typer.cpp

#include "typer.h"
#include <QDebug>

Typer::Typer(QObject *parent) :
    QObject(parent)
{
    m_text = "The quick brown fox jumps over the lazy dog";
    m_idx = 0;
}

void Typer::letterPressed(QString letter)
{
    if ( letter.isEmpty() ) return;
    if ( m_idx >= m_text.size() ) return;

    qDebug() << m_text;
    QString rpl;

    if ( m_text.at(m_idx) == letter )
    {
        rpl = QString("<font color=\"green\">%1</font>").arg(letter);
    }
    else
    {
        rpl = QString("<font color=\"red\">%1</font>").arg(m_text.at(m_idx));
    }

    m_text.replace(m_idx, 1, rpl);
    qDebug() << m_text;
    m_idx += rpl.size();
}

QString Typer::getText()
{
    return m_text;
}

typer.h

#ifndef TYPER_H
#define TYPER_H

#include <QObject>
#include <QString>

class Typer : public QObject
{
    Q_OBJECT
public:
    explicit Typer(QObject *parent = 0);

    Q_INVOKABLE QString getText();

signals:
    void gameEnd();

public slots:
    void letterPressed(QString letter);

private:
    QString m_text;
    int m_idx;
};

#endif // TYPER_H