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

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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

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object Companion

Properties

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open var actions: <Error class: unknown class>

The GdkDragActions that this drop target supports.

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

The GdkDrop that is currently being performed.

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

The GdkDrop that is currently being performed.

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

The GdkContentFormats that determine the supported data formats.

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val gtkDropTargetPointer: <Error class: unknown class><<Error class: unknown class>>
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val gtkEventControllerPointer: <Error class: unknown class><<Error class: unknown class>>
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open var name: String?

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

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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.

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The limit for which events this controller will handle.

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The propagation phase at which this controller will handle events.

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

The value for this drop operation.

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open val widget: Widget?

The widget receiving the GdkEvents that the controller will handle.

Functions

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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.

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

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

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

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

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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.

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

Emitted while the pointer is moving over the drop target.

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

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

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

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

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

Returns the modifier state of the event that is currently being handled by the controller.

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

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

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open fun reject()

Rejects the ongoing drop operation.

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open fun reset()

Resets the @controller to a clean state.

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open fun setStaticName(name: String? = null)

Sets a name on the controller that can be used for debugging.