googlesuggest.cpp Example File
network/googlesuggest/googlesuggest.cpp

 /****************************************************************************
 **
 ** 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 the examples of the Qt Toolkit.
 **
 ** $QT_BEGIN_LICENSE:LGPL$
 ** Commercial Usage
 ** Licensees holding valid Qt Commercial licenses may use this file in
 ** accordance with the Qt Commercial License Agreement provided with the
 ** Software or, alternatively, in accordance with the terms contained in
 ** a written agreement between you and Nokia.
 **
 ** GNU Lesser General Public License Usage
 ** Alternatively, this file may be used under the terms of the GNU Lesser
 ** General Public License version 2.1 as published by the Free Software
 ** Foundation and appearing in the file LICENSE.LGPL included in the
 ** packaging of this file.  Please review the following information to
 ** ensure the GNU Lesser General Public License version 2.1 requirements
 ** will be met: http://www.gnu.org/licenses/old-licenses/lgpl-2.1.html.
 **
 ** In addition, as a special exception, Nokia gives you certain additional
 ** rights.  These rights are described in the Nokia Qt LGPL Exception
 ** version 1.1, included in the file LGPL_EXCEPTION.txt in this package.
 **
 ** GNU General Public License Usage
 ** Alternatively, this file may be used under the terms of the GNU
 ** General Public License version 3.0 as published by the Free Software
 ** Foundation and appearing in the file LICENSE.GPL included in the
 ** packaging of this file.  Please review the following information to
 ** ensure the GNU General Public License version 3.0 requirements will be
 ** met: http://www.gnu.org/copyleft/gpl.html.
 **
 ** If you have questions regarding the use of this file, please contact
 ** Nokia at qt-info@nokia.com.
 ** $QT_END_LICENSE$
 **
 ****************************************************************************/

 #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();
 }