Table Of Contents
Source code for kivy.support
'''
Support
=======
Activate other frameworks/toolkits inside the kivy event loop.
'''
__all__ = ('install_gobject_iteration', 'install_twisted_reactor',
'uninstall_twisted_reactor', 'install_android')
[docs]def install_gobject_iteration():
'''Import and install gobject context iteration inside our event loop.
This is used as soon as gobject is used (like gstreamer).
'''
from kivy.clock import Clock
try:
from gi.repository import GObject as gobject
except ImportError:
import gobject
if hasattr(gobject, '_gobject_already_installed'):
# already installed, don't do it twice.
return
gobject._gobject_already_installed = True
# get gobject mainloop / context
loop = gobject.MainLoop()
gobject.threads_init()
context = loop.get_context()
# schedule the iteration each frame
def _gobject_iteration(*largs):
# XXX we need to loop over context here, otherwise, we might have a lag
loop = 0
while context.pending() and loop < 10:
context.iteration(False)
loop += 1
Clock.schedule_interval(_gobject_iteration, 0)
# -----------------------------------------------------------------------------
# Android support
# -----------------------------------------------------------------------------
g_android_redraw_count = 0
_redraw_event = None
def _android_ask_redraw(*largs):
# after wakeup, we need to redraw more than once, otherwise we get a
# black screen
global g_android_redraw_count
from kivy.core.window import Window
Window.canvas.ask_update()
g_android_redraw_count -= 1
if g_android_redraw_count < 0:
return False
[docs]def install_android():
'''Install hooks for the android platform.
* Automatically sleep when the device is paused.
* Automatically kill the application when the return key is pressed.
'''
try:
import android
except ImportError:
print('Android lib is missing, cannot install android hooks')
return
from kivy.clock import Clock
from kivy.logger import Logger
import pygame
Logger.info('Support: Android install hooks')
# Init the library
android.init()
android.map_key(android.KEYCODE_MENU, pygame.K_MENU)
android.map_key(android.KEYCODE_BACK, pygame.K_ESCAPE)
# Check if android should be paused or not.
# If pause is requested, just leave the app.
def android_check_pause(*largs):
# do nothing until android asks for it.
if not android.check_pause():
return
from kivy.app import App
from kivy.base import stopTouchApp
from kivy.logger import Logger
from kivy.core.window import Window
global g_android_redraw_count, _redraw_event
# try to get the current running application
Logger.info('Android: Must go into sleep mode, check the app')
app = App.get_running_app()
# no running application, stop our loop.
if app is None:
Logger.info('Android: No app running, stop everything.')
stopTouchApp()
return
# try to go to pause mode
if app.dispatch('on_pause'):
Logger.info('Android: App paused, now wait for resume.')
# app goes in pause mode, wait.
android.wait_for_resume()
# is it a stop or resume ?
if android.check_stop():
# app must stop
Logger.info('Android: Android wants to close our app.')
stopTouchApp()
else:
# app resuming now !
Logger.info('Android: Android has resumed, resume the app.')
app.dispatch('on_resume')
Window.canvas.ask_update()
g_android_redraw_count = 25 # 5 frames/seconds for 5 seconds
if _redraw_event is None:
_redraw_event = Clock.schedule_interval(
_android_ask_redraw, 1 / 5)
else:
_redraw_event.cancel()
_redraw_event()
Logger.info('Android: App resume completed.')
# app doesn't support pause mode, just stop it.
else:
Logger.info('Android: App doesn\'t support pause mode, stop.')
stopTouchApp()
Clock.schedule_interval(android_check_pause, 0)
_twisted_reactor_stopper = None
_twisted_reactor_work = None
[docs]def install_twisted_reactor(**kwargs):
'''Installs a threaded twisted reactor, which will schedule one
reactor iteration before the next frame only when twisted needs
to do some work.
Any arguments or keyword arguments passed to this function will be
passed on the the threadedselect reactors interleave function. These
are the arguments one would usually pass to twisted's reactor.startRunning.
Unlike the default twisted reactor, the installed reactor will not handle
any signals unless you set the 'installSignalHandlers' keyword argument
to 1 explicitly. This is done to allow kivy to handle the signals as
usual unless you specifically want the twisted reactor to handle the
signals (e.g. SIGINT).
.. note::
Twisted is not included in iOS build by default. To use it on iOS,
put the twisted distribution (and zope.interface dependency) in your
application directory.
'''
import twisted
# prevent installing more than once
if hasattr(twisted, '_kivy_twisted_reactor_installed'):
return
twisted._kivy_twisted_reactor_installed = True
# don't let twisted handle signals, unless specifically requested
kwargs.setdefault('installSignalHandlers', 0)
# install threaded-select reactor, to use with own event loop
from twisted.internet import _threadedselect
_threadedselect.install()
# now we can import twisted reactor as usual
from twisted.internet import reactor
from twisted.internet.error import ReactorNotRunning
from collections import deque
from kivy.base import EventLoop
from kivy.logger import Logger
from kivy.clock import Clock
# will hold callbacks to twisted callbacks
q = deque()
# twisted will call the wake function when it needs to do work
def reactor_wake(twisted_loop_next):
'''Wakeup the twisted reactor to start processing the task queue
'''
Logger.trace("Support: twisted wakeup call to schedule task")
q.append(twisted_loop_next)
# called every frame, to process the reactors work in main thread
def reactor_work(*args):
'''Process the twisted reactor task queue
'''
Logger.trace("Support: processing twisted task queue")
while len(q):
q.popleft()()
global _twisted_reactor_work
_twisted_reactor_work = reactor_work
# start the reactor, by telling twisted how to wake, and process
def reactor_start(*args):
'''Start the twisted reactor main loop
'''
Logger.info("Support: Starting twisted reactor")
reactor.interleave(reactor_wake, **kwargs)
Clock.schedule_interval(reactor_work, 0)
# make sure twisted reactor is shutdown if eventloop exists
def reactor_stop(*args):
'''Shutdown the twisted reactor main loop
'''
if reactor.threadpool:
Logger.info("Support: Stopping twisted threads")
reactor.threadpool.stop()
Logger.info("Support: Shutting down twisted reactor")
reactor._mainLoopShutdown()
try:
reactor.stop()
except ReactorNotRunning:
pass
import sys
sys.modules.pop('twisted.internet.reactor', None)
global _twisted_reactor_stopper
_twisted_reactor_stopper = reactor_stop
# start and stop the reactor along with kivy EventLoop
Clock.schedule_once(reactor_start, 0)
EventLoop.bind(on_stop=reactor_stop)
[docs]def uninstall_twisted_reactor():
'''Uninstalls the Kivy's threaded Twisted Reactor. No more Twisted
tasks will run after this got called. Use this to clean the
`twisted.internet.reactor` .
.. versionadded:: 1.9.0
'''
import twisted
# prevent uninstalling more than once
if not hasattr(twisted, '_kivy_twisted_reactor_installed'):
return
from kivy.base import EventLoop
global _twisted_reactor_stopper
_twisted_reactor_stopper()
EventLoop.unbind(on_stop=_twisted_reactor_stopper)
del twisted._kivy_twisted_reactor_installed
