samples/event/event.cpp

   1 /////////////////////////////////////////////////////////////////////////////
   2 // Name:        event.cpp
   3 // Purpose:     wxWidgets 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 #if defined(__GNUG__) && !defined(__APPLE__)
  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" wxWidgets headers)
  36 #ifndef WX_PRECOMP
  37     #include "wx/wx.h"
  38 #endif
  39
  40 // ----------------------------------------------------------------------------
  41 // event constants
  42 // ----------------------------------------------------------------------------
  43
  44 // declare a custom event type
  45 //
  46 // note that in wxWin 2.3+ these macros expand simply into the following code:
  47 //
  48 //  extern const wxEventType wxEVT_MY_CUSTOM_COMMAND;
  49 //
  50 //  const wxEventType wxEVT_MY_CUSTOM_COMMAND = wxNewEventType();
  51 //
  52 // and you may use this code directly if you don't care about 2.2 compatibility
  53 BEGIN_DECLARE_EVENT_TYPES()
  54     DECLARE_EVENT_TYPE(wxEVT_MY_CUSTOM_COMMAND, 7777)
  55 END_DECLARE_EVENT_TYPES()
  56
  57 DEFINE_EVENT_TYPE(wxEVT_MY_CUSTOM_COMMAND)
  58
  59 // it may also be convenient to define an event table macro for this event type
  60 #define EVT_MY_CUSTOM_COMMAND(id, fn) \
  61     DECLARE_EVENT_TABLE_ENTRY( \
  62         wxEVT_MY_CUSTOM_COMMAND, id, wxID_ANY, \
  63         (wxObjectEventFunction)(wxEventFunction) wxStaticCastEvent( wxCommandEventFunction, &fn ), \
  64         (wxObject *) NULL \
  65     ),
  66
  67 // ----------------------------------------------------------------------------
  68 // private classes
  69 // ----------------------------------------------------------------------------
  70
  71 // Define a new application type, each program should derive a class from wxApp
  72 class MyApp : public wxApp
  73 {
  74 public:
  75     // override base class virtuals
  76     // ----------------------------
  77
  78     // this one is called on application startup and is a good place for the app
  79     // initialization (doing it here and not in the ctor allows to have an error
  80     // return: if OnInit() returns false, the application terminates)
  81     virtual bool OnInit();
  82 };
  83
  84 // Define a new frame type: this is going to be our main frame
  85 class MyFrame : public wxFrame
  86 {
  87 public:
  88     // ctor(s)
  89     MyFrame(const wxString& title, const wxPoint& pos, const wxSize& size);
  90     virtual ~MyFrame();
  91
  92     void OnQuit(wxCommandEvent& event);
  93     void OnAbout(wxCommandEvent& event);
  94     void OnConnect(wxCommandEvent& event);
  95     void OnDynamic(wxCommandEvent& event);
  96     void OnPushEventHandler(wxCommandEvent& event);
  97     void OnPopEventHandler(wxCommandEvent& event);
  98     void OnTest(wxCommandEvent& event);
  99
 100     void OnFireCustom(wxCommandEvent& event);
 101     void OnProcessCustom(wxCommandEvent& event);
 102
 103     void OnUpdateUIPop(wxUpdateUIEvent& event);
 104
 105 protected:
 106     // number of pushed event handlers
 107     size_t m_nPush;
 108
 109 private:
 110     // any class wishing to process wxWidgets events must use this macro
 111     DECLARE_EVENT_TABLE()
 112 };
 113
 114 // Define a custom event handler
 115 class MyEvtHandler : public wxEvtHandler
 116 {
 117 public:
 118     MyEvtHandler(size_t level) { m_level = level; }
 119
 120     void OnTest(wxCommandEvent& event)
 121     {
 122         wxLogMessage(_T("This is the pushed test event handler #%u"), m_level);
 123
 124         // if we don't skip the event, the other event handlers won't get it:
 125         // try commenting out this line and see what changes
 126         event.Skip();
 127     }
 128
 129 private:
 130     size_t m_level;
 131
 132     DECLARE_EVENT_TABLE()
 133 };
 134
 135 // ----------------------------------------------------------------------------
 136 // constants
 137 // ----------------------------------------------------------------------------
 138
 139 // IDs for the controls and the menu commands
 140 enum
 141 {
 142     // menu items
 143     Event_Quit = 1,
 144     Event_About,
 145     Event_Connect,
 146     Event_Dynamic,
 147     Event_Push,
 148     Event_Pop,
 149     Event_Custom,
 150     Event_Test
 151 };
 152
 153 // status bar fields
 154 enum
 155 {
 156     Status_Main = 0,
 157     Status_Dynamic,
 158     Status_Push
 159 };
 160
 161 // ----------------------------------------------------------------------------
 162 // event tables and other macros for wxWidgets
 163 // ----------------------------------------------------------------------------
 164
 165 // the event tables connect the wxWidgets events with the functions (event
 166 // handlers) which process them. It can be also done at run-time, but for the
 167 // simple menu events like this the static method is much simpler.
