The Sandra Bullock comedy “The Heat” filmed around Dorchester over the weekend. Producers warned the neighborhood last week that crews would be filming an explosion there Sunday afternoon. . . . Canadian news source 24 Hours reports that Boston’s Ben Affleck is not directing the “Justice League” movie. Oh well. . . . “The Hunger Games” actor Alexander Ludwig, who spent his summer filming “Grown Ups 2” on the North Shore, has been cast opposite Dorchester’s Mark Wahlberg in “Lone Survivor,” Ludwig confirmed on Twitter over the weekend.