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
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
|
<?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" />
<title>Qt 4.8: rsslisting.cpp Example File (xml/rsslisting/rsslisting.cpp)</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 -->
</ul>
</div>
</div>
<div class="content mainContent">
<h1 class="title">rsslisting.cpp Example File</h1>
<span class="small-subtitle">xml/rsslisting/rsslisting.cpp</span>
<!-- $$$xml/rsslisting/rsslisting.cpp-description -->
<div class="descr"> <a name="details"></a>
<pre class="cpp"> <span class="comment">/****************************************************************************
**
** Copyright (C) 2012 Nokia Corporation and/or its subsidiary(-ies).
** All rights reserved.
** Contact: Nokia Corporation (qt-info@nokia.com)
**
** This file is part of the examples of the Qt Toolkit.
**
** $QT_BEGIN_LICENSE:BSD$
** 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."
** $QT_END_LICENSE$
**
****************************************************************************/</span>
<span class="comment">/*
rsslisting.cpp
Provides a widget for displaying news items from RDF news sources.
RDF is an XML-based format for storing items of information (see
http://www.w3.org/RDF/ for details).
The widget itself provides a simple user interface for specifying
the URL of a news source, and controlling the downloading of news.
The widget downloads and parses the XML asynchronously, feeding the
data to an XML reader in pieces. This allows the user to interrupt
its operation, and also allows very large data sources to be read.
*/</span>
<span class="preprocessor">#include <QtCore></span>
<span class="preprocessor">#include <QtGui></span>
<span class="preprocessor">#include <QtNetwork></span>
<span class="preprocessor">#include "rsslisting.h"</span>
<span class="comment">/*
Constructs an RSSListing widget with a simple user interface, and sets
up the XML reader to use a custom handler class.
The user interface consists of a line edit, a push button, and a
list view widget. The line edit is used for entering the URLs of news
sources; the push button starts the process of reading the
news.
*/</span>
RSSListing<span class="operator">::</span>RSSListing(<span class="type"><a href="qwidget.html">QWidget</a></span> <span class="operator">*</span>parent)
: <span class="type"><a href="qwidget.html">QWidget</a></span>(parent)<span class="operator">,</span> currentReply(<span class="number">0</span>)
{
<span class="preprocessor">#ifdef Q_OS_SYMBIAN</span>
<span class="comment">// Set Internet Access Point</span>
<span class="type"><a href="qnetworkconfigurationmanager.html">QNetworkConfigurationManager</a></span> manager;
<span class="keyword">const</span> <span class="type">bool</span> canStartIAP <span class="operator">=</span> manager<span class="operator">.</span>capabilities() <span class="operator">&</span> <span class="type"><a href="qnetworkconfigurationmanager.html">QNetworkConfigurationManager</a></span><span class="operator">::</span>CanStartAndStopInterfaces;
<span class="comment">// Is there default access point, use it</span>
<span class="type"><a href="qnetworkconfiguration.html">QNetworkConfiguration</a></span> cfg <span class="operator">=</span> manager<span class="operator">.</span>defaultConfiguration();
<span class="keyword">if</span> (<span class="operator">!</span>cfg<span class="operator">.</span>isValid() <span class="operator">|</span><span class="operator">|</span> <span class="operator">!</span>canStartIAP) {
<span class="comment">// Available Access Points not found</span>
<span class="type"><a href="qmessagebox.html">QMessageBox</a></span><span class="operator">::</span>warning(<span class="keyword">this</span><span class="operator">,</span> <span class="string">"Error"</span><span class="operator">,</span> <span class="string">"No access point"</span>);
<span class="keyword">return</span>;
}
m_session <span class="operator">=</span> <span class="keyword">new</span> <span class="type"><a href="qnetworksession.html">QNetworkSession</a></span>(cfg);
m_session<span class="operator">-</span><span class="operator">></span>open();
m_session<span class="operator">-</span><span class="operator">></span>waitForOpened();
<span class="preprocessor">#endif</span>
lineEdit <span class="operator">=</span> <span class="keyword">new</span> <span class="type"><a href="qlineedit.html">QLineEdit</a></span>(<span class="keyword">this</span>);
lineEdit<span class="operator">-</span><span class="operator">></span>setText(<span class="string">"http://labs.qt.nokia.com/blogs/feed"</span>);
fetchButton <span class="operator">=</span> <span class="keyword">new</span> <span class="type"><a href="qpushbutton.html">QPushButton</a></span>(tr(<span class="string">"Fetch"</span>)<span class="operator">,</span> <span class="keyword">this</span>);
