How to highlight some items in a QTreeView (without inheriting) - qt

Question

I am looking for a way to highlight rows of a QTreeView without reimplementing a QTreeView subclass.
I have seen similar questions:
highlight-specific-substrings-in-a-qtreeview
how-to-make-item-view-render-rich-html-text-in-qt
set-bold-rows-in-a-qtreeview
But they all use delegate. The reason is that I am creating a search text in widgets tool which browse all widgets and find and highlights text in them. Hence, I cannot use delegate.
Is there any possible solution?
Painting a semi-transparent item above it?
Here is the code of the tool which stores the widget and the way to search for text in them.
class GUI_EXPORT QgsSearchHighlightOptionWidget : public QObject
{
Q_OBJECT
public:
/**
* Constructor
* \param widget the widget used to search text into
*/
explicit QgsSearchHighlightOptionWidget( QWidget *widget = nullptr );
/**
* Returns if it valid: if the widget type is handled and if the widget is not still available
*/
bool isValid() { return mWidget && mValid; }
/**
* search for a text pattern and highlight the widget if the text is found
* \returns true if the text pattern is found
*/
bool searchHighlight( const QString &searchText );
/**
* reset the style to the original state
*/
void reset();
/**
* return the widget
*/
QWidget *widget() { return mWidget; }
bool eventFilter( QObject *obj, QEvent *event ) override;
private slots:
void widgetDestroyed();
private:
QPointer< QWidget > mWidget;
QString mStyleSheet;
bool mValid = true;
bool mChangedStyle = false;
std::function < bool( QString )> mTextFound = []( QString searchText ) {Q_UNUSED( searchText ); return false;};
bool mInstalledFilter = false;
};
QgsSearchHighlightOptionWidget::QgsSearchHighlightOptionWidget( QWidget *widget )
: QObject( widget )
, mWidget( widget )
{
if ( qobject_cast<QLabel *>( widget ) )
{
mStyleSheet = QStringLiteral( "QLabel { background-color: yellow; color: blue;}" );
mTextFound = [ = ]( QString searchText ) {return qobject_cast<QLabel *>( mWidget )->text().contains( searchText, Qt::CaseInsensitive );};
}
else if ( qobject_cast<QCheckBox *>( widget ) )
{
mStyleSheet = QStringLiteral( "QCheckBox { background-color: yellow; color: blue;}" );
mTextFound = [ = ]( QString searchText ) {return qobject_cast<QCheckBox *>( mWidget )->text().contains( searchText, Qt::CaseInsensitive );};
}
else if ( qobject_cast<QAbstractButton *>( widget ) )
{
mStyleSheet = QStringLiteral( "QAbstractButton { background-color: yellow; color: blue;}" );
mTextFound = [ = ]( QString searchText ) {return qobject_cast<QAbstractButton *>( mWidget )->text().contains( searchText, Qt::CaseInsensitive );};
}
else if ( qobject_cast<QGroupBox *>( widget ) )
{
mStyleSheet = QStringLiteral( "QGroupBox::title { background-color: yellow; color: blue;}" );
mTextFound = [ = ]( QString searchText ) {return qobject_cast<QGroupBox *>( mWidget )->title().contains( searchText, Qt::CaseInsensitive );};
}
else if ( qobject_cast<QTreeView *>( widget ) )
{
// TODO - style individual matching items
mTextFound = [ = ]( QString searchText )
{
QTreeView *tree = qobject_cast<QTreeView *>( mWidget );
if ( !tree )
return false;
QModelIndexList hits = tree->model()->match( tree->model()->index( 0, 0 ), Qt::DisplayRole, searchText, 1, Qt::MatchContains | Qt::MatchRecursive );
return !hits.isEmpty();
};
}
else
{
mValid = false;
}
if ( mValid )
{
mStyleSheet.prepend( "/*!search!*/" ).append( "/*!search!*/" );
QgsDebugMsgLevel( mStyleSheet, 4 );
connect( mWidget, &QWidget::destroyed, this, &QgsSearchHighlightOptionWidget::widgetDestroyed );
}
}
bool QgsSearchHighlightOptionWidget::searchHighlight( const QString &searchText )
{
bool found = false;
if ( !mWidget )
return found;
if ( !searchText.isEmpty() )
{
found = mTextFound( searchText );
}
if ( found && !mChangedStyle )
{
if ( !mWidget->isVisible() )
{
// show the widget to get initial stylesheet in case it's modified
QgsDebugMsg( QString( "installing event filter on: %1 (%2)" )
.arg( mWidget->objectName() )
.arg( qobject_cast<QLabel *>( mWidget ) ? qobject_cast<QLabel *>( mWidget )->text() : QString() ) );
mWidget->installEventFilter( this );
mInstalledFilter = true;
}
else
{
mWidget->setStyleSheet( mWidget->styleSheet() + mStyleSheet );
mChangedStyle = true;
}
}
return found;
}
bool QgsSearchHighlightOptionWidget::eventFilter( QObject *obj, QEvent *event )
{
if ( mInstalledFilter && event->type() == QEvent::Show && obj == mWidget )
{
mWidget->removeEventFilter( this );
mInstalledFilter = false;
// instead of catching the event and calling show again
// it might be better to use a timer to change the style
// after the widget is shown
#if 1
mWidget->show();
mWidget->setStyleSheet( mWidget->styleSheet() + mStyleSheet );
return true;
#else
QTimer::singleShot( 500, this, [ = ]
{
mWidget->setStyleSheet( mWidget->styleSheet() + mStyleSheet );
mChangedStyle = true;
} );
#endif
}
return QObject::eventFilter( obj, event );
}
void QgsSearchHighlightOptionWidget::reset()
{
if ( mWidget && mValid )
{
if ( mChangedStyle )
{
QString ss = mWidget->styleSheet();
ss.remove( mStyleSheet );
mWidget->setStyleSheet( ss );
mChangedStyle = false;
}
else if ( mInstalledFilter )
{
mWidget->removeEventFilter( this );
mInstalledFilter = false;
}
}
}
void QgsSearchHighlightOptionWidget::widgetDestroyed()
{
mWidget = nullptr;
mValid = false;
}
And here is the code to actually register the widgets from the dialog:
void QgsOptionsDialogBase::registerTextSearchWidgets()
{
mRegisteredSearchWidgets.clear();
for ( int i = 0; i < mOptStackedWidget->count(); i++ )
{
Q_FOREACH ( QWidget *w, mOptStackedWidget->widget( i )->findChildren<QWidget *>() )
{
QgsSearchHighlightOptionWidget *shw = new QgsSearchHighlightOptionWidget( w );
if ( shw->isValid() )
{
QgsDebugMsgLevel( QString( "Registering: %1" ).arg( w->objectName() ), 4 );
mRegisteredSearchWidgets.append( qMakePair( shw, i ) );
}
else
{
delete shw;
}
}
}
}

Answer 1

Reading the docs, I don't know how to do it directly.
Here are some suggestions. Hopefully one works for you:
1) Could you use QTreeWidget instead of QTreeView ?
With this, it should be easy.
Use the item functions and e.g. setBackground() on the item.
2) How about you filter tree instead of highlighting? Using setRowHidden()?
3) If you haven't already, you could also try using QTreeView::keyboardSearch() and see what this does.
4) you could use select* and add a next/previous button to your search box. I.e. you hop through the tree selecting the current search result.