QAction, QToolButton, QToolBar & drag n drop

Dariusz

Hey

I'm trying to learn how I can implement a drag and drop on QToolBar... so far its quite interesting journey.

In essence what I understand so far is that QToolBar, holds QWidgets which points to QActions(widget->defaultAction());

(below code kinds jumps between eventFilter and dragEnterEvent/dropEvent)

So I have installed event filter(Qtoolbar one) on all my QWidgets inside QToolBar via a loop findChild<QWidget*>();

If I perform drag&drop operation on a QAction/QToolButton I'm doing something like : >

bool icToolBar::eventFilter(QObject *watched, QEvent *event) {

    if (event->type() == QEvent::Enter) {
        qDebug() << watched;
        if (!mPressed)mLastAction = static_cast<QToolButton *>(watched)->defaultAction(); // make sure I did not already press on some button/action.
    }

    if (event->type() == QEvent::Leave) {
        if (mLastAction && mPressed) {
            qDebug() << "I had last action thini so i must be dragging?";
        }
        if (!mPressed) {
            mLastAction = nullptr; // clear the last action entered
        };
    }

    if (event->type() == QEvent::MouseButtonPress) {
        mInitialPos = static_cast<QMouseEvent *>(event)->pos(); // I need it to determine drag trigger
        mButton = static_cast<QMouseEvent *>(event)->button(); // need to know which button for later reference
        mPressed = true; 
    }

    if (event->type() == QEvent::MouseMove) {
        if (mPressed && mLastAction != nullptr) { // ensuring that I pressed on a button and that i have it stored. 
            if ((static_cast<QMouseEvent *>(event)->pos() - mInitialPos).manhattanLength() >= QApplication::startDragDistance()) {
                performDragOp();
            }
        }
    }

    if (event->type() == QEvent::MouseButtonRelease) {
        mPressed = false;
        mLastAction = nullptr;
        mButton = Qt::NoButton;
    }

    return QObject::eventFilter(watched, event);
}

void icToolBar::performDragOp() {
    icInternalMime *mimeData = new icInternalMime(); // my custom mime
    mimeData->setMimeType(mType); // setting mime type
    mimeData->setActionBtn(mLastAction); // setting button I captured early

    QDrag *drag = new QDrag(this); // standard drag 
    drag->setMimeData(mimeData);

    switch (mButton) {
        case (Qt::LeftButton): { // deciding which drag type I want to have - no idea if thats the right way tho.
            drag->exec(Qt::MoveAction);
            break;
        }
        case (Qt::RightButton): {
            drag->exec(Qt::CopyAction);
            break;
        }

    }
//// no idea if that stuff needs to be here, debug decide.
    mPressed = false; 
    mLastAction = nullptr;
    mButton = Qt::NoButton;

//I presume after drag.exec() finishes this code runs next... How can I then clear the action that I pressed on. It remaing in a "press state" 
}


void icToolBar::dropEvent(QDropEvent *event) {
    event->accept();
    qDebug() << "im being dropped?"; // yay ? 
    const icInternalMime *mim = dynamic_cast<const icInternalMime *>(event->mimeData());

    QAction *act = mim->getActionBtn(); // retrieve action
    act->installEventFilter(this); // this dont work - and this is the issue. The newly added action, does not have event filter properly installed. So I cant drag it again... 

    addAction(act); // so this properly adds the action back to the toolbar - BUT, will the early configured signal connect() still work? 
    /// In future use insertAction() in order to specify exact position according to hover/drop/position cursor.

    QWidget::dropEvent(event);
}

Now here i have 3 issues.

Once Action gets dropped and re-added. Its event filter is incorrect. I need to re-install event filter on it again. How can I do this ? I can always loop over all children again but that feels "wrong".
If drop action is refused. The original button I pressed on to drag remain pressed. How can I reset its state?
3 . More question than issue. But if I execute the drag/drop this way. Do I need to re-configure connection() on action trigger? I'm hoping that it will still point to the right "command" ?

TIA :- )

Dariusz

Bump bump bump help :- )

Unsolved QAction, QToolButton, QToolBar & drag n drop