Qt 5.11 | Qt Widgets | Echo Plugin Example | echowindow.cpp Example File

Qt 5.11.3 Reference Documentation

# echowindow.cpp Example File

tools/echoplugin/echowindow/echowindow.cpp

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      #include <QtWidgets>

      #include "echowindow.h"

      EchoWindow::EchoWindow()
      {
          createGUI();
          setLayout(layout);
          setWindowTitle("Echo Plugin Example");

          if (!loadPlugin()) {
              QMessageBox::information(this, "Error", "Could not load the plugin");
              lineEdit->setEnabled(false);
              button->setEnabled(false);
          }
      }

      void EchoWindow::sendEcho()
      {
          QString text = echoInterface->echo(lineEdit->text());
          label->setText(text);
      }

      void EchoWindow::createGUI()
      {
          lineEdit = new QLineEdit;
          label = new QLabel;
          label->setFrameStyle(QFrame::Box | QFrame::Plain);
          button = new QPushButton(tr("Send Message"));

          connect(lineEdit, &QLineEdit::editingFinished,
                  this, &EchoWindow::sendEcho);
          connect(button, &QPushButton::clicked,
                  this, &EchoWindow::sendEcho);

          layout = new QGridLayout;
          layout->addWidget(new QLabel(tr("Message:")), 0, 0);
          layout->addWidget(lineEdit, 0, 1);
          layout->addWidget(new QLabel(tr("Answer:")), 1, 0);
          layout->addWidget(label, 1, 1);
          layout->addWidget(button, 2, 1, Qt::AlignRight);
          layout->setSizeConstraint(QLayout::SetFixedSize);
      }

      bool EchoWindow::loadPlugin()
      {
          QDir pluginsDir(qApp->applicationDirPath());
      #if defined(Q_OS_WIN)
          if (pluginsDir.dirName().toLower() == "debug" || pluginsDir.dirName().toLower() == "release")
              pluginsDir.cdUp();
      #elif defined(Q_OS_MAC)
          if (pluginsDir.dirName() == "MacOS") {
              pluginsDir.cdUp();
              pluginsDir.cdUp();
              pluginsDir.cdUp();
          }
      #endif
          pluginsDir.cd("plugins");
          foreach (QString fileName, pluginsDir.entryList(QDir::Files)) {
              QPluginLoader pluginLoader(pluginsDir.absoluteFilePath(fileName));
              QObject *plugin = pluginLoader.instance();
              if (plugin) {
                  echoInterface = qobject_cast<EchoInterface *>(plugin);
                  if (echoInterface)
                      return true;
              }
          }

          return false;
      }