treeWidget <span class="operator">=</span> <span class="keyword">new</span> <span class="type"><a href="qtreewidget.html">QTreeWidget</a></span>(<span class="keyword">this</span>);
connect(treeWidget<span class="operator">,</span> SIGNAL(itemActivated(<span class="type"><a href="qtreewidgetitem.html">QTreeWidgetItem</a></span><span class="operator">*</span><span class="operator">,</span><span class="type">int</span>))<span class="operator">,</span>
<span class="keyword">this</span><span class="operator">,</span> SLOT(itemActivated(<span class="type"><a href="qtreewidgetitem.html">QTreeWidgetItem</a></span><span class="operator">*</span>)));
<span class="type"><a href="qstringlist.html">QStringList</a></span> headerLabels;
headerLabels <span class="operator"><</span><span class="operator"><</span> tr(<span class="string">"Title"</span>) <span class="operator"><</span><span class="operator"><</span> tr(<span class="string">"Link"</span>);
treeWidget<span class="operator">-</span><span class="operator">></span>setHeaderLabels(headerLabels);
treeWidget<span class="operator">-</span><span class="operator">></span>header()<span class="operator">-</span><span class="operator">></span>setResizeMode(<span class="type"><a href="qheaderview.html">QHeaderView</a></span><span class="operator">::</span>ResizeToContents);
connect(<span class="operator">&</span>manager<span class="operator">,</span> SIGNAL(finished(<span class="type"><a href="qnetworkreply.html">QNetworkReply</a></span><span class="operator">*</span>))<span class="operator">,</span>
<span class="keyword">this</span><span class="operator">,</span> SLOT(finished(<span class="type"><a href="qnetworkreply.html">QNetworkReply</a></span><span class="operator">*</span>)));
connect(lineEdit<span class="operator">,</span> SIGNAL(returnPressed())<span class="operator">,</span> <span class="keyword">this</span><span class="operator">,</span> SLOT(fetch()));
connect(fetchButton<span class="operator">,</span> SIGNAL(clicked())<span class="operator">,</span> <span class="keyword">this</span><span class="operator">,</span> SLOT(fetch()));
<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>(<span class="keyword">this</span>);
<span class="type"><a href="qhboxlayout.html">QHBoxLayout</a></span> <span class="operator">*</span>hboxLayout <span class="operator">=</span> <span class="keyword">new</span> <span class="type"><a href="qhboxlayout.html">QHBoxLayout</a></span>;
hboxLayout<span class="operator">-</span><span class="operator">></span>addWidget(lineEdit);
hboxLayout<span class="operator">-</span><span class="operator">></span>addWidget(fetchButton);
layout<span class="operator">-</span><span class="operator">></span>addLayout(hboxLayout);
layout<span class="operator">-</span><span class="operator">></span>addWidget(treeWidget);
setWindowTitle(tr(<span class="string">"RSS listing example"</span>));
<span class="preprocessor">#if !defined(Q_OS_SYMBIAN) && !defined(Q_WS_MAEMO_5)</span>
resize(<span class="number">640</span><span class="operator">,</span><span class="number">480</span>);
<span class="preprocessor">#endif</span>
}
<span class="comment">/*
Starts the network request and connects the needed signals
*/</span>
<span class="type">void</span> RSSListing<span class="operator">::</span>get(<span class="keyword">const</span> <span class="type"><a href="qurl.html">QUrl</a></span> <span class="operator">&</span>url)
{
<span class="type"><a href="qnetworkrequest.html">QNetworkRequest</a></span> request(url);
<span class="keyword">if</span> (currentReply) {
currentReply<span class="operator">-</span><span class="operator">></span>disconnect(<span class="keyword">this</span>);
currentReply<span class="operator">-</span><span class="operator">></span>deleteLater();
}
currentReply <span class="operator">=</span> manager<span class="operator">.</span>get(request);
connect(currentReply<span class="operator">,</span> SIGNAL(readyRead())<span class="operator">,</span> <span class="keyword">this</span><span class="operator">,</span> SLOT(readyRead()));
connect(currentReply<span class="operator">,</span> SIGNAL(metaDataChanged())<span class="operator">,</span> <span class="keyword">this</span><span class="operator">,</span> SLOT(metaDataChanged()));
connect(currentReply<span class="operator">,</span> SIGNAL(error(<span class="type"><a href="qnetworkreply.html">QNetworkReply</a></span><span class="operator">::</span>NetworkError))<span class="operator">,</span> <span class="keyword">this</span><span class="operator">,</span> SLOT(error(<span class="type"><a href="qnetworkreply.html">QNetworkReply</a></span><span class="operator">::</span>NetworkError)));
}
<span class="comment">/*
Starts fetching data from a news source specified in the line
edit widget.
