Tutorial 1 - Hello world

This first tutorial is your basic "Hello world" program. The program consists of a window with the words "Hello world" displayed in the center. It is made up of three files - the source and header for the object that contains the window, and the source that contains the function main.

The HelloWorldDir object - HelloWorldDir.cc and HelloWorldDir.h

The object that holds the window is a HelloWorldDir object which is derived from JXWindowDirector.

HelloWorldDir source file:

/******************************************************************************
 HelloWorldDir.cc

     BASE CLASS = JXWindowDirector

     Written by Glenn Bach - 1997.

 ******************************************************************************/

#include "HelloWorldDir.h"
#include <JXWindow.h>
#include <JXStaticText.h>
#include <jAssert.h>

/******************************************************************************
 Constructor

 ******************************************************************************/

HelloWorldDir::HelloWorldDir
     (
     JXDirector* supervisor
     )
     :
     JXWindowDirector(supervisor)
{
     // Create the Hello World window
     JXWindow* window = new JXWindow(this, 200,100, "Hello World Program");

     // Make sure that new succeeded
     assert( window != NULL );

     // Tell the window director that this is its window
     SetWindow(window);

     // Set the min and max size of the window.
     // This particular pair of operations can also be done
     // by calling window->LockCurrentSize().
     window->SetMinSize(200,100);
     window->SetMaxSize(200,100);

     // Create the object to hold our "Hello World" message.
     // We do not need to keep a pointer to it because the
     // framework will delete it automatically when the window
     // is closed.
     JXStaticText* text = 
         new JXStaticText("Hello World", window, 
             JXWidget::kFixedLeft, JXWidget::kFixedTop,
             20, 40, 160, 20);
     assert( text != NULL );
}

/******************************************************************************
 Destructor

 ******************************************************************************/

HelloWorldDir::~HelloWorldDir()
{
}

HelloWorldDir header file:

/******************************************************************************
 HelloWorldDir.h

     Interface for the HelloWorldDir class

     Written by Glenn Bach - 1997.

 ******************************************************************************/
#ifndef _H_HelloWorldDir
#define _H_HelloWorldDir

#include <JXWindowDirector.h>

class HelloWorldDir : public JXWindowDirector
{
public:

     HelloWorldDir(JXDirector* supervisor);

     virtual ~HelloWorldDir();

private:

     // not allowed

     HelloWorldDir(const HelloWorldDir& source);
     const HelloWorldDir& operator=(const HelloWorldDir& source);
};

#endif

The function main - hello_world.cc

The application and window director objects are created here, and the application is run.

/******************************************************************************
 hello_world.cc
 
 Written by Glenn Bach - 1997. 

 ******************************************************************************/

#include "HelloWorldDir.h"
#include <JXApplication.h>
#include <jAssert.h>

/******************************************************************************
 main

 ******************************************************************************/

int
main
     (
     int     argc,
     char*      argv[]
     )
{
     // Create the application object - there should only be one of these
     JXApplication* app = new JXApplication(&argc, argv);
       
     // Make sure that new succeeded
     assert( app != NULL );

     // Create the window director to maintain the Hello World window
     HelloWorldDir* mainDir = new HelloWorldDir(app);
     assert( mainDir != NULL );

     // Show the window and activate it
     mainDir->Activate();
     
     // Start the event loop
     app->Run();           
     return 0;
}