tkinter.dnd — Drag and drop support

Source code: Lib/tkinter/dnd.py

The 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 Bindings and Events). The function should call 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

class tkinter.dnd.DndHandler(source, event)

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

cancel(event=None)

Cancel the drag-and-drop process.

finish(event, commit=0)

Execute end of drag-and-drop functions.

on_motion(event)

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

on_release(event)

Signal end of drag when the release pattern is triggered.

tkinter.dnd.dnd_start(source, event)

Factory function for drag-and-drop process.