samples/event/event.cpp

   1 /////////////////////////////////////////////////////////////////////////////
   2 // Name:        event.cpp
   3 // Purpose:     wxWindows sample demonstrating different event usage
   4 // Author:      Vadim Zeitlin
   5 // Modified by:
   6 // Created:     31.01.01
   7 // RCS-ID:      $Id$
   8 // Copyright:   (c) 2001 Vadim Zeitlin
   9 // Licence:     wxWindows licence
  10 /////////////////////////////////////////////////////////////////////////////
  11
  12 // ============================================================================
  13 // declarations
  14 // ============================================================================
  15
  16 // ----------------------------------------------------------------------------
  17 // headers
  18 // ----------------------------------------------------------------------------
  19
  20 #ifdef __GNUG__
  21     // DO NOT use event.cpp here, it breaks statics initialization in
  22     // src/common/event.cpp and nothing works at all then!
  23     #pragma implementation "eventsample.cpp"
  24     #pragma interface "eventsample.cpp"
  25 #endif
  26
  27 // For compilers that support precompilation, includes "wx/wx.h".
  28 #include "wx/wxprec.h"
  29
  30 #ifdef __BORLANDC__
  31     #pragma hdrstop
  32 #endif
  33
  34 // for all others, include the necessary headers (this file is usually all you
  35 // need because it includes almost all "standard" wxWindows headers)
  36 #ifndef WX_PRECOMP
  37     #include "wx/wx.h"
  38 #endif
  39
  40 // ----------------------------------------------------------------------------
  41 // private classes
  42 // ----------------------------------------------------------------------------
  43
  44 // Define a new application type, each program should derive a class from wxApp
  45 class MyApp : public wxApp
  46 {
  47 public:
  48     // override base class virtuals
  49     // ----------------------------
  50
  51     // this one is called on application startup and is a good place for the app
  52     // initialization (doing it here and not in the ctor allows to have an error
  53     // return: if OnInit() returns false, the application terminates)
  54     virtual bool OnInit();
  55 };
  56
  57 // Define a new frame type: this is going to be our main frame
  58 class MyFrame : public wxFrame
  59 {
  60 public:
  61     // ctor(s)
  62     MyFrame(const wxString& title, const wxPoint& pos, const wxSize& size);
  63     virtual ~MyFrame();
  64
  65     void OnQuit(wxCommandEvent& event);
  66     void OnAbout(wxCommandEvent& event);
  67     void OnConnect(wxCommandEvent& event);
  68     void OnDynamic(wxCommandEvent& event);
  69     void OnPushEventHandler(wxCommandEvent& event);
  70     void OnPopEventHandler(wxCommandEvent& event);
  71     void OnTest(wxCommandEvent& event);
  72
  73     void OnUpdateUIPop(wxUpdateUIEvent& event);
  74
  75 protected:
  76     // number of pushed event handlers
  77     size_t m_nPush;
  78
  79 private:
  80     // any class wishing to process wxWindows events must use this macro
  81     DECLARE_EVENT_TABLE()
  82 };
  83
  84 // Define a custom event handler
  85 class MyEvtHandler : public wxEvtHandler
  86 {
  87 public:
  88     MyEvtHandler(size_t level) { m_level = level; }
  89
  90     void OnTest(wxCommandEvent& event)
  91     {
  92         wxLogMessage(_T("This is the pushed test event handler #%u"), m_level);
  93
  94         // if we don't skip the event, the other event handlers won't get it:
  95         // try commenting out this line and see what changes
  96         event.Skip();
  97     }
  98
  99 private:
 100     size_t m_level;
 101
 102     DECLARE_EVENT_TABLE()
 103 };
 104
 105 // ----------------------------------------------------------------------------
 106 // constants
 107 // ----------------------------------------------------------------------------
 108
 109 // IDs for the controls and the menu commands
 110 enum
 111 {
 112     // menu items
 113     Event_Quit = 1,
 114     Event_About,
 115     Event_Connect,
 116     Event_Dynamic,
 117     Event_Push,
 118     Event_Pop,
 119     Event_Test
 120 };
 121
 122 // status bar fields
 123 enum
 124 {
 125     Status_Main = 0,
 126     Status_Dynamic,
 127     Status_Push
 128 };
 129
 130 // ----------------------------------------------------------------------------
 131 // event tables and other macros for wxWindows
 132 // ----------------------------------------------------------------------------
 133
 134 // the event tables connect the wxWindows events with the functions (event
 135 // handlers) which process them. It can be also done at run-time, but for the
 136 // simple menu events like this the static method is much simpler.
