Add QListView to QComboBox to display scrollbar correctly
I have a combobox with long texts to fit into the combobox, so when I drop down they show up as "very_long ... long_text".
When I do this:
QAbstractItemView* view = myCombo->view(); view->setHorizontalScrollBarPolicy( Qt::ScrollBarAlwaysOn );
A horizontal scroll bar will appear, but it is inactive and still present in the middle of the lines.
This bugreport says that a custom QListView can be used to get the horizontal scrollbar. So how am I supposed to create this custom QListView that I then add to the combobox?
I tried the following.
QListView* lw = new QListView( 0 );
QStandardItemModel* model = new QStandardItemModel;
QStandardItem *item = new QStandardItem( "long long long long long long long long long long long long text 1" );
QStandardItem *item2 = new QStandardItem( "long long long long long long long long long long long long text 2" );
model->insertRow( 0, item );
model->insertRow( 1, item2 );
lw->setModel( model );
QWidget* test = new QWidget( 0 );
test->setGeometry( 100, 100, 100, 150 );
test->setSizePolicy( QSizePolicy::Fixed, QSizePolicy::Fixed );
QGridLayout* layout = new QGridLayout;
test->setLayout( layout );
layout->addWidget( lw );
layout->setSizeConstraint( QLayout::SizeConstraint::SetFixedSize );
test->show();
Then I have something that I want to see (unfortunately I am not allowed to attach images), there is a scrollbar.
But when I want to add this to the combo:
QListView* lw = new QListView( 0 );
QStandardItemModel* model = new QStandardItemModel;
QStandardItem *item = new QStandardItem( "long long long long long long long long long long long long text 1" );
QStandardItem *item2 = new QStandardItem( "long long long long long long long long long long long long text 2" );
model->insertRow( 0, item );
model->insertRow( 1, item2 );
lw->setModel( model );
QWidget* test = new QWidget( 0 );
test->setWindowTitle( "test" );
test->setGeometry( 100, 100, 100, 150 );
test->setSizePolicy( QSizePolicy::Fixed, QSizePolicy::Fixed );
QGridLayout* layout = new QGridLayout;
test->setLayout( layout );
QComboBox* combo = new QComboBox;
combo->setGeometry( 0, 0, 80, 20 );
combo->setSizePolicy( QSizePolicy::Preferred, QSizePolicy::Fixed );
combo->setView( lw );
layout->addWidget( combo );
layout->setSizeConstraint( QLayout::SizeConstraint::SetFixedSize );
test->show();
Then I get an empty combo. Thanks for any answers.
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You need to set a fixed width for the list view and update it when the combo box changes. Also you need to adjust the width of the list box popup. You can do this with event filters. Here's an example implementation of the concept (don't write in this style during production):
class Test_class : public QObject {
Q_OBJECT
public:
Test_class() {}
virtual ~Test_class() {}
QComboBox* combo_box;
QListView* list_view;
bool eventFilter(QObject *object, QEvent *event) {
if (object == combo_box && event->type() == QEvent::Resize) {
list_view->setFixedWidth(combo_box->width());
} else if (object == list_view && event->type() == QEvent::Show) {
list_view->window()->resize(list_view->width(), list_view->window()->height());
}
return false;
}
};
//...
test->show();
lw->setFixedWidth(200);
lw->setHorizontalScrollBarPolicy(Qt::ScrollBarAlwaysOn);
Test_class test_object;
test_object.combo_box = combo;
test_object.list_view = lw;
lw->installEventFilter(&test_object);
combo->installEventFilter(&test_object);
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