Horizontal scroll bar on QTreeView

[LynneV]

Hello - I hope someone can help, I am stuck. I have a QTreeView, it displays data using a delegate with only a Paint function (it is not editable data) in a QDialog window. I cannot seem to get a horizontal scroll bar. The horizontal scroll bar policy is AsNeeded. I have set the width on column 0 (there is only one column) to wider than the width of the widget, no luck (after setting the model). I have set the size hint for the row in the model to wider than the width of the widget, no luck. I have set the SizeHint for the option/index in the delegate to wider than the width of the widget, no luck. I have set the paint rectangle to wider than the widget width - still no horizontal scroll bar. It truncates the text display (which is wider than the widget width). No one seems to have trouble getting a horizontal scroll bar... but I sure am! I get a vertical scroll bar without any problem.

[wysota]

May we see some code?

[LynneV]

Here is some code, I've cut and pasted so if I left out something interesting, please let me know. Thanks in advance for your kind assistance.

This is adding data rows to the model:

{	
       QStandardItem* row = new QStandardItem();
       int the_level = outline->GetLevel();
 
       XiObjectListIter<XiRwOutputColumn> iter( outline->GetColumnIter() );
       for (iter.Head(); iter.Valid(); iter.Next()) 
          iter.Data()->SetColumnText( iter.Data()->Evaluate() );
 
       QVariant rpt_item_data;
       rpt_item_data.setValue<XiRwOutputLine>( outline); 
       row->setData( rpt_item_data, Qt::DisplayRole ); 
       [B]QSize size = row->sizeHint();
       size.setWidth( 1500 );
       row->setSizeHint( size );[/B]
       row->setFlags( Qt::NoItemFlags );
       while (the_level <= indentations.last() && indentations.last() != 0 && (!outline->IsPreviewHdr().isEmpty() || outline->IsPreviewFtr() ) && rptItems.count() > 0) {
            rptItems.pop_back();  //line that is the current header
            rptItems.pop_back();  //that line's parent
            indentations.pop_back();
       }
 
       if ( !outline->IsPreviewHdr().isEmpty() )
       {
            //append the header line, and then set me as the new parent
            rptItems.last()->appendRow( row );
            row->setData( outline->IsPreviewHdr(), Qt::UserRole+1 );
            indentations << the_level;            
            if (rptItems.last()->rowCount() > 0) {  //parent->rowCount() > 0
                rptItems << rptItems.last()->child(rptItems.last()->rowCount()-1); //parent = parent->child( parent->rowCount()-1 );
                rptItems << rptItems.last();
            } 
       }
       else           
        rptItems.last()->appendRow( row );
 
       //after append:
       int rpt_cnt = rptItems.count();
       int child_cnt = rptItems.last()->rowCount();       
    }

{	
       QStandardItem* row = new QStandardItem();
       int the_level = outline->GetLevel();
     
       XiObjectListIter<XiRwOutputColumn> iter( outline->GetColumnIter() );
       for (iter.Head(); iter.Valid(); iter.Next()) 
          iter.Data()->SetColumnText( iter.Data()->Evaluate() );

       QVariant rpt_item_data;
       rpt_item_data.setValue<XiRwOutputLine>( outline); 
       row->setData( rpt_item_data, Qt::DisplayRole ); 
       [B]QSize size = row->sizeHint();
       size.setWidth( 1500 );
       row->setSizeHint( size );[/B]
       row->setFlags( Qt::NoItemFlags );
       while (the_level <= indentations.last() && indentations.last() != 0 && (!outline->IsPreviewHdr().isEmpty() || outline->IsPreviewFtr() ) && rptItems.count() > 0) {
            rptItems.pop_back();  //line that is the current header
            rptItems.pop_back();  //that line's parent
            indentations.pop_back();
       }
       
       if ( !outline->IsPreviewHdr().isEmpty() )
       {
            //append the header line, and then set me as the new parent
            rptItems.last()->appendRow( row );
            row->setData( outline->IsPreviewHdr(), Qt::UserRole+1 );
            indentations << the_level;            
            if (rptItems.last()->rowCount() > 0) {  //parent->rowCount() > 0
                rptItems << rptItems.last()->child(rptItems.last()->rowCount()-1); //parent = parent->child( parent->rowCount()-1 );
                rptItems << rptItems.last();
            } 
       }
       else           
        rptItems.last()->appendRow( row );

