tkinter.dnd.rst

:mod:`tkinter.dnd` --- Drag and drop support

.. module:: tkinter.dnd
   :platform: Tk
   :synopsis: Tkinter drag-and-drop interface

Source code: :source:`Lib/tkinter/dnd.py`

---

Note

This is experimental and due to be deprecated when it is replaced with the Tk DND.

The :mod:`tkinter.dnd` module provides drag-and-drop support for objects within a single application, within the same window or between windows. To enable an object to be dragged, you must create an event binding for it that starts the drag-and-drop process. Typically, you bind a ButtonPress event to a callback function that you write (see :ref:`Bindings-and-Events`). The function should call :func:`dnd_start`, where 'source' is the object to be dragged, and 'event' is the event that invoked the call (the argument to your callback function).

Selection of a target object occurs as follows:

1. Top-down search of area under mouse for target widget

• Target widget should have a callable dnd_accept attribute
• If dnd_accept is not present or returns None, search moves to parent widget
• If no target widget is found, then the target object is None

2. Call to <old_target>.dnd_leave(source, event)
3. Call to <new_target>.dnd_enter(source, event)
4. Call to <target>.dnd_commit(source, event) to notify of drop
5. Call to <source>.dnd_end(target, event) to signal end of drag-and-drop

The DndHandler class handles drag-and-drop events tracking Motion and ButtonRelease events on the root of the event widget.

.. method:: cancel(event=None)

   Cancel the drag-and-drop process.

.. method:: finish(event, commit=0)

   Execute end of drag-and-drop functions.

.. method:: on_motion(event)

   Inspect area below mouse for target objects while drag is performed.

.. method:: on_release(event)

   Signal end of drag when the release pattern is triggered.

.. function:: dnd_start(source, event)

   Factory function for drag-and-drop process.

.. seealso::

   :ref:`Bindings-and-Events`