samples/except/except.cpp

   1 /////////////////////////////////////////////////////////////////////////////
   2 // Name:        except.cpp
   3 // Purpose:     Except wxWidgets sample
   4 // Author:      Julian Smart
   5 // Modified by:
   6 // Created:     04/01/98
   7 // RCS-ID:      $Id$
   8 // Copyright:   (c) Julian Smart
   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/log.h"
  31
  32     #include "wx/app.h"
  33     #include "wx/frame.h"
  34     #include "wx/dialog.h"
  35     #include "wx/menu.h"
  36
  37     #include "wx/button.h"
  38     #include "wx/sizer.h"
  39
  40     #include "wx/utils.h"
  41     #include "wx/msgdlg.h"
  42 #endif
  43
  44 // ----------------------------------------------------------------------------
  45 // resources
  46 // ----------------------------------------------------------------------------
  47
  48 // the application icon (under Windows and OS/2 it is in resources)
  49 #if defined(__WXGTK__) || defined(__WXMOTIF__) || defined(__WXMAC__) || defined(__WXMGL__) || defined(__WXX11__)
  50     #include "../sample.xpm"
  51 #endif
  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     // program startup
  65     virtual bool OnInit();
  66
  67     // 2nd-level exception handling: we get all the exceptions occuring in any
  68     // event handler here
  69     virtual void HandleEvent(wxEvtHandler *handler,
  70                              wxEventFunction func,
  71                              wxEvent& event) const;
  72
  73     // 3rd, and final, level exception handling: whenever an unhandled
  74     // exception is caught, this function is called
  75     virtual void OnUnhandledException();
  76 };
  77
  78 // Define a new frame type: this is going to be our main frame
  79 class MyFrame : public wxFrame
  80 {
  81 public:
  82     // ctor(s)
  83     MyFrame(const wxString& title, const wxPoint& pos, const wxSize& size,
  84             long style = wxDEFAULT_FRAME_STYLE);
  85
  86     // event handlers (these functions should _not_ be virtual)
  87     void OnQuit(wxCommandEvent& event);
  88     void OnAbout(wxCommandEvent& event);
  89     void OnDialog(wxCommandEvent& event);
  90     void OnThrowString(wxCommandEvent& event);
  91
  92     // 1st-level exception handling: we overload ProcessEvent() to be able to
  93     // catch exceptions which occur in MyFrame methods here
  94     virtual bool ProcessEvent(wxEvent& event);
  95
  96 private:
  97     // any class wishing to process wxWidgets events must use this macro
  98     DECLARE_EVENT_TABLE()
  99 };
 100
 101 // A simple dialog which has only some buttons to throw exceptions
 102 class MyDialog : public wxDialog
 103 {
 104 public:
 105     MyDialog(wxFrame *parent);
 106
 107     // event handlers
 108     void OnThrowInt(wxCommandEvent& event);
 109     void OnThrowObject(wxCommandEvent& event);
 110
 111 private:
 112     DECLARE_EVENT_TABLE()
 113 };
 114
 115 // A trivial exception class
 116 class MyException
 117 {
 118 public:
 119     MyException(const wxString& msg) : m_msg(msg) { }
 120
 121     const wxChar *what() const { return m_msg.c_str(); }
 122
 123 private:
 124     wxString m_msg;
 125 };
 126
 127 // ----------------------------------------------------------------------------
 128 // constants
 129 // ----------------------------------------------------------------------------
 130
 131 // IDs for the controls and the menu commands
 132 enum
 133 {
 134     // control ids
 135     Except_ThrowInt = 100,
 136     Except_ThrowObject,
 137
 138     // menu items
 139     Except_ThrowString = 200,
 140     Except_Dialog,
 141
 142     Except_Quit = wxID_EXIT,
 143     Except_About = wxID_ABOUT
 144 };
 145
 146 // ----------------------------------------------------------------------------
 147 // event tables and other macros for wxWidgets
 148 // ----------------------------------------------------------------------------
 149
 150 // the event tables connect the wxWidgets events with the functions (event
 151 // handlers) which process them. It can be also done at run-time, but for the
 152 // simple menu events like this the static method is much simpler.
 153 BEGIN_EVENT_TABLE(MyFrame, wxFrame)
 154     EVT_MENU(Except_Quit,  MyFrame::OnQuit)
 155     EVT_MENU(Except_About, MyFrame::OnAbout)
 156     EVT_MENU(Except_Dialog, MyFrame::OnDialog)
 157     EVT_MENU(Except_ThrowString, MyFrame::OnThrowString)
 158 END_EVENT_TABLE()
 159
 160 BEGIN_EVENT_TABLE(MyDialog, wxDialog)
 161     EVT_BUTTON(Except_ThrowInt, MyDialog::OnThrowInt)
 162     EVT_BUTTON(Except_ThrowObject, MyDialog::OnThrowObject)
 163 END_EVENT_TABLE()
 164
 165 // Create a new application object: this macro will allow wxWidgets to create
 166 // the application object during program execution (it's better than using a
 167 // static object for many reasons) and also implements the accessor function
 168 // wxGetApp() which will return the reference of the right type (i.e. MyApp and
 169 // not wxApp)
 170 IMPLEMENT_APP(MyApp)
 171
 172 // ============================================================================
 173 // MyApp implementation
 174 // ============================================================================
 175
 176 // 'Main program' equivalent: the program execution "starts" here
 177 bool MyApp::OnInit()
 178 {
 179     // create the main application window
 180     MyFrame *frame = new MyFrame(_T("Except wxWidgets App"),
 181                                  wxPoint(50, 50), wxSize(450, 340));
 182
 183     // and show it (the frames, unlike simple controls, are not shown when
 184     // created initially)
 185     frame->Show(true);
 186
 187     // success: wxApp::OnRun() will be called which will enter the main message
 188     // loop and the application will run. If we returned false here, the
 189     // application would exit immediately.
