`GtkDropTarget` is an event controller to receive Drag-and-Drop operations.
The most basic way to use a `GtkDropTarget` to receive drops on a widget is to create it via [[email protected]], passing in the
`GType` of the data you want to receive and connect to the [[email protected]:GtkDropTarget:drop] signal to receive the
data:
```c 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);
g_signal_connect (target, "drop", G_CALLBACK (on_drop), self); gtk_widget_add_controller (GTK_WIDGET (self), GTK_EVENT_CONTROLLER ( target)); } ```
`GtkDropTarget` supports more options, such as:
* rejecting potential drops via the [[email protected]:GtkDropTarget:accept] signal and the [
[email protected]] function to let other drop targets handle the drop * tracking an ongoing drag operation before the drop
via the [[email protected]:GtkDropTarget:enter], [[email protected]:GtkDropTarget:motion] and [
[email protected]:GtkDropTarget:leave] signals * configuring how to receive data by setting the [
[email protected]:preload] property and listening for its availability via the [[email protected]:value] property
However, `GtkDropTarget` is ultimately modeled in a synchronous way and only supports data transferred via `GType`. If you want full control over an ongoing drop, the [[email protected]] 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.
If you are not interested in receiving the drop, but just want to update UI state during a Drag-and-Drop operation (e.g. switching tabs), you can use [[email protected]].