QThread movetoThread howto?



  • Dear People of the Internet, I'm realy confused about the usage of QThread.
    I got a little class which communicates over a SerialPort with a little robot.
    So far so good. Sadly this class needs to wait for the robot to finish with the execution of his task.

    So i got a small "commincation class"

    //conenction Object
    class SerialConnection: public QObject
    {
        Q_OBJECT
        public:
            explicit SerialConnection( QObject *parent = 0);
            virtual ~SerialConnection();
    
           //evil Method which needs alot of time to executed and needs to be threaded
            int move(QPoint);
    
         //other evil Method needs alot of time
         int concurWorld(bool showMercy);
    }
    

    I got a main class which calls the "move" and concurWorld methods. Those Methods wont be called at the same time.
    All i want to do is to Call those methods in a Thread so it doesnt block my main appplication.
    Somehow it should work like this

    void mainClass::callmove()
    {
        QThread * thread = new QThread();
        SerialConnection  * serial  = new SerialConnection();
       serial->moveToThread(thread);
     //at this point I got no clue how to continue
    
       
    }
    

    I know that i need to change the functions to Slots in my serialconnection class and i know that i can connect the start signal of the thread to one of those slots.
    But how can i parse some arguments to those methods and how can i get the return values? And how can i connect both of them to a thread when there is only the start singnal of thread?
    I feel so dump for asking such a question but the Internet itself seems to be split on deciding which is the right way to use QThreads.

    Thanks for the help



  • class SerialConnection: public QObject
    {
        Q_OBJECT
        public:
            explicit SerialConnection( QObject *parent = 0);
            virtual ~SerialConnection();
    signals:
    void moveReturned(int);
    void concurWorldReturned(int);
    public slots:
    void runMove(QPoint val){emit moveReturned(move(val));}
    void runConcurWorld(bool val){emit concurWorldReturned(concurWorld(val));}
    private:
           //evil Method which needs alot of time to executed and needs to be threaded
            int move(QPoint);
    
         //other evil Method needs alot of time
         int concurWorld(bool showMercy);
    }
    
    void mainClass::callmove()
    {
        QThread * thread = new QThread();
        SerialConnection  * serial  = new SerialConnection();
       serial->moveToThread(thread);
    connect(thread, SIGNAL(finished()), thread, SLOT(deleteLater()));
    connect(thread, SIGNAL(finished()), serial, SLOT(deleteLater()));
    thread->start();
    
       
    }
    

    now you can use any signal connected to the 2 new slots to run it (or use QMetaObject::invokeMethod with Qt::QueuedConnection) and when the process is finished the object will emit the signal with the return value



  • Thank you kind Sir! I'll always be in your debt!
    Cheers.


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