gtk4/org.gtkkn.bindings.gtk/DropTarget

DropTarget

open class DropTarget(pointer: <Error class: unknown class><<Error class: unknown class>>) : EventController

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 ctor@Gtk.DropTarget.new, passing in the GType of the data you want to receive and connect to the signal@Gtk.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));
}

GtkDropTarget supports more options, such as:

rejecting potential drops via the signal@Gtk.DropTarget::accept signal and the method@Gtk.DropTarget.reject function to let other drop targets handle the drop
tracking an ongoing drag operation before the drop via the signal@Gtk.DropTarget::enter, signal@Gtk.DropTarget::motion and signal@Gtk.DropTarget::leave signals
configuring how to receive data by setting the property@Gtk.DropTarget:preload property and listening for its availability via the property@Gtk.DropTarget: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 class@Gtk.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.

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 class@Gtk.DropControllerMotion.

Skipped during bindings generation

parameter n_types: n_types: Out parameter is not supported
parameter types: Array parameter of type GType is not supported

Constructors

DropTarget

constructor(type: <Error class: unknown class>, actions: <Error class: unknown class>)

Creates a new GtkDropTarget object.

constructor(pointer: <Error class: unknown class><<Error class: unknown class>>)

Types

Companion

object Companion

Properties

actions

open var actions: <Error class: unknown class>

The GdkDragActions that this drop target supports.

currentDrop

open val currentDrop: <Error class: unknown class>?

The GdkDrop that is currently being performed.

drop

open val drop: <Error class: unknown class>?

The GdkDrop that is currently being performed.

formats

open val formats: <Error class: unknown class>?

The GdkContentFormats that determine the supported data formats.

gtkDropTargetPointer

val gtkDropTargetPointer: <Error class: unknown class><<Error class: unknown class>>

gtkEventControllerPointer

val gtkEventControllerPointer: <Error class: unknown class><<Error class: unknown class>>

name

open var name: String?

The name for this controller, typically used for debugging purposes.

preload

open var preload: Boolean

Whether the drop data should be preloaded when the pointer is only hovering over the widget but has not been released.

propagationLimit

open var propagationLimit: PropagationLimit

The limit for which events this controller will handle.

propagationPhase

open var propagationPhase: PropagationPhase

The propagation phase at which this controller will handle events.

value

open val value: <Error class: unknown class>?

The value for this drop operation.

widget

open val widget: Widget?

The widget receiving the GdkEvents that the controller will handle.

Functions

connectAccept

fun connectAccept(connectFlags: <Error class: unknown class> = ConnectFlags(0u), handler: (<Error class: unknown class>) -> Boolean): <Error class: unknown class>

Emitted on the drop site when a drop operation is about to begin.

connectDrop

fun connectDrop(connectFlags: <Error class: unknown class> = ConnectFlags(0u), handler: (<Error class: unknown class>, x: Double, y: Double) -> Boolean): <Error class: unknown class>

Emitted on the drop site when the user drops the data onto the widget.

connectEnter

fun connectEnter(connectFlags: <Error class: unknown class> = ConnectFlags(0u), handler: (x: Double, y: Double) -> <Error class: unknown class>): <Error class: unknown class>

Emitted on the drop site when the pointer enters the widget.

connectLeave

fun connectLeave(connectFlags: <Error class: unknown class> = ConnectFlags(0u), handler: () -> Unit): <Error class: unknown class>

Emitted on the drop site when the pointer leaves the widget.

connectMotion

fun connectMotion(connectFlags: <Error class: unknown class> = ConnectFlags(0u), handler: (x: Double, y: Double) -> <Error class: unknown class>): <Error class: unknown class>

Emitted while the pointer is moving over the drop target.

getActions

open fun getActions(): <Error class: unknown class>

Gets the actions that this drop target supports.

getCurrentDrop

open fun getCurrentDrop(): <Error class: unknown class>?

Gets the currently handled drop operation.

getCurrentEvent

open fun getCurrentEvent(): <Error class: unknown class>?

Returns the event that is currently being handled by the controller.

getCurrentEventDevice

open fun getCurrentEventDevice(): <Error class: unknown class>?