checkbox and itemdelegate in a tableview - qt

Question

I'm doing an implementation of a CheckBox that inherits from QitemDelegate, to put it into a QTableView.
the problem is that I get when inserted flush left and I need it centered.
As I understand the method that is responsible for the Paint. I have it written as follows:
void CheckBoxDelegate::paint(QPainter *painter, const QStyleOptionViewItem &option, const QModelIndex &index) const
{
bool checkValue;
QStyleOptionButton BtnStyle;
BtnStyle.state = QStyle::State_Enabled;
if(index.model()->data(index, Qt::DisplayRole).toBool() == true)
{
BtnStyle.state |= QStyle::State_On;
checkValue = true;
}else{
BtnStyle.state |= QStyle::State_Off;
checkValue = false;
}
BtnStyle.direction = QApplication::layoutDirection();
BtnStyle.rect = option.rect;
QApplication::style()->drawControl(QStyle::CE_CheckBox,&BtnStyle,painter );
QApplication::style()->drawControl(QStyle::CE_CheckBox,&BtnStyle,painter );
}
what is missing to appear centered?
so I have the delegated:
.h
class BooleanWidget : public QWidget
{
Q_OBJECT
QCheckBox * checkBox;
public:
BooleanWidget(QWidget * parent = 0)
{
checkBox = new QCheckBox(this);
QHBoxLayout * layout = new QHBoxLayout(this);
layout->addWidget(checkBox,0, Qt::AlignCenter);
}
bool isChecked(){return checkBox->isChecked();}
void setChecked(bool value){checkBox->setChecked(value);}
};
class CheckBoxDelegate : public QItemDelegate
{
Q_OBJECT
private:
BooleanWidget *checkbox;
public:
CheckBoxDelegate(QObject *parent);
~CheckBoxDelegate();
void setEditorData( QWidget *editor,const QModelIndex &index )const;
void setModelData( QWidget *editor,QAbstractItemModel *model,const QModelIndex &index )const;
QWidget *createEditor( QWidget *parent,const QStyleOptionViewItem &/* option */,const QModelIndex &/* index */ )const;
void paint(QPainter *painter, const QStyleOptionViewItem &option, const QModelIndex &index) const;
public slots:
void changed( bool );
};
.cpp
void CheckBoxDelegate::changed( bool value )
{
BooleanWidget *checkbox = static_cast<BooleanWidget*>( sender() );
emit commitData( checkbox );
emit closeEditor( checkbox );
}
QWidget *CheckBoxDelegate::createEditor( QWidget *parent,const QStyleOptionViewItem &/* option */,const QModelIndex &/* index */ ) const
{
BooleanWidget *editor = new BooleanWidget( parent );
connect( editor, SIGNAL( toggled ( bool ) ), this, SLOT( changed( bool ) ) );
return editor;
}
void CheckBoxDelegate::setEditorData( QWidget *editor,const QModelIndex &index ) const
{
int value = index.model()->data(index, Qt::DisplayRole).toInt();
BooleanWidget *checkbox = static_cast<BooleanWidget*>(editor);
if(value == 1)
{
checkbox->setChecked(true);
}
else
{
checkbox->setChecked(false);
}
}
void CheckBoxDelegate::setModelData( QWidget *editor,QAbstractItemModel *model,const QModelIndex &index ) const
{
BooleanWidget *checkBox = qobject_cast<BooleanWidget*>( editor );
Qt::CheckState value;
if(checkBox->isChecked())
value = Qt::Checked;
else
value = Qt::Unchecked;
model->setData( index, value, Qt::DisplayRole);
}
void CheckBoxDelegate::paint(QPainter *painter, const QStyleOptionViewItem &option, const QModelIndex &index) const
{
drawCheck(painter, option, option.rect, index.data().toBool() ? Qt::Checked : Qt::Unchecked);
drawFocus(painter, option, option.rect);
}

Answer 1

If you are extending the QItemDelegate class, it has a drawCheck() function, what will draw you a nince, centered checkbox. You can use it in the paint() function.
Edit:
Here is an example, assuming you have a class called BooleanEditor, what inherits from QItemDelegate:
void BooleanEditor::paint(QPainter *painter, const QStyleOptionViewItem &option, const QModelIndex &index) const
{
drawCheck(painter, option, option.rect, index.data().toBool() ? Qt::Checked : Qt::Unchecked);
drawFocus(painter, option, option.rect);
}
For keeping the checkbox centered when entering the edit mode, you can do something like this:
class BooleanWidget : public QWidget
{
Q_OBJECT
QCheckBox * checkBox;
public:
BooleanWidget(QWidget * parent = 0)
{
checkBox = new QCheckBox(this);
QHBoxLayout * layout = new QHBoxLayout(this);
layout->addWidget(checkBox,0, Qt::AlignCenter);
}
bool isChecked(){return checkBox->isChecked();}
void setChecked(bool value){checkBox->setChecked(value);}
};
And in your ItemDelegates createEditor() method return an instance of this BooleanWidget class. In your setModelData() and setEditorData() you can now cast your input widget to this BooleanWidget:
BooleanWidget * widget = qobject_cast<BooleanWidget*>(editor);
and then use the is/setChecked method.