 137 BEGIN_EVENT_TABLE(MyFrame, wxFrame)
 138     EVT_MENU(Event_Quit,  MyFrame::OnQuit)
 139     EVT_MENU(Event_About, MyFrame::OnAbout)
 140
 141     EVT_MENU(Event_Connect, MyFrame::OnConnect)
 142
 143     EVT_MENU(Event_Test, MyFrame::OnTest)
 144     EVT_MENU(Event_Push, MyFrame::OnPushEventHandler)
 145     EVT_MENU(Event_Pop, MyFrame::OnPopEventHandler)
 146
 147     EVT_UPDATE_UI(Event_Pop, MyFrame::OnUpdateUIPop)
 148 END_EVENT_TABLE()
 149
 150 BEGIN_EVENT_TABLE(MyEvtHandler, wxEvtHandler)
 151     EVT_MENU(Event_Test, MyEvtHandler::OnTest)
 152 END_EVENT_TABLE()
 153
 154 // Create a new application object: this macro will allow wxWindows to create
 155 // the application object during program execution (it's better than using a
 156 // static object for many reasons) and also declares the accessor function
 157 // wxGetApp() which will return the reference of the right type (i.e. MyApp and
 158 // not wxApp)
 159 IMPLEMENT_APP(MyApp)
 160
 161 // ============================================================================
 162 // implementation
 163 // ============================================================================
 164
 165 // ----------------------------------------------------------------------------
 166 // the application class
 167 // ----------------------------------------------------------------------------
 168
 169 // 'Main program' equivalent: the program execution "starts" here
 170 bool MyApp::OnInit()
 171 {
 172     // create the main application window
 173     MyFrame *frame = new MyFrame("Event wxWindows Sample",
 174                                  wxPoint(50, 50), wxSize(450, 340));
 175
 176     // and show it (the frames, unlike simple controls, are not shown when
 177     // created initially)
 178     frame->Show(TRUE);
 179
 180     // success: wxApp::OnRun() will be called which will enter the main message
 181     // loop and the application will run. If we returned FALSE here, the
 182     // application would exit immediately.
 183     return TRUE;
 184 }
 185
 186 // ----------------------------------------------------------------------------
 187 // main frame
 188 // ----------------------------------------------------------------------------
 189
 190 // frame constructor
 191 MyFrame::MyFrame(const wxString& title, const wxPoint& pos, const wxSize& size)
 192        : wxFrame((wxFrame *)NULL, -1, title, pos, size)
 193 {
 194     // create a menu bar
 195     wxMenu *menuFile = new wxMenu;
 196
 197     menuFile->Append(Event_About, "&About...\tCtrl-A", "Show about dialog");
 198     menuFile->AppendSeparator();
 199     menuFile->Append(Event_Quit, "E&xit\tAlt-X", "Quit this program");
 200
 201     wxMenu *menuEvent = new wxMenu;
 202     menuEvent->Append(Event_Connect, "&Connect\tCtrl-C",
 203                      "Connect or disconnect the dynamic event handler",
 204                      TRUE /* checkable */);
 205     menuEvent->Append(Event_Dynamic, "&Dynamic event\tCtrl-D",
 206                       "Dynamic event sample - only works after Connect");
 207     menuEvent->AppendSeparator();
 208     menuEvent->Append(Event_Push, "&Push event handler\tCtrl-P",
 209                       "Push event handler for test event");
 210     menuEvent->Append(Event_Pop, "P&op event handler\tCtrl-O",
 211                       "Pop event handler for test event");
 212     menuEvent->Append(Event_Test, "Test event\tCtrl-T",
 213                       "Test event processed by pushed event handler");
 214
 215     // now append the freshly created menu to the menu bar...
