window does not popup before process start -> tried sleep() method, but “fails”

Question

I tried to use the sleep method before some processes start just to give a popup window the time to appear:

    Processmethod()
{

    QDialog *ProcessMessage = new QDialog;      
    Ui::DialogProcessMessage Dialog;            
    Dialog.setupUi(ProcessMessage);             
    ProcessMessage->setModal(true);
    ProcessMessage->setAttribute(Qt::WA_DeleteOnClose); 
    ProcessMessage->show();

    sleep(500);

    PROCESSES START                     
}

My problem is, that the popup window just appears after the process is finished instead of before the process starts. If I deactivate the process that should start after the window appeared the popup window works fine.Are the processes responsible for the popup window fail? Where is my fault? greetings

Answer 1

Add

qApp->processEvents();

before the sleep call.

Answer 2

I assume sleep is Windows function? Do not use it. Use QTimer to start process later:

ProcessMessage->show();
QTimer::singleShot(500, processObject, SLOT(start()));