When adding an Exam or Event, app crash when 1 time field is empty

[f4ww4z]

Steps to reproduce:

1. Add a new event
2. Fill in the Date and Start time field, leave Time finished empty.
3. Click the check (done) button.
4. App crash

Log:

org.threeten.bp.format.DateTimeParseException: Text '26/01/2019 ' could not be parsed at index 11
        at org.threeten.bp.format.DateTimeFormatter.parseToBuilder(DateTimeFormatter.java:1588)
        at org.threeten.bp.format.DateTimeFormatter.parse(DateTimeFormatter.java:1491)
        at org.threeten.bp.LocalDateTime.parse(LocalDateTime.java:444)

This is because the program tries to combine Date and Start time, which returns a good DateTime format as both fields are filled. But when it combines Date with Time finished, it returns just a Date format as Time finished is empty.

It can be vice versa (e.g. Start time is empty, Time finished is filled)

Possible solution

Make sure that all fields are filled in first, before parsing dates.