Timer stop from slot

Anna

Hello to all,

I've got a problem concerning a timer: I would like to have it started when a button is clicked and stop it, when the button is clicked again.
But I can't access the timer created in the constructor by a slot or a function...
How can I do it right?

@Andon::Andon(QWidget *parent) :
QWidget(parent),
ui(new Ui::Andon)
{
ui->setupUi(this);

QTimer *timer = new QTimer(this);
connect(timer, SIGNAL(timeout()), this, SLOT(showTime()));

}

void Andon::on_pushButton_clicked()
{

if(ui->pushButton->isChecked())
{
    ui->pushButton->setText("Stop");
    timer.start(1000);
}
else
{
    ui->pushButton->setText("Start");
    timer.stop();
}

}@

goetz

you must put the variable holding the pointer to the time as a member variable into the class:

@
class QTimer;

class Andon : public QWidget
{
Q_OBJECT
public:
Andon(QWidget *parent);

// more stuff

private:
QTimer *timer;
};

// in the implementation:

Andon::Andon(QWidget *parent) :
    QWidget(parent),
    ui(new Ui::Andon)
{
    ui->setupUi(this);

    timer = new QTimer(this);
    connect(timer, SIGNAL(timeout()), this, SLOT(showTime()));
}

void Andon::on_pushButton_clicked()
{

    if(ui->pushButton->isChecked())
    {
        ui->pushButton->setText("Stop");
        timer->start(1000);
    }
    else
    {
        ui->pushButton->setText("Start");
        timer->stop();
    }
}
@

Also not the change of timer.start to timer->start, as you are operating on a pointer.

DeVeL-2010

Hi Anna,

make *QTimer timer a member variable of your class Andon. Then you can use it also in Andon::on_pushButton_clicked() like
@ timer->stop();@

uranusjr

Shouldn't it be timer->stop()?

To access timer, you need to declare it as an instance variable, not a local variable in the constructor. The following should work:

@
class Andon : public QWidget
{
Q_OBJECT

public:
Andon(QWidget *parent = 0);

public slots:
void on_pushButton_clicked();

private:
QTimer *timer;
};

Andon::Andon(QWidget *parent) :
QWidget(parent),
ui(new Ui::Andon)
{
ui->setupUi(this);

timer = new QTimer(this);
connect(timer, SIGNAL(timeout()), this, SLOT(showTime()));

}

void Andon::on_pushButton_clicked()
{

if(ui->pushButton->isChecked())
{
    ui->pushButton->setText("Stop");
    timer->start(1000);
}
else
{
    ui->pushButton->setText("Start");
    timer->stop();
}

}
@

Anna

thank you for your kind replies!

I've implemented it in my andon class and also created an instance in the constructor like uranusjr wrote.
but now i get the error-message: request for member 'start' in '((Andon*)this)->Andon::timer', which is of non-class type 'QTimer*'

goetz

Did you change timer.start() to timer->start() (and the same with stop too)?

Anna

oh, right! that was it ^^

thank you guys!