I'd advise against the spray can adhesive, especially for such a large headliner. It's okay for small projects such as seats. But with something like a headliner that's constantly fighting gravity and extreme temperatures, it's durability is very questionable. You can get the real stuff from an upholstery supply house or online- do it right or do it twice!
This is in my '01 XJ. It had a light grey fabric headliner that was completely sagging. I replaced it with graphite colored, leather-grained vinyl. I used an old Harbor Freight sprayer to apply the glue.
Brushed off the decomposed foam:
Sprayed both surfaces and worked from the easy end (front) to the difficult end (rear with the built-in speaker pods):
After lots of pulling and grunting to lay it flat on the compound curves:
Cut, wrapped and glued the edges of the holes:
Installed:
This material is MUCH heavier than regular headliner fabric, but I have zero doubts about it staying up. Also, this was my first headliner experience.