Difference between revisions of "Proxy model example code"

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Related to [http://developer.qt.nokia.com/faq/answer/how_can_i_implement_my_own_proxy_model_that_is_more_advanced_than_just_sort this <span class="caps">FAQ</span> entry] ''[developer.qt.nokia.com]''.
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[[Category:snippets]]<br />[[Category:HowTo]]<br />[[Category:Developing with Qt]]
  
===Categories:===
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Related to &quot;this FAQ entry&amp;quot;:http://developer.qt.nokia.com/faq/answer/how_can_i_implement_my_own_proxy_model_that_is_more_advanced_than_just_sort.
  
* [[:Category:Developing with Qt|Developing_with_Qt]]
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<code><br />#include &lt;QtGui&amp;gt;
* [[:Category:HowTo|HowTo]]
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* [[:Category:snippets|snippets]]
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QList&amp;lt;QStandardItem *&gt; list;
 +
 
 +
class SortProxy : public QAbstractProxyModel<br />{<br /> Q_OBJECT
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 +
public:<br /> SortProxy(QObject *parent = 0) : QAbstractProxyModel(parent), hideThem(false)<br /> {<br /> fixModel();<br /> }
 +
 
 +
int rowCount(const QModelIndex &amp;parent) const<br /> {<br /> QModelIndex sourceParent;<br /> if (parent.isValid())<br /> sourceParent = mapToSource(parent);<br /> int count = 0;<br /> QMapIterator&amp;lt;QPersistentModelIndex, QPersistentModelIndex&amp;gt; it(proxySourceParent);<br /> while (it.hasNext()) {<br /> it.next();<br /> if (it.value() == sourceParent)<br /> count++;<br /> }<br /> return count;<br /> }
 +
 
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int columnCount(const QModelIndex &amp;) const<br /> {<br /> return 1;<br /> }
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QModelIndex index(int row, int column, const QModelIndex &amp;parent = QModelIndex()) const<br /> {<br /> QModelIndex sourceParent;<br /> if (parent.isValid())<br /> sourceParent = mapToSource(parent);<br /> QMapIterator&amp;lt;QPersistentModelIndex, QPersistentModelIndex&amp;gt; it(proxySourceParent);<br /> while (it.hasNext()) {<br /> it.next();<br /> if (it.value()  sourceParent &amp;amp;&amp;amp; it.key().row()  row &amp;&amp;<br /> it.key().column() == column)<br /> return it.key();<br /> }<br /> return QModelIndex();<br /> }
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QModelIndex parent(const QModelIndex &amp;child) const<br /> {<br /> QModelIndex mi = proxySourceParent.value(child);<br /> if (mi.isValid())<br /> return mapFromSource(mi);<br /> return QModelIndex();<br /> }
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QModelIndex mapToSource(const QModelIndex &amp;proxyIndex) const<br /> {<br /> if (!proxyIndex.isValid())<br /> return QModelIndex();<br /> return mapping.key(proxyIndex);<br /> }
 +
 
