Timer doesn't stop

[smoon]

Hi,

I have the problem, that the timer doesn't stop. What I'm doing wrong?

QBasicTimer *timer = new QBasicTimer();
timer->start(1000, this);
qDebug() << timer->timerId();
while(timer->isActive()) {
// do something
}

QBasicTimer *timer = new QBasicTimer();
timer->start(1000, this);
qDebug() << timer->timerId();
while(timer->isActive()) {
// do something
}

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[unit]

From QT Doc: This is a fast, lightweight, and low-level class used by Qt internally. We recommend using the higher-level QTimer class rather than this class if you want to use timers in your applications. Note that this timer is a repeating timer that will send subsequent timer events unless the stop() function is called.

[smoon]

Also tried QTimer with setSingleShot(true), same Problem...

[unit]

Ok. I known problem. You should use qApp->processEvents(); in while loop. I write simple code with two type of timer. Try it.

#ifndef MAINWINDOW_H
#define MAINWINDOW_H
 
#include <QMainWindow>
#include <QBasicTimer>
#include <QTimer>
 
namespace Ui {
    class MainWindow;
}
 
class MainWindow : public QMainWindow
{
    Q_OBJECT
 
public:
    explicit MainWindow(QWidget *parent = 0);
    ~MainWindow();
 
private:
    void timerEvent(QTimerEvent * event);
 
private slots:
    void on_pushButton_clicked();
    void on_pushButton_2_clicked();
 
private:
    Ui::MainWindow *ui;
    int isRun;
    QBasicTimer *basictimer;
    QTimer *timer;
};
 
#endif // MAINWINDOW_H

#ifndef MAINWINDOW_H
#define MAINWINDOW_H

#include <QMainWindow>
#include <QBasicTimer>
#include <QTimer>

namespace Ui {
    class MainWindow;
}

class MainWindow : public QMainWindow
{
    Q_OBJECT

public:
    explicit MainWindow(QWidget *parent = 0);
    ~MainWindow();

private:
    void timerEvent(QTimerEvent * event);

private slots:
    void on_pushButton_clicked();
    void on_pushButton_2_clicked();

private:
    Ui::MainWindow *ui;
    int isRun;
    QBasicTimer *basictimer;
    QTimer *timer;
};

#endif // MAINWINDOW_H

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#include "mainwindow.h"
#include "ui_mainwindow.h"
 
MainWindow::MainWindow(QWidget *parent) :
    QMainWindow(parent),
    ui(new Ui::MainWindow)
{
    ui->setupUi(this);
    isRun = 0;
}
 
MainWindow::~MainWindow()
{
    delete ui;
}
 
void MainWindow::on_pushButton_clicked()
{
    timer = new QTimer();
    timer->setSingleShot(true);
    timer->start(5000);
    int i=0;
    while(timer->isActive())
    {
        ++i;
        ui->label->setText("Running " + QString::number(i));
        qApp->processEvents();
    }
    ui->label->setText("Stopped");
    delete timer;
}
 
void MainWindow::on_pushButton_2_clicked()
{
    basictimer = new QBasicTimer();
    isRun=1;
    basictimer->start(5000, this);
    int i=0;
    while(isRun)
    {
        ++i;
        ui->label->setText("Running " + QString::number(i));
        qApp->processEvents();
    }
    ui->label->setText("Stopped");
    delete basictimer;
}
 
void MainWindow::timerEvent(QTimerEvent * event)
{
    if(event->timerId()==basictimer->timerId())
    {
        basictimer->stop();
        isRun=0;
    }
    else QMainWindow::timerEvent(event);
}

#include "mainwindow.h"
#include "ui_mainwindow.h"

MainWindow::MainWindow(QWidget *parent) :
    QMainWindow(parent),
    ui(new Ui::MainWindow)
{
    ui->setupUi(this);
    isRun = 0;
}

MainWindow::~MainWindow()
{
    delete ui;
}

void MainWindow::on_pushButton_clicked()
{
    timer = new QTimer();
    timer->setSingleShot(true);
    timer->start(5000);
    int i=0;
    while(timer->isActive())
    {
        ++i;
        ui->label->setText("Running " + QString::number(i));
        qApp->processEvents();
    }
    ui->label->setText("Stopped");
    delete timer;
}

void MainWindow::on_pushButton_2_clicked()
{
    basictimer = new QBasicTimer();
    isRun=1;
    basictimer->start(5000, this);
    int i=0;
    while(isRun)
    {
        ++i;
        ui->label->setText("Running " + QString::number(i));
        qApp->processEvents();
    }
    ui->label->setText("Stopped");
    delete basictimer;
}

void MainWindow::timerEvent(QTimerEvent * event)
{
    if(event->timerId()==basictimer->timerId())
    {
        basictimer->stop();
        isRun=0;
    }
    else QMainWindow::timerEvent(event);
}

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[smoon]

Thanks, it's working now. Used your first example with QTimer.

[vinithr]

Thanks This post really helped me lot.