复选框和itemdelegate

我正在实现一个从QitemDelegate继承的CheckBox，将其放入QTableView中。

问题是，当插入时向左齐平，我需要它居中。

正如我所理解的负责绘制的方法。我把它写如下：

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 );
}

缺少什么才能显得居中？

所以我委托了

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);
}

如果您正在扩展QItemDelegate类，它有一个drawCheck（）函数，它将为您绘制一个居中的复选框。您可以在paint（）函数中使用它。

编辑：

这里有一个例子，假设您有一个名为BooleanEditor的类，它继承自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);
}

为了在进入编辑模式时保持复选框居中，您可以执行以下操作：

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);}
};

在ItemDelegates createEditor（）方法中，返回这个BooleanWidget类的一个实例。在您的setModelData（）和setEditorData（）中，您现在可以将您的输入小部件转换为这个BooleanWidget:

BooleanWidget * widget = qobject_cast<BooleanWidget*>(editor);

然后使用is/setChecked方法。

我用以下项目委托解决了这个问题：

booleanpitemdelegate.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

booleanpitemdelegate.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);
}

我希望，我能帮上忙。

这就是我为allign编辑器控件所做的：

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;
}

解决了如下问题：

认为它继承了itemDelegate的QStyledItemDelegate和重新实现的方法"paint"one_answers"editorEvent"。

在方法"editorEvent"中，会发出一个信号，指示选择了哪一行。

这是代码

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);
    }

};

我有一个连接QTableView的类这样做：

connect(check,SIGNAL(clickSignal(int)),this,SLOT(CheckMark(int))); //check the itemDelegate

使用标记为

的检查执行操作

没有太多的大惊小怪，而不是直接设置rect:

BtnStyle.rect = option.rect;

构建一个新的QRect，并将x坐标向右移动，如您所愿：

QRect r = option.rect;
QRect r1(r.x() + 34, r.y(), r.width(), r.height());
BtnStyle.rect = r1;

Python中的解决方案将复选框居中，并允许用户在此处选中/取消选中

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