1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
|
/****************************************************************************
**
** Copyright (C) 2009 Nokia Corporation and/or its subsidiary(-ies).
** Contact: Nokia Corporation (qt-info@nokia.com)
**
** This file is part of the documentation of the Qt Toolkit.
**
** $QT_BEGIN_LICENSE:LGPL$
** No Commercial Usage
** This file contains pre-release code and may not be distributed.
** You may use this file in accordance with the terms and conditions
** contained in the either Technology Preview License Agreement or the
** Beta Release License Agreement.
**
** GNU Lesser General Public License Usage
** Alternatively, this file may be used under the terms of the GNU Lesser
** General Public License version 2.1 as published by the Free Software
** Foundation and appearing in the file LICENSE.LGPL included in the
** packaging of this file. Please review the following information to
** ensure the GNU Lesser General Public License version 2.1 requirements
** will be met: http://www.gnu.org/licenses/old-licenses/lgpl-2.1.html.
**
** In addition, as a special exception, Nokia gives you certain
** additional rights. These rights are described in the Nokia Qt LGPL
** Exception version 1.0, included in the file LGPL_EXCEPTION.txt in this
** package.
**
** GNU General Public License Usage
** Alternatively, this file may be used under the terms of the GNU
** General Public License version 3.0 as published by the Free Software
** Foundation and appearing in the file LICENSE.GPL included in the
** packaging of this file. Please review the following information to
** ensure the GNU General Public License version 3.0 requirements will be
** met: http://www.gnu.org/copyleft/gpl.html.
**
** If you are unsure which license is appropriate for your use, please
** contact the sales department at http://qt.nokia.com/contact.
** $QT_END_LICENSE$
**
****************************************************************************/
/*!
\example script/calculator
\title QtScript Calculator Example
\ingroup scripting
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 uses the special local variable
__qt_sender__ to access the object that triggered the signal;
this gives us a simple way to retrieve the value of the digit
that was clicked.
\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.
*/
|