The line edit is made read only to prevent the user from modifying its
contents during the fetch; this is only for cosmetic purposes.
The fetch button is disabled, the list view is cleared, and we
define the last list view item to be 0, meaning that there are no
existing items in the list.
A URL is created with the raw contents of the line edit and
a get is initiated.
*/</span>
<span class="type">void</span> RSSListing<span class="operator">::</span>fetch()
{
lineEdit<span class="operator">-</span><span class="operator">></span>setReadOnly(<span class="keyword">true</span>);
fetchButton<span class="operator">-</span><span class="operator">></span>setEnabled(<span class="keyword">false</span>);
treeWidget<span class="operator">-</span><span class="operator">></span>clear();
xml<span class="operator">.</span>clear();
<span class="type"><a href="qurl.html">QUrl</a></span> url(lineEdit<span class="operator">-</span><span class="operator">></span>text());
get(url);
}
<span class="type">void</span> RSSListing<span class="operator">::</span>metaDataChanged()
{
<span class="type"><a href="qurl.html">QUrl</a></span> redirectionTarget <span class="operator">=</span> currentReply<span class="operator">-</span><span class="operator">></span>attribute(<span class="type"><a href="qnetworkrequest.html">QNetworkRequest</a></span><span class="operator">::</span>RedirectionTargetAttribute)<span class="operator">.</span>toUrl();
<span class="keyword">if</span> (redirectionTarget<span class="operator">.</span>isValid()) {
get(redirectionTarget);
}
}
<span class="comment">/*
Reads data received from the RDF source.
We read all the available data, and pass it to the XML
stream reader. Then we call the XML parsing function.
*/</span>
<span class="type">void</span> RSSListing<span class="operator">::</span>readyRead()
{
<span class="type">int</span> statusCode <span class="operator">=</span> currentReply<span class="operator">-</span><span class="operator">></span>attribute(<span class="type"><a href="qnetworkrequest.html">QNetworkRequest</a></span><span class="operator">::</span>HttpStatusCodeAttribute)<span class="operator">.</span>toInt();
<span class="keyword">if</span> (statusCode <span class="operator">></span><span class="operator">=</span> <span class="number">200</span> <span class="operator">&</span><span class="operator">&</span> statusCode <span class="operator"><</span> <span class="number">300</span>) {
<span class="type"><a href="qbytearray.html">QByteArray</a></span> data <span class="operator">=</span> currentReply<span class="operator">-</span><span class="operator">></span>readAll();
xml<span class="operator">.</span>addData(data);
parseXml();
}
}
<span class="comment">/*
Finishes processing an HTTP request.
The default behavior is to keep the text edit read only.
If an error has occurred, the user interface is made available
to the user for further input, allowing a new fetch to be
started.
If the HTTP get request has finished, we make the
user interface available to the user for further input.
*/</span>
<span class="type">void</span> RSSListing<span class="operator">::</span>finished(<span class="type"><a href="qnetworkreply.html">QNetworkReply</a></span> <span class="operator">*</span>reply)
{
Q_UNUSED(reply);
lineEdit<span class="operator">-</span><span class="operator">></span>setReadOnly(<span class="keyword">false</span>);
fetchButton<span class="operator">-</span><span class="operator">></span>setEnabled(<span class="keyword">true</span>);
}
<span class="comment">/*
Parses the XML data and creates treeWidget items accordingly.
