QTableView with a checkbox

[wysota]

I'd stick with the delegate thing. Otherwise you'll have to reimplement the model without really needing it. The delegate will give you much more flexibility.

[maxpower]

Okay, so I see in the docs how to subclass ItemDelegate and make my own. However, it appears you assign the delegate for the whole view. I only want to change the delegate for one column. How is this accomplished?

mAx

[jpn]

Qt 4.2 introduces new functions:

• QAbstractItemView::setItemDelegateForRow()
• QAbstractItemView::setItemDelegateForColumn()

In Qt 4.1 you'll just have to check the column of the passed model index:

void MyItemDelegate::delegateFunction(const QModelIndex& index, ...)
{
    if (index.isValid() && index.column() == INTERESTING_COLUMN)
    {
        // appropriate column in question, do the custom thing
    }
    else
    {
        // pass to the base class implementation
        QItemDelegate::delegateFunction(index, ...);
    }
}

void MyItemDelegate::delegateFunction(const QModelIndex& index, ...)
{
    if (index.isValid() && index.column() == INTERESTING_COLUMN)
    {
        // appropriate column in question, do the custom thing
    }
    else
    {
        // pass to the base class implementation
        QItemDelegate::delegateFunction(index, ...);
    }
}

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[maxpower]

Okay, thanks for the help I am getting close now. I converted the included exmaple for the sponbox delegate to a checkbox delegate and compiled it and it worked great. However, once I changed the code fome setItemDelegate to setItemDelegateForColumn, it no longer worked at all. Do I need to change something in the example code for the custom delegate to work with just one column? I am using 4.2.

Thanks
mAx

[maxpower]

Anybody have an idea? I just tried 4.2.1 but no love there either.

mAx

[jpn]

Looks like QAbstractItemView::itemDelegateForRow/Column are not used pretty much for anything (yet?)... Anyway, I already gave you a solution which works with old good "normal" delegates.. and it has been discussed earlier..

[maxpower]

Okay, I edited the spinbox example again and with your code it properly displays a checkbox in the first column. However, I tried to use the exact same code in my program and it doesn't work. The column and row headers are present but there is no data, nor checkboxes or even grid lines. What did i do wring?

Thanks
mAx

[jpn]

Does everything work correctly without the custom delegate? Which QItemDelegate functions have you actaully overridden? Did you by any chance override QItemDelegate::paint()?

[maxpower]

Yes, everything works fine if I do not use setItemDelegate. I overrode createEditor, setEditor, setModelData, and updateModelGeometry. As I said before, my code works fine by itself, just not inside my db program.

Applying the delegate:

if(viewInit)
	{
		model->submitAll();
		delete model;
	}
	int rowCount = 0;
	model = new QSqlTableModel();
	model->setTable(tableName);
	model->setEditStrategy(QSqlTableModel::OnManualSubmit);
	model->select();
	model->removeColumn(8);
	rowCount = model->rowCount();
	ui.tableTV->setModel(model);
	checkboxDelegate delegate;
	ui.tableTV->setItemDelegate(&delegate);
	ui.tableTV->resizeColumnToContents(2);
	ui.tableTV->hideColumn(0);
	ui.tableTV->setEditTriggers(QAbstractItemView::CurrentChanged);
	ui.tableTV->setAlternatingRowColors(true);
	ui.tableTV->scrollToBottom();

if(viewInit)
	{
		model->submitAll();
		delete model;
	}
	int rowCount = 0;
	model = new QSqlTableModel();
	model->setTable(tableName);
	model->setEditStrategy(QSqlTableModel::OnManualSubmit);
	model->select();
	model->removeColumn(8);
	rowCount = model->rowCount();
	ui.tableTV->setModel(model);
	checkboxDelegate delegate;
	ui.tableTV->setItemDelegate(&delegate);
	ui.tableTV->resizeColumnToContents(2);
	ui.tableTV->hideColumn(0);
	ui.tableTV->setEditTriggers(QAbstractItemView::CurrentChanged);
	ui.tableTV->setAlternatingRowColors(true);
	ui.tableTV->scrollToBottom();

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The delegate:

checkboxDelegate::checkboxDelegate(QObject *parent)
    : QItemDelegate(parent)
{
}
 