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QModelIndex mapFromSource(const QModelIndex &amp;sourceIndex) const<br /> {<br /> if (!sourceIndex.isValid())<br /> return QModelIndex();<br /> return mapping.value(sourceIndex);<br /> }
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 +
public slots:<br /> void hideEverythingButA1AndChildren()<br /> {<br /> hideThem = !hideThem;<br /> // Now we set up the proxy &lt;<s>&gt; source mappings<br /> emit layoutAboutToBeChanged();<br /> fixModel();<br /> emit layoutChanged();<br /> }
 +
<br />private:<br /> void fixModel()<br /> {<br /> mapping.clear();<br /> proxySourceParent.clear();<br /> for (int i=0;i&amp;lt;list.size();i+'') {<br /> QStandardItem *si = list.at(i);<br /> if (hideThem) {<br /> if (!si-&gt;text().startsWith(&quot;A&amp;quot;) || !si-&gt;parent())<br /> continue;<br /> QModelIndex proxy = createIndex(si-&gt;row(), si-&gt;column(), si-&gt;index().internalPointer());<br /> mapping.insert(QPersistentModelIndex(si-&gt;index()), proxy);<br /> QModelIndex sourceParent;<br /> if (si-&gt;parent()<s>&gt;parent())<br /> sourceParent = si</s>&gt;parent()<s>&gt;index();<br /> proxySourceParent.insert(proxy, sourceParent);<br /> } else {<br /> QModelIndex proxy = createIndex(si</s>&gt;row(), si-&gt;column(), si-&gt;index().internalPointer());<br /> mapping.insert(QPersistentModelIndex(si-&gt;index()), proxy);<br /> QModelIndex sourceParent;<br /> if (si-&gt;parent())<br /> sourceParent = si-&gt;parent()<s>&gt;index();<br /> proxySourceParent.insert(proxy, sourceParent);<br /> }<br /> }<br /> }<br /> QMap&amp;lt;QPersistentModelIndex, QPersistentModelIndex&amp;gt; mapping;<br /> QMap&amp;lt;QPersistentModelIndex, QPersistentModelIndex&amp;gt; proxySourceParent;<br /> bool hideThem;<br />};
 +
<br />SortProxy *proxyModel = 0;
 +
<br />class Tree : public QTreeView<br />{<br /> Q_OBJECT
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<br />public:<br /> Tree(QWidget *parent = 0) : QTreeView(parent)<br /> {<br /> QStandardItemModel *sourceModel = new QStandardItemModel(this);
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<br /> QStandardItem *parentA = sourceModel</s>&gt;invisibleRootItem();<br /> for (int i = 0; i &lt; 2;i) {<br /> itemA = new QStandardItem(QString(&quot;A %0&amp;quot;).arg(i));<br /> parentA-&gt;appendRow(itemA);<br /> parentA = itemA;<br /> list.append(itemA);<br /> }<br /> itemA = new QStandardItem(QString(&quot;A 2&amp;quot;));<br /> parentA-&gt;appendRow(itemA);<br /> list.append(itemA);<br /> itemA3 = new QStandardItem(QString(&quot;A 3&amp;quot;));<br /> list.append(itemA3);<br /> parentA-&gt;appendRow(itemA3);<br /> itemA4 = new QStandardItem(QString(&quot;A 4&amp;quot;));<br /> list.append(itemA4);<br /> parentA-&gt;appendRow(itemA4);<br /> itemNonA = new QStandardItem(QString(&quot;Non A&amp;quot;));<br /> list.append(itemNonA);<br /> parentA-&gt;appendRow(itemNonA);
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<br /> QStandardItem *parentB = sourceModel-&gt;invisibleRootItem();<br /> for (int i = 0; i &lt; 3;i) {<br /> itemB = new QStandardItem(QString(&quot;B %0&amp;quot;).arg(i));<br /> parentB-&gt;appendRow(itemB);<br /> parentB = itemB;<br /> list.append(itemB);<br /> }
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<br /> QStandardItem *parentC = sourceModel-&gt;invisibleRootItem();<br /> for (int i = 0; i &lt; 3;i) {<br /> itemC = new QStandardItem(QString(&quot;C %0&amp;quot;).arg(i));<br /> parentC-&gt;appendRow(itemC);<br /> parentC = itemC;<br /> list.append(itemC);
 +
<br /> }
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<br /> proxyModel = new SortProxy(this);<br /> proxyModel-&gt;setSourceModel(sourceModel);<br /> setModel(proxyModel);<br /> expandAll();<br /> }<br /> QStandardItem *itemA;<br /> QStandardItem *itemA3;<br /> QStandardItem *itemA4;<br /> QStandardItem *itemNonA;<br /> QStandardItem *itemB;<br /> QStandardItem '''itemC;<br />};
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<br />#include &quot;main.moc&amp;quot;
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<br />int main(int argc, char'''*argv)<br />{<br /> QApplication app(argc, argv);<br /> QWidget widget;<br /> QPushButton *button = new QPushButton(&quot;Make only A1'' 'A' children visible&amp;quot;, &amp;widget);<br /> Tree *tree = new Tree(&amp;widget);<br /> QVBoxLayout *lay = new QVBoxLayout(&amp;widget);<br /> lay</s>&gt;addWidget(button);<br /> QObject::connect(button, SIGNAL (clicked()), proxyModel, SLOT (hideEverythingButA1AndChildren()));<br /> lay-&gt;addWidget(tree);<br /> widget.show();<br /> return app.exec&amp;amp;#40;&amp;#41;;<br />}<br /></code>

Revision as of 09:28, 24 February 2015



Related to "this FAQ entry&quot;:http://developer.qt.nokia.com/faq/answer/how_can_i_implement_my_own_proxy_model_that_is_more_advanced_than_just_sort.


#include <QtGui&gt;

QList&lt;QStandardItem *> list;

class SortProxy : public QAbstractProxyModel
{
Q_OBJECT

public:
SortProxy(QObject *parent = 0) : QAbstractProxyModel(parent), hideThem(false)
{
fixModel();
}

int rowCount(const QModelIndex &parent) const
{
QModelIndex sourceParent;
if (parent.isValid())
sourceParent = mapToSource(parent);
int count = 0;
QMapIterator&lt;QPersistentModelIndex, QPersistentModelIndex&gt; it(proxySourceParent);
while (it.hasNext()) {
it.next();
if (it.value() == sourceParent)
count++;
}
return count;
}

int columnCount(const QModelIndex &) const
{
return 1;
}

QModelIndex index(int row, int column, const QModelIndex &parent = QModelIndex()) const
{
QModelIndex sourceParent;
if (parent.isValid())
sourceParent = mapToSource(parent);
QMapIterator&lt;QPersistentModelIndex, QPersistentModelIndex&gt; it(proxySourceParent);
while (it.hasNext()) {
it.next();
if (it.value() sourceParent &amp;&amp; it.key().row() row &&
it.key().column() == column)
return it.key();
}
return QModelIndex();
}

