Qt 5.11 | Qt Network | Google Suggest Example | googlesuggest.cpp Example File

Qt 5.11.3 Reference Documentation

# googlesuggest.cpp Example File

googlesuggest/googlesuggest.cpp

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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();
      }