 168 BEGIN_EVENT_TABLE(MyFrame, wxFrame)
 169     EVT_MENU(Event_Quit,  MyFrame::OnQuit)
 170     EVT_MENU(Event_About, MyFrame::OnAbout)
 171
 172     EVT_MENU(Event_Connect, MyFrame::OnConnect)
 173
 174     EVT_MENU(Event_Custom, MyFrame::OnFireCustom)
 175     EVT_MENU(Event_Test, MyFrame::OnTest)
 176     EVT_MENU(Event_Push, MyFrame::OnPushEventHandler)
 177     EVT_MENU(Event_Pop, MyFrame::OnPopEventHandler)
 178
 179     EVT_UPDATE_UI(Event_Pop, MyFrame::OnUpdateUIPop)
 180
 181     EVT_MY_CUSTOM_COMMAND(wxID_ANY, MyFrame::OnProcessCustom)
 182
 183     // the line below would also work if OnProcessCustom() were defined as
 184     // taking a wxEvent (as required by EVT_CUSTOM) and not wxCommandEvent
 185     //EVT_CUSTOM(wxEVT_MY_CUSTOM_COMMAND, wxID_ANY, MyFrame::OnProcessCustom)
 186 END_EVENT_TABLE()
 187
 188 BEGIN_EVENT_TABLE(MyEvtHandler, wxEvtHandler)
 189     EVT_MENU(Event_Test, MyEvtHandler::OnTest)
 190 END_EVENT_TABLE()
 191
 192 // Create a new application object: this macro will allow wxWidgets to create
 193 // the application object during program execution (it's better than using a
 194 // static object for many reasons) and also declares the accessor function
 195 // wxGetApp() which will return the reference of the right type (i.e. MyApp and
 196 // not wxApp)
 197 IMPLEMENT_APP(MyApp)
 198
 199 // ============================================================================
 200 // implementation
 201 // ============================================================================
 202
 203 // ----------------------------------------------------------------------------
 204 // the application class
 205 // ----------------------------------------------------------------------------
 206
 207 // 'Main program' equivalent: the program execution "starts" here
 208 bool MyApp::OnInit()
 209 {
 210     // create the main application window
 211     MyFrame *frame = new MyFrame(_T("Event wxWidgets Sample"),
 212                                  wxPoint(50, 50), wxSize(600, 340));
 213
 214     // and show it (the frames, unlike simple controls, are not shown when
 215     // created initially)
 216     frame->Show(true);
 217
 218     // success: wxApp::OnRun() will be called which will enter the main message
 219     // loop and the application will run. If we returned false here, the
 220     // application would exit immediately.
 221     return true;
 222 }
 223
 224 // ----------------------------------------------------------------------------
 225 // main frame
 226 // ----------------------------------------------------------------------------
 227
 228 // frame constructor
 229 MyFrame::MyFrame(const wxString& title, const wxPoint& pos, const wxSize& size)
 230        : wxFrame((wxFrame *)NULL, wxID_ANY, title, pos, size)
 231 {
 232     // init members
 233     m_nPush = 0;
 234
 235     // create a menu bar
 236     wxMenu *menuFile = new wxMenu;
 237
 238     menuFile->Append(Event_About, _T("&About...\tCtrl-A"), _T("Show about dialog"));
 239     menuFile->AppendSeparator();
 240     menuFile->Append(Event_Quit, _T("E&xit\tAlt-X"), _T("Quit this program"));
 241
 242     wxMenu *menuEvent = new wxMenu;
 243     menuEvent->Append(Event_Connect, _T("&Connect\tCtrl-C"),
 244                      _T("Connect or disconnect the dynamic event handler"),
 245                      true /* checkable */);
 246     menuEvent->Append(Event_Dynamic, _T("&Dynamic event\tCtrl-D"),
 247                       _T("Dynamic event sample - only works after Connect"));
 248     menuEvent->AppendSeparator();
 249     menuEvent->Append(Event_Push, _T("&Push event handler\tCtrl-P"),
 250                       _T("Push event handler for test event"));
 251     menuEvent->Append(Event_Pop, _T("P&op event handler\tCtrl-O"),
 252                       _T("Pop event handler for test event"));
 253     menuEvent->Append(Event_Test, _T("Test event\tCtrl-T"),
 254                       _T("Test event processed by pushed event handler"));
 255     menuEvent->AppendSeparator();
 256     menuEvent->Append(Event_Custom, _T("Fire c&ustom event\tCtrl-U"),
 257                       _T("Generate a custom event"));
 258
 259     // now append the freshly created menu to the menu bar...
