2、wxWidgets介绍--菜单栏、状态栏、图标简介

wxWidgets

wxWidgets是一个用来编写C++程序的GUI（图形用户界面）工具包。它是一个开源的、成熟的、跨平台的工具包。wxWidgets应用程序能在所有主流的操作系统上运行，Windows，Unix，Mac。这个项目由Julian Smart在1992年启动。wxWidgets提供各种各样的C++类来处理数据流、数据库、多线程、在线帮助、应用程序设置。wxWidgets由大量的窗口小部件组成。

接下来我们一步步的完成一个Hello World的窗口程序：

首先，搭建一个非常简单的框架：

#include <wx/wx.h>

class MyFrame : public wxFrame
{
public:
    MyFrame(const wxString& title): wxFrame(NULL, wxID_ANY, title) {}

};

class MyApp : public wxApp
{
public:
    virtual bool OnInit()
    {
        MyFrame * pframe = new MyFrame(wxT("Hello World"));
        pframe->Show(true);
        return true;
    }

};
IMPLEMENT_APP(MyApp)

执行结果：

特点：

1. 没有main()函数，实际上是包含在wxWidgets框架中看不到。
2. 一个应用程序类App，一个框架类Frame。
3. Frame在App的OnInit()函数中实例化。

   注意：这里Frame没有销毁，可能会内存泄露(通常这么处理也不会有太大问题，因为窗口关闭时，OS会收回所有资源)。

然后给窗口添加状态栏

#include <wx/wx.h>

//框架类wxFrame
class MyFrame : public wxFrame
{
public:
    MyFrame(const wxString& title): wxFrame(NULL, wxID_ANY, title)
    {
        //添加状态栏
        CreateStatusBar();
        //将状态栏分为两栏
        //CreateStatusBar(2);
        SetStatusText(wxT("Welcome to wxWidgets!"));
    }

};

//应用程序类APP
class MyApp : public wxApp
{
public:
    //Frame的实例化
    virtual bool OnInit()
    {
        MyFrame * pframe = new MyFrame(wxT("Hello World"));
        pframe->Show(true);
        return true;
    }

};
//声明应用程序
IMPLEMENT_APP(MyApp)

添加菜单

#include <wx/wx.h>

//框架类wxFrame
class MyFrame : public wxFrame
{
public:
    MyFrame(const wxString& title): wxFrame(NULL, wxID_ANY, title)
    {
        //定义菜单
        wxMenu *menuFile = new wxMenu;
        menuFile->Append(wxID_EXIT, wxT("Exit ... 	Alt+X"), wxT("Quit this program"));

        wxMenu *menuHelp = new wxMenu;
        menuHelp->Append(wxID_ABORT, wxT("&About ... 	F1"), wxT("Show about frame"));

        //定义菜单栏
        wxMenuBar *menuBar = new wxMenuBar;
        
        //向菜单栏添加菜单
        menuBar->Append(menuFile, wxT("&File"));
        menuBar->Append(menuHelp, wxT("&Help"));
        
        //将菜单栏添加到wxFrame中
        SetMenuBar(menuBar);

        //添加状态栏
        CreateStatusBar();
        //将状态栏分为两栏
        //CreateStatusBar(2);
        SetStatusText(wxT("Welcome to wxWidgets!"));
    }

};

//应用程序类APP
class MyApp : public wxApp
{
public:
    //Frame的实例化
    virtual bool OnInit()
    {
        MyFrame * pframe = new MyFrame(wxT("Hello World"));
        pframe->Show(true);
        return true;
    }

};
//声明应用程序
IMPLEMENT_APP(MyApp)

添加菜单事件、添加应用显示图标

#include <wx/wx.h>
#include "icon.xpm"

//框架类wxFrame
class MyFrame : public wxFrame
{
public:
    MyFrame(const wxString& title): wxFrame(NULL, wxID_ANY, title)
    {
        //定义菜单
        wxMenu *menuFile = new wxMenu;
        menuFile->Append(wxID_EXIT, wxT("Exit ... 	Alt+X"), wxT("Quit this program"));

        wxMenu *menuHelp = new wxMenu;
        menuHelp->Append(wxID_ABOUT, wxT("&About ... 	F1"), wxT("Show about frame"));

