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
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
|
<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd">
<html xmlns="http://www.w3.org/1999/xhtml" xml:lang="en_US" lang="en_US">
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
<!-- eventtransitions.qdoc -->
<title>Qt 4.8: Event Transitions Example</title>
<link rel="stylesheet" type="text/css" href="style/offline.css" />
</head>
<body>
<div class="header" id="qtdocheader">
<div class="content">
<a href="index.html" class="qtref"><span>Qt Reference Documentation</span></a>
</div>
<div class="breadcrumb toolblock">
<ul>
<li class="first"><a href="index.html">Home</a></li>
<!-- Breadcrumbs go here -->
<li><a href="all-examples.html">Examples</a></li>
<li>Event Transitions Example</li>
</ul>
</div>
</div>
<div class="content mainContent">
<h1 class="title">Event Transitions Example</h1>
<span class="subtitle"></span>
<!-- $$$statemachine/eventtransitions-description -->
<div class="descr"> <a name="details"></a>
<p>Files:</p>
<ul>
<li><a href="statemachine-eventtransitions-main-cpp.html">statemachine/eventtransitions/main.cpp</a></li>
<li><a href="statemachine-eventtransitions-eventtransitions-pro.html">statemachine/eventtransitions/eventtransitions.pro</a></li>
</ul>
<p>The Event Transitions example shows how to use event transitions, a feature of <a href="statemachine-api.html">The State Machine Framework</a>.<pre class="cpp"> <span class="keyword">class</span> Window : <span class="keyword">public</span> <span class="type"><a href="qwidget.html">QWidget</a></span>
{
<span class="keyword">public</span>:
Window(<span class="type"><a href="qwidget.html">QWidget</a></span> <span class="operator">*</span>parent <span class="operator">=</span> <span class="number">0</span>)
: <span class="type"><a href="qwidget.html">QWidget</a></span>(parent)
{
<span class="type"><a href="qpushbutton.html">QPushButton</a></span> <span class="operator">*</span>button <span class="operator">=</span> <span class="keyword">new</span> <span class="type"><a href="qpushbutton.html">QPushButton</a></span>(<span class="keyword">this</span>);
button<span class="operator">-</span><span class="operator">></span>setSizePolicy(<span class="type"><a href="qsizepolicy.html">QSizePolicy</a></span><span class="operator">::</span>Expanding<span class="operator">,</span> <span class="type"><a href="qsizepolicy.html">QSizePolicy</a></span><span class="operator">::</span>Expanding);
<span class="type"><a href="qvboxlayout.html">QVBoxLayout</a></span> <span class="operator">*</span>layout <span class="operator">=</span> <span class="keyword">new</span> <span class="type"><a href="qvboxlayout.html">QVBoxLayout</a></span>;
layout<span class="operator">-</span><span class="operator">></span>addWidget(button);
layout<span class="operator">-</span><span class="operator">></span>setContentsMargins(<span class="number">80</span><span class="operator">,</span> <span class="number">80</span><span class="operator">,</span> <span class="number">80</span><span class="operator">,</span> <span class="number">80</span>);
setLayout(layout);</pre>
<p>The <tt>Window</tt> class's constructors begins by creating a button.</p>
<pre class="cpp"> <span class="type"><a href="qstatemachine.html">QStateMachine</a></span> <span class="operator">*</span>machine <span class="operator">=</span> <span class="keyword">new</span> <span class="type"><a href="qstatemachine.html">QStateMachine</a></span>(<span class="keyword">this</span>);
<span class="type"><a href="qstate.html">QState</a></span> <span class="operator">*</span>s1 <span class="operator">=</span> <span class="keyword">new</span> <span class="type"><a href="qstate.html">QState</a></span>();
s1<span class="operator">-</span><span class="operator">></span>assignProperty(button<span class="operator">,</span> <span class="string">"text"</span><span class="operator">,</span> <span class="string">"Outside"</span>);
<span class="type"><a href="qstate.html">QState</a></span> <span class="operator">*</span>s2 <span class="operator">=</span> <span class="keyword">new</span> <span class="type"><a href="qstate.html">QState</a></span>();
s2<span class="operator">-</span><span class="operator">></span>assignProperty(button<span class="operator">,</span> <span class="string">"text"</span><span class="operator">,</span> <span class="string">"Inside"</span>);</pre>
<p>Two states, <tt>s1</tt> and <tt>s2</tt>, are created; upon entry they will assign "Outside" and "Inside" to the button's text, respectively.</p>
<pre class="cpp"> <span class="type"><a href="qeventtransition.html">QEventTransition</a></span> <span class="operator">*</span>enterTransition <span class="operator">=</span> <span class="keyword">new</span> <span class="type"><a href="qeventtransition.html">QEventTransition</a></span>(button<span class="operator">,</span> <span class="type"><a href="qevent.html">QEvent</a></span><span class="operator">::</span>Enter);
enterTransition<span class="operator">-</span><span class="operator">></span>setTargetState(s2);
s1<span class="operator">-</span><span class="operator">></span>addTransition(enterTransition);</pre>
<p>When the button receives an event of type <a href="qevent.html#Type-enum">QEvent::Enter</a> and the state machine is in state <tt>s1</tt>, the machine will transition to state <tt>s2</tt>.</p>
