QT最简单的程序执行过程分析（内含C++基础知识）

打开QT Creator，新建一个“应用程序-Qt Widgets Application”项目：

输入名称scdc之后点击下一步。

在“构建套件”这个页面中直接点出下一步，然后再输入自己的类名DataCenter，其它不用手动改过来，QT会自动修改，如下图所示：

再点下一步，完成即可了。

这个时候直接点击左下方的“运行”按键，窗体就会出现了。

先看一看项目列表中所列的文件

这些文件分别是：

1. datacenter.h
2. datacenter.cpp
3. main.cpp
4. datacenter.ui
5. ui_datacenter.h 这个文件没有在左边的列表中，而是被datacenter.cpp所包含。

datacenter.h

#ifndef DATACENTER_H
#define DATACENTER_H

#include <QMainWindow>

namespace Ui {
class DataCenter;
}

class DataCenter : public QMainWindow
{
    Q_OBJECT

public:
    explicit DataCenter(QWidget *parent = 0);
    ~DataCenter();

private:
    Ui::DataCenter *ui;
};

#endif // DATACENTER_H

datacenter.cpp

#include "datacenter.h"
#include "ui_datacenter.h"

DataCenter::DataCenter(QWidget *parent) :
    QMainWindow(parent),
    ui(new Ui::DataCenter)
{
    ui->setupUi(this);
}

DataCenter::~DataCenter()
{
    delete ui;
}

与其他函数不同，构造函数除了有名字，参数列表和函数体之外，还可以有初始化列表，初始化列表以冒号开头，后跟一系列以逗号分隔的初始化字段。上面的QMainWindow(parent)和ui(new Ui::DataCenter)就是初始化列表。

main.cpp

#include "datacenter.h"
#include <QApplication>

int main(int argc, char *argv[])
{
    QApplication a(argc, argv);
    DataCenter w;
    w.show();

    return a.exec();
}

ui_datacenter.h

/********************************************************************************
** Form generated from reading UI file ‘datacenter.ui‘
**
** Created by: Qt User Interface Compiler version 5.2.0
**
** WARNING! All changes made in this file will be lost when recompiling UI file!
********************************************************************************/

#ifndef UI_DATACENTER_H
#define UI_DATACENTER_H

#include <QtCore/QVariant>
#include <QtWidgets/QAction>
#include <QtWidgets/QApplication>
#include <QtWidgets/QButtonGroup>
#include <QtWidgets/QHeaderView>
#include <QtWidgets/QMainWindow>
#include <QtWidgets/QMenu>
#include <QtWidgets/QMenuBar>
#include <QtWidgets/QPushButton>
#include <QtWidgets/QStatusBar>
#include <QtWidgets/QTextBrowser>
#include <QtWidgets/QToolBar>
#include <QtWidgets/QWidget>

QT_BEGIN_NAMESPACE

class Ui_DataCenter
{
public:
    QAction *actionLicense;
    QAction *actionAbout;
    QAction *actionNew;
    QAction *actionOpen;
    QAction *actionSave;
    QAction *actionSave_as;
    QAction *actionTemp_list;
    QAction *actionExit;
    QWidget *centralWidget;
    QPushButton *pushButton;
    QTextBrowser *textBrowser;
    QMenuBar *menuBar;
    QMenu *File;
    QMenu *View;
    QMenu *Tool;
    QMenu *About;
    QToolBar *mainToolBar;
    QStatusBar *statusBar;

