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 // For compilers that support precompilation, includes "wx/wx.h".
  21 #include "wx/wxprec.h"
  22
  23 #ifdef __BORLANDC__
  24     #pragma hdrstop
  25 #endif
  26
  27 // for all others, include the necessary headers (this file is usually all you
  28 // need because it includes almost all "standard" wxWidgets headers)
  29 #ifndef WX_PRECOMP
  30     #include "wx/wx.h"
  31 #endif
  32
  33 // ----------------------------------------------------------------------------
  34 // event constants
  35 // ----------------------------------------------------------------------------
  36
  37 // declare a custom event type
  38 //
  39 // note that in wxWin 2.3+ these macros expand simply into the following code:
  40 //
  41 //  extern const wxEventType wxEVT_MY_CUSTOM_COMMAND;
  42 //
  43 //  const wxEventType wxEVT_MY_CUSTOM_COMMAND = wxNewEventType();
  44 //
  45 // and you may use this code directly if you don't care about 2.2 compatibility
  46 BEGIN_DECLARE_EVENT_TYPES()
  47     DECLARE_EVENT_TYPE(wxEVT_MY_CUSTOM_COMMAND, 7777)
  48 END_DECLARE_EVENT_TYPES()
  49
  50 DEFINE_EVENT_TYPE(wxEVT_MY_CUSTOM_COMMAND)
  51
  52 // it may also be convenient to define an event table macro for this event type
  53 #define EVT_MY_CUSTOM_COMMAND(id, fn) \
  54     DECLARE_EVENT_TABLE_ENTRY( \
  55         wxEVT_MY_CUSTOM_COMMAND, id, wxID_ANY, \
  56         (wxObjectEventFunction)(wxEventFunction) wxStaticCastEvent( wxCommandEventFunction, &fn ), \
  57         (wxObject *) NULL \
  58     ),
  59
  60 // ----------------------------------------------------------------------------
  61 // private classes
  62 // ----------------------------------------------------------------------------
  63
  64 // Define a new application type, each program should derive a class from wxApp
  65 class MyApp : public wxApp
  66 {
  67 public:
  68     // override base class virtuals
  69     // ----------------------------
  70
  71     // this one is called on application startup and is a good place for the app
  72     // initialization (doing it here and not in the ctor allows to have an error
  73     // return: if OnInit() returns false, the application terminates)
  74     virtual bool OnInit();
  75 };
  76
  77 // Define a new frame type: this is going to be our main frame
  78 class MyFrame : public wxFrame
  79 {
  80 public:
  81     // ctor(s)
  82     MyFrame(const wxString& title, const wxPoint& pos, const wxSize& size);
  83     virtual ~MyFrame();
  84
  85     void OnQuit(wxCommandEvent& event);
  86     void OnAbout(wxCommandEvent& event);
  87     void OnConnect(wxCommandEvent& event);
  88     void OnDynamic(wxCommandEvent& event);
  89     void OnPushEventHandler(wxCommandEvent& event);
  90     void OnPopEventHandler(wxCommandEvent& event);
  91     void OnTest(wxCommandEvent& event);
  92
  93     void OnFireCustom(wxCommandEvent& event);
  94     void OnProcessCustom(wxCommandEvent& event);
  95
  96     void OnUpdateUIPop(wxUpdateUIEvent& event);
  97
  98 protected:
  99     // number of pushed event handlers
 100     unsigned m_nPush;
 101
 102 private:
 103     // any class wishing to process wxWidgets events must use this macro
 104     DECLARE_EVENT_TABLE()
 105 };
 106
 107 // Define a custom event handler
 108 class MyEvtHandler : public wxEvtHandler
 109 {
 110 public:
 111     MyEvtHandler(size_t level) { m_level = level; }
 112
 113     void OnTest(wxCommandEvent& event)
 114     {
 115         wxLogMessage(_T("This is the pushed test event handler #%u"), m_level);
 116
 117         // if we don't skip the event, the other event handlers won't get it:
 118         // try commenting out this line and see what changes
 119         event.Skip();
 120     }
 121
 122 private:
 123     unsigned m_level;
 124
 125     DECLARE_EVENT_TABLE()
 126 };
 127
 128 // ----------------------------------------------------------------------------
 129 // constants
 130 // ----------------------------------------------------------------------------
 131
 132 // IDs for the controls and the menu commands
 133 enum
 134 {
 135     // menu items
 136     Event_Quit = 1,
 137     Event_About,
 138     Event_Connect,
 139     Event_Dynamic,
 140     Event_Push,
 141     Event_Pop,
 142     Event_Custom,
 143     Event_Test
 144 };
 145
 146 // status bar fields
 147 enum
 148 {
 149     Status_Main = 0,
 150     Status_Dynamic,
 151     Status_Push
 152 };
 153
 154 // ----------------------------------------------------------------------------
 155 // event tables and other macros for wxWidgets
 156 // ----------------------------------------------------------------------------
 157
 158 // the event tables connect the wxWidgets events with the functions (event
 159 // handlers) which process them. It can be also done at run-time, but for the
 160 // simple menu events like this the static method is much simpler.
