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 // 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, -1, \
  63         (wxObjectEventFunction)(wxEventFunction)(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 wxWindows 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 wxWindows
 163 // ----------------------------------------------------------------------------
 164
 165 // the event tables connect the wxWindows 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(-1, MyFrame::OnProcessCustom)
 182
 183     // this would also work:
 184     //EVT_CUSTOM(wxEVT_MY_CUSTOM_COMMAND, -1, MyFrame::OnProcessCustom)
 185 END_EVENT_TABLE()
 186
 187 BEGIN_EVENT_TABLE(MyEvtHandler, wxEvtHandler)
 188     EVT_MENU(Event_Test, MyEvtHandler::OnTest)
 189 END_EVENT_TABLE()
 190
 191 // Create a new application object: this macro will allow wxWindows to create
 192 // the application object during program execution (it's better than using a
 193 // static object for many reasons) and also declares the accessor function
 194 // wxGetApp() which will return the reference of the right type (i.e. MyApp and
 195 // not wxApp)
 196 IMPLEMENT_APP(MyApp)
 197
 198 // ============================================================================
 199 // implementation
 200 // ============================================================================
 201
 202 // ----------------------------------------------------------------------------
 203 // the application class
 204 // ----------------------------------------------------------------------------
 205
 206 // 'Main program' equivalent: the program execution "starts" here
 207 bool MyApp::OnInit()
 208 {
 209     // create the main application window
 210     MyFrame *frame = new MyFrame(_T("Event wxWindows Sample"),
 211                                  wxPoint(50, 50), wxSize(600, 340));
 212
 213     // and show it (the frames, unlike simple controls, are not shown when
 214     // created initially)
 215     frame->Show(TRUE);
 216
 217     // success: wxApp::OnRun() will be called which will enter the main message
 218     // loop and the application will run. If we returned FALSE here, the
 219     // application would exit immediately.
 220     return TRUE;
 221 }
 222
 223 // ----------------------------------------------------------------------------
 224 // main frame
 225 // ----------------------------------------------------------------------------
 226
 227 // frame constructor
 228 MyFrame::MyFrame(const wxString& title, const wxPoint& pos, const wxSize& size)
 229        : wxFrame((wxFrame *)NULL, -1, title, pos, size)
 230 {
 231     // init members
 232     m_nPush = 0;
 233
 234     // create a menu bar
 235     wxMenu *menuFile = new wxMenu;
 236
 237     menuFile->Append(Event_About, _T("&About...\tCtrl-A"), _T("Show about dialog"));
 238     menuFile->AppendSeparator();
 239     menuFile->Append(Event_Quit, _T("E&xit\tAlt-X"), _T("Quit this program"));
 240
 241     wxMenu *menuEvent = new wxMenu;
 242     menuEvent->Append(Event_Connect, _T("&Connect\tCtrl-C"),
 243                      _T("Connect or disconnect the dynamic event handler"),
 244                      TRUE /* checkable */);
 245     menuEvent->Append(Event_Dynamic, _T("&Dynamic event\tCtrl-D"),
 246                       _T("Dynamic event sample - only works after Connect"));
 247     menuEvent->AppendSeparator();
 248     menuEvent->Append(Event_Push, _T("&Push event handler\tCtrl-P"),
 249                       _T("Push event handler for test event"));
 250     menuEvent->Append(Event_Pop, _T("P&op event handler\tCtrl-O"),
 251                       _T("Pop event handler for test event"));
 252     menuEvent->Append(Event_Test, _T("Test event\tCtrl-T"),
 253                       _T("Test event processed by pushed event handler"));
 254     menuEvent->AppendSeparator();
 255     menuEvent->Append(Event_Custom, _T("Fire c&ustom event\tCtrl-U"),
 256                       _T("Generate a custom event"));
 257
 258     // now append the freshly created menu to the menu bar...
 259     wxMenuBar *menuBar = new wxMenuBar();
 260     menuBar->Append(menuFile, _T("&File"));
 261     menuBar->Append(menuEvent, _T("&Event"));
 262
 263     // ... and attach this menu bar to the frame
 264     SetMenuBar(menuBar);
 265
 266 #if wxUSE_STATUSBAR
 267     CreateStatusBar(3);
 268     SetStatusText(_T("Welcome to wxWindows event sample"));
 269     SetStatusText(_T("Dynamic: off"), Status_Dynamic);
 270     SetStatusText(_T("Push count: 0"), Status_Push);
 271 #endif // wxUSE_STATUSBAR
 272 }
 273
 274 MyFrame::~MyFrame()
 275 {
 276     // we must pop any remaining event handlers to avoid memory leaks and
 277     // crashes!
