How to control MainWindow widget from Thread ?

Hiloshi

Hi All,

I create a MainWindow , a button and a listWidget on my mainwindow.cpp by:

MainWindow::MainWindow(QWidget *parent) : QMainWindow(parent), ui(new Ui::MainWindow)

void MainWindow::on_pushButton_2_clicked()
{
    ui->listWidget_2->addItem("abc");
}

Then I create a thread by Qthread as below:

class T3Thread : public QThread
{
    Q_OBJECT

private:
    void run()
     {
         //ui->listWidget_2->addItem("567");
         for (int i = 0; i <= 100; i++)
         {          
             delay(20);
         }
     }
};

I want to show some information to my listWiget_2, however listWidget_2 not belong to "T3Thread",
so compiler will fail if I add "ui->listWidget_2->addItem("567");".

I understand this issue is cause by ui not declared in T3Thread, but I do not now how to fix it.

Any suggestion will be very appreciate.

Thanks,

VRonin

Create a signal in the thread like Q_SIGNAL void addItemToList(const QString&);
Create a slot in MainWindow like void addItemToList(const QString& val){ui->listWidget_2->addItem(val);}
connect them connect(t3thread,&T3Thread::addItemToList,this,&MainWindow::addItemToList,Qt::QueuedConnection);
emit the signal from the thread when you want to add an item emit addItemToList("567");

P.S.
Almost mandatory reading: https://mayaposch.wordpress.com/2011/11/01/how-to-really-truly-use-qthreads-the-full-explanation/

Hiloshi

This post is deleted!

Hiloshi

@VRonin
Thanks for your help. I should spend some time to try your suggestion and study the link in more detail.