Qt 4.8: googlesuggest.cpp Example File (network/googlesuggest/googlesuggest.cpp)

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# googlesuggest.cpp Example File

network/googlesuggest/googlesuggest.cpp

     /****************************************************************************
     **
     ** Copyright (C) 2012 Digia Plc and/or its subsidiary(-ies).
     ** Contact: http://www.qt-project.org/legal
     **
     ** 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 Digia Plc 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."
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     ** $QT_END_LICENSE$
     **
     ****************************************************************************/

     #include "googlesuggest.h"

     #define GSUGGEST_URL "http://google.com/complete/search?output=toolbar&q=%1"

     GSuggestCompletion::GSuggestCompletion(QLineEdit *parent): QObject(parent), editor(parent)
     {
         popup = new QTreeWidget;
         popup->setWindowFlags(Qt::Popup);
         popup->setFocusPolicy(Qt::NoFocus);
         popup->setFocusProxy(parent);
         popup->setMouseTracking(true);

         popup->setColumnCount(2);
         popup->setUniformRowHeights(true);
         popup->setRootIsDecorated(false);
         popup->setEditTriggers(QTreeWidget::NoEditTriggers);
         popup->setSelectionBehavior(QTreeWidget::SelectRows);
         popup->setFrameStyle(QFrame::Box | QFrame::Plain);
         popup->setHorizontalScrollBarPolicy(Qt::ScrollBarAlwaysOff);
         popup->header()->hide();

         popup->installEventFilter(this);

         connect(popup, SIGNAL(itemClicked(QTreeWidgetItem*,int)),
                 SLOT(doneCompletion()));

         timer = new QTimer(this);
         timer->setSingleShot(true);
         timer->setInterval(500);
         connect(timer, SIGNAL(timeout()), SLOT(autoSuggest()));
         connect(editor, SIGNAL(textEdited(QString)), timer, SLOT(start()));

         connect(&networkManager, SIGNAL(finished(QNetworkReply*)),
                 this, SLOT(handleNetworkData(QNetworkReply*)));

     }

     GSuggestCompletion::~GSuggestCompletion()
     {
         delete popup;
     }

     bool GSuggestCompletion::eventFilter(QObject *obj, QEvent *ev)
     {
         if (obj != popup)
             return false;

         if (ev->type() == QEvent::MouseButtonPress) {
             popup->hide();
             editor->setFocus();
             return true;
         }

         if (ev->type() == QEvent::KeyPress) {

             bool consumed = false;
             int key = static_cast<QKeyEvent*>(ev)->key();
             switch (key) {
             case Qt::Key_Enter:
             case Qt::Key_Return:
                 doneCompletion();
                 consumed = true;

             case Qt::Key_Escape:
                 editor->setFocus();
                 popup->hide();
                 consumed = true;

             case Qt::Key_Up:
             case Qt::Key_Down:
             case Qt::Key_Home:
             case Qt::Key_End:
             case Qt::Key_PageUp:
             case Qt::Key_PageDown:
                 break;

             default:
                 editor->setFocus();
                 editor->event(ev);
                 popup->hide();
                 break;
             }

             return consumed;
         }

         return false;
     }

     void GSuggestCompletion::showCompletion(const QStringList &choices, const QStringList &hits)
     {

         if (choices.isEmpty() || choices.count() != hits.count())
             return;

         const QPalette &pal = editor->palette();
         QColor color = pal.color(QPalette::Disabled, QPalette::WindowText);

         popup->setUpdatesEnabled(false);
         popup->clear();
         for (int i = 0; i < choices.count(); ++i) {
             QTreeWidgetItem * item;
             item = new QTreeWidgetItem(popup);
             item->setText(0, choices[i]);
             item->setText(1, hits[i]);
             item->setTextAlignment(1, Qt::AlignRight);
             item->setTextColor(1, color);
         }
         popup->setCurrentItem(popup->topLevelItem(0));
         popup->resizeColumnToContents(0);
         popup->resizeColumnToContents(1);
         popup->adjustSize();
         popup->setUpdatesEnabled(true);

         int h = popup->sizeHintForRow(0) * qMin(7, choices.count()) + 3;
         popup->resize(popup->width(), h);

         popup->move(editor->mapToGlobal(QPoint(0, editor->height())));
         popup->setFocus();
         popup->show();
     }

     void GSuggestCompletion::doneCompletion()
     {
         timer->stop();
         popup->hide();
         editor->setFocus();
         QTreeWidgetItem *item = popup->currentItem();
         if (item) {
             editor->setText(item->text(0));
             QMetaObject::invokeMethod(editor, "returnPressed");
         }
     }

     void GSuggestCompletion::autoSuggest()
     {
         QString str = editor->text();
         QString url = QString(GSUGGEST_URL).arg(str);
         networkManager.get(QNetworkRequest(QString(url)));
     }

     void GSuggestCompletion::preventSuggest()
     {
         timer->stop();
     }

     void GSuggestCompletion::handleNetworkData(QNetworkReply *networkReply)
     {
         QUrl url = networkReply->url();
         if (!networkReply->error()) {
             QStringList choices;
             QStringList hits;

             QByteArray response(networkReply->readAll());
             QXmlStreamReader xml(response);
             while (!xml.atEnd()) {
                 xml.readNext();
                 if (xml.tokenType() == QXmlStreamReader::StartElement)
                     if (xml.name() == "suggestion") {
                         QStringRef str = xml.attributes().value("data");
                         choices << str.toString();
                     }
                 if (xml.tokenType() == QXmlStreamReader::StartElement)
                     if (xml.name() == "num_queries") {
                         QStringRef str = xml.attributes().value("int");
                         hits << str.toString();
                     }
             }

             showCompletion(choices, hits);
         }

         networkReply->deleteLater();
     }