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 = );

     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 *>();