A hinge assembly includes a first connecting member, a second connecting member, and a pivot subassembly. The pivot subassembly connects the first connecting member to the second connecting member. The pivot subassembly includes a rotatable shaft, a sleeve, and a positioning ring. The rotatable shaft is non-rotatably connected to the first connecting member. The sleeve is sleeved on the rotatable shaft, and non-rotatably connected to the rotatable shaft. The positioning ring is non-rotatably connected to the second connecting member. The sleeve defines two positioning cutouts, and the positioning ring defines two positioning protrusions engaging with the positioning cutouts. When the rotatable shaft rotates, one of the sleeve and the positioning ring deforms, so that the at least one positioning protrusion disengages from the at least one positioning cutout.