Delegate的使用

新建一个Delegate类继承自QStyledItemDelegate：

#ifndef QWINTSPINDELEGATE_H
#define QWINTSPINDELEGATE_H

//#include    
//#include    
#include    

class QWIntSpinDelegate : public QStyledItemDelegate
{
    Q_OBJECT
public:
    QWIntSpinDelegate(QObject *parent=0);

//自定义代理组件必须继承以下4个函数

//创建编辑组件
    QWidget *createEditor(QWidget *parent, const QStyleOptionViewItem &option,
                          const QModelIndex &index) const Q_DECL_OVERRIDE;

//从数据模型获取数据，显示到代理组件中
    void setEditorData(QWidget *editor, const QModelIndex &index) const Q_DECL_OVERRIDE;

//将代理组件的数据，保存到数据模型中
    void setModelData(QWidget *editor, QAbstractItemModel *model,
                      const QModelIndex &index) const Q_DECL_OVERRIDE;

//更新代理编辑组件的大小
    void updateEditorGeometry(QWidget *editor, const QStyleOptionViewItem &option,
                              const QModelIndex &index) const Q_DECL_OVERRIDE;
};

#endif // QWINTSPINDELEGATE_H

创建代理编辑组件：

QWidget *QWIntSpinDelegate::createEditor(QWidget *parent, const QStyleOptionViewItem &option,const QModelIndex &index) const
{
	//创建代理编辑器
	QSpinBox* editot = new QSpinBox(parent);
	editot->setFrame(false);//设置为无边框
	editot->setMinimum(0);
	editot->setMaximum(10000);
	return editot;
}

从数据模型获取数值：

void QWIntSpinDelegate::setEditorData(QWidget *editor,const QModelIndex &index) const
{
	//从数据模型获取数据显示到代理组件中
	//获取模型索引指向的单元格数据
	int value = index.model()->data(index, Qt::EditRole).toInt();
	QSpinBox* spinBox = static_cast(editor);  //强制类型转换
	spinBox->setValue(value);//设置编辑器的数值
}

将代理组件的数据保存到数据模型中：

void QWIntSpinDelegate::setModelData(QWidget* editor, QAbstractItemModel* model, const QModelIndex& index) const
{
	//将代理组件的数据保存到数据模型中
	QSpinBox* spinBox = static_cast(editor);
	spinBox->interpretText();//数据被修改后触发信号
	int value = spinBox->value();
	model->setData(index, value, Qt::EditRole);//将从组件获取到的值更新到数据模型
}

设置组件大小：

void QWIntSpinDelegate::updateEditorGeometry(QWidget *editor, const QStyleOptionViewItem &option, const QModelIndex &index) const
{ //设置组件大小
	editor->setGeometry(option.rect);
}

头文件：

#ifndef QWFLOATSPINDELEGATE_H
#define QWFLOATSPINDELEGATE_H

#include    
#include    
#include    

class QWFloatSpinDelegate : public QStyledItemDelegate
{
    Q_OBJECT
public:
    QWFloatSpinDelegate(QObject *parent=0);

//自定义代理组件必须继承以下4个函数
//创建编辑组件
    QWidget *createEditor(QWidget *parent, const QStyleOptionViewItem &option,
                          const QModelIndex &index) const Q_DECL_OVERRIDE;

    void setEditorData(QWidget *editor, const QModelIndex &index) const Q_DECL_OVERRIDE;
    void setModelData(QWidget *editor, QAbstractItemModel *model,
                      const QModelIndex &index) const Q_DECL_OVERRIDE;
    void updateEditorGeometry(QWidget *editor, const QStyleOptionViewItem &option,
                              const QModelIndex &index) const Q_DECL_OVERRIDE;
};

#endif // QWFLOATSPINDELEGATE_H

#ifndef QWCOMBOBOXDELEGATE_H
#define QWCOMBOBOXDELEGATE_H

#include    

class QWComboBoxDelegate : public QItemDelegate
{
    Q_OBJECT

public:
    QWComboBoxDelegate(QObject *parent=0);

//自定义代理组件必须继承以下4个函数
    QWidget *createEditor(QWidget *parent, const QStyleOptionViewItem &option,
                          const QModelIndex &index) const Q_DECL_OVERRIDE;

    void setEditorData(QWidget *editor, const QModelIndex &index) const Q_DECL_OVERRIDE;
    void setModelData(QWidget *editor, QAbstractItemModel *model,
                      const QModelIndex &index) const Q_DECL_OVERRIDE;
    void updateEditorGeometry(QWidget *editor, const QStyleOptionViewItem &option,
                              const QModelIndex &index) const Q_DECL_OVERRIDE;
};

