Qt 4.8: chatdialog.cpp Example File (network/network-chat/chatdialog.cpp)

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# chatdialog.cpp Example File

network/network-chat/chatdialog.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:
     **
     ** "Redistribution and use in source and binary forms, with or without
     ** modification, are permitted provided that the following conditions are
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     **   * Redistributions of source code must retain the above copyright
     **     notice, this list of conditions and the following disclaimer.
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     **     notice, this list of conditions and the following disclaimer in
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     **     from this software without specific prior written permission.
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     #include <QtGui>

     #include "chatdialog.h"

     ChatDialog::ChatDialog(QWidget *parent)
         : QDialog(parent)
     {
         setupUi(this);

         lineEdit->setFocusPolicy(Qt::StrongFocus);
         textEdit->setFocusPolicy(Qt::NoFocus);
         textEdit->setReadOnly(true);
         listWidget->setFocusPolicy(Qt::NoFocus);

         connect(lineEdit, SIGNAL(returnPressed()), this, SLOT(returnPressed()));
         connect(lineEdit, SIGNAL(returnPressed()), this, SLOT(returnPressed()));
         connect(&client, SIGNAL(newMessage(QString,QString)),
                 this, SLOT(appendMessage(QString,QString)));
         connect(&client, SIGNAL(newParticipant(QString)),
                 this, SLOT(newParticipant(QString)));
         connect(&client, SIGNAL(participantLeft(QString)),
                 this, SLOT(participantLeft(QString)));

         myNickName = client.nickName();
         newParticipant(myNickName);
         tableFormat.setBorder(0);
         QTimer::singleShot(10 * 1000, this, SLOT(showInformation()));
     }

     void ChatDialog::appendMessage(const QString &from, const QString &message)
     {
         if (from.isEmpty() || message.isEmpty())
             return;

         QTextCursor cursor(textEdit->textCursor());
         cursor.movePosition(QTextCursor::End);
         QTextTable *table = cursor.insertTable(1, 2, tableFormat);
         table->cellAt(0, 0).firstCursorPosition().insertText('<' + from + "> ");
         table->cellAt(0, 1).firstCursorPosition().insertText(message);
         QScrollBar *bar = textEdit->verticalScrollBar();
         bar->setValue(bar->maximum());
     }

     void ChatDialog::returnPressed()
     {
         QString text = lineEdit->text();
         if (text.isEmpty())
             return;

         if (text.startsWith(QChar('/'))) {
             QColor color = textEdit->textColor();
             textEdit->setTextColor(Qt::red);
             textEdit->append(tr("! Unknown command: %1")
                              .arg(text.left(text.indexOf(' '))));
             textEdit->setTextColor(color);
         } else {
             client.sendMessage(text);
             appendMessage(myNickName, text);
         }

         lineEdit->clear();
     }

     void ChatDialog::newParticipant(const QString &nick)
     {
         if (nick.isEmpty())
             return;

         QColor color = textEdit->textColor();
         textEdit->setTextColor(Qt::gray);
         textEdit->append(tr("* %1 has joined").arg(nick));
         textEdit->setTextColor(color);
         listWidget->addItem(nick);
     }

     void ChatDialog::participantLeft(const QString &nick)
     {
         if (nick.isEmpty())
             return;

         QList<QListWidgetItem *> items = listWidget->findItems(nick,
                                                                Qt::MatchExactly);
         if (items.isEmpty())
             return;

         delete items.at(0);
         QColor color = textEdit->textColor();
         textEdit->setTextColor(Qt::gray);
         textEdit->append(tr("* %1 has left").arg(nick));
         textEdit->setTextColor(color);
     }

     void ChatDialog::showInformation()
     {
         if (listWidget->count() == 1) {
             QMessageBox::information(this, tr("Chat"),
                                      tr("Launch several instances of this "
                                         "program on your local network and "
                                         "start chatting!"));
         }
     }