But what if I later change my mind - or want the app to give the email program options each time an email is to be sent - how can I implement this? If seems even uninstalling the app does not reset the choice......
in my device i get the question and i (the device user) have the chanc to select one an click on OPEN ONCE or OPEN ALWAYS.
If is choose open once i´l get the same question next time.
If i choose open always no more questions are shown instead the selected item will be used always.
It has nothing to do with Fileprovider. It is a feature of Android to show the selection and to give the user a choice to open it once or always.
It may be differently implemented in different Androids.
Edit to add:
Found in internet.
My understanding is that before 6.0 you could select one of the two options "just once" or "always" when selecting an app to open a file. Now, however, it seems that the option for "just once" doesn't exist and it automatically assumes you want to use that app "always" for files of those types.