What if your child shows signs of readiness for potty training but still won't go?

Don't push. Overeagerness in toilet training can result in constipation from hell, as a child who decides that "holding it" is good will decide that "holding it forever" is even better.
He walks from room . to room, pulls his pants & up & down, is dry for 2 hrs. & says " pee-pee", "poo-poo" or "potty" to indicate he senses the urge to "go"? Use diapers, not pull-ups. Change him in the bathroom. Flush BM's down the toilet. Model using the toilet. Buy a Little Looster stool & some bubble soap. When he asks what they're for, casually say, "They're for when you choose to sit on the toilet." See below.
Control realization. Smart children sometimes come to realize that for first time in their lives they can actually control something and attempts to forcibly train can only have negative consequences. Let child sit on potty if they wish, but don't tell them to push it out. This can result in them contracting pelvic floor muscles coincident with abdominal wall muscles & can lead to bladder dysfunction. .