DropTarget
Object Hierarchy:
Description:
GtkDropTarget is an event controller implementing a simple way to receive Drag-and-Drop operations.
The most basic way to use a DropTarget to receive drops on a widget is to create it via DropTarget passing in the Type of the data you want to receive and connect to the on_drop signal to receive the data:
static gboolean
on_drop (GtkDropTarget *target,
const GValue *value,
double x,
double y,
gpointer data)
{
MyWidget *self = data;
// Call the appropriate setter depending on the type of data
// that we received
if (G_VALUE_HOLDS (value, G_TYPE_FILE))
my_widget_set_file (self, g_value_get_object (value));
else if (G_VALUE_HOLDS (value, GDK_TYPE_PIXBUF))
my_widget_set_pixbuf (self, g_value_get_object (value));
else
return FALSE;
return TRUE;
}
static void
my_widget_init (MyWidget *self)
{
GtkDropTarget *target =
gtk_drop_target_new (G_TYPE_INVALID, GDK_ACTION_COPY);
// This widget accepts two types of drop types: GFile objects
// and GdkPixbuf objects
gtk_drop_target_set_gtypes (target, (GTypes [2]) {
G_TYPE_FILE,
GDK_TYPE_PIXBUF,
}, 2);
gtk_widget_add_controller (GTK_WIDGET (self), GTK_EVENT_CONTROLLER (target));
}
DropTarget supports more options, such as:
* rejecting potential drops via the accept signal and the reject function to let other drop targets handle the drop * tracking an ongoing drag operation before the drop via the enter, motion and leave signals * configuring how to receive data by setting the preload property and listening for its availability via the value property
However, DropTarget is ultimately modeled in a synchronous way and only supports data transferred via Type. If you want full control over an ongoing drop, the DropTargetAsync object gives you this ability.
While a pointer is dragged over the drop target's widget and the drop has not been rejected, that widget will receive the gtk_state_flag_drop_active state, which can be used to style the widget.