 216     wxMenuBar *menuBar = new wxMenuBar();
 217     menuBar->Append(menuFile, "&File");
 218     menuBar->Append(menuEvent, "&Event");
 219
 220     // ... and attach this menu bar to the frame
 221     SetMenuBar(menuBar);
 222
 223 #if wxUSE_STATUSBAR
 224     CreateStatusBar(3);
 225     SetStatusText("Welcome to wxWindows event sample");
 226     SetStatusText(_T("Dynamic: off"), Status_Dynamic);
 227     SetStatusText(_T("Push count: 0"), Status_Push);
 228 #endif // wxUSE_STATUSBAR
 229 }
 230
 231 MyFrame::~MyFrame()
 232 {
 233     // we must pop any remaining event handlers to avoid memory leaks and
 234     // crashes!
 235     while ( m_nPush-- != 0 )
 236     {
 237         PopEventHandler(TRUE /* delete handler */);
 238     }
 239 }
 240
 241 // ----------------------------------------------------------------------------
 242 // standard event handlers
 243 // ----------------------------------------------------------------------------
 244
 245 void MyFrame::OnQuit(wxCommandEvent& WXUNUSED(event))
 246 {
 247     // TRUE is to force the frame to close
 248     Close(TRUE);
 249 }
 250
 251 void MyFrame::OnAbout(wxCommandEvent& WXUNUSED(event))
 252 {
 253     wxMessageBox(_T("Event sample shows different ways of using events\n"
 254                     "© 2001 Vadim Zeitlin"),
 255                  _T("About Event Sample"), wxOK | wxICON_INFORMATION, this);
 256 }
 257
 258 // ----------------------------------------------------------------------------
 259 // dynamic event handling stuff
 260 // ----------------------------------------------------------------------------
 261
 262 void MyFrame::OnDynamic(wxCommandEvent& WXUNUSED(event))
 263 {
 264     wxMessageBox(_T("This is a dynamic event handler which can be connected "
 265                     "and disconnected during run-time."),
 266                  _T("Dynamic Event Handler"), wxOK | wxICON_INFORMATION, this);
 267 }
 268
 269 void MyFrame::OnConnect(wxCommandEvent& event)
 270 {
 271     if ( event.IsChecked() )
 272     {
 273         // disconnect
 274         Connect(Event_Dynamic, -1, wxEVT_COMMAND_MENU_SELECTED,
 275                 (wxObjectEventFunction)
 276                 (wxEventFunction)
 277                 (wxCommandEventFunction)&MyFrame::OnDynamic);
 278
 279         SetStatusText(_T("You can now use \"Dynamic\" item in the menu"));
 280         SetStatusText(_T("Dynamic: on"), Status_Dynamic);
 281     }
 282     else // connect
 283     {
 284         Disconnect(Event_Dynamic, -1, wxEVT_COMMAND_MENU_SELECTED);
 285
 286         SetStatusText(_T("You can no more use \"Dynamic\" item in the menu"));
 287         SetStatusText(_T("Dynamic: off"), Status_Dynamic);
 288     }
 289 }
 290
 291 // ----------------------------------------------------------------------------
 292 // push/pop event handlers support
 293 // ----------------------------------------------------------------------------
 294
 295 void MyFrame::OnPushEventHandler(wxCommandEvent& WXUNUSED(event))
 296 {
 297     PushEventHandler(new MyEvtHandler(++m_nPush));
 298
 299     SetStatusText(wxString::Format(_T("Push count: %u"), m_nPush), Status_Push);
 300 }
 301
 302 void MyFrame::OnPopEventHandler(wxCommandEvent& WXUNUSED(event))
 303 {
 304     wxCHECK_RET( m_nPush, _T("this command should be disabled!") );
 305
 306     PopEventHandler(TRUE /* delete handler */);
 307     m_nPush--;
 308
 309     SetStatusText(wxString::Format(_T("Push count: %u"), m_nPush), Status_Push);
 310 }
 311
 312 void MyFrame::OnTest(wxCommandEvent& event)
 313 {
 314     wxLogMessage(_T("This is the test event handler in the main frame"));
 315 }
 316
 317 void MyFrame::OnUpdateUIPop(wxUpdateUIEvent& event)
 318 {
 319     event.Enable( m_nPush > 0 );
 320 }
 321