Qt 5.11 | Qt Network | Network Chat Example | chatdialog.cpp Example File

Qt 5.11.3 Reference Documentation

# chatdialog.cpp Example File

network-chat/chatdialog.cpp

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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!"));
          }
      }