Fellow programmers,
I have a little problem and I can't find it's source.
I derived a new class from "Goocanvas::Canvas" (This one inherits Gtk::Container what's important, if you don't use Goocanvas you can still help) called "InteractiveBoard" and overloaded four functions which handle drag & drop events:
- bool on_drag_motion(const Glib::RefPtr< Gdk::DragContext >& context, int x, int y, guint time)
- void on_drag_data_received(const Glib::RefPtr<Gdk::DragContext>& context, int x, int y, const Gtk::SelectionData& selData, guint info, guint time)
- bool on_drag_drop(const Glib::RefPtr<Gdk::DragContext>& context, int x, int y, guint time)
- void on_drag_leave(const Glib::RefPtr<Gdk::DragContext>& context, guint time)
The problem is, "on_drag_motion" is called only once! And it should be called on every mouse movement. The program stops responding after finishing "on_drag_data_received" ("drag_get_data" is called within "on_drag_motion") and ending "on_drag_motion". If I remove "drag_get_data" it works as it should.
If I don't overload "on_drag_data_received" it works too but I need it. If I overload it with empty function, problem exists. It's the proof that the problem lays not in what I've written in my handler but in something I'm missing.
Here are the bodies of these functions:
Code:
bool InteractiveBoard::on_drag_motion(const Glib::RefPtr< Gdk::DragContext >& context, int x, int y, guint time)
{
std::cerr << "motion -- x: "<<x<<" y: "<<y<<std::endl;
if(draggedWidget)
{
std::cerr << "Dragging widget\n";
draggedWidgetRefPtr->set_property("x", x);
draggedWidgetRefPtr->set_property("y", y);
context->drag_status(Gdk::ACTION_COPY, time);
std::cerr << "After dragging->set status";
}
else
{
const Glib::ustring target = drag_dest_find_target(context);
if(target.empty()) return false;
requestedData = true;
dataRequestedForDrop = false;
std::cerr << "Calling drag_get_data\n";
drag_get_data(context, target, time);
std::cerr << "Returned! :)\n";
}
std::cerr << "Canvas::on_drag_motion start\n";
Goocanvas::Canvas::on_drag_motion(context,x,y,time);
std::cerr << "Canvas::on_drag_motion end\n";
return true;
}
void InteractiveBoard::on_drag_data_received(const Glib::RefPtr<Gdk::DragContext>& context, int x, int y, const Gtk::SelectionData& selData, guint info, guint time)
{
std::cerr << "I'm kinda in on_drag_data_received\n";
if(!draggedWidget)
{
std::cerr << "Creating ellipse at "<<x<<" "<<y<<std::endl;
draggedWidget = true;
draggedWidgetRefPtr = Goocanvas::Ellipse::create(x,y,50,50);
get_root_item()->add_child(draggedWidgetRefPtr);
}
if(dataRequestedForDrop && draggedWidget)
{
std::cerr << "Finishing drag\n";
context->drag_finish(true, false, time);
}
else if(!dataRequestedForDrop && draggedWidget)
{
std::cerr << "Calling context->set_status\n";
context->drag_status(Gdk::ACTION_COPY, time);
std::cerr << "Called\n";
}
}
bool InteractiveBoard::on_drag_drop(const Glib::RefPtr<Gdk::DragContext>& context, int x, int y, guint time)
{
std::cerr << "on_drag_drop";
const Glib::ustring target = drag_dest_find_target(context);
if(target.empty()) return false;
dataRequestedForDrop = true;
drag_get_data(context, target, time);
return true;
}
void InteractiveBoard::on_drag_leave(const Glib::RefPtr<Gdk::DragContext>& context, guint time)
{
std::cerr << "on_drag_leave\n";
if(!draggedWidget) return;
if(!dataRequestedForDrop)
draggedWidgetRefPtr->remove();
draggedWidgetRefPtr.reset();
draggedWidget = false;
Goocanvas::Canvas::on_drag_leave(context, time);
}
These functions are almost identical to ones showed in the ToolPallette example from gtkmm book:
http://git.gnome.org/browse/gtkmm-do...ette/canvas.cc
Sorry for my bad english. I'm from Poland, but I always try to write with some degree of communicative language. If you find any mistakes please correct me.
I count on your's help! :)
D&D motion event handler called only once. [gtkmm 3 && goocanvasmm (irrelevant)]
