[Qt-interest] problem with createEditor method of QItemDelegate when the returned QWidget has a layout

[TP]

Hi,

Ok, someone has given part of the solution on the pyqt-pykde forum, and it
leads me to the final solution: replace the LabelAndSpinBox constructor by
the following. Only two lines have been added:

    this->setAutoFillBackground( 1 );
    L->setContentsMargins(0, 0, 0, 0);

LabelAndSpinBox::LabelAndSpinBox( QWidget * parent )
        : QWidget( parent )
{
    label = new QLabel( tr("Find &what:") );
    spinbox = new QSpinBox;

    this->setAutoFillBackground( 1 );

    QHBoxLayout * L = new QHBoxLayout;
    L->setContentsMargins(0, 0, 0, 0);
    L->addWidget( label );
    L->addWidget( spinbox );

    this->setLayout( L );
}

Thanks everybody,

Julien


TP wrote:

> Hi,
> 
> Try the example at the end of this message: it is a table with editable
> items. This is a modified version of the example "spinboxdelegate" of
> the Qt examples ("itemviews" section). When the user double-clicks on an
> item, a LabelAndSpinBox instance is created as delegate. The problem is
> that the QHBoxLayout layout of this delegate does not expand to occupy all
> the available space; therefore the item data value remains visible and the
> delegate is too small. How to make it work correctly?
> I have asked the same question on pyqt-pykde mailing list, but I prefer
> asking on the Qt forum too, because of a larger community.
> 
> Thanks,
> 
> Julien
> 
> 
> ///////////////////////////////////////////////////////////////////
> 
> #include <QApplication>
> #include <QPushButton>
> #include <QStandardItem>
> #include <QTableView>
> #include <QModelIndex>
> #include <QSpinBox>
> #include <QLabel>
> #include <QHBoxLayout>
> #include <QItemDelegate>
> 
> //////////////////////////////////////////////////////////////////////////
> //                                                                      //
> //                           LabelAndSpinBox                            //
> //                                                                      //
> //////////////////////////////////////////////////////////////////////////
> 
> class LabelAndSpinBox : public QWidget
> {
>     public:
>         LabelAndSpinBox( QWidget * parent = 0 );
>         void setMinimum( int value = 0 );
>         void setMaximum( int value = 1 );
>         void setValue( int value = 0 );
>         int value();
>     private:
>         QLabel * label;
>         QSpinBox * spinbox;
> };
> 
> LabelAndSpinBox::LabelAndSpinBox( QWidget * parent )
>         : QWidget( parent )
> {
>     label = new QLabel( tr("Find &what:") );
>     spinbox = new QSpinBox;
> 
>     QHBoxLayout * L = new QHBoxLayout;
>     L->addWidget( label );
>     L->addWidget( spinbox );
> 
>     this->setLayout( L );
> }
> 
> void LabelAndSpinBox::setMinimum( int value )
> {
>     spinbox->setMinimum( value );
> }
> 
> void LabelAndSpinBox::setMaximum( int value )
> {
>     spinbox->setMaximum( value );
> }
> 
> void LabelAndSpinBox::setValue( int value )
> {
>     spinbox->setValue( value );
> }
> 
> int LabelAndSpinBox::value()
> {
>     return spinbox->value();
> }
> 
> //////////////////////////////////////////////////////////////////////////
> //                                                                      //
> //                           spinboxdelegate                            //
> //                                                                      //
> //////////////////////////////////////////////////////////////////////////
> 
> class SpinBoxDelegate : public QItemDelegate
> {
>     public:
>         SpinBoxDelegate( QObject * parent = 0 ):QItemDelegate( parent ){ }
>         QWidget * createEditor( QWidget * parent
>                 , const QStyleOptionViewItem & option
>                 , const QModelIndex & index ) const;
>         void setEditorData( QWidget * editor
>                 , const QModelIndex & index );
>         void setModelData( QWidget * editor
>                 , QAbstractItemModel * model
>                 , const QModelIndex & index ) const;
>         void updateEditorGeometry( QWidget *editor,
>                     const QStyleOptionViewItem &option
>                     , const QModelIndex &/* index */) const;
> };
> 
> void SpinBoxDelegate::updateEditorGeometry( QWidget *editor,
>              const QStyleOptionViewItem &option
>              , const QModelIndex &/* index */) const
> {
>     editor->setGeometry(option.rect);
> }
> 
> // The "const" are very important!
> QWidget * SpinBoxDelegate::createEditor( QWidget * parent
>         , const QStyleOptionViewItem & option
>         , const QModelIndex & index ) const
> {
>     LabelAndSpinBox * editor = new LabelAndSpinBox( parent );
>     editor->setMinimum( 0 );
>     editor->setMaximum( 100 );
>     return editor;
> }
> 
> void SpinBoxDelegate::setModelData(
>         QWidget * editor
>         , QAbstractItemModel * model
>         , const QModelIndex & index ) const
> {
>     int value = dynamic_cast<LabelAndSpinBox *> ( editor )->value();
>     QVariant qv( value );
>     model->setData( index, qv );
> }
> 
> 
> void setEditorData( QWidget * editor
>         , const QModelIndex & index )
> {
>     int value = index.model()->data( index
>             , Qt::DisplayRole ).toInt();
>     dynamic_cast<LabelAndSpinBox *> ( editor )->setValue( value );
> }
> 
> 
> 
> //////////////////////////////////////////////////////////////////////////
> //                                                                      //
> //                                 main                                 //
> //                                                                      //
> //////////////////////////////////////////////////////////////////////////
> 
> 
> int main( int argc, char **argv )
> {
>     QApplication a( argc, argv );
> 
>     QStandardItemModel model( 4, 2 );
>     QTableView tableView;
> 
>     tableView.setModel( & model );
> 
>     SpinBoxDelegate delegate;
>     tableView.setItemDelegate( & delegate );
> 
>     for ( int row = 0; row<4; row++ )
>     {
>         for ( int col = 0; col<2; col++ )
>         {
>             QModelIndex index = model.index(row, col );
>             QVariant qv( (row+1) * (col+1) );
>             model.setData( index, qv );
>         }
>     }
> 
>     tableView.setWindowTitle( "Spin Box Delegate" );
>     tableView.show();
> 
>     return a.exec();
> }
> ///////////////////////////////////////////////////////////////////

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