I've the following situation:
Basically I've a QTreeWidget with some items, and a canvas that's a subclass of a QGraphicsView. What I want to accomplish is to drag a QTreeWidgetItem in the QGraphicsView subclass. When the mouse is released in the QGraphicsView subclass I want to create a new shape (let's say a circle) with some data of the dragged item (let's say the name itself written inside the circle).
I was able to enable the drag from the QTreeWidget by using the setDragEnabled(true) method, and I'm able to receive the event in the QGraphicsView, because when I enter its area it calls the dragEnterEvent.
In my subclass I've a QGraphicsScene, like this:
#ifndef SEQUENCECANVAS_HPP_
#define SEQUENCECANVAS_HPP_
#include <QWidget>
#include <QGraphicsScene>
#include <QGraphicsView>
class SequenceCanvas : public QGraphicsView {
Q_OBJECT
public:
SequenceCanvas(QWidget* parent = nullptr);
virtual ~SequenceCanvas() = default;
protected:
void dragEnterEvent(QDragEnterEvent* event) override;
void dropEvent(QDropEvent* event) override;
private:
void createWidgets();
void createLayout();
private:
QGraphicsScene m_scene;
};
#endif // !SEQUENCECANVAS_HPP_
#include "SequenceCanvas.hpp"
#include <QString>
#include <QHBoxLayout>
#include <QDragEnterEvent>
#include <QMimeData>
SequenceCanvas::SequenceCanvas(QWidget* parent) :
QGraphicsView(parent) {
createWidgets();
createLayout();
setScene(&m_scene);
setAcceptDrops(true);
}
void SequenceCanvas::dragEnterEvent(QDragEnterEvent* event) {
event->acceptProposedAction(); // no filter at the moment I just want to test
}
void SequenceCanvas::dropEvent(QDropEvent* event) {
int i = 0; // just for putting a breakpoint now. Its breakpoint is never raised
}
void SequenceCanvas::createWidgets() {
}
void SequenceCanvas::createLayout() {
}
Even if the dragEnterEvent is called when my mouse enter my widget during the drag, the dropEvent method is not called, so when I release the mouse inside my SequenceCanvas class nothing happens.
Basically I've two questions:
- How can I raise the drop event inside my
SequenceCanvasclass that's a subclass ofQGraphicsView? - How can I pass custom data (let's say a vector of strings) with the drop event, so I can pass all needed information for managing the event?
EDIT:
I missed to reimplement the void dragMoveEvent(QDragMoveEvent* event) method. I've added it and now I receive drop events. I need to know how to pass custom data with a drag-drop event now... Thanks to zeFrenchy.
My class body now is:
SequenceCanvas::SequenceCanvas(QWidget* parent) :
QGraphicsView(parent) {
createWidgets();
createLayout();
setScene(&m_scene);
setAcceptDrops(true);
bool ok = acceptDrops();
}
///////////////////////////////////////////////////////////////////////////////
// VIRTUAL PROTECTED SECTION //
///////////////////////////////////////////////////////////////////////////////
void SequenceCanvas::dragEnterEvent(QDragEnterEvent* event) {
event->acceptProposedAction();
}
void SequenceCanvas::dragMoveEvent(QDragMoveEvent* event) {
event->acceptProposedAction();
}
void SequenceCanvas::dropEvent(QDropEvent* event) {
int i = 0;
}
///////////////////////////////////////////////////////////////////////////////
// PRIVATE SECTION //
///////////////////////////////////////////////////////////////////////////////
void SequenceCanvas::createWidgets() {
}
void SequenceCanvas::createLayout() {
}
