chatdialog.cpp Example File

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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!"));
      }
  }