Improve wording and formatting in "Hello World" example
Minor fixes to the "Hello World" example in the manual to make its style more consistent and the text more readable. Closes https://github.com/wxWidgets/wxWidgets/pull/657
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adrian5
Vadim Zeitlin
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@ -24,7 +24,7 @@ them). For the platforms with support for precompiled headers, as indicated by
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only include it for the other ones:
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@code
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// wxWidgets "Hello world" Program
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// wxWidgets "Hello World" Program
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// For compilers that support precompilation, includes "wx/wx.h".
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#include <wx/wxprec.h>
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@ -35,11 +35,11 @@ only include it for the other ones:
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@endcode
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Practically every app should define a new class derived from wxApp. By
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overriding wxApp's OnInit() virtual method the program can be initialized, e.g.
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by creating a new main window.
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overriding wxApp's OnInit() virtual method the program can be initialized,
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e.g. by creating a new main window.
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@code
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class MyApp: public wxApp
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class MyApp : public wxApp
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{
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public:
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virtual bool OnInit();
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@ -48,20 +48,20 @@ public:
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The main window is created by deriving a class from wxFrame and giving it a
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menu and a status bar in its constructor. Also, any class that wishes to
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respond to any "event" (such as mouse clicks or messages from the menu or a
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respond to an "event" (such as mouse clicks, messages from the menu, or a
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button) must declare an event table using the macro below.
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Finally, the way to react to such events must be done in "event handlers" which
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are just functions (or functors, including lambdas if you're using C++11)
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Finally, reacting to such events is done via "event handlers" which are
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just functions (or functors, including lambdas if you're using C++11)
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taking the @c event parameter of the type corresponding to the event being
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handled, e.g. wxCommandEvent for the events from simple controls such as
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buttons, text fields and also menu items. In our sample, we react to three menu
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items, one for our custom menu command and two for the standard "Exit" and
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"About" commands (any program should normally implement the latter two). Notice
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that these handlers don't need to be neither virtual nor public.
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buttons, text fields and also menu items. In our example, we react to three
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menu items: our custom "Hello", and the "Exit" and "About" items (any program
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should normally implement the latter two). Notice that these handlers don't
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need to be virtual or public.
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@code
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class MyFrame: public wxFrame
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class MyFrame : public wxFrame
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{
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public:
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MyFrame();
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@ -84,13 +84,13 @@ enum
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};
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@endcode
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Notice that you don't need to define identifiers for the "About" and "Exit" as
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wxWidgets already predefines and the standard values such as wxID_ABOUT and
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wxID_EXIT should be used whenever possible, as they can be handled in a special
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Notice that you don't need to define identifiers for "About" and "Exit", as
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wxWidgets already predefines standard values such as wxID_ABOUT and wxID_EXIT.
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You should use these whenever possible, as they can be handled in a special
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way by a particular platform.
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As in all programs there must be a "main" function. Under wxWidgets main is
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implemented inside ::wxIMPLEMENT_APP() macro, which creates an application
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As in all programs, there must be a "main" function. Under wxWidgets, main is
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implemented inside the ::wxIMPLEMENT_APP() macro, which creates an application
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instance of the specified class and starts running the GUI event loop. It is
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used simply as:
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@ -100,23 +100,23 @@ wxIMPLEMENT_APP(MyApp);
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As mentioned above, wxApp::OnInit() is called upon startup and should be used
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to initialize the program, maybe showing a "splash screen" and creating the
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main window (or several). As frames are created hidden by default, to allow
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creating their child windows before showing them, we also need to explicitly
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show it to make it appear on the screen. Finally, we return @true from this
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method to indicate successful initialization:
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main window (or several). Frames are created hidden by default, to allow the
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creation of child windows before displaying them. We thus need to explicitly
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show them. Finally, we return @true from this method to indicate successful
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initialization:
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@code
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bool MyApp::OnInit()
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{
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MyFrame *frame = new MyFrame();
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frame->Show( true );
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frame->Show(true);
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return true;
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}
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@endcode
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In the constructor of the main window (or later on) we create a menu with our
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menu items as well as a status bar to be shown at the bottom of the main
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window. Both have to be associated with the frame with respective calls.
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In the constructor of the main window (or later on), we create a menu with our
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menu items, as well as a status bar to be shown at the bottom of the main
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window. Both have to be bound to the frame with respective calls.
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@code
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MyFrame::MyFrame()
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@ -132,39 +132,40 @@ MyFrame::MyFrame()
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menuHelp->Append(wxID_ABOUT);
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wxMenuBar *menuBar = new wxMenuBar;
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menuBar->Append( menuFile, "&File" );
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menuBar->Append( menuHelp, "&Help" );
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menuBar->Append(menuFile, "&File");
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menuBar->Append(menuHelp, "&Help");
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SetMenuBar( menuBar );
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SetMenuBar(menuBar);
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CreateStatusBar();
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SetStatusText( "Welcome to wxWidgets!" );
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SetStatusText("Welcome to wxWidgets!");
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... continued below ...
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@endcode
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Notice that we don't need to specify the labels for the standard menu items
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@c wxID_ABOUT and @c wxID_EXIT, they will be given standard (even correctly
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translated) labels and also standard accelerators correct for the current
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platform making your program behaviour more native. For this reason you should
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prefer reusing the standard ids (see @ref page_stockitems) if possible.