 190     return true;
 191 }
 192
 193 void
 194 MyApp::HandleEvent(wxEvtHandler *handler,
 195                    wxEventFunction func,
 196                    wxEvent& event) const
 197 {
 198     try
 199     {
 200         wxApp::HandleEvent(handler, func, event);
 201     }
 202     catch ( int i )
 203     {
 204         wxLogError(_T("Caught an int %d in MyApp."), i);
 205     }
 206 }
 207
 208 void MyApp::OnUnhandledException()
 209 {
 210     wxMessageBox(_T("Unhandled exception caught, program will terminate."),
 211                  _T("wxExcept Sample"), wxOK | wxICON_ERROR);
 212 }
 213
 214 // ============================================================================
 215 // MyFrame implementation
 216 // ============================================================================
 217
 218 // frame constructor
 219 MyFrame::MyFrame(const wxString& title, const wxPoint& pos, const wxSize& size, long style)
 220        : wxFrame(NULL, wxID_ANY, title, pos, size, style)
 221 {
 222     // set the frame icon
 223     SetIcon(wxICON(mondrian));
 224
 225 #if wxUSE_MENUS
 226     // create a menu bar
 227     wxMenu *menuFile = new wxMenu;
 228     menuFile->Append(Except_Dialog, _T("Show &dialog\tCtrl-D"));
 229     menuFile->Append(Except_ThrowString, _T("Throw a &string\tCtrl-S"));
 230     menuFile->AppendSeparator();
 231     menuFile->Append(Except_Quit, _T("E&xit\tCtrl-Q"), _T("Quit this program"));
 232
 233     wxMenu *helpMenu = new wxMenu;
 234     helpMenu->Append(Except_About, _T("&About...\tF1"), _T("Show about dialog"));
 235
 236     // now append the freshly created menu to the menu bar...
 237     wxMenuBar *menuBar = new wxMenuBar();
 238     menuBar->Append(menuFile, _T("&File"));
 239     menuBar->Append(helpMenu, _T("&Help"));
 240
 241     // ... and attach this menu bar to the frame
 242     SetMenuBar(menuBar);
 243 #endif // wxUSE_MENUS
 244
 245 #if wxUSE_STATUSBAR && !defined(__WXWINCE__)
 246     // create a status bar just for fun (by default with 1 pane only)
 247     CreateStatusBar(2);
 248     SetStatusText(_T("Welcome to wxWidgets!"));
 249 #endif // wxUSE_STATUSBAR
 250 }
 251
 252 bool MyFrame::ProcessEvent(wxEvent& event)
 253 {
 254     try
 255     {
 256         return wxFrame::ProcessEvent(event);
 257     }
 258     catch ( const wxChar *msg )
 259     {
 260         wxLogMessage(_T("Caught a string \"%s\" in MyFrame"), msg);
 261
 262         return true;
 263     }
 264 }
 265
 266 void MyFrame::OnQuit(wxCommandEvent& WXUNUSED(event))
 267 {
 268     // true is to force the frame to close
 269     Close(true);
 270 }
 271
 272 void MyFrame::OnDialog(wxCommandEvent& WXUNUSED(event))
 273 {
 274     try
 275     {
 276         MyDialog dlg(this);
 277
 278         dlg.ShowModal();
 279     }
 280     catch ( ... )
 281     {
 282         Destroy();
 283         throw;
 284     }
 285 }
 286
 287 void MyFrame::OnThrowString(wxCommandEvent& WXUNUSED(event))
 288 {
 289     throw _T("some string");
 290 }
 291
 292 void MyFrame::OnAbout(wxCommandEvent& WXUNUSED(event))
 293 {
 294     wxString msg;
 295     msg.Printf( _T("This is the About dialog of the except sample.\n")
 296                 _T("Welcome to %s"), wxVERSION_STRING);
 297
 298     wxMessageBox(msg, _T("About Except"), wxOK | wxICON_INFORMATION, this);
 299 }
 300
 301 // ============================================================================
 302 // MyDialog implementation
 303 // ============================================================================
 304
 305 MyDialog::MyDialog(wxFrame *parent)
 306         : wxDialog(parent, wxID_ANY, wxString(_T("Throw exception dialog")))
 307 {
 308     wxSizer *sizerTop = new wxBoxSizer(wxVERTICAL);
 309
 310     sizerTop->Add(new wxButton(this, Except_ThrowInt, _T("Throw &int")),
 311                   0, wxCENTRE | wxALL, 5);
 312     sizerTop->Add(new wxButton(this, Except_ThrowObject, _T("Throw &object")),
 313                   0, wxCENTRE | wxALL, 5);
 314     sizerTop->Add(new wxButton(this, wxID_CANCEL, _T("&Cancel")),
 315                   0, wxCENTRE | wxALL, 5);
 316
 317     SetSizer(sizerTop);
 318     sizerTop->Fit(this);
 319 }
 320
 321 void MyDialog::OnThrowInt(wxCommandEvent& WXUNUSED(event))
 322 {
 323     throw 17;
 324 }
 325
 326 void MyDialog::OnThrowObject(wxCommandEvent& WXUNUSED(event))
 327 {
 328     throw MyException(_T("Exception thrown from the dialog"));
 329 }
 330