DropTarget

Object Hierarchy:

Object hierarchy for DropTarget

Description:

[ CCode ( type_id = "gtk_drop_target_get_type ()" ) ]
public class DropTarget : EventController

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.


Namespace: Gtk
Package: gtk4

Content:

Properties:

  • public DragAction actions { get; set; }
    The DragActions that this drop target supports
  • public Drop drop { get; }
    The Drop that is currently being performed
  • public ContentFormats formats { owned get; }
    The ContentFormats that determine the supported data formats
  • public bool preload { get; set; }
    Whether the drop data should be preloaded when the pointer is only hovering over the widget but has not been released.
  • public Value value { get; }
    The value for this drop operation or null if the data has not been loaded yet or no drop operation is going on.

Creation methods:

Methods:

Signals:

  • public signal bool accept (Drop drop)
    The accept signal is emitted on the drop site when a drop operation is about to begin.
  • public signal DragAction enter (double x, double y)
    The enter signal is emitted on the drop site when the pointer enters the widget.
  • public signal void leave ()
    The leave signal is emitted on the drop site when the pointer leaves the widget.
  • public signal DragAction motion (double x, double y)
    The motion signal is emitted while the pointer is moving over the drop target.
  • public signal bool on_drop (Value value, double x, double y)
    The on_drop signal is emitted on the drop site when the user drops the data onto the widget.

Inherited Members:

All known members inherited from class Gtk.EventController
All known members inherited from class GLib.Object