Height-adjustable folding chair

A height-adjustable folding chair, comprising

• a base,
• a plurality of retractable arms connected to the base, and
• a plurality of legs connected to the base;
• wherein
• the base comprises a support enclosing an inner cavity and a locking assembly arranged in the inner cavity;
• the support comprises an upper receiving portion connected to the plurality of retractable arms and a lower receiving portion connected to the plurality of legs;
• the locking assembly comprises a leg unlock button inserted in the inner cavity and slidable relative to the support, a first spring arranged in the leg unlock button, and a first locking block connected to the leg unlock button;
• the first locking block comprises a plurality of protruding portions protruding radially outward from a center axis;
• an end opening is partially formed on an end of each protruding portion;
• the first locking block defines a plurality of locking slots each with a downward opening;
• an end of each leg connected to the lower receiving portion defines a positioning slot and is arranged with a positioning tongue protruding from an edge of the positioning slot and a positioning block protruding upward from a bottom of the positioning slot and matched with a corresponding one of the plurality of locking slots;
• the positioning tongue abuts against an outer wall of the end of each protruding portion in condition of the leg being unfolded to a first unfolded state relative to the base;
• and the positioning tongue enters the corresponding locking slot through the end opening and abuts against an inner wall of the end of each protruding portion, in condition of the leg being unfolded to a second unfolded state relative to the base.