Qt 4.8: echowindow.cpp Example File (tools/echoplugin/echowindow/echowindow.cpp)

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# echowindow.cpp Example File

tools/echoplugin/echowindow/echowindow.cpp

     /****************************************************************************
     **
     ** Copyright (C) 2015 The Qt Company Ltd.
     ** Contact: http://www.qt.io/licensing/
     **
     ** This file is part of the examples of the Qt Toolkit.
     **
     ** $QT_BEGIN_LICENSE:BSD$
     ** You may use this file under the terms of the BSD license as follows:
     **
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     ** modification, are permitted provided that the following conditions are
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     **     notice, this list of conditions and the following disclaimer in
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     #include <QtGui>

     #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, SIGNAL(editingFinished()),
                 this, SLOT(sendEcho()));
         connect(button, SIGNAL(clicked()),
                 this, SLOT(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;
     }