在 Qt 中按下按钮时，GUI 设计不会更新

Question

I'm trying to change colors on a graphic view to simulate traffic lights but I'm not sure why the colors doesn't change when the start button is clicked

    void MainWindow::empezar_ciclo(){

    sleep_asm(3);  // waits a certain time to change color
    semdirE->setBrush(QBrush(Qt::red)); // changes the color of a drawed dot
}

    void MainWindow::on_start_clicked(){

  
    MainWindow:ui->start->hide();
   
   empezar_ciclo();}

Answer 1

it should work after all its following the program common order