[deb_shairplay.git] / AirTV-Qt / qtsingleapplication / doc / html / qtsingleapplication-example-loader.html

<?xml version="1.0" encoding="iso-8859-1"?>
<!DOCTYPE html
    PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN" "DTD/xhtml1-strict.dtd">
<html xmlns="http://www.w3.org/1999/xhtml" xml:lang="en" lang="en">
<!-- loader.qdoc -->
<head>
  <title>Loading Documents</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">&nbsp;&nbsp;</td><td class="postheader" valign="center"><a href="index.html"><font color="#004faf">Home</font></a></td>
</tr></table><h1 class="title">Loading Documents<br /><span class="subtitle"></span>
</h1>
<p>The application in this example loads or prints the documents passed as commandline parameters to further instances of this application.</p>
<pre><span class="comment"> /****************************************************************************
 **
 ** Copyright (C) 2010 Nokia Corporation and/or its subsidiary(-ies).
 ** All rights reserved.
 **
 ** Contact: Nokia Corporation (qt-info@nokia.com)
 **
 ** This file is part of a 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;QtCore/QFile&gt;
 #include &lt;QtGui/QMainWindow&gt;
 #include &lt;QtGui/QPrinter&gt;
 #include &lt;QtGui/QPainter&gt;
 #include &lt;QtGui/QTextEdit&gt;
 #include &lt;QtGui/QMdiArea&gt;
 #include &lt;QtCore/QTextStream&gt;

 class MainWindow : public QMainWindow
 {
     Q_OBJECT
 public:
     MainWindow();

 public slots:
     void handleMessage(const QString&amp; message);

 signals:
     void needToShow();

 private:
     QMdiArea *workspace;
 };</pre>
<p>The user interface in this application is a <a href="http://qt.nokia.com/doc/4.6/qmainwindow.html">QMainWindow</a> subclass with a <a href="http://qt.nokia.com/doc/4.6/qmdiarea.html">QMdiArea</a> as the central widget. It implements a slot <tt>handleMessage()</tt> that will be connected to the messageReceived() signal of the <a href="qtsingleapplication.html">QtSingleApplication</a> class.</p>
<pre> MainWindow::MainWindow()
 {
     workspace = new QMdiArea(this);

     setCentralWidget(workspace);
 }</pre>
<p>The <a href="http://qt.nokia.com/doc/4.6/designer-to-know.html">MainWindow</a> constructor creates a minimal user interface.</p>
<pre> void MainWindow::handleMessage(const QString&amp; message)
 {
     enum Action {
         Nothing,
         Open,
         Print
     } action;

     action = Nothing;
     QString filename = message;
     if (message.toLower().startsWith(&quot;/print &quot;)) {
         filename = filename.mid(7);
         action = Print;
     } else if (!message.isEmpty()) {
         action = Open;
     }
     if (action == Nothing) {
         emit needToShow();
         return;
     }

     QFile file(filename);
     QString contents;
     if (file.open(QIODevice::ReadOnly))
         contents = file.readAll();
     else
         contents = &quot;[[Error: Could not load file &quot; + filename + &quot;]]&quot;;

     QTextEdit *view = new QTextEdit;
     view-&gt;setPlainText(contents);

     switch(action) {</pre>
<p>The handleMessage() slot interprets the message passed in as a filename that can be prepended with <i>/print</i> to indicate that the file should just be printed rather than loaded.</p>
<pre>     case Print:
         {
             QPrinter printer;
             view-&gt;print(&amp;printer);
             delete view;
         }
         break;

     case Open:
         {
             workspace-&gt;addSubWindow(view);
             view-&gt;setWindowTitle(message);
             view-&gt;show();
             emit needToShow();
         }
         break;
     default:
         break;
     };
 }</pre>
<p>Loading the file will also activate the window.</p>
<pre> #include &quot;main.moc&quot;

 int main(int argc, char **argv)
 {
     QtSingleApplication instance(&quot;File loader QtSingleApplication example&quot;, argc, argv);
     QString message;
     for (int a = 1; a &lt; argc; ++a) {
         message += argv[a];
         if (a &lt; argc-1)
             message += &quot; &quot;;
     }

     if (instance.sendMessage(message))
         return 0;</pre>
<p>The <tt>main</tt> entry point function creates a <a href="qtsingleapplication.html">QtSingleApplication</a> object, and creates a message to send to a running instance of the application. If the message was sent successfully the process exits immediately.</p>
<pre>     MainWindow mw;
     mw.handleMessage(message);
     mw.show();

