How to use QTimer for pausing and resuming ?

[qt_user_154]

Hello,

I need some help on the usage of Qtimer.

I work with Qt 5.0.2 and here my problem :

I am trying to develop a Timer, and the interface is simple :

There is just 2 button : the button "Start", to launch the timer, and the "Pause" Button, and a QtimeEdit to display the time.

This screenshot shows how it looks like : http://img834.imageshack.us/img834/1046/5ks6.png

The problem is that the pause function doesn't work. I have read all the documentation about Qtimer here : http://harmattan-dev.nokia.com/docs/...t4/qtimer.html and here : http://qt.developpez.com/doc/5.0-snapshot/qtimer/ , but no result.

This is the source code I have : (I put only what is needed)

// Creation of the Buttons and the time area
    void MainWindow::createBottom()
    {
 
        bottom = new QWidget();
 
        play = new QPushButton("Launch",this);
        pause = new QPushButton("Pause",this);
        play->setDisabled(false);
        pause->setDisabled(true);
        timeEdit = new QTimeEdit(this);
        timeEdit->setDisplayFormat("mm:ss");
 
        layout->addWidget(play);
        layout->addWidget(pause);
        layout->addWidget(timeEdit );
        bottom->setLayout(layout);
 
        connect(play, SIGNAL(clicked()), this, SLOT(startSimulation()));
        connect(pause, SIGNAL(clicked()), this, SLOT(pauseSimulation()));
    }
 
    // to resume the timer where is was stopped
    void MainWindow::resumeSimulation()
    {
        timer->blockSignals( false );
        pause->setText("Pause");
        pause->disconnect(SIGNAL(clicked()));
        connect(pause, SIGNAL(clicked()), this, SLOT(pauseSimulation())); 
        paused = false;
 
        timer->start();
        int timeOfPause = time->restart();
        int timeTotal = timeOfPause + timeElapsed;
        time->addMSecs(-timeTotal);
 
    }
 
    // to Start the timer
    void MainWindow::pauseSimulation()
    {
        timer->blockSignals(true);
        pause->setText("Resume");
        timer->stop();
        play->setDisabled(false);
        //pause->setDisabled(true);
        pause->disconnect(SIGNAL(clicked()));
 
        connect(pause, SIGNAL(clicked()), this, SLOT(resumeSimulation())); 
        paused = true;
    }
 
    // to Start the timer from zero.
    void MainWindow::startSimulation()
    {
 
        timer = new QTimer(this);
        connect(timer, SIGNAL(timeout()), this , SLOT(updateTime()));
        timer->start(500);
        play->setDisabled(true);
 
        pause->setDisabled(false);
    }
void MainWindow::updateTime()
{
    if(time == NULL)
    {
       time = new QTime(0,0,0,0);
       time->start();
    }
    //timeEdit->setTime(QTime::fromS(time->elapsed()));
    //time = &(time->addMSecs(1000));
    if(hasRestart)
    {
        time->restart();
        time->addMSecs(-timeElapsed);
        hasRestart = false;
    }
    else
    {
        timeElapsed =+ time->elapsed();
    }
    int seconds = 0;
    int minutes = 0;
    int hours = 0;
 
    if(!paused)
    {
            seconds = (timeElapsed/1000)%60;
            minutes = (timeElapsed/60000)%60;
            hours =  (timeElapsed/3600000)%24;
            std::cout << "Test : " << hours << ":" << minutes << ":" << seconds << std::endl;
            timeEdit->setTime(QTime(0,minutes,seconds,0));
            timeEdit->update();
    }
}

// Creation of the Buttons and the time area
    void MainWindow::createBottom()
    {

        bottom = new QWidget();

        play = new QPushButton("Launch",this);
        pause = new QPushButton("Pause",this);
        play->setDisabled(false);
        pause->setDisabled(true);
        timeEdit = new QTimeEdit(this);
        timeEdit->setDisplayFormat("mm:ss");

        layout->addWidget(play);
        layout->addWidget(pause);
        layout->addWidget(timeEdit );
        bottom->setLayout(layout);

        connect(play, SIGNAL(clicked()), this, SLOT(startSimulation()));
        connect(pause, SIGNAL(clicked()), this, SLOT(pauseSimulation()));
    }