*/</span>
<span class="type">void</span> RSSListing<span class="operator">::</span>parseXml()
{
<span class="keyword">while</span> (<span class="operator">!</span>xml<span class="operator">.</span>atEnd()) {
xml<span class="operator">.</span>readNext();
<span class="keyword">if</span> (xml<span class="operator">.</span>isStartElement()) {
<span class="keyword">if</span> (xml<span class="operator">.</span>name() <span class="operator">=</span><span class="operator">=</span> <span class="string">"item"</span>)
linkString <span class="operator">=</span> xml<span class="operator">.</span>attributes()<span class="operator">.</span>value(<span class="string">"rss:about"</span>)<span class="operator">.</span>toString();
currentTag <span class="operator">=</span> xml<span class="operator">.</span>name()<span class="operator">.</span>toString();
} <span class="keyword">else</span> <span class="keyword">if</span> (xml<span class="operator">.</span>isEndElement()) {
<span class="keyword">if</span> (xml<span class="operator">.</span>name() <span class="operator">=</span><span class="operator">=</span> <span class="string">"item"</span>) {
<span class="type"><a href="qtreewidgetitem.html">QTreeWidgetItem</a></span> <span class="operator">*</span>item <span class="operator">=</span> <span class="keyword">new</span> <span class="type"><a href="qtreewidgetitem.html">QTreeWidgetItem</a></span>;
item<span class="operator">-</span><span class="operator">></span>setText(<span class="number">0</span><span class="operator">,</span> titleString);
item<span class="operator">-</span><span class="operator">></span>setText(<span class="number">1</span><span class="operator">,</span> linkString);
treeWidget<span class="operator">-</span><span class="operator">></span>addTopLevelItem(item);
titleString<span class="operator">.</span>clear();
linkString<span class="operator">.</span>clear();
}
} <span class="keyword">else</span> <span class="keyword">if</span> (xml<span class="operator">.</span>isCharacters() <span class="operator">&</span><span class="operator">&</span> <span class="operator">!</span>xml<span class="operator">.</span>isWhitespace()) {
<span class="keyword">if</span> (currentTag <span class="operator">=</span><span class="operator">=</span> <span class="string">"title"</span>)
titleString <span class="operator">+</span><span class="operator">=</span> xml<span class="operator">.</span>text()<span class="operator">.</span>toString();
<span class="keyword">else</span> <span class="keyword">if</span> (currentTag <span class="operator">=</span><span class="operator">=</span> <span class="string">"link"</span>)
linkString <span class="operator">+</span><span class="operator">=</span> xml<span class="operator">.</span>text()<span class="operator">.</span>toString();
}
}
<span class="keyword">if</span> (xml<span class="operator">.</span>error() <span class="operator">&</span><span class="operator">&</span> xml<span class="operator">.</span>error() <span class="operator">!</span><span class="operator">=</span> <span class="type"><a href="qxmlstreamreader.html">QXmlStreamReader</a></span><span class="operator">::</span>PrematureEndOfDocumentError) {
<a href="qtglobal.html#qWarning">qWarning</a>() <span class="operator"><</span><span class="operator"><</span> <span class="string">"XML ERROR:"</span> <span class="operator"><</span><span class="operator"><</span> xml<span class="operator">.</span>lineNumber() <span class="operator"><</span><span class="operator"><</span> <span class="string">": "</span> <span class="operator"><</span><span class="operator"><</span> xml<span class="operator">.</span>errorString();
}
}
<span class="comment">/*
Open the link in the browser
*/</span>
<span class="type">void</span> RSSListing<span class="operator">::</span>itemActivated(<span class="type"><a href="qtreewidgetitem.html">QTreeWidgetItem</a></span> <span class="operator">*</span> item)
{
<span class="type"><a href="qdesktopservices.html">QDesktopServices</a></span><span class="operator">::</span>openUrl(<span class="type"><a href="qurl.html">QUrl</a></span>(item<span class="operator">-</span><span class="operator">></span>text(<span class="number">1</span>)));
}
<span class="type">void</span> RSSListing<span class="operator">::</span>error(<span class="type"><a href="qnetworkreply.html">QNetworkReply</a></span><span class="operator">::</span>NetworkError)
{
<a href="qtglobal.html#qWarning">qWarning</a>(<span class="string">"error retrieving RSS feed"</span>);
currentReply<span class="operator">-</span><span class="operator">></span>disconnect(<span class="keyword">this</span>);
currentReply<span class="operator">-</span><span class="operator">></span>deleteLater();
currentReply <span class="operator">=</span> <span class="number">0</span>;
}</pre>
</div>
<!-- @@@xml/rsslisting/rsslisting.cpp -->
<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>
|
