In pig trainer's view trainee is a dawdler (9)
I believe the answer is:
slowcoach
'a dawdler' is the definition.
(I know that slowcoach is a type of trailer)
'in pig trainer's view trainee' is the wordplay.
'in' indicates putting letters inside.
'pig' becomes 'sow' (I've seen this in another clue).
'trainer's view' becomes 'coach' (I am not sure about this - if you are sure you should give a lot more credence to this answer).
'trainee' becomes 'l'.
'sow'+'coach'='sowcoach'
'sowcoach' placed around 'l' is 'SLOWCOACH'.
'is' acts as a link.
Can you help me to learn more?
(Other definitions for slowcoach that I've seen before include "Person (or transport?) taking a long time" , "One who takes time to do things" , "Not a rapid operator" , "Snail" , "Tortoise-like walker" .)