I was stopped by police for riding a bike at night without a lite; was restrained and searched. Legal or not?

I was riding a bike at night and was stopped by gang taskforce cops who restrained and searched me under the pretense of a traffic violation. The violation was subsequently dismissed as having no merit by the court. I feel they bullied me and abused their authority. Do they have the right to stop a citizen, demand they produce id and search their persons?