    void setupUi(QMainWindow *DataCenter)
    {
        if (DataCenter->objectName().isEmpty())
            DataCenter->setObjectName(QStringLiteral("DataCenter"));
        DataCenter->resize(800, 600);
        QIcon icon;
        icon.addFile(QStringLiteral(":/res/scdc.ico"), QSize(), QIcon::Normal, QIcon::Off);
        DataCenter->setWindowIcon(icon);
        actionLicense = new QAction(DataCenter);
        actionLicense->setObjectName(QStringLiteral("actionLicense"));
        actionLicense->setIcon(icon);
        actionAbout = new QAction(DataCenter);
        actionAbout->setObjectName(QStringLiteral("actionAbout"));
        actionNew = new QAction(DataCenter);
        actionNew->setObjectName(QStringLiteral("actionNew"));
        actionOpen = new QAction(DataCenter);
        actionOpen->setObjectName(QStringLiteral("actionOpen"));
        actionSave = new QAction(DataCenter);
        actionSave->setObjectName(QStringLiteral("actionSave"));
        actionSave_as = new QAction(DataCenter);
        actionSave_as->setObjectName(QStringLiteral("actionSave_as"));
        actionTemp_list = new QAction(DataCenter);
        actionTemp_list->setObjectName(QStringLiteral("actionTemp_list"));
        actionExit = new QAction(DataCenter);
        actionExit->setObjectName(QStringLiteral("actionExit"));
        centralWidget = new QWidget(DataCenter);
        centralWidget->setObjectName(QStringLiteral("centralWidget"));
        pushButton = new QPushButton(centralWidget);
        pushButton->setObjectName(QStringLiteral("pushButton"));
        pushButton->setGeometry(QRect(60, 100, 75, 23));
        textBrowser = new QTextBrowser(centralWidget);
        textBrowser->setObjectName(QStringLiteral("textBrowser"));
        textBrowser->setGeometry(QRect(300, 110, 441, 381));
        DataCenter->setCentralWidget(centralWidget);
        menuBar = new QMenuBar(DataCenter);
        menuBar->setObjectName(QStringLiteral("menuBar"));
        menuBar->setGeometry(QRect(0, 0, 800, 23));
        File = new QMenu(menuBar);
        File->setObjectName(QStringLiteral("File"));
        View = new QMenu(menuBar);
        View->setObjectName(QStringLiteral("View"));
        Tool = new QMenu(menuBar);
        Tool->setObjectName(QStringLiteral("Tool"));
        About = new QMenu(menuBar);
        About->setObjectName(QStringLiteral("About"));
        DataCenter->setMenuBar(menuBar);
        mainToolBar = new QToolBar(DataCenter);
        mainToolBar->setObjectName(QStringLiteral("mainToolBar"));
        mainToolBar->setMovable(false);
        DataCenter->addToolBar(Qt::TopToolBarArea, mainToolBar);
        DataCenter->insertToolBarBreak(mainToolBar);
        statusBar = new QStatusBar(DataCenter);
        statusBar->setObjectName(QStringLiteral("statusBar"));
        DataCenter->setStatusBar(statusBar);

        menuBar->addAction(File->menuAction());
        menuBar->addAction(View->menuAction());
        menuBar->addAction(Tool->menuAction());
        menuBar->addAction(About->menuAction());
        File->addAction(actionNew);
        File->addAction(actionOpen);
        File->addAction(actionSave);
        File->addAction(actionSave_as);
        File->addSeparator();
        File->addAction(actionTemp_list);
        File->addSeparator();
        File->addAction(actionExit);
        About->addAction(actionLicense);
        About->addAction(actionAbout);

        retranslateUi(DataCenter);

        QMetaObject::connectSlotsByName(DataCenter);
    } // setupUi

    void retranslateUi(QMainWindow *DataCenter)
    {
        DataCenter->setWindowTitle(QApplication::translate("DataCenter", "DataCenter - Copyright 2012-2014 senscom", 0));
        actionLicense->setText(QApplication::translate("DataCenter", "\350\256\270\345\217\257", 0));
        actionAbout->setText(QApplication::translate("DataCenter", "\345\205\263\344\272\216", 0));
        actionNew->setText(QApplication::translate("DataCenter", "New", 0));
        actionOpen->setText(QApplication::translate("DataCenter", "Open", 0));
        actionSave->setText(QApplication::translate("DataCenter", "Save", 0));
        actionSave_as->setText(QApplication::translate("DataCenter", "Save as...", 0));
        actionTemp_list->setText(QApplication::translate("DataCenter", "temp list....", 0));
        actionExit->setText(QApplication::translate("DataCenter", "Exit", 0));
        pushButton->setText(QApplication::translate("DataCenter", "PushButton", 0));
        File->setTitle(QApplication::translate("DataCenter", "\346\226\207\344\273\266", 0));
        View->setTitle(QApplication::translate("DataCenter", "\346\237\245\347\234\213", 0));
        Tool->setTitle(QApplication::translate("DataCenter", "\345\267\245\345\205\267", 0));
        About->setTitle(QApplication::translate("DataCenter", "\345\205\263\344\272\216", 0));
    } // retranslateUi

};

namespace Ui {
    class DataCenter: public Ui_DataCenter {};
} // namespace Ui

QT_END_NAMESPACE

#endif // UI_DATACENTER_H