<pre class="cpp"> <span class="type"><a href="qeventtransition.html">QEventTransition</a></span> <span class="operator">*</span>leaveTransition <span class="operator">=</span> <span class="keyword">new</span> <span class="type"><a href="qeventtransition.html">QEventTransition</a></span>(button<span class="operator">,</span> <span class="type"><a href="qevent.html">QEvent</a></span><span class="operator">::</span>Leave);
leaveTransition<span class="operator">-</span><span class="operator">></span>setTargetState(s1);
s2<span class="operator">-</span><span class="operator">></span>addTransition(leaveTransition);</pre>
<p>When the button receives an event of type <a href="qevent.html#Type-enum">QEvent::Leave</a> and the state machine is in state <tt>s2</tt>, the machine will transition back to state <tt>s1</tt>.</p>
<pre class="cpp"> <span class="type"><a href="qstate.html">QState</a></span> <span class="operator">*</span>s3 <span class="operator">=</span> <span class="keyword">new</span> <span class="type"><a href="qstate.html">QState</a></span>();
s3<span class="operator">-</span><span class="operator">></span>assignProperty(button<span class="operator">,</span> <span class="string">"text"</span><span class="operator">,</span> <span class="string">"Pressing..."</span>);
<span class="type"><a href="qeventtransition.html">QEventTransition</a></span> <span class="operator">*</span>pressTransition <span class="operator">=</span> <span class="keyword">new</span> <span class="type"><a href="qeventtransition.html">QEventTransition</a></span>(button<span class="operator">,</span> <span class="type"><a href="qevent.html">QEvent</a></span><span class="operator">::</span>MouseButtonPress);
pressTransition<span class="operator">-</span><span class="operator">></span>setTargetState(s3);
s2<span class="operator">-</span><span class="operator">></span>addTransition(pressTransition);
<span class="type"><a href="qeventtransition.html">QEventTransition</a></span> <span class="operator">*</span>releaseTransition <span class="operator">=</span> <span class="keyword">new</span> <span class="type"><a href="qeventtransition.html">QEventTransition</a></span>(button<span class="operator">,</span> <span class="type"><a href="qevent.html">QEvent</a></span><span class="operator">::</span>MouseButtonRelease);
releaseTransition<span class="operator">-</span><span class="operator">></span>setTargetState(s2);
s3<span class="operator">-</span><span class="operator">></span>addTransition(releaseTransition);</pre>
<p>Next, the state <tt>s3</tt> is created. <tt>s3</tt> will be entered when the button receives an event of type <a href="qevent.html#Type-enum">QEvent::MouseButtonPress</a> and the state machine is in state <tt>s2</tt>. When the button receives an event of type <a href="qevent.html#Type-enum">QEvent::MouseButtonRelease</a> and the state machine is in state <tt>s3</tt>, the machine will transition back to state <tt>s2</tt>.</p>
<pre class="cpp"> machine<span class="operator">-</span><span class="operator">></span>addState(s1);
machine<span class="operator">-</span><span class="operator">></span>addState(s2);
machine<span class="operator">-</span><span class="operator">></span>addState(s3);
machine<span class="operator">-</span><span class="operator">></span>setInitialState(s1);
machine<span class="operator">-</span><span class="operator">></span>start();
}
};</pre>
<p>Finally, the states are added to the machine as top-level states, the initial state is set to be <tt>s1</tt> ("Outside"), and the machine is started.</p>
<pre class="cpp"> <span class="type">int</span> main(<span class="type">int</span> argc<span class="operator">,</span> <span class="type">char</span> <span class="operator">*</span><span class="operator">*</span>argv)
{
<span class="type"><a href="qapplication.html">QApplication</a></span> app(argc<span class="operator">,</span> argv);
Window window;
window<span class="operator">.</span>resize(<span class="number">300</span><span class="operator">,</span> <span class="number">300</span>);
<span class="preprocessor">#if defined(Q_OS_SYMBIAN)</span>
window<span class="operator">.</span>showMaximized();
<span class="preprocessor">#else</span>
window<span class="operator">.</span>show();
<span class="preprocessor">#endif</span>
<span class="keyword">return</span> app<span class="operator">.</span>exec();
}</pre>
<p>The main() function constructs a Window object and shows it.</p>
</div>
<!-- @@@statemachine/eventtransitions -->
<div class="ft">
<span></span>
</div>
</div>
<div class="footer">
<p>
<acronym title="Copyright">©</acronym> 2012 Nokia Corporation and/or its
subsidiaries. Documentation contributions included herein are the copyrights of
their respective owners.</p>
<br />
<p>
The documentation provided herein is licensed under the terms of the
<a href="http://www.gnu.org/licenses/fdl.html">GNU Free Documentation
License version 1.3</a> as published by the Free Software Foundation.</p>
<p>
Documentation sources may be obtained from <a href="http://www.qt-project.org">
www.qt-project.org</a>.</p>
<br />
<p>
Nokia, Qt and their respective logos are trademarks of Nokia Corporation
in Finland and/or other countries worldwide. All other trademarks are property
of their respective owners. <a title="Privacy Policy"
href="http://en.gitorious.org/privacy_policy/">Privacy Policy</a></p>
</div>
</body>
</html>
|