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@c wxID_ABOUT and @c wxID_EXIT — they will be given standard (even correctly
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translated) labels and standard accelerators correct for the current
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platform, making our program behaviour more native. For this reason, you
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should prefer reusing the standard ids (see @ref page_stockitems) where
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possible.
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We also have to actually connect our event handlers to the events we want to
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handle in them, by calling Bind() to send all the menu events, identified by
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wxEVT_MENU event type, with the specified ID to the given function. The
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We also have to connect our event handlers to the events we want to handle in
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them. We do this by calling Bind() to send all the menu events (identified by
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wxEVT_MENU event type) with the specified ID to the given function. The
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parameters we pass to Bind() are
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-# The event type, e.g. wxEVT_MENU or wxEVT_BUTTON or wxEVT_SIZE or one
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-# The event type, e.g. wxEVT_MENU, wxEVT_BUTTON, wxEVT_SIZE, or one
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of many other events used by wxWidgets.
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-# Pointer to the member function to call and the object to call it on. In
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this case we just call our own function, hence we pass `this` for this
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object itself, but we could call a member function of another object too.
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And we could could also use a non-member function here, and, in fact,
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anything that can be called passing it a wxCommandEvent could be used here.
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-# The optional identifier allowing to select just some events of wxEVT_MENU
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-# A Pointer to the method to call, and the object to call it on. In
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this case, we just call our own function, and pass the `this` pointer
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for the object itself. We could instead call the method of another object,
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or a non-member function — in fact, any object that can be called with a
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wxCommandEvent, can be used here.
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-# An optional identifier, allowing us to select just some events of wxEVT_MENU
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type, namely those from the menu item with the given ID, instead of handling
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all of them in the provided handler. This is especially useful with the menu
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items and rarely used with other kinds of events.
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all of them in the provided handler. This is mainly useful with menu items
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and rarely with other kinds of events.
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@code
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... continued from above ...
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@ -183,7 +184,7 @@ If there is no other main window left, the application will quit.
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@code
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void MyFrame::OnExit(wxCommandEvent& event)
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{
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Close( true );
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Close(true);
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}
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@endcode
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@ -193,14 +194,14 @@ case a typical "About" window with information about the program.
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@code
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void MyFrame::OnAbout(wxCommandEvent& event)
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{
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wxMessageBox( "This is a wxWidgets' Hello world sample",
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"About Hello World", wxOK | wxICON_INFORMATION );
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wxMessageBox("This is a wxWidgets Hello World example",
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"About Hello World", wxOK | wxICON_INFORMATION);
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}
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@endcode
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The implementation of custom menu command handler may perform whatever task
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your program needs to do, in this case we will simply show a message from it as
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befits a hello world example:
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befits a Hello World example:
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@code
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void MyFrame::OnHello(wxCommandEvent& event)
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@ -223,7 +224,7 @@ void MyFrame::OnHello(wxCommandEvent& event)
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Here is the entire program that can be copied and pasted:
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@code
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// wxWidgets "Hello world" Program
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// wxWidgets "Hello World" Program
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// For compilers that support precompilation, includes "wx/wx.h".
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#include <wx/wxprec.h>
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@ -232,13 +233,13 @@ Here is the entire program that can be copied and pasted:
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#include <wx/wx.h>
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#endif
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class MyApp: public wxApp
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class MyApp : public wxApp
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{
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public:
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virtual bool OnInit();
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};
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class MyFrame: public wxFrame
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class MyFrame : public wxFrame
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{
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public:
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MyFrame();
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@ -259,12 +260,12 @@ wxIMPLEMENT_APP(MyApp);
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bool MyApp::OnInit()
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{
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MyFrame *frame = new MyFrame();
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frame->Show( true );
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frame->Show(true);
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return true;
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}
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MyFrame::MyFrame()
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: wxFrame(NULL, wxID_ANY, "Hello World")
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: wxFrame(NULL, wxID_ANY, "Hello World")
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{
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wxMenu *menuFile = new wxMenu;
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menuFile->Append(ID_Hello, "&Hello...\tCtrl-H",
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@ -276,13 +277,13 @@ MyFrame::MyFrame()
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menuHelp->Append(wxID_ABOUT);
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wxMenuBar *menuBar = new wxMenuBar;
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menuBar->Append( menuFile, "&File" );
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menuBar->Append( menuHelp, "&Help" );
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menuBar->Append(menuFile, "&File");
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menuBar->Append(menuHelp, "&Help");
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SetMenuBar( menuBar );
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CreateStatusBar();
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SetStatusText( "Welcome to wxWidgets!" );
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SetStatusText("Welcome to wxWidgets!");
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Bind(wxEVT_MENU, &MyFrame::OnHello, this, ID_Hello);
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Bind(wxEVT_MENU, &MyFrame::OnAbout, this, wxID_ABOUT);
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@ -291,13 +292,13 @@ MyFrame::MyFrame()
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void MyFrame::OnExit(wxCommandEvent& event)
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{
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Close( true );
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Close(true);
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}
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void MyFrame::OnAbout(wxCommandEvent& event)
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{
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wxMessageBox( "This is a wxWidgets' Hello world sample",
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"About Hello World", wxOK | wxICON_INFORMATION );
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wxMessageBox("This is a wxWidgets Hello World example",
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"About Hello World", wxOK | wxICON_INFORMATION);
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}
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void MyFrame::OnHello(wxCommandEvent& event)
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