- Qt 5.5
- Qt Network
- Network Chat Example
- chatdialog.cpp Example File
- Qt 5.5.1 Reference Documentation

# chatdialog.cpp Example File

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:
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    #include <QtWidgets>

    #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!"));
        }
    }