@page overview_helloworld Hello World Example
+@tableofcontents
+
This page shows a very simple wxWidgets program that can be used as a skeleton
for your own code. While it does nothing very useful, it introduces a couple of
important concepts and explains how to write a working wxWidgets application.
-First, you have to include wxWidgets' header files, of course. This can
-be done on a file by file basis (such as @c wx/window.h</tt>) or using one
-global include (@c wx/wx.h) which includes most of the commonly needed headers
-(although not all of them as there are simply too many wxWidgets headers to
-pull in all of them). For the platforms with support for precompiled headers,
-as indicated by @c WX_PRECOMP, this global header is already included by @c
-wx/wxprec.h so we only include it for the other ones:
+First, you have to include wxWidgets' header files, of course. This can be done
+on a file by file basis (such as @c wx/window.h) or using one global include
+(@c wx/wx.h) which includes most of the commonly needed headers (although not
+all of them as there are simply too many wxWidgets headers to pull in all of
+them). For the platforms with support for precompiled headers, as indicated by
+@c WX_PRECOMP, this global header is already included by @c wx/wxprec.h so we
+only include it for the other ones:
@code
-// wxWidgets "Hello world" Program
+// wxWidgets "Hello world" Program
// For compilers that support precompilation, includes "wx/wx.h".
#include <wx/wxprec.h>
};
@endcode
-The main window is created by deriving a class from wxFrame and
-giving it a menu and a status bar in its constructor. Also, any class
-that wishes to respond to any "event" (such as mouse clicks or
-messages from the menu or a button) must declare an event table
-using the macro below.
+The main window is created by deriving a class from wxFrame and giving it a
+menu and a status bar in its constructor. Also, any class that wishes to
+respond to any "event" (such as mouse clicks or messages from the menu or a
+button) must declare an event table using the macro below.
-Finally, the way to react to such events must be done in "handlers".
-In our sample, we react to three menu items, one for our custom menu
-command and two for the standard "Exit" and "About" commands (any program
-should normally implement the latter two). Notice that these handlers
-don't need to be neither virtual nor public.
+Finally, the way to react to such events must be done in "handlers". In our
+sample, we react to three menu items, one for our custom menu command and two
+for the standard "Exit" and "About" commands (any program should normally
+implement the latter two). Notice that these handlers don't need to be neither
+virtual nor public.
@code
class MyFrame: public wxFrame
};
@endcode
-Notice that you don't need to define identifiers for the "About" and "Exit"
-We then proceed to actually implement an event table in which the events
-are routed to their respective handler functions in the class MyFrame.
+Notice that you don't need to define identifiers for the "About" and "Exit". We
+then proceed to actually implement an event table in which the events are
+routed to their respective handler functions in the class MyFrame.
-There are predefined macros for routing all common events, ranging from
-the selection of a list box entry to a resize event when a user resizes
-a window on the screen. If @c wxID_ANY is given as the ID, the given handler will be
-invoked for any event of the specified type, so that you could add just
-one entry in the event table for all menu commands or all button commands etc.
+There are predefined macros for routing all common events, ranging from the
+selection of a list box entry to a resize event when a user resizes a window on
+the screen. If @c wxID_ANY is given as the ID, the given handler will be
+invoked for any event of the specified type, so that you could add just one
+entry in the event table for all menu commands or all button commands etc.
-The origin of the event can still be distinguished in the event handler as
-the (only) parameter in an event handler is a reference to a wxEvent object,
-which holds various information about the event (such as the ID of and a
-pointer to the class, which emitted the event).
+The origin of the event can still be distinguished in the event handler as the
+(only) parameter in an event handler is a reference to a wxEvent object, which
+holds various information about the event (such as the ID of and a pointer to
+the class, which emitted the event).
@code
wxBEGIN_EVENT_TABLE(MyFrame, wxFrame)
wxEND_EVENT_TABLE()
@endcode
-As in all programs there must be a "main" function. Under wxWidgets main is implemented
-using this macro, which creates an application instance and starts the program.
+As in all programs there must be a "main" function. Under wxWidgets main is
+implemented using this macro, which creates an application instance and starts
+the program.
@code
wxIMPLEMENT_APP(MyApp)
@endcode
-As mentioned above, wxApp::OnInit() is called upon startup and should be
-used to initialize the program, maybe showing a "splash screen" and creating
-the main window (or several). The frame should get a title bar text ("Hello World")
-and a position and start-up size. One frame can also be declared to be the
-top window. Returning @true indicates a successful initialization.
+As mentioned above, wxApp::OnInit() is called upon startup and should be used
+to initialize the program, maybe showing a "splash screen" and creating the
+main window (or several). The frame should get a title bar text ("Hello World")
+and a position and start-up size. One frame can also be declared to be the top
+window. Returning @true indicates a successful initialization.
@code
bool MyApp::OnInit()
{
- MyFrame *frame = new MyFrame( "Hello World", wxPoint(50,50), wxSize(450,340) );
+ MyFrame *frame = new MyFrame( "Hello World", wxPoint(50, 50), wxSize(450, 340) );
frame->Show( true );
return true;
}
@endcode
-In the constructor of the main window (or later on) we create a menu with our menu
-items as well as a status bar to be shown at the bottom of the main window. Both have
-to be associated with the frame with respective calls.
+In the constructor of the main window (or later on) we create a menu with our
+menu items as well as a status bar to be shown at the bottom of the main
+window. Both have to be associated with the frame with respective calls.
@code
MyFrame::MyFrame(const wxString& title, const wxPoint& pos, const wxSize& size)
The implementation of custom menu command handler may perform whatever task
your program needs to do, in this case we will simply show a message from it as
befits a hello world example:
+
@code
void MyFrame::OnHello(wxCommandEvent& event)
{
@endcode
Here is the entire program that can be copied and pasted:
+
@code
-// wxWidgets "Hello world" Program
+// wxWidgets "Hello world" Program
// For compilers that support precompilation, includes "wx/wx.h".
#include <wx/wxprec.h>
bool MyApp::OnInit()
{
- MyFrame *frame = new MyFrame( "Hello World", wxPoint(50,50), wxSize(450,340) );
+ MyFrame *frame = new MyFrame( "Hello World", wxPoint(50, 50), wxSize(450, 340) );
frame->Show( true );
return true;
}
@endcode
*/
-
projects / wxWidgets.git / blobdiff