 278     while ( m_nPush-- != 0 )
 279     {
 280         PopEventHandler(TRUE /* delete handler */);
 281     }
 282 }
 283
 284 // ----------------------------------------------------------------------------
 285 // standard event handlers
 286 // ----------------------------------------------------------------------------
 287
 288 void MyFrame::OnQuit(wxCommandEvent& WXUNUSED(event))
 289 {
 290     // TRUE is to force the frame to close
 291     Close(TRUE);
 292 }
 293
 294 void MyFrame::OnAbout(wxCommandEvent& WXUNUSED(event))
 295 {
 296     wxMessageBox( wxT("Event sample shows different ways of using events\n")
 297                   wxT("© 2001 Vadim Zeitlin"),
 298                   wxT("About Event Sample"), wxOK | wxICON_INFORMATION, this );
 299 }
 300
 301 // ----------------------------------------------------------------------------
 302 // dynamic event handling stuff
 303 // ----------------------------------------------------------------------------
 304
 305 void MyFrame::OnDynamic(wxCommandEvent& WXUNUSED(event))
 306 {
 307     wxMessageBox
 308     (
 309         wxT("This is a dynamic event handler which can be connected ")
 310         wxT("and disconnected at run-time."),
 311         wxT("Dynamic Event Handler"), wxOK | wxICON_INFORMATION, this
 312     );
 313 }
 314
 315 void MyFrame::OnConnect(wxCommandEvent& event)
 316 {
 317     if ( event.IsChecked() )
 318     {
 319         // disconnect
 320         Connect(Event_Dynamic, -1, wxEVT_COMMAND_MENU_SELECTED,
 321                 (wxObjectEventFunction)
 322                 (wxEventFunction)
 323                 (wxCommandEventFunction)&MyFrame::OnDynamic);
 324
 325         SetStatusText(_T("You can now use \"Dynamic\" item in the menu"));
 326         SetStatusText(_T("Dynamic: on"), Status_Dynamic);
 327     }
 328     else // connect
 329     {
 330         Disconnect(Event_Dynamic, -1, wxEVT_COMMAND_MENU_SELECTED);
 331
 332         SetStatusText(_T("You can no more use \"Dynamic\" item in the menu"));
 333         SetStatusText(_T("Dynamic: off"), Status_Dynamic);
 334     }
 335 }
 336
 337 // ----------------------------------------------------------------------------
 338 // push/pop event handlers support
 339 // ----------------------------------------------------------------------------
 340
 341 void MyFrame::OnPushEventHandler(wxCommandEvent& WXUNUSED(event))
 342 {
 343     PushEventHandler(new MyEvtHandler(++m_nPush));
 344
 345     SetStatusText(wxString::Format(_T("Push count: %u"), m_nPush), Status_Push);
 346 }
 347
 348 void MyFrame::OnPopEventHandler(wxCommandEvent& WXUNUSED(event))
 349 {
 350     wxCHECK_RET( m_nPush, _T("this command should be disabled!") );
 351
 352     PopEventHandler(TRUE /* delete handler */);
 353     m_nPush--;
 354
 355     SetStatusText(wxString::Format(_T("Push count: %u"), m_nPush), Status_Push);
 356 }
 357
 358 void MyFrame::OnTest(wxCommandEvent& event)
 359 {
 360     wxLogMessage(_T("This is the test event handler in the main frame"));
 361 }
 362
 363 void MyFrame::OnUpdateUIPop(wxUpdateUIEvent& event)
 364 {
 365     event.Enable( m_nPush > 0 );
 366 }
 367
 368 // ----------------------------------------------------------------------------
 369 // custom event methods
 370 // ----------------------------------------------------------------------------
 371
 372 void MyFrame::OnFireCustom(wxCommandEvent& event)
 373 {
 374     wxCommandEvent eventCustom(wxEVT_MY_CUSTOM_COMMAND);
 375
 376     wxPostEvent(this, eventCustom);
 377 }
 378
 379 void MyFrame::OnProcessCustom(wxCommandEvent& event)
 380 {
 381     wxLogMessage(_T("Got a custom event!"));
 382 }
 383