Qt QTableView如何有一个只有复选框的列

Question

我们在 Qt 4.6.3 中使用QTableView，并且需要一个在每个单元格中只有一个复选框的列。我们使用QAbstractTableModel 的自定义子类作为QTableView 的模型。现在，我们有一个通过设置Qt::ItemIsUserCheckable 标志的复选框。但是我们不知道如何去掉复选框旁边的空白文本框！

我们怎样才能让列只有有一个复选框，没有别的？

Answer 1

这里有一个解决方案。为使其正常工作，您的列应该不设置Qt::ItemIsEditable 或Qt::ItemIsUserCheckable 标志。这会从Qt::DisplayRole 中读取布尔值并使用Qt::EditRole 调用setData()（即not Qt::CheckStateRole。）

#include "check_box_delegate.h"

#include <QtGui/QApplication>
#include <QtGui/QMouseEvent>

static QRect CheckBoxRect(const QStyleOptionViewItem &view_item_style_options) {
  QStyleOptionButton check_box_style_option;
  QRect check_box_rect = QApplication::style()->subElementRect(
      QStyle::SE_CheckBoxIndicator,
      &check_box_style_option);
  QPoint check_box_point(view_item_style_options.rect.x() +
                         view_item_style_options.rect.width() / 2 -
                         check_box_rect.width() / 2,
                         view_item_style_options.rect.y() +
                         view_item_style_options.rect.height() / 2 -
                         check_box_rect.height() / 2);
  return QRect(check_box_point, check_box_rect.size());
}

CheckBoxDelegate::CheckBoxDelegate(QObject *parent)
  : QStyledItemDelegate(parent) {
}

void CheckBoxDelegate::paint(QPainter *painter,
                             const QStyleOptionViewItem &option,
                             const QModelIndex &index) const {
  bool checked = index.model()->data(index, Qt::DisplayRole).toBool();

  QStyleOptionButton check_box_style_option;
  check_box_style_option.state |= QStyle::State_Enabled;
  if (checked) {
    check_box_style_option.state |= QStyle::State_On;
  } else {
    check_box_style_option.state |= QStyle::State_Off;
  }
  check_box_style_option.rect = CheckBoxRect(option);

  QApplication::style()->drawControl(QStyle::CE_CheckBox,
                                     &check_box_style_option,
                                     painter);
}

// This is essentially copied from QStyledItemEditor, except that we
// have to determine our own "hot zone" for the mouse click.
bool CheckBoxDelegate::editorEvent(QEvent *event,
                                   QAbstractItemModel *model,
                                   const QStyleOptionViewItem &option,
                                   const QModelIndex &index) {
  if ((event->type() == QEvent::MouseButtonRelease) ||
      (event->type() == QEvent::MouseButtonDblClick)) {
    QMouseEvent *mouse_event = static_cast<QMouseEvent*>(event);
    if (mouse_event->button() != Qt::LeftButton ||
        !CheckBoxRect(option).contains(mouse_event->pos())) {
      return false;
    }
    if (event->type() == QEvent::MouseButtonDblClick) {
      return true;
    }
  } else if (event->type() == QEvent::KeyPress) {
    if (static_cast<QKeyEvent*>(event)->key() != Qt::Key_Space &&
        static_cast<QKeyEvent*>(event)->key() != Qt::Key_Select) {
      return false;
    }
  } else {
    return false;
  }

  bool checked = index.model()->data(index, Qt::DisplayRole).toBool();
  return model->setData(index, !checked, Qt::EditRole);
}

Answer 2

注意：Dave 的答案也适用于使用 PySide 或 PyQt4 的 Python。我翻译了它，效果很好。此外，我添加了复选框不接受用户输入并在单元格不可编辑时显示为只读状态的功能。 感谢 Dave 的代码！

class CheckBoxDelegate(QStyledItemDelegate):

    def createEditor(self, parent, option, index):
        '''
        Important, otherwise an editor is created if the user clicks in this cell.
        '''
        return None

    def paint(self, painter, option, index):
        '''
        Paint a checkbox without the label.
        '''
        checked = bool(index.model().data(index, Qt.DisplayRole))
        check_box_style_option = QStyleOptionButton()

        if (index.flags() & Qt.ItemIsEditable) > 0:
            check_box_style_option.state |= QStyle.State_Enabled
        else:
            check_box_style_option.state |= QStyle.State_ReadOnly

        if checked:
            check_box_style_option.state |= QStyle.State_On
        else:
            check_box_style_option.state |= QStyle.State_Off

        check_box_style_option.rect = self.getCheckBoxRect(option)
            if not index.model().hasFlag(index, Qt.ItemIsEditable):
            check_box_style_option.state |= QStyle.State_ReadOnly

        QApplication.style().drawControl(QStyle.CE_CheckBox, check_box_style_option, painter)


    def editorEvent(self, event, model, option, index):
        '''
        Change the data in the model and the state of the checkbox
        if the user presses the left mousebutton or presses
        Key_Space or Key_Select and this cell is editable. Otherwise do nothing.
        '''
        if not (index.flags() & Qt.ItemIsEditable) > 0:
            return False

        # Do not change the checkbox-state
        if event.type() == QEvent.MouseButtonRelease or event.type() == QEvent.MouseButtonDblClick:
            if event.button() != Qt.LeftButton or not self.getCheckBoxRect(option).contains(event.pos()):
                return False
            if event.type() == QEvent.MouseButtonDblClick:
                return True
        elif event.type() == QEvent.KeyPress:
            if event.key() != Qt.Key_Space and event.key() != Qt.Key_Select:
                return False
        else:
            return False

        # Change the checkbox-state
        self.setModelData(None, model, index)
        return True

    def setModelData (self, editor, model, index):
        '''
        The user wanted to change the old state in the opposite.
        '''
        newValue = not bool(index.model().data(index, Qt.DisplayRole))
        model.setData(index, newValue, Qt.EditRole)


    def getCheckBoxRect(self, option):
        check_box_style_option = QStyleOptionButton()
        check_box_rect = QApplication.style().subElementRect(QStyle.SE_CheckBoxIndicator, check_box_style_option, None)
        check_box_point = QPoint (option.rect.x() +
                             option.rect.width() / 2 -
                             check_box_rect.width() / 2,
                             option.rect.y() +
                             option.rect.height() / 2 -
                             check_box_rect.height() / 2)
        return QRect(check_box_point, check_box_rect.size())