QWidget *checkboxDelegate::createEditor(QWidget *parent,
    const QStyleOptionViewItem &option,
    const QModelIndex &index) const
{
	if(index.isValid() && index.column() == checkboxCol)
	{
		QCheckBox *editor = new QCheckBox(parent);
    	editor->installEventFilter(const_cast<checkboxDelegate*>(this));
    	return editor;
   	}
   	else
   	{
   		return QItemDelegate::createEditor(parent, option, index);
  		}
}
 
void checkboxDelegate::setEditorData(QWidget *editor,
                                    const QModelIndex &index) const
{
	if(index.isValid() && index.column() == checkboxCol)
	{
		QString value = index.model()->data(index, Qt::DisplayRole).toString();
 
    	QCheckBox *checkBox = static_cast<QCheckBox*>(editor);
    	if(value == "Y")
    		checkBox->setCheckState(Qt::Checked);
    	else
    		checkBox->setCheckState(Qt::Unchecked);
   		}
   		else
   		{
   			QItemDelegate::setEditorData(editor, index);
  			}
}
 
void checkboxDelegate::setModelData(QWidget *editor, QAbstractItemModel *model,
                                   const QModelIndex &index) const
{
	if(index.isValid() && index.column() == checkboxCol)
	{
    	QCheckBox *checkBox = static_cast<QCheckBox*>(editor);
    	QString value;
   		if(checkBox->checkState() == Qt::Checked)
   			value = "Y";
   		else
   			value = "N";
 
    	model->setData(index, value);
   	}
   	else
   	{
   		QItemDelegate::setModelData(editor, model, index);
  		}
}
 
void checkboxDelegate::updateEditorGeometry(QWidget *editor,
    const QStyleOptionViewItem &option, const QModelIndex &index) const
{
	if(index.isValid() && index.column() == checkboxCol)
	    editor->setGeometry(option.rect);
	else
		QItemDelegate::updateEditorGeometry(editor, option, index);
 
}

checkboxDelegate::checkboxDelegate(QObject *parent)
    : QItemDelegate(parent)
{
}

QWidget *checkboxDelegate::createEditor(QWidget *parent,
    const QStyleOptionViewItem &option,
    const QModelIndex &index) const
{
	if(index.isValid() && index.column() == checkboxCol)
	{
		QCheckBox *editor = new QCheckBox(parent);
    	editor->installEventFilter(const_cast<checkboxDelegate*>(this));
    	return editor;
   	}
   	else
   	{
   		return QItemDelegate::createEditor(parent, option, index);
  		}
}

void checkboxDelegate::setEditorData(QWidget *editor,
                                    const QModelIndex &index) const
{
	if(index.isValid() && index.column() == checkboxCol)
	{
		QString value = index.model()->data(index, Qt::DisplayRole).toString();

    	QCheckBox *checkBox = static_cast<QCheckBox*>(editor);
    	if(value == "Y")
    		checkBox->setCheckState(Qt::Checked);
    	else
    		checkBox->setCheckState(Qt::Unchecked);
   		}
   		else
   		{
   			QItemDelegate::setEditorData(editor, index);
  			}
}

void checkboxDelegate::setModelData(QWidget *editor, QAbstractItemModel *model,
                                   const QModelIndex &index) const
{
	if(index.isValid() && index.column() == checkboxCol)
	{
    	QCheckBox *checkBox = static_cast<QCheckBox*>(editor);
    	QString value;
   		if(checkBox->checkState() == Qt::Checked)
   			value = "Y";
   		else
   			value = "N";

    	model->setData(index, value);
   	}
   	else
   	{
   		QItemDelegate::setModelData(editor, model, index);
  		}
}

void checkboxDelegate::updateEditorGeometry(QWidget *editor,
    const QStyleOptionViewItem &option, const QModelIndex &index) const
{
	if(index.isValid() && index.column() == checkboxCol)
	    editor->setGeometry(option.rect);
	else
		QItemDelegate::updateEditorGeometry(editor, option, index);
	    	
}

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[jpn]

Allocate the delegate object on the heap so it won't get destroyed as soon as it gets out of scope:

checkboxDelegate* delegate = new checkboxDelegate(this);
ui.tableTV->setItemDelegate(delegate);

checkboxDelegate* delegate = new checkboxDelegate(this);
ui.tableTV->setItemDelegate(delegate);

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Edit: oops, forgot the important keyword new

[maxpower]

That did it, thanks alot!!!!

mAx