Answer 2

I solve this problem with the following item delegate:
booleanitemdelegate.h
#ifndef BOOLEANITEMDELEGATE_H
#define BOOLEANITEMDELEGATE_H
#include <QItemDelegate>
class BooleanItemDelegate : public QItemDelegate
{
public:
BooleanItemDelegate(QObject *parent);
public:
void paint(QPainter *painter, const QStyleOptionViewItem &option, const QModelIndex &index) const;public:
bool editorEvent(QEvent *event, QAbstractItemModel *model, const QStyleOptionViewItem &option, const QModelIndex &index);
};
#endif // BOOLEANITEMDELEGATE_H
booleanitemdelegate.cpp
#include "booleanitemdelegate.h"
BooleanItemDelegate::BooleanItemDelegate(QObject *parent):
QItemDelegate(parent)
{
}
void BooleanItemDelegate::paint(QPainter *painter, const QStyleOptionViewItem &option, const QModelIndex &index) const
{
drawCheck(painter, option, option.rect, index.data().toBool() ? Qt::Checked : Qt::Unchecked);
drawFocus(painter, option, option.rect);
}
bool BooleanItemDelegate::editorEvent(QEvent *event, QAbstractItemModel *model, const QStyleOptionViewItem &option, const QModelIndex &index)
{
if(event->type() == QEvent::MouseButtonRelease){
model->setData(index, !model->data(index).toBool());
event->accept();
}
return QItemDelegate::editorEvent(event, model, option, index);
}
I hope, I can help.

Answer 3

that's what I did to center-allign the editor control:
QWidget *checkBoxDelegate::createEditor(QWidget *parent, const QStyleOptionViewItem &option, const QModelIndex &index) const {
QCheckBox *editor = new QCheckBox(parent);
editor->setTristate(allowTriState); //my class' variable
// this does the trick :)
editor->setStyleSheet("QCheckBox {margin-left: 43%; margin-right: 57%;}");
// this should do it better
// editor->setStyleSheet("QCheckBox {margin-left: auto; margin-right: auto;}");
// but in my case the checkbox is slightly to the left of original
return editor;
}

Answer 4

solved the problem as follows:
believes that inherits from the itemDelegate QStyledItemDelegate and reimplemented methods "paint" and "editorEvent".
In the method "editorEvent" emit a signal that indicates which row was selected.
Here is the code
class ItemDelegate : public QStyledItemDelegate
{
Q_OBJECT
signals:
void clickSignal(int);
public:
ItemDelegate(QObject *parent = 0)
: QStyledItemDelegate(parent)
{
}
void paint ( QPainter * painter, const QStyleOptionViewItem & option, const QModelIndex & index ) const
{
QStyleOptionViewItemV4 viewItemOption(option);
if (index.column() == 0) {
const int textMargin = QApplication::style()->pixelMetric(QStyle::PM_FocusFrameHMargin) + 1;
QRect newRect = QStyle::alignedRect(option.direction, Qt::AlignCenter,
QSize(option.decorationSize.width() + 5,option.decorationSize.height()),
QRect(option.rect.x() + textMargin, option.rect.y(),
option.rect.width() - (2 * textMargin), option.rect.height()));
viewItemOption.rect = newRect;
}
QStyledItemDelegate::paint(painter, viewItemOption, index);
}
virtual bool editorEvent(QEvent *event, QAbstractItemModel *model, const QStyleOptionViewItem &option,
const QModelIndex &index)
{
Q_ASSERT(event);
Q_ASSERT(model);
// make sure that the item is checkable
Qt::ItemFlags flags = model->flags(index);
if (!(flags & Qt::ItemIsUserCheckable) || !(flags & Qt::ItemIsEnabled))
return false;
// make sure that we have a check state
QVariant value = index.data(Qt::CheckStateRole);
if (!value.isValid())
return false;
// make sure that we have the right event type
if (event->type() == QEvent::MouseButtonRelease) {
const int textMargin = QApplication::style()->pixelMetric(QStyle::PM_FocusFrameHMargin) + 1;
QRect checkRect = QStyle::alignedRect(option.direction, Qt::AlignCenter,
option.decorationSize,
QRect(option.rect.x() + (2 * textMargin), option.rect.y(),
option.rect.width() - (2 * textMargin),
option.rect.height()));
} else {
return false;
}
Qt::CheckState state = (static_cast<Qt::CheckState>(value.toInt()) == Qt::Checked
? Qt::Unchecked : Qt::Checked);
emit(clickSignal(index.row()));
return model->setData(index, state, Qt::CheckStateRole);
}
};
the class where I have a connect QTableView do this:
connect(check,SIGNAL(clickSignal(int)),this,SLOT(CheckMark(int))); //check the itemDelegate
performed the operation with the check that were marked

Answer 5

Without too much fussing instead of directly setting rect:
BtnStyle.rect = option.rect;
Construct a new QRect and move x coordinate to the right as much as you like:
QRect r = option.rect;
QRect r1(r.x() + 34, r.y(), r.width(), r.height());
BtnStyle.rect = r1;

Answer 6

The solution in Python to center checkbox and allow user check/uncheck here