     QObject::connect(&amp;instance, SIGNAL(messageReceived(const QString&amp;)),
                      &amp;mw, SLOT(handleMessage(const QString&amp;)));

     instance.setActivationWindow(&amp;mw, false);
     QObject::connect(&amp;mw, SIGNAL(needToShow()), &amp;instance, SLOT(activateWindow()));

     return instance.exec();
 }</pre>
<p>If the message could not be sent the application starts up. Note that <tt>false</tt> is passed to the call to setActivationWindow() to prevent automatic activation for every message received, e.g&#x2e; when the application should just print a file. Instead, the message handling function determines whether activation is requested, and signals that by emitting the needToShow() signal. This is then simply connected directly to <a href="qtsingleapplication.html">QtSingleApplication</a>'s activateWindow() slot.</p>
<p /><address><hr /><div align="center">
<table width="100%" cellspacing="0" border="0"><tr class="address">
<td width="30%" align="left">Copyright &copy; 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>
Commit	Line	Data
15c988f7 JB	1	<?xml version="1.0" encoding="iso-8859-1"?>
	2	<!DOCTYPE html
	3	PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN" "DTD/xhtml1-strict.dtd">
	4	<html xmlns="http://www.w3.org/1999/xhtml" xml:lang="en" lang="en">
	5	<!-- loader.qdoc -->
	6	<head>
	7	<title>Loading Documents</title>
	8	<link href="classic.css" rel="stylesheet" type="text/css" />
	9	</head>
	10	<body>
	11	<table border="0" cellpadding="0" cellspacing="0" width="100%">
	12	<tr>
	13	<td align="left" valign="top" width="32"><img src="images/qt-logo.png" align="left" width="57" height="67" border="0" /></td>
	14	<td width="1">  </td><td class="postheader" valign="center"><a href="index.html"><font color="#004faf">Home</font></a></td>
	15	</tr></table><h1 class="title">Loading Documents<br /><span class="subtitle"></span>
	16	</h1>
	17	<p>The application in this example loads or prints the documents passed as commandline parameters to further instances of this application.</p>
	18	<pre><span class="comment"> /****************************************************************************
	19	**
	20	** Copyright (C) 2010 Nokia Corporation and/or its subsidiary(-ies).
	21	** All rights reserved.
	22	**
	23	** Contact: Nokia Corporation (qt-info@nokia.com)
	24	**
	25	** This file is part of a Qt Solutions component.
	26	**
	27	** You may use this file under the terms of the BSD license as follows:
	28	**
	29	** "Redistribution and use in source and binary forms, with or without
	30	** modification, are permitted provided that the following conditions are
	31	** met:
	32	** * Redistributions of source code must retain the above copyright
	33	** notice, this list of conditions and the following disclaimer.
	34	** * Redistributions in binary form must reproduce the above copyright
	35	** notice, this list of conditions and the following disclaimer in
	36	** the documentation and/or other materials provided with the
	37	** distribution.
	38	** * Neither the name of Nokia Corporation and its Subsidiary(-ies) nor
	39	** the names of its contributors may be used to endorse or promote
	40	** products derived from this software without specific prior written
	41	** permission.
	42	**
	43	** THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
	44	** "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
	45	** LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
	46	** A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
	47	** OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
	48	** SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
	49	** LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
	50	** DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
	51	** THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
	52	** (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
	53	** OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE."
	54	**
	55	****************************************************************************/</span>
	56
	57	#include <qtsingleapplication.h>
	58	#include <QtCore/QFile>
	59	#include <QtGui/QMainWindow>
	60	#include <QtGui/QPrinter>
	61	#include <QtGui/QPainter>
