QT PushButton freeze problem

  • Hello

    I have a small problem with the Push buttons on the QT. If I have a for() loop or do while logic under the push buttons, the cursor is freezing while the logic is not completely executed.


    @private slots:
    void on_pushButton_clicked ();
    void on_Blower_ON_Button_pressed();
    int on_Blower_OFF_Button_clicked();@

    With the for() loop cursor is available after it executes all logic inside the loop.

    @void MainWindow::on_pushButton_2_clicked()
    for (int i=0; i<7;i++)


    But when I have a do while, it freezes completely making it infinite loop

    @void MainWindow::on_Blower_ON_Button_pressed()

    }while (on_Blower_OFF_Button_clicked());


    Do I need to initialize the buttons in other way, or is the a specific functions that I need to call to make the buttons non blocking elements.

  • Lifetime Qt Champion


    It's your while loop that freezes everything. Do you really need that ? What do you do in that loop ?

    Also note that slots don't have return values.

  • Yes, do while loop freezes the cursor and program itself. I cannot click any other push button. My idea in this is that I have an on button (with do while loop inside ) and off button to stop doing what it was doing.
    Do while loop is required to make a motor running, because I need to send the same hexadecimal value every 40ms.

    Is it better instead of do while achieve the same result with the interrupts or make a parallel routine?

  • Lifetime Qt Champion

    Way simpler: use either a QTimer or the timerEvent from your widget.


    configure the timer to use a 40ms interval

    connect the QTimer timeout signal to a custom slot sending the value

    connect your start button to the QTimer start slot

    connect your stop button to the QTimer stop slot

    No loop needed

Log in to reply

Looks like your connection to Qt Forum was lost, please wait while we try to reconnect.