       //after append:
       int rpt_cnt = rptItems.count();
       int child_cnt = rptItems.last()->rowCount();       
    }

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This is the size hint in the delegate:

if (qVariantCanConvert<XiRwOutputLine>(index.model()->data(index, Qt::DisplayRole ))) 
     {
         XiRwOutputLine outline = qVariantValue<XiRwOutputLine>(index.model()->data( index, Qt::EditRole )); 
 
         QSize row_height = QStyledItemDelegate::sizeHint(option, index);
         row_height.setHeight( outline->GetFHeight() );
         [B]row_height.setWidth( 1500 );[/B]
         return row_height;         
     }
    else{
       QSize row_height = QStyledItemDelegate::sizeHint(option, index);
       row_height.setHeight( row_height.height() );
      [B] row_height.setWidth( 1500 );[/B]
       return row_height; 
    }

if (qVariantCanConvert<XiRwOutputLine>(index.model()->data(index, Qt::DisplayRole ))) 
     {
         XiRwOutputLine outline = qVariantValue<XiRwOutputLine>(index.model()->data( index, Qt::EditRole )); 
        
         QSize row_height = QStyledItemDelegate::sizeHint(option, index);
         row_height.setHeight( outline->GetFHeight() );
         [B]row_height.setWidth( 1500 );[/B]
         return row_height;         
     }
    else{
       QSize row_height = QStyledItemDelegate::sizeHint(option, index);
       row_height.setHeight( row_height.height() );
      [B] row_height.setWidth( 1500 );[/B]
       return row_height; 
    }

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This is the paint function:

QRect paint_rect = option.rect;
         XiRwOutputLine outline = qVariantValue<XiRwOutputLine>(index.model()->data( index, Qt::EditRole ));
         [B]paint_rect.setWidth( outline->GetWidth() );[/B]
         painter->fillRect(paint_rect, qVariantValue<QBrush>(index.model()->data( index, Qt::BackgroundRole )));
 
         QTextDocument q_txt;
         QPen orig_pen = painter->pen(); 
         QFont orig_font = painter->font();
        //set line font, 
         QFont qfont = outline->GetQFont();
         QColor qcolor = outline->GetColor();
         QRect r = option.rect;  
        //iterate through columns and create a print line for painting
         XiObjectListIter<XiRwOutputColumn> iter( outline->GetColumnIter() );
           for (iter.Head(); iter.Valid(); iter.Next()) 
           {          
             painter->setFont( iter.Data()->GetColumnFont() );             
             if( iter.Data()->GetColumnColor().isValid() )
               painter->setPen( iter.Data()->GetColumnColor() );
             else
               painter->setPen( qcolor );            
 
             r.setWidth( iter.Data()->GetWidth() );
             QString col_text( (char*)iter.Data()->GetColumnText()); 
             if( col_text.contains( "<!DOCTYPE html" ) )
             {
                 q_txt.setHtml( col_text );
                 QAbstractTextDocumentLayout::PaintContext context;
                 q_txt.setPageSize( r.size());
                 painter->translate(r.x(),r.y());
                 q_txt.documentLayout()->draw(painter, context);
                 painter->restore();
             }
             else
             {        
                 switch (iter.Data()->GetJustification()) {	               
			             case XiRwOutputColumn::Right:
				             painter->drawText(r,Qt::AlignRight,col_text);
				             break;
			             case XiRwOutputColumn::Center:
				             painter->drawText(r,Qt::AlignCenter,col_text);
				             break;
                   case XiRwOutputColumn::Wrap:
                     painter->drawText(r,Qt::TextWordWrap,col_text);
				             break;		
                   default:                 
                     painter->drawText(r,col_text);
                 }
             }
             r.setLeft( r.right()+3);             
          }
          painter->setFont( orig_font );
          painter->setPen( orig_pen ) ;           
         }
 
        else
        {
        QStyledItemDelegate::paint(painter, option, index);
        }

QRect paint_rect = option.rect;
         XiRwOutputLine outline = qVariantValue<XiRwOutputLine>(index.model()->data( index, Qt::EditRole ));
         [B]paint_rect.setWidth( outline->GetWidth() );[/B]
         painter->fillRect(paint_rect, qVariantValue<QBrush>(index.model()->data( index, Qt::BackgroundRole )));
         
