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 the area under the mouse for a target widget:

   • the target widget should have a callable dnd_accept attribute;

   • if dnd_accept is not present or returns None, the search moves to the parent widget;

   • if no target widget is found, 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 the drop.

5. Call to <source>.dnd_end(target, event) to signal the 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 a 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 the drag-and-drop process. Return the DndHandler instance managing the drag, or None if a drag could not be started.