        //定义菜单栏
        wxMenuBar *menuBar = new wxMenuBar;

        //向菜单栏添加菜单
        menuBar->Append(menuFile, wxT("&File"));
        menuBar->Append(menuHelp, wxT("&Help"));

        //将菜单栏添加到wxFrame中
        SetMenuBar(menuBar);

        //添加状态栏
        CreateStatusBar();
        //将状态栏分为两栏
        //CreateStatusBar(2);
        SetStatusText(wxT("Welcome to wxWidgets!"));

        //设置应用显示图标
        SetIcon(wxIcon(icon_xpm));

    }

    //定义事件处理函数
    void OnQuit(wxCommandEvent& event);
    void OnAbout(wxCommandEvent& event);
private:
    //声明事件表
    DECLARE_EVENT_TABLE()
};

//应用程序类APP
class MyApp : public wxApp
{
public:
    //Frame的实例化
    virtual bool OnInit()
    {
        MyFrame * pframe = new MyFrame(wxT("Hello World"));
        pframe->Show(true);
        return true;
    }

};
//声明应用程序
IMPLEMENT_APP(MyApp)

//定义事件表，完成事件和处理函数的映射
BEGIN_EVENT_TABLE(MyFrame, wxFrame)
    EVT_MENU(wxID_ABOUT, MyFrame::OnAbout)
    EVT_MENU(wxID_EXIT, MyFrame::OnQuit)
END_EVENT_TABLE()

//事件处理函数的实现
void MyFrame::OnAbout(wxCommandEvent& event)
{
    wxString msg;
    msg.Printf(wxT("About hello wxWidgets"), wxVERSION_STRING);

    wxMessageBox(msg, wxT("About wxWidgets"), wxOK | wxICON_INFORMATION, this);
}

void MyFrame::OnQuit(wxCommandEvent& event)
{
    Close();
}

icon.xpm

/* XPM */
static const char * icon_xpm[] = {
/* columns rows colors chars-per-pixel */
"32 32 6 1",
"  c black",
". c navy",
"X c red",
"o c yellow",
"O c gray100",
"+ c None",
/* pixels */
"++++++++++++++++++++++++++++++++",
"++++++++++++++++++++++++++++++++",
"++++++++++++++++++++++++++++++++",
"++++++++++++++++++++++++++++++++",
"++++++++++++++++++++++++++++++++",
"++++++++              ++++++++++",
"++++++++ ............ ++++++++++",
"++++++++ ............ ++++++++++",
"++++++++ .OO......... ++++++++++",
"++++++++ .OO......... ++++++++++",
"++++++++ .OO......... ++++++++++",
"++++++++ .OO......              ",
"++++++++ .OO...... oooooooooooo ",
"         .OO...... oooooooooooo ",
" XXXXXXX .OO...... oOOooooooooo ",
" XXXXXXX .OO...... oOOooooooooo ",
" XOOXXXX ......... oOOooooooooo ",
" XOOXXXX ......... oOOooooooooo ",
" XOOXXXX           oOOooooooooo ",
" XOOXXXXXXXXX ++++ oOOooooooooo ",
" XOOXXXXXXXXX ++++ oOOooooooooo ",
" XOOXXXXXXXXX ++++ oOOooooooooo ",
" XOOXXXXXXXXX ++++ oooooooooooo ",
" XOOXXXXXXXXX ++++ oooooooooooo ",
" XXXXXXXXXXXX ++++              ",
" XXXXXXXXXXXX ++++++++++++++++++",
"              ++++++++++++++++++",
"++++++++++++++++++++++++++++++++",
"++++++++++++++++++++++++++++++++",
"++++++++++++++++++++++++++++++++",
"++++++++++++++++++++++++++++++++",
"++++++++++++++++++++++++++++++++"
};