 161 BEGIN_EVENT_TABLE(MyFrame, wxFrame)
 162     EVT_MENU(Event_Quit,  MyFrame::OnQuit)
 163     EVT_MENU(Event_About, MyFrame::OnAbout)
 164
 165     EVT_MENU(Event_Connect, MyFrame::OnConnect)
 166
 167     EVT_MENU(Event_Custom, MyFrame::OnFireCustom)
 168     EVT_MENU(Event_Test, MyFrame::OnTest)
 169     EVT_MENU(Event_Push, MyFrame::OnPushEventHandler)
 170     EVT_MENU(Event_Pop, MyFrame::OnPopEventHandler)
 171
 172     EVT_UPDATE_UI(Event_Pop, MyFrame::OnUpdateUIPop)
 173
 174     EVT_MY_CUSTOM_COMMAND(wxID_ANY, MyFrame::OnProcessCustom)
 175
 176     // the line below would also work if OnProcessCustom() were defined as
 177     // taking a wxEvent (as required by EVT_CUSTOM) and not wxCommandEvent
 178     //EVT_CUSTOM(wxEVT_MY_CUSTOM_COMMAND, wxID_ANY, MyFrame::OnProcessCustom)
 179 END_EVENT_TABLE()
 180
 181 BEGIN_EVENT_TABLE(MyEvtHandler, wxEvtHandler)
 182     EVT_MENU(Event_Test, MyEvtHandler::OnTest)
 183 END_EVENT_TABLE()
 184
 185 // Create a new application object: this macro will allow wxWidgets to create
 186 // the application object during program execution (it's better than using a
 187 // static object for many reasons) and also declares the accessor function
 188 // wxGetApp() which will return the reference of the right type (i.e. MyApp and
 189 // not wxApp)
 190 IMPLEMENT_APP(MyApp)
 191
 192 // ============================================================================
 193 // implementation
 194 // ============================================================================
 195
 196 // ----------------------------------------------------------------------------
 197 // the application class
 198 // ----------------------------------------------------------------------------
 199
 200 // 'Main program' equivalent: the program execution "starts" here
 201 bool MyApp::OnInit()
 202 {
 203     if ( !wxApp::OnInit() )
 204         return false;
 205
 206     // create the main application window
 207     MyFrame *frame = new MyFrame(_T("Event wxWidgets Sample"),
 208                                  wxPoint(50, 50), wxSize(600, 340));
 209
 210     // and show it (the frames, unlike simple controls, are not shown when
 211     // created initially)
 212     frame->Show(true);
 213
 214     // success: wxApp::OnRun() will be called which will enter the main message
 215     // loop and the application will run. If we returned false here, the
 216     // application would exit immediately.
 217     return true;
 218 }
 219
 220 // ----------------------------------------------------------------------------
 221 // main frame
 222 // ----------------------------------------------------------------------------
 223
 224 // frame constructor
 225 MyFrame::MyFrame(const wxString& title, const wxPoint& pos, const wxSize& size)
 226        : wxFrame((wxFrame *)NULL, wxID_ANY, title, pos, size)
 227 {
 228     // init members
 229     m_nPush = 0;
 230
 231     // create a menu bar
 232     wxMenu *menuFile = new wxMenu;
 233
 234     menuFile->Append(Event_About, _T("&About...\tCtrl-A"), _T("Show about dialog"));
 235     menuFile->AppendSeparator();
 236     menuFile->Append(Event_Quit, _T("E&xit\tAlt-X"), _T("Quit this program"));
 237
 238     wxMenu *menuEvent = new wxMenu;
 239     menuEvent->Append(Event_Connect, _T("&Connect\tCtrl-C"),
 240                      _T("Connect or disconnect the dynamic event handler"),
 241                      true /* checkable */);
 242     menuEvent->Append(Event_Dynamic, _T("&Dynamic event\tCtrl-D"),
 243                       _T("Dynamic event sample - only works after Connect"));
 244     menuEvent->AppendSeparator();
 245     menuEvent->Append(Event_Push, _T("&Push event handler\tCtrl-P"),
 246                       _T("Push event handler for test event"));
 247     menuEvent->Append(Event_Pop, _T("P&op event handler\tCtrl-O"),
 248                       _T("Pop event handler for test event"));
 249     menuEvent->Append(Event_Test, _T("Test event\tCtrl-T"),
 250                       _T("Test event processed by pushed event handler"));
 251     menuEvent->AppendSeparator();
 252     menuEvent->Append(Event_Custom, _T("Fire c&ustom event\tCtrl-U"),
 253                       _T("Generate a custom event"));
 254
 255     // now append the freshly created menu to the menu bar...
