goldendict-ng/qtsingleapplication/doc/html/qtsingleapplication-example-trivial.html

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<p>The application in this example has a log-view that displays messages sent by further instances of the same application.</p>
<p>The example demonstrates the use of the <a href="qtsingleapplication.html">QtSingleApplication</a> class to detect and communicate with a running instance of the application using the sendMessage() API. The messageReceived() signal is used to display received messages in a <a href="http://qt.nokia.com/doc/4.6/qtextedit.html">QTextEdit</a> log.</p>
<pre><span class="comment"> /****************************************************************************
 **
 ** Copyright (C) 2013 Digia Plc and/or its subsidiary(-ies).
 ** Contact: http://www.qt-project.org/legal
 **
 ** This file is part of the Qt Solutions component.
 **
 ** You may use this file under the terms of the BSD license as follows:
 **
 ** &quot;Redistribution and use in source and binary forms, with or without
 ** modification, are permitted provided that the following conditions are
 ** met:
 **   * Redistributions of source code must retain the above copyright
 **     notice, this list of conditions and the following disclaimer.
 **   * Redistributions in binary form must reproduce the above copyright
 **     notice, this list of conditions and the following disclaimer in
 **     the documentation and/or other materials provided with the
 **     distribution.
 **   * Neither the name of Nokia Corporation and its Subsidiary(-ies) nor
 **     the names of its contributors may be used to endorse or promote
 **     products derived from this software without specific prior written
 **     permission.
 **
 ** THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
 ** &quot;AS IS&quot; AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
 ** LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
 ** A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
 ** OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
 ** SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
 ** LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
 ** DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
 ** THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 ** (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
 ** OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.&quot;
 **
 ****************************************************************************/</span>

 #include &lt;qtsingleapplication.h&gt;
 #include &lt;QtGui/QTextEdit&gt;

 class TextEdit : public QTextEdit
 {
     Q_OBJECT
 public:
     TextEdit(QWidget *parent = 0)
         : QTextEdit(parent)
     {}
 public slots:
     void append(const QString &amp;str)
     {
         QTextEdit::append(str);
     }
 };

 #include &quot;main.moc&quot;

 int main(int argc, char **argv)
 {
     QtSingleApplication instance(argc, argv);</pre>
<p>The example has only the <tt>main</tt> entry point function. A <a href="qtsingleapplication.html">QtSingleApplication</a> object is created immediately.</p>
<pre>     if (instance.sendMessage(&quot;Wake up!&quot;))
         return 0;</pre>
<p>If another instance of this application is already running, sendMessage() will succeed, and this instance just exits immediately.</p>
<pre>     TextEdit logview;
     logview.setReadOnly(true);
     logview.show();</pre>
<p>Otherwise the instance continues as normal and creates the user interface.</p>
<pre>     instance.setActivationWindow(&amp;logview);

     QObject::connect(&amp;instance, SIGNAL(messageReceived(const QString&amp;)),
                      &amp;logview, SLOT(append(const QString&amp;)));

