Qt multithreading and let the second thread update the main (UI) thread

[Cupidvogel]

So I have a view (say QFrame) in the main thread (currently there is only a single thread where the entire application resides), where I need to show some query results when the user enters some query term in the text box and presses Enter. This is how it works, I have class called QueryFinder which I instantiate with the query term. Then I call execute(), which polls some internal database for some time to get query results. While instantiating QueryFinder, I also pass the view (the QFrame from which the user queried) and that is held as a view object in the QueryFinder class. Whenever any query result match is found, I call something like fView->updateView(searchResult), and the view has the appropriate method update to show the result. The results keep on coming until the database polling is complete.

Now the database polling is pretty memory intensive, so while the querying goes on, the UI becomes kind of unresponsive. A loading gif image, for example, which signifies the ongoing querying, often stalls and freezes. So I want to separate out the entire querying part into a separate thread, and that thread should poll, and update the view (which is in a separate thread, the main one). How do I do this in Qt/C++? Here is my pseudocode:

//view code
//after user presses enter
if (!finder)
{
    finder->stop();
}
finder = new QueryFinder(this, queryTerm);
finder->execute();
 
void updateView(QueryResult &result)
{
    //display the query result properly
}
 
//QueryFinder code, header file
class QueryFinder: public QObject
{
    public:
        QUeryFinder(QWidget *, QueryTerm&);
        void execute();
        void stop();
 
    private:
        bool shouldStop;
        QWidget *fView;
        QueryTerm fTerm;
}
 
 
//QueryFinder code, implementation file
QueryFinder::QueryFinder(QWidget *w, QueryTerm& term): fView(w), fTerm(term)
{
    shouldStop = false;
}
 
void QueryFinder::execute()
{
    //do the polling and if any result found, say newResult, update view, but only if no new query request has come in 
    //the meantime, else abnson this object altogether
    while (cursor->hasNext()) {
        newResult = cursor->getCurResult();
        if (!shouldStop)
            fView->updateView(newResult);
        else
            return;
    }
}
 
void QueryFinder::stop()
{
    shouldStop = true;
}

//view code
//after user presses enter
if (!finder)
{
    finder->stop();
}
finder = new QueryFinder(this, queryTerm);
finder->execute();

void updateView(QueryResult &result)
{
    //display the query result properly
}

//QueryFinder code, header file
class QueryFinder: public QObject
{
    public:
        QUeryFinder(QWidget *, QueryTerm&);
        void execute();
        void stop();

    private:
        bool shouldStop;
        QWidget *fView;
        QueryTerm fTerm;
}


//QueryFinder code, implementation file
QueryFinder::QueryFinder(QWidget *w, QueryTerm& term): fView(w), fTerm(term)
{
    shouldStop = false;
}

void QueryFinder::execute()
{
    //do the polling and if any result found, say newResult, update view, but only if no new query request has come in 
    //the meantime, else abnson this object altogether
    while (cursor->hasNext()) {
        newResult = cursor->getCurResult();
        if (!shouldStop)
            fView->updateView(newResult);
        else
            return;
    }
}

void QueryFinder::stop()
{
    shouldStop = true;
}

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If you observe, not only the updating the view, even the stop method needs to go from one thread to another. How do I accomplish this? I have never done any multithreading in Qt/C++.