系统常量对话框QT实现

1.运行结果：

2.代码

main.cpp

 #include "constantdiag.h"
 #include <QtWidgets/QApplication>

 int main(int argc, char *argv[])
 {
     QApplication a(argc, argv);
     constantDiag w;
     w.show();
     return a.exec();
 }

constantDialog.h

 #ifndef CONSTANTDIAG_H
 #define CONSTANTDIAG_H

 #include <QtWidgets/QWidget>
 #include <QHBoxLayout>
 #include <QPushButton>
 #include <QStandardItemModel>
 #include <QTableView>
 #include <QVBoxLayout>
 #include <QHeaderView>
 #include <QLabel>

 class ComboDelegate;

 class constantDiag : public QWidget
 {
     Q_OBJECT

 public:
     constantDiag(QWidget *parent = );
     ~constantDiag();

 public slots:
     void addConstant();
     void reduceConstant();

 private:
     QHBoxLayout *secondHLayout;
     QPushButton *btnConstantPlus;
     QPushButton *btnConstantMinus;
     QStandardItemModel *model;
     QTableView *tableview;
     QVBoxLayout *wholeLayout;
     QHBoxLayout *thirdHLayout;
     QPushButton *btnOk;
     QPushButton *btnCancel;
     QHBoxLayout *topLayout;
     QLabel *titleLabel;
     QVBoxLayout *wholeVLayout;
     ComboDelegate *comboDelegate;
 };

 #endif // CONSTANTDIAG_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

constantDialog.cpp

 #include "constantdiag.h"

 constantDiag::constantDiag(QWidget *parent)
     : QWidget(parent)
 {
     setWindowTitle(QString::fromLocal8Bit("系统常量"));
     resize(,);

     wholeLayout = new QVBoxLayout(parent);

     secondHLayout = new QHBoxLayout();
     secondHLayout->addStretch();

     btnConstantPlus = new QPushButton;
     btnConstantPlus->setText("+");
     secondHLayout->addWidget(btnConstantPlus);

     btnConstantMinus = new QPushButton;
     btnConstantMinus->setText("-");
     secondHLayout->addWidget(btnConstantMinus);

     secondHLayout->setStretch(,);
     secondHLayout->setStretch(,);
     secondHLayout->setStretch(,);

     wholeLayout->addLayout(secondHLayout);

     model = new QStandardItemModel(,);
     model->setHeaderData(,Qt::Horizontal,QString::fromLocal8Bit("名称"));
     model->setHeaderData(,Qt::Horizontal,QString::fromLocal8Bit("值"));
     model->setHeaderData(,Qt::Horizontal,QString::fromLocal8Bit("单位"));
     tableview = new QTableView(parent);
     tableview->setModel(model);
     tableview->verticalHeader()->setVisible(false);
     tableview->horizontalHeader()->setSectionResizeMode(, QHeaderView::Stretch);
     tableview->horizontalHeader()->setSectionResizeMode(, QHeaderView::Stretch);
     tableview->horizontalHeader()->setSectionResizeMode(, QHeaderView::Stretch);
     comboDelegate = new ComboDelegate;
     tableview->setItemDelegateForColumn(,comboDelegate);
     //tableview->verticalHeader()->setSectionResizeMode(0,QHeaderView::Stretch);
     //tableview->verticalHeader()->setSectionResizeMode(1,QHeaderView::Stretch);

     wholeLayout->addWidget(tableview);

     thirdHLayout = new QHBoxLayout;
     thirdHLayout->addStretch();

     btnOk = new QPushButton;
     btnOk->setText(QString::fromLocal8Bit("确定"));
     btnCancel = new QPushButton;
     btnCancel->setText(QString::fromLocal8Bit("取消"));
     thirdHLayout->addWidget(btnOk);
     thirdHLayout->addWidget(btnCancel);

     thirdHLayout->setStretch(,);
     thirdHLayout->setStretch(,);
     thirdHLayout->setStretch(,);

     wholeLayout->addLayout(thirdHLayout);
     //wholeLayout->setSizeConstraint(QLayout::SetFixedSize);
     //wholeLayout->setStretchFactor(secondHLayout, 1);
     //wholeLayout->setStretchFactor(tableview, 2);
     //wholeLayout->setStretchFactor(thirdHLayout, 1);

     setLayout(wholeLayout);

     connect(btnConstantPlus,SIGNAL(clicked()),this,SLOT(addConstant()));
     connect(btnConstantMinus,SIGNAL(clicked()),this,SLOT(reduceConstant()));
 }

 constantDiag::~constantDiag()
 {

 }

 void constantDiag::addConstant()
 {
     int row = model->rowCount();
     model->insertRow(row);
 }

 void constantDiag::reduceConstant()
 {
     int row = model->rowCount();
     model->removeRow(--row);
 }

 #include <QComboBox>

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

 QWidget *ComboDelegate::createEditor(QWidget *parent,const QStyleOptionViewItem &/*option*/,const QModelIndex &/*index*/) const
 {
     QComboBox *editor = new QComboBox(parent);
     //editor->lineEdit()->setAlignment(Qt::AlignCenter);
     editor->setEditable(true);
     //editor->setStyleSheet("QComboBox{border:1px solid gray;}""QComboBox QAbstractItemView::item{height:25px;}");

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

 void ComboDelegate::setEditorData(QWidget *editor,const QModelIndex &index) const
 {
     QString str =index.model()->data(index).toString();
     QComboBox *box = static_cast<QComboBox*>(editor);
     int i=box->findText(str);
     box->setCurrentIndex(i);
 }

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

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