DropTarget

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, (GTypes [2]) {
G_TYPE_FILE,
GDK_TYPE_PIXBUF,
}, 2);

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].

class DropTarget : EventController {

protected

GtkDropTarget* gtkDropTarget;

GtkDropTarget* getDropTargetStruct(bool transferOwnership);

void* getStruct();

this(GtkDropTarget* gtkDropTarget, bool ownedRef);

static GType getType();

this(GType type, GdkDragAction actions);

GdkDragAction getActions();

Drop getDrop();

ContentFormats getFormats();

GType[] getGtypes();

bool getPreload();

Value getValue();

void reject();

void setActions(GdkDragAction actions);

void setGtypes(GType[] types);

void setPreload(bool preload);

gulong addOnAccept(bool delegate(Drop, DropTarget) dlg, ConnectFlags connectFlags);

gulong addOnDrop(bool delegate(Value, double, double, DropTarget) dlg, ConnectFlags connectFlags);

gulong addOnEnter(GdkDragAction delegate(double, double, DropTarget) dlg, ConnectFlags connectFlags);

gulong addOnLeave(void delegate(DropTarget) dlg, ConnectFlags connectFlags);

gulong addOnMotion(GdkDragAction delegate(double, double, DropTarget) dlg, ConnectFlags connectFlags);

}

Constructors

this this(GtkDropTarget* gtkDropTarget, bool ownedRef): Sets our main struct and passes it to the parent class.
this this(GType type, GdkDragAction actions): Creates a new GtkDropTarget object.

Members

Functions

addOnAccept gulong addOnAccept(bool delegate(Drop, DropTarget) dlg, ConnectFlags connectFlags): Emitted on the drop site when a drop operation is about to begin.
addOnDrop gulong addOnDrop(bool delegate(Value, double, double, DropTarget) dlg, ConnectFlags connectFlags): Emitted on the drop site when the user drops the data onto the widget.
addOnEnter gulong addOnEnter(GdkDragAction delegate(double, double, DropTarget) dlg, ConnectFlags connectFlags): Emitted on the drop site when the pointer enters the widget.
addOnLeave gulong addOnLeave(void delegate(DropTarget) dlg, ConnectFlags connectFlags): Emitted on the drop site when the pointer leaves the widget.
addOnMotion gulong addOnMotion(GdkDragAction delegate(double, double, DropTarget) dlg, ConnectFlags connectFlags): Emitted while the pointer is moving over the drop target.
getActions GdkDragAction getActions(): Gets the actions that this drop target supports.
getDrop Drop getDrop(): Gets the currently handled drop operation.
getDropTargetStruct GtkDropTarget* getDropTargetStruct(bool transferOwnership): Get the main Gtk struct
getFormats ContentFormats getFormats(): Gets the data formats that this drop target accepts.
getGtypes GType[] getGtypes(): Gets the list of supported GTypes for @self.
getPreload bool getPreload(): Gets whether data should be preloaded on hover.
getStruct void* getStruct(): the main Gtk struct as a void*
getValue Value getValue(): Gets the current drop data, as a GValue.
reject void reject(): Rejects the ongoing drop operation.
setActions void setActions(GdkDragAction actions): Sets the actions that this drop target supports.
setGtypes void setGtypes(GType[] types): Sets the supported GTypes for this drop target.
setPreload void setPreload(bool preload): Sets whether data should be preloaded on hover.

Static functions

getType GType getType()

Variables

gtkDropTarget GtkDropTarget* gtkDropTarget;: the main Gtk struct

Inherited Members

From EventController

gtkEventController GtkEventController* gtkEventController;: the main Gtk struct
getEventControllerStruct GtkEventController* getEventControllerStruct(bool transferOwnership): Get the main Gtk struct
getStruct void* getStruct(): the main Gtk struct as a void*
getType GType getType()
getCurrentEvent Event getCurrentEvent(): Returns the event that is currently being handled by the controller, and %NULL at other times.
getCurrentEventDevice Device getCurrentEventDevice(): Returns the device of the event that is currently being handled by the controller, and %NULL otherwise.
getCurrentEventState GdkModifierType getCurrentEventState(): Returns the modifier state of the event that is currently being handled by the controller, and 0 otherwise.
getCurrentEventTime uint getCurrentEventTime(): Returns the timestamp of the event that is currently being handled by the controller, and 0 otherwise.
getName string getName(): Gets the name of @controller.
getPropagationLimit GtkPropagationLimit getPropagationLimit(): Gets the propagation limit of the event controller.
getPropagationPhase GtkPropagationPhase getPropagationPhase(): Gets the propagation phase at which @controller handles events.
getWidget Widget getWidget(): Returns the #GtkWidget 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(GtkPropagationLimit limit): Sets the event propagation limit on the event controller.
setPropagationPhase void setPropagationPhase(GtkPropagationPhase phase): Sets the propagation phase at which a controller handles events.