Button assembly and electronic device with the same

A button assembly comprising:

• a keycap comprising a resisting member and an operating member, the operating member extending substantially perpendicular from the resisting member, the operating member being configured to extend through a through hole of a sidewall of an electronic device and being configured to extend external to the sidewall of the electronic device;
• a washer provided between the resisting member and the sidewall to seal a gap between the resisting member and the sidewall, the washer being configured to pivot on the operating member;
• a positioning member fixed to a bottom of the electronic device, the positioning member being configured to separate from the sidewall of the electronic device by a preset distance;
• and
• a fixing member configured to affix a flexible circuit board of the electronic device to the positioning member, the fixing member being provided to position a switch of the flexible circuit board abutting against the resisting member at a position opposite to the keycap;
• the keycap positioned at the sidewall via the switch, the resisting member being provided to bias the washer toward the sidewall to seal a gap between the resisting member and the sidewall.