f4fcc29197
Added initial artprov.tex. Sorted out duff references. git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@15035 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775
57 lines
2.1 KiB
TeX
57 lines
2.1 KiB
TeX
\section{wxApp overview}\label{wxappoverview}
|
|
|
|
Classes: \helpref{wxApp}{wxapp}
|
|
|
|
A wxWindows application does not have a {\it main} procedure; the equivalent is the
|
|
\rtfsp\helpref{OnInit}{wxapponinit} member defined for a class derived from wxApp.\rtfsp
|
|
\rtfsp{\it OnInit} will usually create a top window as a bare minimum.
|
|
|
|
Unlike in earlier versions of wxWindows, OnInit does not return a frame. Instead it
|
|
returns a boolean value which indicates whether processing should continue (TRUE) or not (FALSE).
|
|
You call \helpref{wxApp::SetTopWindow}{wxappsettopwindow} to let wxWindows know
|
|
about the top window.
|
|
|
|
Note that the program's command line arguments, represented by {\it
|
|
argc} and {\it argv}, are available from within wxApp member functions.
|
|
|
|
An application closes by destroying all windows. Because all frames must
|
|
be destroyed for the application to exit, it is advisable to use parent
|
|
frames wherever possible when creating new frames, so that deleting the
|
|
top level frame will automatically delete child frames. The alternative
|
|
is to explicitly delete child frames in the top-level frame's \helpref{wxCloseEvent}{wxcloseevent}\rtfsp
|
|
handler.
|
|
|
|
In emergencies the \helpref{wxExit}{wxexit} function can be called to kill the
|
|
application.
|
|
|
|
An example of defining an application follows:
|
|
|
|
\begin{verbatim}
|
|
class DerivedApp : public wxApp
|
|
{
|
|
public:
|
|
virtual bool OnInit();
|
|
};
|
|
|
|
IMPLEMENT_APP(DerivedApp)
|
|
|
|
bool DerivedApp::OnInit()
|
|
{
|
|
wxFrame *the_frame = new wxFrame(NULL, argv[0]);
|
|
...
|
|
SetTopWindow(the_frame);
|
|
|
|
return TRUE;
|
|
}
|
|
\end{verbatim}
|
|
|
|
Note the use of IMPLEMENT\_APP(appClass), which allows wxWindows to dynamically create an instance of the application object
|
|
at the appropriate point in wxWindows initialization. Previous versions of wxWindows used
|
|
to rely on the creation of a global application object, but this is no longer recommended,
|
|
because required global initialization may not have been performed at application object
|
|
construction time.
|
|
|
|
You can also use DECLARE\_APP(appClass) in a header file to declare the wxGetApp function which returns
|
|
a reference to the application object.
|
|
|