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在这一章,我们将会概括介绍如何创建wxWidgets程序。我们将会创建第一个简单的例子,展示如何显示一个图标。接下来我们将会用一个简单的例子说明如何响应事件。最后,我们将会看到这些小部件是如何与wxWidgets程序进行交互的。 ### 一个简单的程序 首先我们创建一个非常简单的wxWidgets程序。 simple.h ```cpp #include class Simple : public wxFrame { public: Simple(const wxString & title); }; ``` simple.cpp ```cpp #include "simple.h" Simple::Simple(const wxString & title) : wxFrame(NULL, wxID_ANY, title, wxDefaultPosition, wxSize(250, 150)) { Centre(); } ``` main.h ```cpp #include class MyApp : public wxApp { public: virtual bool OnInit(); }; ``` main.cpp ```cpp #include "main.h" #include "simple.h" IMPLEMENT_APP(MyApp) bool MyApp::OnInit() { Simple * simple = new Simple(_T("Simple")); simple->Show(true); return true; } ``` 这个小例子在屏幕上显示了一个小窗口,并且这个窗口是居中显示的。 > Centre(); 这个方法使这个窗口居中显示在屏幕上(水平和垂直)。 > IMPLEMENT_APP(MyApp); The code thar implements the application is hidden behind the macro.这是一段代码的复制粘贴,我们通常不用去关心。 ![](http://images.cnitblog.com/blog/535266/201311/27165053-c47f45a65aef4ffe802937bd286d18db.png) ### 应用程序图标 在这个例子中,我们给我们的程序提供一个图标,这是一个在窗口的左上角显示一个小图标的标准方法。这个图标是作为一个xpm格式文件被包含进这个程序。 icon.h ```cpp #include class Icon : public wxFrame { public: Icon(const wxString & title); }; ``` icon.cpp ```cpp #include "icon.h" #include "icon.xpm" Icon::Icon(const wxString & title) : wxFrame(NULL, wxID_ANY, title, wxDefaultPosition, wxSize(250, 150)) { SetIcon(wxIcon(icon_xpm)); Centre(); } ``` main.h ```cpp #include class MyApp : public wxApp { public: virtual bool OnInit(); }; ``` main.cpp ```cpp #include "main.h" #include "icon.h" IMPLEMENT_APP(MyApp) bool MyApp::OnInit() { Icon * icon = new Icon(_T("Icon")); icon->Show(true); return true; } ``` icon.xpm ```cpp /* 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 ++++++++++++++++++", " ++++++++++++++++++", "++++++++++++++++++++++++++++++++", "++++++++++++++++++++++++++++++++", "++++++++++++++++++++++++++++++++", "++++++++++++++++++++++++++++++++", "++++++++++++++++++++++++++++++++" }; ``` 在我们的程序中我们显示了一个小的wxWidgetsLogo图标。 > SetIcon(wxIcon(icon_xpm)); 显示图标是上面这行代码的做的工作。XPM(X PixMap)是一种以ASCII码表现的图像格式。 ![](http://images.cnitblog.com/blog/535266/201311/27165053-8b9a7b23ba7d4aa9809ae473da0f1d02.png) ### 一个简单的按钮 在接下来的这个例子中,我们在框架上创建了一个按钮。我们将会看到,如何建立一个简单的事件处理程序。 button.h ```cpp #include class Button : public wxFrame { public: Button(const wxString & title); void OnQuit(wxCommandEvent & event); }; ``` button.cpp ```cpp #include "button.h" Button::Button(const wxString & title) : wxFrame(NULL, wxID_ANY, title, wxDefaultPosition, wxSize(270, 150)) { wxPanel * panel = new wxPanel(this, wxID_ANY); wxButton * button = new wxButton(panel, wxID_EXIT, _T("Quit"), wxPoint(20, 20)); Connect(wxID_EXIT, wxEVT_COMMAND_BUTTON_CLICKED, wxCommandEventHandler(Button::OnQuit)); button->SetFocus(); // This sets the window to receive keyboard input Centre(); } void Button::OnQuit(wxCommandEvent & WXUNUSED(event)) { Close(true); } ``` main.h ```cpp #include class MyApp : public wxApp { public: virtual bool OnInit(); }; ``` main.cpp ```cpp #include "main.h" #include "button.h" IMPLEMENT_APP(MyApp) bool MyApp::OnInit() { Button * button = new Button(_T("Button")); button->Show(true); return true; } ``` > wxPanel * panel = new wxPanel(this, wxID_ANY); 首先我们创建一个wxPanel组件,这将被放置到一个wxFrame组件中。 > wxButton * button = new wxButton(panel, wxID_EXIT, _T("Quit"), wxPoint(20, 20)); 我们建立了一个wxButton组件,它被放置在panel上,我们使用wxWidgets预定义的id:wxID_EXIT绑定这个按钮,按钮上面的标签文字是"Quit",按钮被放置的坐标为(20, 20),坐标系的起点是左上角。 > Connect(wxID_EXIT, wxEVT_COMMAND_BUTTON_CLICKED, wxCommandEventHandler(Button::OnQuit)); 如果我们点击这个按钮,一个wxEVT_COMMAND_BUTTON_CLICKED事件就会被触发,我们把这个事件和OnQuit()方法捆绑在一起,所以当我们点击按钮时,OnQuit()方法就会被调用。 > Button->SetFocus(); 我们把键盘的焦点设置到这个按钮上,所以如果我们按下回车键就相当于按钮被按下了。 > Close(true); 在OnQuit()方法中,我们调用了Close()方法,这将会终结我们的应用程序。 ![](http://images.cnitblog.com/blog/535266/201311/27165053-7bab9db31b234d3f80f3cc27555442a5.png) ### 组件之间的通信 知道各个组件之间如何互相通信很重要,请看下面这个例子。 panels.h ```cpp #include #include class LeftPanel : public wxPanel { public: LeftPanel(wxPanel * parent); void OnPlus(wxCommandEvent & event); void OnMinus(wxCommandEvent & event); wxButton * m_plus; wxButton * m_minus; wxPanel * m_parent; int count; }; class RightPanel : public wxPanel { public: RightPanel(wxPanel * parent); void OnSetText(wxCommandEvent & event); wxStaticText * m_text; }; const int ID_PLUS = 101; const int ID_MINUS = 102; ``` panels.cpp ```cpp #include #include "communicate.h" LeftPanel::LeftPanel(wxPanel * parent) : wxPanel(parent, wxID_ANY, wxPoint(-1, -1), wxSize(-1, -1), wxBORDER_SUNKEN) { count = 0; m_parent = parent; m_plus = new wxButton(this, ID_PLUS, _T("+"), wxPoint(10, 10)); m_minus = new wxButton(this, ID_MINUS, _T("-"), wxPoint(10, 60)); Connect(ID_PLUS, wxEVT_COMMAND_BUTTON_CLICKED, wxCommandEventHandler(LeftPanel::OnPlus)); Connect(ID_MINUS, wxEVT_COMMAND_BUTTON_CLICKED, wxCommandEventHandler(LeftPanel::OnMinus)); } void LeftPanel::OnPlus(wxCommandEvent & WXUNUSED(event)) { count++; Communicate * comm = (Communicate *)(m_parent->GetParent()); comm->m_rp->m_text->SetLabel(wxString::Format(_T("%d"), count)); } void LeftPanel::OnMinus(wxCommandEvent & WXUNUSED(event)) { count--; Communicate * comm = (Communicate *)(m_parent->GetParent()); comm->m_rp->m_text->SetLabel(wxString::Format(_T("%d"), count)); } RightPanel::RightPanel(wxPanel * parent) : wxPanel(parent, wxID_ANY, wxDefaultPosition, wxSize(270, 150), wxBORDER_SUNKEN) { m_text = new wxStaticText(this, -1, _T("0"), wxPoint(40, 60)); } ``` communicate.h ```cpp #include "panels.h" #include class Communicate : public wxFrame { public: Communicate(const wxString & title); LeftPanel * m_lp; RightPanel * m_rp; wxPanel * m_parent; }; ``` communicate.cpp ```cpp #include "communicate.h" Communicate::Communicate(const wxString & title) : wxFrame(NULL, wxID_ANY, title, wxDefaultPosition, wxSize(290, 150)) { m_parent = new wxPanel(this, wxID_ANY); wxBoxSizer * hbox = new wxBoxSizer(wxHORIZONTAL); m_lp = new LeftPanel(m_parent); m_rp = new RightPanel(m_parent); hbox->Add(m_lp, 1, wxEXPAND | wxALL, 5); hbox->Add(m_rp, 1, wxEXPAND | wxALL, 5); m_parent->SetSizer(hbox); this->Centre(); } ``` main.h ```cpp #include class MyApp : public wxApp { public: virtual bool OnInit(); }; ``` main.cpp ```cpp #include "main.h" #include "communicate.h" IMPLEMENT_APP(MyApp) bool MyApp::OnInit() { Communicate * communicate = new Communicate(_T("Communicate")); communicate->Show(true); return true; } ``` 在我们的例子中,我们有两个panel,一个左边一个右边,左边的有两个按钮,右边的有一个静态文本控件。按钮改变显示在右panel中的数字。问题是,我们是如何获得静态文本控件的指针的? > m_parent = parent; 在LeftPanel里我们存储了父组件的地址,这是一个wxPanel组件。 > Communicate * comm = (Communicate *)m_parent->GetParent(); Comm->m_rp->m_text->SetLabel(wxString::Format(_T("%d"), count));` 这两行是这个例子中最重要的两行,它展示了如何操纵那个放在右panel中的静态文本控件。首先我们取得了左panel和右panel的父窗口指针,这个父窗口组件有一个指向右panel的指针,并且右panel有一个指向静态文本控件的指针。 ![](http://images.cnitblog.com/blog/535266/201311/27165054-cf60059569f94f66a73e661a55ebb949.png)