drag_dest_set


Description:

public void drag_dest_set (Widget widget, DestDefaults flags, TargetEntry[]? targets, DragAction actions)

Sets a widget as a potential drop destination, and adds default behaviors.

The default behaviors listed in flags have an effect similar to installing default handlers for the widget’s drag-and-drop signals (drag_motion, drag_drop, ...). They all exist for convenience. When passing ALL for instance it is sufficient to connect to the widget’s drag_data_received signal to get primitive, but consistent drag-and-drop support.

Things become more complicated when you try to preview the dragged data, as described in the documentation for drag_motion. The default behaviors described by flags make some assumptions, that can conflict with your own signal handlers. For instance DROP causes invokations of drag_status in the context of drag_motion, and invokations of drag_finish in drag_data_received. Especially the later is dramatic, when your own drag_motion handler calls drag_get_data to inspect the dragged data.

There’s no way to set a default action here, you can use the drag_motion callback for that. Here’s an example which selects the action to use depending on whether the control key is pressed or not:

static void
drag_motion (GtkWidget *widget,
GdkDragContext *context,
gint x,
gint y,
guint time)
{
GdkModifierType mask;

gdk_window_get_pointer (gtk_widget_get_window (widget),
NULL, NULL, &mask);
if (mask & GDK_CONTROL_MASK)
gdk_drag_status (context, GDK_ACTION_COPY, time);
else
gdk_drag_status (context, GDK_ACTION_MOVE, time);
}

Parameters:

this

a Widget

flags

which types of default drag behavior to use

targets

a pointer to an array of TargetEntrys indicating the drop types that this this will accept, or null. Later you can access the list with drag_dest_get_target_list and drag_dest_find_target.

actions

a bitmask of possible actions for a drop onto this this.

n_targets

the number of entries in targets


Namespace: Gtk
Package: gtk+-3.0