at an active pen that communicates with a plurality of touch screens:

in response to the active pen being within a preset distance from a first touch screen of the plurality of touchscreens, detecting, by the active pen, an uplink signal sent by the first touch screen, wherein the preset distance is less than or equal to 10 mm;

sending, by the active pen, a coding signal to the first touch screen in a designated period of time after the uplink signal has been detected, wherein the coding signal is configured for the first touch screen to determine information about a position of the active pen on the first touch screen;

receiving, by the active pen, a first wireless signal sent by the first touch screen in response to the first touch screen detecting that a strength of the coding signal is greater than a first threshold and a number of times that the coding signal is detected is greater than a second threshold, wherein the first threshold and the second threshold are each greater than 0, and wherein the first wireless signal carries identification information of the first touch screen;

detecting, by the active pen, among the plurality of touch screens, the first touch screen as a touch screen that is currently close to or in contact with the active pen according to the identification information of the first touch screen;

receiving, by the active pen, a second wireless signal sent by a second touch screen after the active pen is switched from the first touch screen to the second touch screen of the plurality of touch screens, wherein the second wireless signal carries identification information of the second touch screen; and

detecting, by the active pen, that the active pen has switched from the first touch screen to the second touch screen according to the identification information of the second touch screen different from the identification information of the first touch screen.