Delegate（QLabel和QComboBox）

一.最终效果

二.实现思路

1.createEditor（）中create两个控件，分别是QLabel和QComboBox，将其添加到一个widget中，然后返回该widget；

2.setEditorData()中，通过1中返回的widget找到label，设置参数；

3.setModelData（）中，通过1中返回的widget找到combobox，找到当前选中的index，将其更新到model中；

4.updateEditorGeometrey（）不变；

代码如下：

comboboxDelegate.h

#ifndef COMBODELEGATE_H
#define COMBODELEGATE_H

#include <QItemDelegate>

class ComboDelegate : public QItemDelegate
{
    Q_OBJECT
public:
    ComboDelegate(QObject *parent = 0);

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

};

#endif // COMBODELEGATE_H

comboboxDelegate.cpp

#include <QComboBox>
#include <QDebug>

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

QWidget *ComboDelegate::createEditor(QWidget *parent,const QStyleOptionViewItem &/*option*/,const QModelIndex &/*index*/) const
{

    QComboBox *comboBox = new QComboBox();
    comboBox->setObjectName("comboBox");    //为该对象设置名字，否则后面使用findchild（）函数会出错
    //editor->lineEdit()->setAlignment(Qt::AlignCenter);
    comboBox->setEditable(true);
    //editor->setStyleSheet("QComboBox{border:1px solid gray;}""QComboBox QAbstractItemView::item{height:25px;}");

    //editor->setView(new QListView());
    comboBox->addItem("N");
    comboBox->addItem("m");
    comboBox->addItem("m/s");
    comboBox->installEventFilter(const_cast<ComboDelegate*>(this));

    QLabel *label = new QLabel;
    label->setObjectName("label");
    label->setText(tr("m/s"));

    QHBoxLayout *hLay = new QHBoxLayout;
    hLay->addWidget(comboBox);
    hLay->addWidget(label);

    QWidget *wighet = new QWidget(parent);
    wighet->setLayout(hLay);
    return wighet;
}

void ComboDelegate::setEditorData(QWidget *editor,const QModelIndex &index) const
{
    //QString str =index.model()->data(index).toString();
    QString str = "m";
    //QString str = "meos";
    QWidget *box = static_cast<QWidget*>(editor);
    //QPushButton *button = parentWidget->findChild<QPushButton *>("button1");
    //QComboBox *comboBox = static_cast<QComboBox *>(box->findChild<QComboBox *>("editor"));
    //int i = comboBox->findText(str);
    //comboBox->setCurrentIndex(i);
    //QComboBox *combo = new QComboBox(comboBox);
    QLabel *label = editor->findChild<QLabel *>("label");
    //label->setText(str);
    qDebug("Test:%s",qPrintable(label->text()));
    //label->setText(tr("1"));
    //box->findChild<QComboBox *>("editor")->setCurrentIndex(i);
}

void ComboDelegate::setModelData(QWidget *editor, QAbstractItemModel *model, const QModelIndex &index) const
{
    QWidget *box = static_cast<QWidget*>(editor);
    QComboBox *comboBox= box->findChild<QComboBox *>();
    QString str = comboBox->currentText();
    model->setData(index,str);
}

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

三. 注意以下几个函数：

1.comboBox->setObjectName("comboBox"); 

2.QWidget *box = static_cast<QWidget*>(editor);

3.QLabel *label = editor->findChild<QLabel *>("label");

4.QComboBox *comboBox= box->findChild<QComboBox *>();