#endif // QWCOMBOBOXDELEGATE_H

cpp文件：

#include "qwfloatspindelegate.h"

#include  

QWFloatSpinDelegate::QWFloatSpinDelegate(QObject *parent):QStyledItemDelegate(parent)
{

}

QWidget *QWFloatSpinDelegate::createEditor(QWidget *parent,
   const QStyleOptionViewItem &option, const QModelIndex &index) const
{
    Q_UNUSED(option);
    Q_UNUSED(index);

    QDoubleSpinBox *editor = new QDoubleSpinBox(parent);
    editor->setFrame(false);
    editor->setMinimum(0);
    editor->setDecimals(2);
    editor->setMaximum(10000);

    return editor;
}

void QWFloatSpinDelegate::setEditorData(QWidget *editor,
                      const QModelIndex &index) const
{
    float value = index.model()->data(index, Qt::EditRole).toFloat();
    QDoubleSpinBox *spinBox = static_cast(editor);
    spinBox->setValue(value);
}

void QWFloatSpinDelegate::setModelData(QWidget *editor, QAbstractItemModel *model, const QModelIndex &index) const
{
    QDoubleSpinBox *spinBox = static_cast(editor);
    spinBox->interpretText();
    float value = spinBox->value();
    QString str=QString::asprintf("%.2f",value);

    model->setData(index, str, Qt::EditRole);
}

void QWFloatSpinDelegate::updateEditorGeometry(QWidget *editor, const QStyleOptionViewItem &option, const QModelIndex &index) const
{
    editor->setGeometry(option.rect);
}

#include "qwcomboboxdelegate.h"

#include    

QWComboBoxDelegate::QWComboBoxDelegate(QObject *parent):QItemDelegate(parent)
{

}

QWidget *QWComboBoxDelegate::createEditor(QWidget *parent,
       const QStyleOptionViewItem &option, const QModelIndex &index) const
{
    QComboBox *editor = new QComboBox(parent);

    editor->addItem("优");
    editor->addItem("良");
    editor->addItem("一般");
    editor->addItem("不合格");

    return editor;
}

void QWComboBoxDelegate::setEditorData(QWidget *editor, const QModelIndex &index) const
{
    QString str = index.model()->data(index, Qt::EditRole).toString();

    QComboBox *comboBox = static_cast(editor);
    comboBox->setCurrentText(str);
}

void QWComboBoxDelegate::setModelData(QWidget *editor, QAbstractItemModel *model, const QModelIndex &index) const
{
    QComboBox *comboBox = static_cast(editor);

    QString str = comboBox->currentText();

    model->setData(index, str, Qt::EditRole);
}

void QWComboBoxDelegate::updateEditorGeometry(QWidget *editor,
                const QStyleOptionViewItem &option, const QModelIndex &index) const
{
    editor->setGeometry(option.rect);
}

在主窗口中：

创建数据模型和Item项选择模型：

QStandardItemModel* theModel;//数据模型
	QItemSelectionModel* theSelection;//Item项选择模型
theModel = new QStandardItemModel(2,6,this);
	theSelection = new QItemSelectionModel(theModel);

定义当前项变化的槽函数并进行连接：

QLabel* LabCellText;//当前单元格内容
void MainWindow::on_currentChanged(const QModelIndex ¤t, const QModelIndex &previous)
{
    Q_UNUSED(previous);
    if (current.isValid())
    {
        LabCellPos->setText(QString::asprintf("当前单元格：%d行，%d列",
                                  current.row(),current.column()));
        QStandardItem   *aItem;
        aItem=theModel->itemFromIndex(current); //从模型索引获得Item
        this->LabCellText->setText("单元格内容："+aItem->text());

        QFont   font=aItem->font();
        ui->actFontBold->setChecked(font.bold());
    }
}

connect(theSelection, SIGNAL(currentChanged(QModelIndex, QModelIndex)), this, SLOT(on_currentChanged(QModelIndex, QModelIndex)));

为各列设置自定义代理组件:

QWIntSpinDelegate intSpinDelegate;//整型数
	QWFloatSpinDelegate floatSpinDelegate;//浮点数
	QWComboBoxDelegate comboBoxDelegate;//列表选择

ui.tableView->setItemDelegateForColumn(0, &intSpinDelegate);
	ui.tableView->setItemDelegateForColumn(1,&floatSpinDelegate);
	ui.tableView->setItemDelegateForColumn(1, &floatSpinDelegate);
	ui.tableView->setItemDelegateForColumn(2, &floatSpinDelegate);
	ui.tableView->setItemDelegateForColumn(3, &floatSpinDelegate);
	ui.tableView->setItemDelegateForColumn(4,&comboBoxDelegate);