Timer not connecting to private SLOT

[been_1990]

This is my header:

#ifndef ALARMH_H
#define ALARMH_H
 
class Alarm : public QObject
{
    Q_OBJECT
 
public:
    Alarm(QString file)
{
// code here
}
    int parseXML(QDomDocument doc, QString file)
{
// code here
}
    void checkAlarm()
    {
        QTimer *timer = new QTimer(this);
        connect(timer, SIGNAL(timeout()), this, SLOT(checkTime()));
        qDebug() << timer->timerId();
        timer->start(100);
    }
private:
    QString alarmName;
    QTime alarmTime;
    QDate alarmDate;
    QString alarmSound;
    QString alarmMessage;
    QString alarmApp;
    QString alarmAppArg;
 
signals:
    void soundAlarm();
 
private slots:
    void checkTime()
    {
        qDebug() << "check ....";
    }
 
 
};
#endif // ALARMH_H

#ifndef ALARMH_H
#define ALARMH_H

class Alarm : public QObject
{
    Q_OBJECT

public:
    Alarm(QString file)
{
// code here
}
    int parseXML(QDomDocument doc, QString file)
{
// code here
}
    void checkAlarm()
    {
        QTimer *timer = new QTimer(this);
        connect(timer, SIGNAL(timeout()), this, SLOT(checkTime()));
        qDebug() << timer->timerId();
        timer->start(100);
    }
private:
    QString alarmName;
    QTime alarmTime;
    QDate alarmDate;
    QString alarmSound;
    QString alarmMessage;
    QString alarmApp;
    QString alarmAppArg;

signals:
    void soundAlarm();

private slots:
    void checkTime()
    {
        qDebug() << "check ....";
    }


};
#endif // ALARMH_H

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I use it in .cpp:

Alarm a(filename);
a.checkAlarm();

Alarm a(filename);
a.checkAlarm();

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But the timer somehow does not call the SLOT once it's timed out. Probably my mistake, but where?

[yogeshgokul]

Please create your timer variable class level. So now your header will be:

#ifndef ALARMH_H
#define ALARMH_H
 
class Alarm : public QObject
{
    Q_OBJECT
    QTimer *timer;
public:
    Alarm(QString file)
{
// code here
}
    int parseXML(QDomDocument doc, QString file)
{
// code here
}
    void checkAlarm()
    {
        timer = new QTimer(this);
        if(!connect(timer, SIGNAL(timeout()), this, SLOT(checkTime()))
        {
           qDebug()<<"Critical!! Cannot connect";
         }
 
        qDebug() << timer->timerId();
        timer->start(100);
    }
private:
    QString alarmName;
    QTime alarmTime;
    QDate alarmDate;
    QString alarmSound;
    QString alarmMessage;
    QString alarmApp;
    QString alarmAppArg;
 
signals:
    void soundAlarm();
 
private slots:
    void checkTime()
    {
        qDebug() << "check ....";
    }
 
 
};
#endif // ALARMH_H

#ifndef ALARMH_H
#define ALARMH_H
 
class Alarm : public QObject
{
    Q_OBJECT
    QTimer *timer;
public:
    Alarm(QString file)
{
// code here
}
    int parseXML(QDomDocument doc, QString file)
{
// code here
}
    void checkAlarm()
    {
        timer = new QTimer(this);
        if(!connect(timer, SIGNAL(timeout()), this, SLOT(checkTime()))
        {
           qDebug()<<"Critical!! Cannot connect";
         }
        
        qDebug() << timer->timerId();
        timer->start(100);
    }
private:
    QString alarmName;
    QTime alarmTime;
    QDate alarmDate;
    QString alarmSound;
    QString alarmMessage;
    QString alarmApp;
    QString alarmAppArg;
 
signals:
    void soundAlarm();
 
private slots:
    void checkTime()
    {
        qDebug() << "check ....";
    }
 
 
};
#endif // ALARMH_H

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[been_1990]

Still no sign of the SLOT being called.

[wysota]

You are creating your object on the stack. If it's inside some scope, like a function or method other than main, it will go out of scope and be destroyed.

[been_1990]

Ok, I finnaly understand the whole heap/stack stuff now. Thanks wysota.
It's working now.
Off topic:
What do you think about the Class? Will having , let's say, 20 new Alarm classes affect the programs usage of computers rescources to much?