">QItemSelectionModel </td>
<td class="paramname"><em>selectionModel</em></td>
</tr>
<tr>
<td></td>
<td>)</td>
<td></td>
<td></td>
<td width="100%"> </td>
</tr></table>
</div>
<div class="memdoc"><p>Sets the QItemSelectionModel whose state is persisted.
</p></div></div><a class="anchor" name="setView"></a>
<div class="memitem">
<div class="memproto">
<table class="memname"><tr>
<td class="memname"> setView</td>
<td>(</td>
<td class="paramtype"> <em>self</em>, </td>
<td class="paramname"></td>
</tr><tr>
<td class="memname"></td>
<td></td>
<td class="paramtype">QAbstractItemView </td>
<td class="paramname"><em>view</em></td>
</tr>
<tr>
<td></td>
<td>)</td>
<td></td>
<td></td>
<td width="100%"> </td>
</tr></table>
</div>
<div class="memdoc"><p>Sets the view whose state is persisted.
</p></div></div><a class="anchor" name="view"></a>
<div class="memitem">
<div class="memproto">
<table class="memname"><tr>
<td class="memname">QAbstractItemView view</td>
<td>(</td>
<td class="paramtype"> </td>
<td class="paramname"><em>self</em> )</td>
<td width="100%"> </td>
</tr>
</table>
</div>
<div class="memdoc"><p>The view whose state is persisted.
</p></div></div>
</div>
</div>
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