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c++qtqt4

Display a QMessageBox from a QThread

I want to display a message box from a separate thread, however, I get this error:

QThread: Destroyed while thread is still running

Can anyone explain how to display a message box from a thread?

Solution

  • Emit a signal. Since you cannot do UI stuff in a Qthread, instead send your message as an argument of your signal.

    signal decalaration in your qthread:

    signals:
  void write2SysStatus(QString theMessage);

    emitting the signal from the qthread:

    emit write2SysStatus("Some status");

    slot declaration/definition in QMainWindow:

    public slots:
  void eWriteLine ( QString theMessage ){
       //this is where you use you message box.
  }

    connecting of the slot and signal:

    connect(pFPSengine, SIGNAL(write2SysStatus(QString)), this,SLOT(eWriteLine(QString)));