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

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1/****************************************************************************
2**
3** Copyright (C) 2011 Nokia Corporation and/or its subsidiary(-ies).
4** All rights reserved.
5** Contact: Nokia Corporation ([email protected])
6**
7** This file is part of the documentation of the Qt Toolkit.
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9** $QT_BEGIN_LICENSE:FDL$
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13** Software or, alternatively, in accordance with the terms contained in a
14** written agreement between you and Nokia.
15**
16** GNU Free Documentation License
17** Alternatively, this file may be used under the terms of the GNU Free
18** Documentation License version 1.3 as published by the Free Software
19** Foundation and appearing in the file included in the packaging of this
20** file.
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22** If you have questions regarding the use of this file, please contact
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26****************************************************************************/
27
28/*!
29 \example script/calculator
30 \title QtScript Calculator Example
31
32 In this simple QtScript example, we show how to implement the
33 functionality of a calculator widget.
34
35 \image qtscript-calculator-example.png
36
37 The program logic in this example is a fairly straight port of the logic in the C++ \l{Calculator Example}.
38 The graphical user interface is defined in a UI file.
39
40 The C++ part of the example consists of four steps:
41 \list
42 \o Evaluate the script code that defines the \c{Calculator} class.
43
44 \snippet examples/script/calculator/main.cpp 0a
45 \snippet examples/script/calculator/main.cpp 0b
46
47 \o Create a widget from the UI file using QUiLoader.
48
49 \snippet examples/script/calculator/main.cpp 1
50
51 \o Call the Calculator constructor function to create a new \c{Calculator} script object, passing the widget as argument.
52
53 \snippet examples/script/calculator/main.cpp 2
54
55 \o Show the widget and start the application event loop.
56
57 \snippet examples/script/calculator/main.cpp 3
58
59 \endlist
60
61 On the script side, the \c{Calculator} constructor function
62 initializes the instance variables of the new \c{Calculator}
63 object, and connects the clicked() signal of the form's buttons
64 to corresponding functions defined in the \c{Calculator} prototype
65 object; the effect is that when a button is clicked, the proper
66 script function will be invoked to carry out the operation.
67
68 \snippet examples/script/calculator/calculator.js 0
69
70 A \c{Calculator} object is just a plain script object; it is not
71 a widget. Instead, it stores a reference to the calculator form
72 (the widget) in an instance variable, \c{ui}. The calculator
73 script functions can access components of the form by referring
74 to the proper children of the \c{ui} member.
75
76 \snippet examples/script/calculator/calculator.js 1
77
78 The digitClicked() function is called when a digit button is
79 clicked, with the input digit as argument.
80
81 \snippet examples/script/calculator/calculator.js 2
82
83 The changeSign() function shows how we retrieve the text property
84 of the calculator's display, change it appropriately, and write
85 back the new value.
86
87
88*/
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