问题
I'm creating RSS app in PyQt and I'm trying to find a good way to program updates. I found this Executing periodic actions in Python but maybe there is Qt specific way to do this things.
I know update period for each feed so I want to run update at specific time(hh:mm).
Making 10 minute loop that will check current time and run a update if its grater than next predicted feed update seems missing the point of knowing specific time to run it.
回答1:
You should use QTimer in Qt applications. Usually you don't need to care about specific update time, as the goal is regular periodic check. So the most straightforward approarch is to create a timer for each feed and set the update interval of each timer (e.g. 10 minutes).
If you for some reason really want to make an update at specific time, you can use something like QDateTime::currentDateTime().msecsTo(targetTime) to calculate timer interval, use QTimer::setSingleShot to make the timer non-periodic and set another timer when the first one is expired.
It may be reasonable to do timer->setTimerType(Qt::VeryCoarseTimer) because you don't need much accuracy and Qt can optimize performance and power consuming in some cases.
Note that you generally cannot use Python's means to set up timers because Qt has its own event loop and won't allow other libraries to run something in the middle of it.
来源：https://stackoverflow.com/questions/28900532/how-to-get-function-to-run-at-specyfic-time-using-python-and-pyqt-not-using-cron