 260     wxMenuBar *menuBar = new wxMenuBar();
 261     menuBar->Append(menuFile, _T("&File"));
 262     menuBar->Append(menuEvent, _T("&Event"));
 263
 264     // ... and attach this menu bar to the frame
 265     SetMenuBar(menuBar);
 266
 267 #if wxUSE_STATUSBAR
 268     CreateStatusBar(3);
 269     SetStatusText(_T("Welcome to wxWidgets event sample"));
 270     SetStatusText(_T("Dynamic: off"), Status_Dynamic);
 271     SetStatusText(_T("Push count: 0"), Status_Push);
 272 #endif // wxUSE_STATUSBAR
 273 }
 274
 275 MyFrame::~MyFrame()
 276 {
 277     // we must pop any remaining event handlers to avoid memory leaks and
 278     // crashes!
 279     while ( m_nPush-- != 0 )
 280     {
 281         PopEventHandler(true /* delete handler */);
 282     }
 283 }
 284
 285 // ----------------------------------------------------------------------------
 286 // standard event handlers
 287 // ----------------------------------------------------------------------------
 288
 289 void MyFrame::OnQuit(wxCommandEvent& WXUNUSED(event))
 290 {
 291     // true is to force the frame to close
 292     Close(true);
 293 }
 294
 295 void MyFrame::OnAbout(wxCommandEvent& WXUNUSED(event))
 296 {
 297     wxMessageBox( wxT("Event sample shows different ways of using events\n")
 298                   wxT("© 2001 Vadim Zeitlin"),
 299                   wxT("About Event Sample"), wxOK | wxICON_INFORMATION, this );
 300 }
 301
 302 // ----------------------------------------------------------------------------
 303 // dynamic event handling stuff
 304 // ----------------------------------------------------------------------------
 305
 306 void MyFrame::OnDynamic(wxCommandEvent& WXUNUSED(event))
 307 {
 308     wxMessageBox
 309     (
 310         wxT("This is a dynamic event handler which can be connected ")
 311         wxT("and disconnected at run-time."),
 312         wxT("Dynamic Event Handler"), wxOK | wxICON_INFORMATION, this
 313     );
 314 }
 315
 316 void MyFrame::OnConnect(wxCommandEvent& event)
 317 {
 318     if ( event.IsChecked() )
 319     {
 320         // disconnect
 321         Connect(Event_Dynamic, wxID_ANY, wxEVT_COMMAND_MENU_SELECTED,
 322                 (wxObjectEventFunction)
 323                 (wxEventFunction)
 324                 (wxCommandEventFunction)&MyFrame::OnDynamic);
 325
 326 #if wxUSE_STATUSBAR
 327         SetStatusText(_T("You can now use \"Dynamic\" item in the menu"));
 328         SetStatusText(_T("Dynamic: on"), Status_Dynamic);
 329 #endif // wxUSE_STATUSBAR
 330     }
 331     else // connect
 332     {
 333         Disconnect(Event_Dynamic, wxID_ANY, wxEVT_COMMAND_MENU_SELECTED);
 334
 335 #if wxUSE_STATUSBAR
 336         SetStatusText(_T("You can no more use \"Dynamic\" item in the menu"));
 337         SetStatusText(_T("Dynamic: off"), Status_Dynamic);
 338 #endif // wxUSE_STATUSBAR
 339     }
 340 }
 341
 342 // ----------------------------------------------------------------------------
 343 // push/pop event handlers support
 344 // ----------------------------------------------------------------------------
 345
 346 void MyFrame::OnPushEventHandler(wxCommandEvent& WXUNUSED(event))
 347 {
 348     PushEventHandler(new MyEvtHandler(++m_nPush));
 349
 350 #if wxUSE_STATUSBAR
 351     SetStatusText(wxString::Format(_T("Push count: %u"), m_nPush), Status_Push);
 352 #endif // wxUSE_STATUSBAR
 353 }
 354
 355 void MyFrame::OnPopEventHandler(wxCommandEvent& WXUNUSED(event))
 356 {
 357     wxCHECK_RET( m_nPush, _T("this command should be disabled!") );
 358
 359     PopEventHandler(true /* delete handler */);
 360     m_nPush--;
 361
 362 #if wxUSE_STATUSBAR
 363     SetStatusText(wxString::Format(_T("Push count: %u"), m_nPush), Status_Push);
 364 #endif // wxUSE_STATUSBAR
 365 }
 366
 367 void MyFrame::OnTest(wxCommandEvent& WXUNUSED(event))
 368 {
 369     wxLogMessage(_T("This is the test event handler in the main frame"));
 370 }
 371
 372 void MyFrame::OnUpdateUIPop(wxUpdateUIEvent& event)
 373 {
 374     event.Enable( m_nPush > 0 );
 375 }
 376
 377 // ----------------------------------------------------------------------------
 378 // custom event methods
 379 // ----------------------------------------------------------------------------
 380
 381 void MyFrame::OnFireCustom(wxCommandEvent& WXUNUSED(event))
 382 {
 383     wxCommandEvent eventCustom(wxEVT_MY_CUSTOM_COMMAND);
 384
 385     wxPostEvent(this, eventCustom);
 386 }
 387
 388 void MyFrame::OnProcessCustom(wxCommandEvent& WXUNUSED(event))
 389 {
 390     wxLogMessage(_T("Got a custom event!"));
 391 }
 392