• That is interesting, so using this widget, can I make an drink water reminder app?

  • Sure. All this is based on dates (including time) written to a file.
    Basically, you set the timer to one hour, then the goal time is now+1h.
    When the widget is loaded, the target time is read again and compared to now. If the difference is <= 0 you get an alert. Only thing is that the widget has to be running to alert. But it does not have to run the whole time, like a timer app.

    You could create a setting where reminders should start and write that to the file.
    Then after a certain time alert and write the next alerting time to the file.

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