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