Why do I select a Screen when I create a Transition?

[Will Wilson]

I am creating a Workflow.  I added a new Transition, and one of the fields was "Screen" - I am not sure what it means to associate a Screen to a Transition.

[Elifcan Cakmak · Accepted solution]

hi

if you need to get some input from the user when transitioning the issue, like for example when starting development you might want to learn how many days it will take to solve, then you can add a custom field to a screen and add this screen to your transition. but you don't have to add a screen, it is not compulsory. it is up to your operation.

[Will Wilson]

so the selected screen (if there is one) is shown when the transition occurs?  Who is it shown to?  The user who caused the transition?

[Elifcan Cakmak]

yes exactly, it is shown while the transition occuring and shown to the user who is making that transition.

[Deleted user]

For example: 

When one of our engineers moves a Bug to 'Completed' we want them to enter information into the Cause and the Solution fields. We have a screen with those two items on it as required fields. That way we always get that information filled out.

[Jeremy Gaudet]

To expand on this slightly, the screen can be used to fill in missing information that would otherwise cause it to fail a validator.  The screen is shown when the transition is selected (which means it has already passed any Conditions on the transition), but before any validators are executed.  Any data supplied or changed while on the screen will be the data seen by each validator. If the screen is cancelled, the transition does not execute and you remain in the original state.

A very typical example is that a "Resolve Issue" transition generally includes a screen that allows one to select the "Resolution".  A "Close Issue" transition that is after "Resolve Issue" does not, but a "Close Issue" transition that happens before "Resolve Issue" does, so as to also behave like "Resolve Issue".

An example going the other way is that you can use post functions to set the resolution depending on the transition; if you do that, you don't need a screen, and if you have a screen, you wouldn't want to also include that field.

Finally, in particular for the "Resolution" example, you can use workflow properties to restrict what resolutions are available on that screen, by setting them on the transition.

https://confluence.atlassian.com/jira/workflow-properties-189949.html