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