         QTextDocument q_txt;
         QPen orig_pen = painter->pen(); 
         QFont orig_font = painter->font();
        //set line font, 
         QFont qfont = outline->GetQFont();
         QColor qcolor = outline->GetColor();
         QRect r = option.rect;  
        //iterate through columns and create a print line for painting
         XiObjectListIter<XiRwOutputColumn> iter( outline->GetColumnIter() );
           for (iter.Head(); iter.Valid(); iter.Next()) 
           {          
             painter->setFont( iter.Data()->GetColumnFont() );             
             if( iter.Data()->GetColumnColor().isValid() )
               painter->setPen( iter.Data()->GetColumnColor() );
             else
               painter->setPen( qcolor );            

             r.setWidth( iter.Data()->GetWidth() );
             QString col_text( (char*)iter.Data()->GetColumnText()); 
             if( col_text.contains( "<!DOCTYPE html" ) )
             {
                 q_txt.setHtml( col_text );
                 QAbstractTextDocumentLayout::PaintContext context;
                 q_txt.setPageSize( r.size());
                 painter->translate(r.x(),r.y());
                 q_txt.documentLayout()->draw(painter, context);
                 painter->restore();
             }
             else
             {        
                 switch (iter.Data()->GetJustification()) {	               
			             case XiRwOutputColumn::Right:
				             painter->drawText(r,Qt::AlignRight,col_text);
				             break;
			             case XiRwOutputColumn::Center:
				             painter->drawText(r,Qt::AlignCenter,col_text);
				             break;
                   case XiRwOutputColumn::Wrap:
                     painter->drawText(r,Qt::TextWordWrap,col_text);
				             break;		
                   default:                 
                     painter->drawText(r,col_text);
                 }
             }
             r.setLeft( r.right()+3);             
          }
          painter->setFont( orig_font );
          painter->setPen( orig_pen ) ;           
         }
 
        else
        {
        QStyledItemDelegate::paint(painter, option, index);
        }

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this is the code for setting the model in the rpt_view TreeView:

if (realized) 
  {	
    report->finished = FALSE;
    rpt_view->setItemDelegate( new RWPreviewDelegate( )); 
    rpt_view->setModel( rpt_model );
    [B]rpt_view->setColumnWidth( 0,1500 );[/B] 
    if( report->finished )
		    report->UnRealize();
  }

if (realized) 
  {	
    report->finished = FALSE;
    rpt_view->setItemDelegate( new RWPreviewDelegate( )); 
    rpt_view->setModel( rpt_model );
    [B]rpt_view->setColumnWidth( 0,1500 );[/B] 
    if( report->finished )
		    report->UnRealize();
  }

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[wysota]

How is your view set up? Does it have stretchLastColumn property set to true? What are the resize policies of the columns?

[LynneV]

Thank you so much for your quick response - it is appreciated. I'm using the Qt designer for this dialog, and all the items are set to the default except that I turned off word wrap and set the horizontal scroll bar to 'Always On'. I see a stretchHeaderLastSection, and that's checked. But I don't have a header, do I need one? The size policy for the QTreeView is Preferred, Expanding. I don't see a stretchLastColumn property or resize policies for individual columns - I must be looking in the wrong place, where do I find those? I set the resizeColumnToContents(0), but it doesn't seem to make a difference. Thanks again for your help.

[wysota]

I see a stretchHeaderLastSection, and that's checked.

Switch it off.

But I don't have a header, do I need one?

With a tree view you always have a header, it might not be visible though.

I don't see a stretchLastColumn property or resize policies for individual columns - I must be looking in the wrong place, where do I find those?

In the docs of QHeaderView

I set the resizeColumnToContents(0)

Bad idea.

[LynneV]

The solution ended up to be: QStandardItemModel->SetHorizontalHeaderLabels( QStringList) AND QTreeView->setColumnWidth( 0, line_width ). Ether alone would not work..but together they do the trick! Why is resizeColumntoContents not a good idea? Just curious.

[wysota]

Why is resizeColumntoContents not a good idea?

Because you are probably calling it before the sizes are calculated so it's likely a no-op.