DropTarget

gtk.drop_target.DropTarget is an event controller to receive Drag-and-Drop operations.

The most basic way to use a gtk.drop_target.DropTarget to receive drops on a widget is to create it via gtk.drop_target.DropTarget.new_, passing in the gobject.types.TYPE_FLAG_RESERVED_ID_BIT of the data you want to receive and connect to the gtk.drop_target.DropTarget.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, (GType [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));
}

gtk.drop_target.DropTarget supports more options, such as:

rejecting potential drops via the gtk.drop_target.DropTarget.accept signal and the gtk.drop_target.DropTarget.reject function to let other drop targets handle the drop
tracking an ongoing drag operation before the drop via the gtk.drop_target.DropTarget.enter, gtk.drop_target.DropTarget.motion and gtk.drop_target.DropTarget.leave signals
configuring how to receive data by setting the gtk.drop_target.DropTarget.gboolean property and listening for its availability via the gtk.drop_target.DropTarget.GObject.Value property

However, gtk.drop_target.DropTarget is ultimately modeled in a synchronous way and only supports data transferred via gobject.types.TYPE_FLAG_RESERVED_ID_BIT. If you want full control over an ongoing drop, the gtk.drop_target_async.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.types.StateFlags.DropActive 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 gtk.drop_controller_motion.DropControllerMotion.

class DropTarget : EventController {

this(gobject.types.GType type, gdk.types.DragAction actions);

gdk.types.DragAction getActions();

gdk.drop.Drop getCurrentDrop();

gdk.drop.Drop getDrop();

gdk.content_formats.ContentFormats getFormats();

gobject.types.GType[] getGtypes();

bool getPreload();

gobject.value.Value getValue();

void reject();

void setActions(gdk.types.DragAction actions);

void setGtypes(gobject.types.GType[] types);

void setPreload(bool preload);

ulong connectAccept(T callback, Flag!"After" after);

ulong connectDrop(T callback, Flag!"After" after);

ulong connectEnter(T callback, Flag!"After" after);

ulong connectLeave(T callback, Flag!"After" after);

ulong connectMotion(T callback, Flag!"After" after);

}

Constructors

this this(gobject.types.GType type, gdk.types.DragAction actions): Creates a new gtk.drop_target.DropTarget object.

Members

Functions

connectAccept ulong connectAccept(T callback, Flag!"After" after): Connect to Accept signal.
connectDrop ulong connectDrop(T callback, Flag!"After" after): Connect to Drop signal.
connectEnter ulong connectEnter(T callback, Flag!"After" after): Connect to Enter signal.
connectLeave ulong connectLeave(T callback, Flag!"After" after): Connect to Leave signal.
connectMotion ulong connectMotion(T callback, Flag!"After" after): Connect to Motion signal.
getActions gdk.types.DragAction getActions(): Gets the actions that this drop target supports.
getCurrentDrop gdk.drop.Drop getCurrentDrop(): Gets the currently handled drop operation.
getDrop gdk.drop.Drop getDrop(): Gets the currently handled drop operation.
getFormats gdk.content_formats.ContentFormats getFormats(): Gets the data formats that this drop target accepts.
getGtypes gobject.types.GType[] getGtypes(): Gets the list of supported gobject.types.TYPE_FLAG_RESERVED_ID_BITs that can be dropped on the target.
getPreload bool getPreload(): Gets whether data should be preloaded on hover.
getValue gobject.value.Value getValue(): Gets the current drop data, as a gobject.value.Value.
reject void reject(): Rejects the ongoing drop operation.
setActions void setActions(gdk.types.DragAction actions): Sets the actions that this drop target supports.
setGtypes void setGtypes(gobject.types.GType[] types): Sets the supported gobject.types.TYPE_FLAG_RESERVED_ID_BITs for this drop target.
setPreload void setPreload(bool preload): Sets whether data should be preloaded on hover.

Inherited Members

From EventController

getCurrentEvent gdk.event.Event getCurrentEvent(): Returns the event that is currently being handled by the controller.
getCurrentEventDevice gdk.device.Device getCurrentEventDevice(): Returns the device of the event that is currently being handled by the controller.
getCurrentEventState gdk.types.ModifierType getCurrentEventState(): Returns the modifier state of the event that is currently being handled by the controller.
getCurrentEventTime uint getCurrentEventTime(): Returns the timestamp of the event that is currently being handled by the controller.
getName string getName(): Gets the name of controller.
getPropagationLimit gtk.types.PropagationLimit getPropagationLimit(): Gets the propagation limit of the event controller.
getPropagationPhase gtk.types.PropagationPhase getPropagationPhase(): Gets the propagation phase at which controller handles events.
getWidget gtk.widget.Widget getWidget(): Returns the gtk.widget.Widget this controller relates to.
reset void reset(): Resets the controller to a clean state.
setName void setName(string name): Sets a name on the controller that can be used for debugging.
setPropagationLimit void setPropagationLimit(gtk.types.PropagationLimit limit): Sets the event propagation limit on the event controller.
setPropagationPhase void setPropagationPhase(gtk.types.PropagationPhase phase): Sets the propagation phase at which a controller handles events.
setStaticName void setStaticName(string name): Sets a name on the controller that can be used for debugging.

gtk drop_target classes

DropTarget