1\section{Writing a wxWidgets application: a rough guide}\label{roughguide} 2 3To set a wxWidgets application going, you will need to derive a \helpref{wxApp}{wxapp} class and 4override \helpref{wxApp::OnInit}{wxapponinit}. 5 6An application must have a top-level \helpref{wxFrame}{wxframe} or \helpref{wxDialog}{wxdialog} window. 7Each frame may contain one or more instances of classes such as \helpref{wxPanel}{wxpanel}, \helpref{wxSplitterWindow}{wxsplitterwindow}\rtfsp 8or other windows and controls. 9 10A frame can have a \helpref{wxMenuBar}{wxmenubar}, a \helpref{wxToolBar}{wxtoolbar}, a status line, and a \helpref{wxIcon}{wxicon} for 11when the frame is iconized. 12 13A \helpref{wxPanel}{wxpanel} is used to place controls (classes derived from \helpref{wxControl}{wxcontrol}) 14which are used for user interaction. Examples of controls are \helpref{wxButton}{wxbutton}, 15\rtfsp\helpref{wxCheckBox}{wxcheckbox}, \helpref{wxChoice}{wxchoice}, \helpref{wxListBox}{wxlistbox}, 16\rtfsp\helpref{wxRadioBox}{wxradiobox}, \helpref{wxSlider}{wxslider}. 17 18Instances of \helpref{wxDialog}{wxdialog} can also be used for controls and they have 19the advantage of not requiring a separate frame. 20 21Instead of creating a dialog box and populating it with items, it is possible to choose 22one of the convenient common dialog classes, such as \helpref{wxMessageDialog}{wxmessagedialog}\rtfsp 23and \helpref{wxFileDialog}{wxfiledialog}. 24 25You never draw directly onto a window - you use a {\it device context} (DC). \helpref{wxDC}{wxdc} is 26the base for \helpref{wxClientDC}{wxclientdc}, \helpref{wxPaintDC}{wxpaintdc}, \helpref{wxMemoryDC}{wxmemorydc}, \helpref{wxPostScriptDC}{wxpostscriptdc}, 27\rtfsp\helpref{wxMemoryDC}{wxmemorydc}, \helpref{wxMetafileDC}{wxmetafiledc} and \helpref{wxPrinterDC}{wxprinterdc}. 28If your drawing functions have {\bf wxDC} as a parameter, you can pass any of these DCs 29to the function, and thus use the same code to draw to several different devices. 30You can draw using the member functions of {\bf wxDC}, such as \helpref{wxDC::DrawLine}{wxdcdrawline}\rtfsp 31and \helpref{wxDC::DrawText}{wxdcdrawtext}. Control colour on a window (\helpref{wxColour}{wxcolour}) with 32brushes (\helpref{wxBrush}{wxbrush}) and pens (\helpref{wxPen}{wxpen}). 33 34To intercept events, you add a DECLARE\_EVENT\_TABLE macro to the window class declaration, 35and put a BEGIN\_EVENT\_TABLE ... END\_EVENT\_TABLE block in the implementation file. Between these 36macros, you add event macros which map the event (such as a mouse click) to a member function. 37These might override predefined event handlers such as for \helpref{wxKeyEvent}{wxkeyevent} and 38\rtfsp\helpref{wxMouseEvent}{wxmouseevent}. 39 40Most modern applications will have an on-line, hypertext help system; for this, you 41need wxHelp and the \helpref{wxHelpController}{wxhelpcontroller} class to control 42wxHelp. 43 44GUI applications aren't all graphical wizardry. List and hash table needs are 45catered for by \helpref{wxList}{wxlist} and \helpref{wxHashMap}{wxhashmap}. 46You will undoubtedly need some platform-independent \helpref{file functions}{filefunctions}, 47and you may find it handy to maintain and search a list of paths using \helpref{wxPathList}{wxpathlist}. 48There's a \helpref{miscellany}{miscellany} of operating system and other functions. 49 50See also \helpref{Classes by Category}{classesbycat} for a list of classes. 51 52