googlesuggest.cpp Example File

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 #include "googlesuggest.h"

 const QString gsuggestUrl(QStringLiteral("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.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;
             break;

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

         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 QVector<QString> &choices)
 {
     if (choices.isEmpty())
         return;

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

     popup->setUpdatesEnabled(false);
     popup->clear();

     for (const auto &choice : choices) {
         auto item  = new QTreeWidgetItem(popup);
         item->setText(0, choice);
         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 = gsuggestUrl.arg(str);
     networkManager.get(QNetworkRequest(url));
 }

 void GSuggestCompletion::preventSuggest()
 {
     timer.stop();
 }

 void GSuggestCompletion::handleNetworkData(QNetworkReply *networkReply)
 {
     QUrl url = networkReply->url();
     if (networkReply->error() == QNetworkReply::NoError) {
         QVector<QString> 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();
 }