     return instance.exec();</pre>
<p>The <tt>logview</tt> object is also set as the application's activation window. Every time a message is received, the window will be raised and activated automatically.</p>
<p>The messageReceived() signal is also connected to the <a href="http://qt.nokia.com/doc/4.6/qtextedit.html">QTextEdit</a>'s append() slot. Every message received from further instances of this application will be displayed in the log.</p>
<p>Finally the event loop is entered.</p>
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<td width="30%" align="left">Copyright &copy; 2010 Nokia Corporation and/or its subsidiary(-ies)</td>
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Switch to QtSingleApplication for maintaining single instance running. This should put an end to all those pidfile-related problems. 2010-11-20 13:43:55 +00:00			`<?xml version="1.0" encoding="iso-8859-1"?>`
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			`<head>`
			`<title>A Trivial Example</title>`
			`<link href="classic.css" rel="stylesheet" type="text/css" />`
			`</head>`
			`<body>`
			`<table border="0" cellpadding="0" cellspacing="0" width="100%">`
			`<tr>`
			`<td align="left" valign="top" width="32"><img src="images/qt-logo.png" align="left" width="57" height="67" border="0" /></td>`
			`<td width="1">  </td><td class="postheader" valign="center"><a href="index.html"><font color="#004faf">Home</font></a></td>`
			`</tr></table><h1 class="title">A Trivial Example<br /><span class="subtitle"></span>`
			`</h1>`
			`<p>The application in this example has a log-view that displays messages sent by further instances of the same application.</p>`
			`<p>The example demonstrates the use of the <a href="qtsingleapplication.html">QtSingleApplication</a> class to detect and communicate with a running instance of the application using the sendMessage() API. The messageReceived() signal is used to display received messages in a <a href="http://qt.nokia.com/doc/4.6/qtextedit.html">QTextEdit</a> log.</p>`
			`<pre><span class="comment"> /****************************************************************************`
			`**`
Updated to the latest qtsingleapplication, as part of fix for #212. The sources are already updated to be compatible with Qt5. 2013-02-03 21:00:15 +00:00			`** Copyright (C) 2013 Digia Plc and/or its subsidiary(-ies).`
			`** Contact: http://www.qt-project.org/legal`
Switch to QtSingleApplication for maintaining single instance running. This should put an end to all those pidfile-related problems. 2010-11-20 13:43:55 +00:00			`**`
Updated to the latest qtsingleapplication, as part of fix for #212. The sources are already updated to be compatible with Qt5. 2013-02-03 21:00:15 +00:00			`** This file is part of the Qt Solutions component.`
Switch to QtSingleApplication for maintaining single instance running. This should put an end to all those pidfile-related problems. 2010-11-20 13:43:55 +00:00			`**`
			`** You may use this file under the terms of the BSD license as follows:`
			`**`
			`** "Redistribution and use in source and binary forms, with or without`
			`** modification, are permitted provided that the following conditions are`
			`** met:`
			`** * Redistributions of source code must retain the above copyright`
			`** notice, this list of conditions and the following disclaimer.`
			`** * Redistributions in binary form must reproduce the above copyright`
			`** notice, this list of conditions and the following disclaimer in`
			`** the documentation and/or other materials provided with the`
			`** distribution.`
			`** * Neither the name of Nokia Corporation and its Subsidiary(-ies) nor`
			`** the names of its contributors may be used to endorse or promote`
			`** products derived from this software without specific prior written`
			`** permission.`
			`**`
			`** THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS`
			`** "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT`
			`** LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR`
			`** A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT`
			`** OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,`
			`** SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT`
			`** LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,`
			`** DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY`
			`** THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT`
			`** (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE`
			`** OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE."`
			`**`
			`****************************************************************************/</span>`

			`#include <qtsingleapplication.h>`
			`#include <QtGui/QTextEdit>`

			`class TextEdit : public QTextEdit`
			`{`
			`Q_OBJECT`
			`public:`
			`TextEdit(QWidget *parent = 0)`
			`: QTextEdit(parent)`
			`{}`
			`public slots:`
			`void append(const QString &str)`
			`{`
			`QTextEdit::append(str);`
			`}`
			`};`

			`#include "main.moc"`

			`int main(int argc, char **argv)`
			`{`
			`QtSingleApplication instance(argc, argv);</pre>`
			`<p>The example has only the <tt>main</tt> entry point function. A <a href="qtsingleapplication.html">QtSingleApplication</a> object is created immediately.</p>`
			`<pre> if (instance.sendMessage("Wake up!"))`
			`return 0;</pre>`
			`<p>If another instance of this application is already running, sendMessage() will succeed, and this instance just exits immediately.</p>`
			`<pre> TextEdit logview;`
			`logview.setReadOnly(true);`
			`logview.show();</pre>`
			`<p>Otherwise the instance continues as normal and creates the user interface.</p>`
			`<pre> instance.setActivationWindow(&logview);`

			`QObject::connect(&instance, SIGNAL(messageReceived(const QString&)),`
			`&logview, SLOT(append(const QString&)));`

			`return instance.exec();</pre>`
			`<p>The <tt>logview</tt> object is also set as the application's activation window. Every time a message is received, the window will be raised and activated automatically.</p>`
			`<p>The messageReceived() signal is also connected to the <a href="http://qt.nokia.com/doc/4.6/qtextedit.html">QTextEdit</a>'s append() slot. Every message received from further instances of this application will be displayed in the log.</p>`
			`<p>Finally the event loop is entered.</p>`
			`<p /><address><hr /><div align="center">`
			`<table width="100%" cellspacing="0" border="0"><tr class="address">`
			`<td width="30%" align="left">Copyright © 2010 Nokia Corporation and/or its subsidiary(-ies)</td>`
			`<td width="40%" align="center"><a href="http://qt.nokia.com/doc/trademarks.html">Trademarks</a></td>`
			`<td width="30%" align="right"><div align="right">Qt Solutions</div></td>`
			`</tr></table></div></address></body>`
			`</html>`