A.F.
That's about the time my daughter started doing that, too. She used to happily eat whatever we put on her plate. She's a bit more finicky now. However, I find that at a meal if I give her two or three things on her plate, she'll pick one and eat all of that. If she's still hungry, she'll typically try #2. She may or may not eat much of it.
Also, about that time she started wanting to eat with a spoon or fork. Loading up a spoon or fork with the food and allowing her to put it in her mouth also helps.
Just keep offering him a variety of foods. He will eat when he's hungry, especially since he's been such a good eater up until now. It's not that he doesn't like the food any more, he's just experimenting with control in this area.
Edit: It will make a difference - are you feeding him baby food or regular food that you eat? If you're still on baby food, sounds like it's time to move to feeding him whatever you're eating. Check out Baby Led Weaning if you're not sure how to prepare it.