58 lines
1.7 KiB
Python
58 lines
1.7 KiB
Python
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__all__ = ('event', )
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import typing as T
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import types
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from functools import partial
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from asyncgui import _current_task, _sleep_forever
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@types.coroutine
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def event(event_dispatcher, event_name, *, filter=None, stop_dispatching=False) -> T.Awaitable[tuple]:
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'''
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Returns an awaitable that can be used to wait for:
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* a Kivy event to occur.
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* a Kivy property's value to change.
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.. code-block::
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# Wait for a button to be pressed.
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await event(button, 'on_press')
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# Wait for an 'on_touch_down' event to occur.
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__, touch = await event(widget, 'on_touch_down')
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# Wait for 'widget.x' to change.
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__, x = await ak.event(widget, 'x')
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The ``filter`` parameter:
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.. code-block::
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# Wait for an 'on_touch_down' event to occur inside a widget.
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__, touch = await event(widget, 'on_touch_down', filter=lambda w, t: w.collide_point(*t.opos))
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# Wait for 'widget.x' to become greater than 100.
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if widget.x <= 100:
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await event(widget, 'x', filter=lambda __, x: x > 100)
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The ``stop_dispatching`` parameter:
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It only works for events not for properties.
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See :ref:`kivys-event-system` for details.
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'''
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task = (yield _current_task)[0][0]
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bind_id = event_dispatcher.fbind(event_name, partial(_callback, filter, task, stop_dispatching))
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assert bind_id # check if binding succeeded
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try:
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return (yield _sleep_forever)[0]
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finally:
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event_dispatcher.unbind_uid(event_name, bind_id)
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def _callback(filter, task, stop_dispatching, *args, **kwargs):
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if (filter is None) or filter(*args, **kwargs):
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task._step(*args)
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return stop_dispatching
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