source: trunk/doc/src/examples/qtscriptcalculator.qdoc@ 1168

/****************************************************************************
**
** Copyright (C) 2011 Nokia Corporation and/or its subsidiary(-ies).
** All rights reserved.
** Contact: Nokia Corporation ([email protected])
**
** This file is part of the documentation of the Qt Toolkit.
**
** $QT_BEGIN_LICENSE:FDL$
** Commercial Usage
** Licensees holding valid Qt Commercial licenses may use this file in
** accordance with the Qt Commercial License Agreement provided with the
** Software or, alternatively, in accordance with the terms contained in a
** written agreement between you and Nokia.
**
** GNU Free Documentation License
** Alternatively, this file may be used under the terms of the GNU Free
** Documentation License version 1.3 as published by the Free Software
** Foundation and appearing in the file included in the packaging of this
** file.
**
** If you have questions regarding the use of this file, please contact
** Nokia at [email protected].
** $QT_END_LICENSE$
**
****************************************************************************/

/*!
    \example script/calculator
    \title QtScript Calculator Example

    In this simple QtScript example, we show how to implement the
    functionality of a calculator widget.

    \image qtscript-calculator-example.png

    The program logic in this example is a fairly straight port of the logic in the C++ \l{Calculator Example}.
    The graphical user interface is defined in a UI file.

    The C++ part of the example consists of four steps:
    \list
    \o Evaluate the script code that defines the \c{Calculator} class.

    \snippet examples/script/calculator/main.cpp 0a
    \snippet examples/script/calculator/main.cpp 0b

    \o Create a widget from the UI file using QUiLoader.

    \snippet examples/script/calculator/main.cpp 1

    \o Call the Calculator constructor function to create a new \c{Calculator} script object, passing the widget as argument.

    \snippet examples/script/calculator/main.cpp 2

    \o Show the widget and start the application event loop.

    \snippet examples/script/calculator/main.cpp 3

    \endlist

    On the script side, the \c{Calculator} constructor function
    initializes the instance variables of the new \c{Calculator}
    object, and connects the clicked() signal of the form's buttons
    to corresponding functions defined in the \c{Calculator} prototype
    object; the effect is that when a button is clicked, the proper
    script function will be invoked to carry out the operation.

    \snippet examples/script/calculator/calculator.js 0

    A \c{Calculator} object is just a plain script object; it is not
    a widget. Instead, it stores a reference to the calculator form
    (the widget) in an instance variable, \c{ui}. The calculator
    script functions can access components of the form by referring
    to the proper children of the \c{ui} member.

    \snippet examples/script/calculator/calculator.js 1

    The digitClicked() function is called when a digit button is
    clicked, with the input digit as argument.

    \snippet examples/script/calculator/calculator.js 2

    The changeSign() function shows how we retrieve the text property
    of the calculator's display, change it appropriately, and write
    back the new value.


*/