googlesuggest.cpp Example File

  /****************************************************************************
  **
  ** Copyright (C) 2016 The Qt Company Ltd.
  ** Contact: https://www.qt.io/licensing/
  **
  ** This file is part of the examples of the Qt Toolkit.
  **
  ** $QT_BEGIN_LICENSE:BSD$
  ** Commercial License Usage
  ** Licensees holding valid commercial Qt licenses may use this file in
  ** accordance with the commercial license agreement provided with the
  ** Software or, alternatively, in accordance with the terms contained in
  ** a written agreement between you and The Qt Company. For licensing terms
  ** and conditions see https://www.qt.io/terms-conditions. For further
  ** information use the contact form at https://www.qt.io/contact-us.
  **
  ** BSD License Usage
  ** Alternatively, 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 The Qt Company Ltd 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."
  **
  ** $QT_END_LICENSE$
  **
  ****************************************************************************/

  #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(1);
      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)
  {

      if (choices.isEmpty())
          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->setTextColor(0, color);
      }
      popup->setCurrentItem(popup->topLevelItem(0));
      popup->resizeColumnToContents(0);
      popup->setUpdatesEnabled(true);

      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;

          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();
                  }
          }

          showCompletion(choices);
      }

      networkReply->deleteLater();
  }