Event handling : Accessing another widget's property [SOLVED]

ccbaci

OK, this should be easy.

I tried to handle drop event onto a QGraphicsView widget. Incoming data dragged from a QTreeView widget. For that, I re-implemented these methods:

@void QGraphicsScene::dragEnterEvent(QGraphicsSceneDragDropEvent *event)
{
event.accept();
}

void QGraphicsScene::dragMoveEvent(QGraphicsSceneDragDropEvent *event)
{
event.accept();
}

void QGraphicsScene::dropEvent(QGraphicsSceneDragDropEvent *event)
{
event.accept();
}

void QGraphicsView::dropEvent(QDropEvent *event)
{
QPixmap pixmap(event->mimedata()->urls()[0].toString().remove(0,8));
this.scene()->addPixmap(pixmap);
}@

This works fine; but how can I change another graphicsview scene within this widget's drop event? That is:

@void QGraphicsView::dropEvent(QDropEvent *event)
{
QPixmap pixmap(event->mimedata()->urls()[0].toString().remove(0,8));
// I cannot access ui; and cannot access other widgets...:
ui->anotherview->scene()->addPixmap(pixmap);
}@

sierdzio

Well, does that not work? Are you getting any errors?

ccbaci

Access to Mainwindow widgets from QGraphicsView class is forbidden.

ui->anotherview doesn't work.

Should I create a subclass of QGraphicsView (that inherits it), then promote my graphicsview widgets to that class and create signals there? Then I can connect to mainwindow slots. That was the only way I could think of.

sierdzio

Wait so you have modified source code of Qt itself right now? I don't get your setup :)

In general, since you are reimplementing events you should subclass. Then there are numerous ways to get to your main window and update the other scene.

You can change mainWindow into a Singleton and then include it in your subclass (perfectly legal, although I find it ugly).

You can use meta object system to get to your parent (which probably is your MainWindow), then find the other view using findChildren<>() and set the property using QObject::setProperty().

Or you can send the signal from your subclass notifying your MainWindow (or anotherView directly) that a change needs to be made.

ccbaci

I actually rewrote drag drop events of qgraphics and qscene :) I get "inconsistent dll" warning but it worked fine. I will subclass them right now. I will try the meta object method as the signalling method (which was the only thing i could think of) requires more effort.

ccbaci

meta method worked fine man; thanks! btw, how do you accept an answer in this forum ? :)

sierdzio

Hey, that's nice to hear! Happy coding!

In general we just add "[Solved]" to the subject (edit your initial post, then add [Solved] to the title). I'll tag it for you.