QModelIndex parent(const QModelIndex &child) const
{
QModelIndex mi = proxySourceParent.value(child);
if (mi.isValid())
return mapFromSource(mi);
return QModelIndex();
}

QModelIndex mapToSource(const QModelIndex &proxyIndex) const
{
if (!proxyIndex.isValid())
return QModelIndex();
return mapping.key(proxyIndex);
}

QModelIndex mapFromSource(const QModelIndex &sourceIndex) const
{
if (!sourceIndex.isValid())
return QModelIndex();
return mapping.value(sourceIndex);
}

public slots:
void hideEverythingButA1AndChildren()
{
hideThem = !hideThem;
// Now we set up the proxy <> source mappings
emit layoutAboutToBeChanged();
fixModel();
emit layoutChanged();
}
private:
void fixModel()
{
mapping.clear();
proxySourceParent.clear();
for (int i=0;i&lt;list.size();i+) {
QStandardItem *si = list.at(i);
if (hideThem) {
if (!si->text().startsWith("A&quot;) || !si->parent())
continue;
QModelIndex proxy = createIndex(si->row(), si->column(), si->index().internalPointer());
mapping.insert(QPersistentModelIndex(si->index()), proxy);
QModelIndex sourceParent;
if (si->parent()>parent())
sourceParent = si
>parent()>index();
proxySourceParent.insert(proxy, sourceParent);
} else {
QModelIndex proxy = createIndex(si
>row(), si->column(), si->index().internalPointer());
mapping.insert(QPersistentModelIndex(si->index()), proxy);
QModelIndex sourceParent;
if (si->parent())
sourceParent = si->parent()>index();
proxySourceParent.insert(proxy, sourceParent);
}
}
}
QMap&lt;QPersistentModelIndex, QPersistentModelIndex&gt; mapping;
QMap&lt;QPersistentModelIndex, QPersistentModelIndex&gt; proxySourceParent;
bool hideThem;
};

SortProxy *proxyModel = 0;
class Tree : public QTreeView
{
Q_OBJECT
public:
Tree(QWidget *parent = 0) : QTreeView(parent)
{
QStandardItemModel *sourceModel = new QStandardItemModel(this);
QStandardItem *parentA = sourceModel
>invisibleRootItem();
for (int i = 0; i < 2;i) {
itemA = new QStandardItem(QString("A %0&quot;).arg(i));
parentA->appendRow(itemA);
parentA = itemA;
list.append(itemA);
}
itemA = new QStandardItem(QString("A 2&quot;));
parentA->appendRow(itemA);
list.append(itemA);
itemA3 = new QStandardItem(QString("A 3&quot;));
list.append(itemA3);
parentA->appendRow(itemA3);
itemA4 = new QStandardItem(QString("A 4&quot;));
list.append(itemA4);
parentA->appendRow(itemA4);
itemNonA = new QStandardItem(QString("Non A&quot;));
list.append(itemNonA);
parentA->appendRow(itemNonA);
QStandardItem *parentB = sourceModel->invisibleRootItem();
for (int i = 0; i < 3;i) {
itemB = new QStandardItem(QString("B %0&quot;).arg(i));
parentB->appendRow(itemB);
parentB = itemB;
list.append(itemB);
}
QStandardItem *parentC = sourceModel->invisibleRootItem();
for (int i = 0; i < 3;i) {
itemC = new QStandardItem(QString("C %0&quot;).arg(i));
parentC->appendRow(itemC);
parentC = itemC;
list.append(itemC);
}
proxyModel = new SortProxy(this);
proxyModel->setSourceModel(sourceModel);
setModel(proxyModel);
expandAll();
}
QStandardItem *itemA;
QStandardItem *itemA3;
QStandardItem *itemA4;
QStandardItem *itemNonA;
QStandardItem *itemB;
QStandardItem itemC;
};


#include "main.moc&quot;
int main(int argc, char'*argv)
{
QApplication app(argc, argv);
QWidget widget;
QPushButton *button = new QPushButton("Make only A1
'A' children visible&quot;, &widget);
Tree *tree = new Tree(&widget);
QVBoxLayout *lay = new QVBoxLayout(&widget);
lay
>addWidget(button);
QObject::connect(button, SIGNAL (clicked()), proxyModel, SLOT (hideEverythingButA1AndChildren()));
lay->addWidget(tree);
widget.show();
return app.exec&amp;#40;&#41;;
}