    // to resume the timer where is was stopped
    void MainWindow::resumeSimulation()
    {
        timer->blockSignals( false );
        pause->setText("Pause");
        pause->disconnect(SIGNAL(clicked()));
        connect(pause, SIGNAL(clicked()), this, SLOT(pauseSimulation())); 
        paused = false;

        timer->start();
        int timeOfPause = time->restart();
        int timeTotal = timeOfPause + timeElapsed;
        time->addMSecs(-timeTotal);

    }

    // to Start the timer
    void MainWindow::pauseSimulation()
    {
        timer->blockSignals(true);
        pause->setText("Resume");
        timer->stop();
        play->setDisabled(false);
        //pause->setDisabled(true);
        pause->disconnect(SIGNAL(clicked()));

        connect(pause, SIGNAL(clicked()), this, SLOT(resumeSimulation())); 
        paused = true;
    }

    // to Start the timer from zero.
    void MainWindow::startSimulation()
    {

        timer = new QTimer(this);
        connect(timer, SIGNAL(timeout()), this , SLOT(updateTime()));
        timer->start(500);
        play->setDisabled(true);

        pause->setDisabled(false);
    }
void MainWindow::updateTime()
{
    if(time == NULL)
    {
       time = new QTime(0,0,0,0);
       time->start();
    }
    //timeEdit->setTime(QTime::fromS(time->elapsed()));
    //time = &(time->addMSecs(1000));
    if(hasRestart)
    {
        time->restart();
        time->addMSecs(-timeElapsed);
        hasRestart = false;
    }
    else
    {
        timeElapsed =+ time->elapsed();
    }
    int seconds = 0;
    int minutes = 0;
    int hours = 0;

    if(!paused)
    {
            seconds = (timeElapsed/1000)%60;
            minutes = (timeElapsed/60000)%60;
            hours =  (timeElapsed/3600000)%24;
            std::cout << "Test : " << hours << ":" << minutes << ":" << seconds << std::endl;
            timeEdit->setTime(QTime(0,minutes,seconds,0));
            timeEdit->update();
    }
}

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time, timer, and hasRestart are defined in a header file :

QTime* time;
QTimer *timer;
boolean hasRestart;

When I push the Start button, the timer starts well, but when I push "Pause" it only pause it on the graphic interface, but when I resume, it shows the present time as if it hadn't paused.

For instance :

I start.
I pause at 00:05. It blocks apparently the timer.
I wait for 10 seconds. I resume the timer, it shows 00:15 instead of 00:06

How could I fix that ?

Thank you !

EDIT : I have added some code that was missing in the updateTime() method.

[wysota]

Don't block signals, just call stop() on the timer. And don't disconnect any signals. Make the connections once in the constructor and don't modify them afterwards.

[qt_user_154]

Thanks wysota I have commented the lines :

void MainWindow::resumeSimulation()
{
   //timer->blockSignals( false );
   ...
}
 
 void MainWindow::pauseSimulation()
{
  //timer->blockSignals(true);
 ...
}

void MainWindow::resumeSimulation()
{
   //timer->blockSignals( false );
   ...
}

 void MainWindow::pauseSimulation()
{
  //timer->blockSignals(true);
 ...
}

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but this time when I resume it restarts from zero, not from the time I have paused.

[wagmare]

setInterval() use it http://harmattan-dev.nokia.com/docs/...#interval-prop

[qt_user_154]

you mean before timer->start() in the resumeSimulation() method ?

It doens't work...

[wysota]

but this time when I resume it restarts from zero, not from the time I have paused.

You need to adjust the way you calculate the time flow.

[qt_user_154]

Since it is a common pause, what sould I calculate ? I just want the timer to resume...

[wysota]

Since it is a common pause, what sould I calculate ? I just want the timer to resume...

Do you want me to give you hints or to write a complete solution for you? In general you have to have some variable where you calculate the amount of time that has passed since the timer was initialized and increase that amount upon every timer tick.