	62	#include <QtGui/QTextEdit>
	63	#include <QtGui/QMdiArea>
	64	#include <QtCore/QTextStream>
65
66	class MainWindow : public QMainWindow
67	{
68	Q_OBJECT
69	public:
70	MainWindow();
71
72	public slots:
73	void handleMessage(const QString& message);
74
75	signals:
76	void needToShow();
77
78	private:
79	QMdiArea *workspace;
80	};</pre>
81	<p>The user interface in this application is a <a href="http://qt.nokia.com/doc/4.6/qmainwindow.html">QMainWindow</a> subclass with a <a href="http://qt.nokia.com/doc/4.6/qmdiarea.html">QMdiArea</a> as the central widget. It implements a slot <tt>handleMessage()</tt> that will be connected to the messageReceived() signal of the <a href="qtsingleapplication.html">QtSingleApplication</a> class.</p>
82	<pre> MainWindow::MainWindow()
83	{
84	workspace = new QMdiArea(this);
85
86	setCentralWidget(workspace);
87	}</pre>
88	<p>The <a href="http://qt.nokia.com/doc/4.6/designer-to-know.html">MainWindow</a> constructor creates a minimal user interface.</p>
89	<pre> void MainWindow::handleMessage(const QString& message)
90	{
91	enum Action {
92	Nothing,
93	Open,
94	Print
95	} action;
96
97	action = Nothing;
98	QString filename = message;
99	if (message.toLower().startsWith("/print ")) {
100	filename = filename.mid(7);
101	action = Print;
102	} else if (!message.isEmpty()) {
103	action = Open;
104	}
105	if (action == Nothing) {
106	emit needToShow();
107	return;
108	}
109
110	QFile file(filename);
111	QString contents;
112	if (file.open(QIODevice::ReadOnly))
113	contents = file.readAll();
114	else
115	contents = "[[Error: Could not load file " + filename + "]]";
116
117	QTextEdit *view = new QTextEdit;
118	view->setPlainText(contents);
119
120	switch(action) {</pre>
121	<p>The handleMessage() slot interprets the message passed in as a filename that can be prepended with <i>/print</i> to indicate that the file should just be printed rather than loaded.</p>
122	<pre> case Print:
123	{
124	QPrinter printer;
125	view->print(&printer);
126	delete view;
127	}
128	break;
129
130	case Open:
131	{
132	workspace->addSubWindow(view);
133	view->setWindowTitle(message);
134	view->show();
135	emit needToShow();
136	}
137	break;
138	default:
139	break;
140	};
141	}</pre>
142	<p>Loading the file will also activate the window.</p>
143	<pre> #include "main.moc"
144
145	int main(int argc, char **argv)
146	{
147	QtSingleApplication instance("File loader QtSingleApplication example", argc, argv);
148	QString message;
149	for (int a = 1; a < argc; ++a) {
150	message += argv[a];
151	if (a < argc-1)
152	message += " ";
153	}
154
155	if (instance.sendMessage(message))
156	return 0;</pre>
157	<p>The <tt>main</tt> entry point function creates a <a href="qtsingleapplication.html">QtSingleApplication</a> object, and creates a message to send to a running instance of the application. If the message was sent successfully the process exits immediately.</p>
158	<pre> MainWindow mw;
159	mw.handleMessage(message);
160	mw.show();
161
162	QObject::connect(&instance, SIGNAL(messageReceived(const QString&)),
163	&mw, SLOT(handleMessage(const QString&)));
164
165	instance.setActivationWindow(&mw, false);
166	QObject::connect(&mw, SIGNAL(needToShow()), &instance, SLOT(activateWindow()));
167
168	return instance.exec();
169	}</pre>
170	<p>If the message could not be sent the application starts up. Note that <tt>false</tt> is passed to the call to setActivationWindow() to prevent automatic activation for every message received, e.g. when the application should just print a file. Instead, the message handling function determines whether activation is requested, and signals that by emitting the needToShow() signal. This is then simply connected directly to <a href="qtsingleapplication.html">QtSingleApplication</a>'s activateWindow() slot.</p>
171	<p /><address><hr /><div align="center">
172	<table width="100%" cellspacing="0" border="0"><tr class="address">
173	<td width="30%" align="left">Copyright © 2010 Nokia Corporation and/or its subsidiary(-ies)</td>
174	<td width="40%" align="center"><a href="http://qt.nokia.com/doc/trademarks.html">Trademarks</a></td>
175	<td width="30%" align="right"><div align="right">Qt Solutions</div></td>
176	</tr></table></div></address></body>
177	</html>