 256     wxMenuBar *menuBar = new wxMenuBar();
 257     menuBar->Append(menuFile, _T("&File"));
 258     menuBar->Append(menuEvent, _T("&Event"));
 259
 260     // ... and attach this menu bar to the frame
 261     SetMenuBar(menuBar);
 262
 263 #if wxUSE_STATUSBAR
 264     CreateStatusBar(3);
 265     SetStatusText(_T("Welcome to wxWidgets event sample"));
 266     SetStatusText(_T("Dynamic: off"), Status_Dynamic);
 267     SetStatusText(_T("Push count: 0"), Status_Push);
 268 #endif // wxUSE_STATUSBAR
 269 }
 270
 271 MyFrame::~MyFrame()
 272 {
 273     // we must pop any remaining event handlers to avoid memory leaks and
 274     // crashes!
 275     while ( m_nPush-- != 0 )
 276     {
 277         PopEventHandler(true /* delete handler */);
 278     }
 279 }
 280
 281 // ----------------------------------------------------------------------------
 282 // standard event handlers
 283 // ----------------------------------------------------------------------------
 284
 285 void MyFrame::OnQuit(wxCommandEvent& WXUNUSED(event))
 286 {
 287     // true is to force the frame to close
 288     Close(true);
 289 }
 290
 291 void MyFrame::OnAbout(wxCommandEvent& WXUNUSED(event))
 292 {
 293     wxMessageBox( wxT("Event sample shows different ways of using events\n")
 294                   wxT("(c) 2001 Vadim Zeitlin"),
 295                   wxT("About Event Sample"), wxOK | wxICON_INFORMATION, this );
 296 }
 297
 298 // ----------------------------------------------------------------------------
 299 // dynamic event handling stuff
 300 // ----------------------------------------------------------------------------
 301
 302 void MyFrame::OnDynamic(wxCommandEvent& WXUNUSED(event))
 303 {
 304     wxMessageBox
 305     (
 306         wxT("This is a dynamic event handler which can be connected ")
 307         wxT("and disconnected at run-time."),
 308         wxT("Dynamic Event Handler"), wxOK | wxICON_INFORMATION, this
 309     );
 310 }
 311
 312 void MyFrame::OnConnect(wxCommandEvent& event)
 313 {
 314     if ( event.IsChecked() )
 315     {
 316         // disconnect
 317         Connect(Event_Dynamic, wxID_ANY, wxEVT_COMMAND_MENU_SELECTED,
 318                 (wxObjectEventFunction)
 319                 (wxEventFunction)
 320                 (wxCommandEventFunction)&MyFrame::OnDynamic);
 321
 322 #if wxUSE_STATUSBAR
 323         SetStatusText(_T("You can now use \"Dynamic\" item in the menu"));
 324         SetStatusText(_T("Dynamic: on"), Status_Dynamic);
 325 #endif // wxUSE_STATUSBAR
 326     }
 327     else // connect
 328     {
 329         Disconnect(Event_Dynamic, wxID_ANY, wxEVT_COMMAND_MENU_SELECTED);
 330
 331 #if wxUSE_STATUSBAR
 332         SetStatusText(_T("You can no more use \"Dynamic\" item in the menu"));
 333         SetStatusText(_T("Dynamic: off"), Status_Dynamic);
 334 #endif // wxUSE_STATUSBAR
 335     }
 336 }
 337
 338 // ----------------------------------------------------------------------------
 339 // push/pop event handlers support
 340 // ----------------------------------------------------------------------------
 341
 342 void MyFrame::OnPushEventHandler(wxCommandEvent& WXUNUSED(event))
 343 {
 344     PushEventHandler(new MyEvtHandler(++m_nPush));
 345
 346 #if wxUSE_STATUSBAR
 347     SetStatusText(wxString::Format(_T("Push count: %u"), m_nPush), Status_Push);
 348 #endif // wxUSE_STATUSBAR
 349 }
 350
 351 void MyFrame::OnPopEventHandler(wxCommandEvent& WXUNUSED(event))
 352 {
 353     wxCHECK_RET( m_nPush, _T("this command should be disabled!") );
 354
 355     PopEventHandler(true /* delete handler */);
 356     m_nPush--;
 357
 358 #if wxUSE_STATUSBAR
 359     SetStatusText(wxString::Format(_T("Push count: %u"), m_nPush), Status_Push);
 360 #endif // wxUSE_STATUSBAR
 361 }
 362
 363 void MyFrame::OnTest(wxCommandEvent& WXUNUSED(event))
 364 {
 365     wxLogMessage(_T("This is the test event handler in the main frame"));
 366 }
 367
 368 void MyFrame::OnUpdateUIPop(wxUpdateUIEvent& event)
 369 {
 370     event.Enable( m_nPush > 0 );
 371 }
 372
 373 // ----------------------------------------------------------------------------
 374 // custom event methods
 375 // ----------------------------------------------------------------------------
 376
 377 void MyFrame::OnFireCustom(wxCommandEvent& WXUNUSED(event))
 378 {
 379     wxCommandEvent eventCustom(wxEVT_MY_CUSTOM_COMMAND);
 380
 381     wxPostEvent(this, eventCustom);
 382 }
 383
 384 void MyFrame::OnProcessCustom(wxCommandEvent& WXUNUSED(event))
 385 {
 386     wxLogMessage(_T("Got a custom event!"));
 387 }
 388