A method implemented on a computing device having one or more processors (140; 310) and one or more storage media (150; 320; 490), the method comprising: obtaining a first operating state of an X-ray imaging device; causing a first interface to be displayed via a terminal (130; 206, 800; 900; 1000; 1100; 1200; 1300; 1400; 1500), the first interface corresponding to a second operating state of the X-ray imaging device, wherein the first interface includes a first key corresponding to the second operating state; obtaining, via the first interface of the terminal, a first input from a user, the first input being associated with the second operating state of the X-ray imaging device; determining whether the first input satisfies a switch condition;and upon a determination that the first input satisfies the switch condition, transmitting, to the X-ray imaging device, a first instruction to switch the X-ray imaging device from the first operating state to the second operating state; and transmitting, to the terminal, a second instruction to switch the terminal from the first interface to a second interface corresponding to a third operating state of the X-ray imaging device, wherein the second interface includes a further key corresponding to the third operating state, and wherein the first key is marked inactive or disappears in the second interface,the first operating state is an exposure pending state in which the X-ray imaging device waits for a scan, the second operating state is an exposure preparation state in which one or more parameters of the X-ray imaging device are adjusted to prepare for the scan, and the third operating state is an exposure state in which X-rays are emitted to an object to be scanned. obtaining a first operating state of an X-ray imaging device; causing a first interface to be displayed via a terminal (130; 206, 800; 900; 1000; 1100; 1200; 1300; 1400; 1500), the first interface corresponding to a second operating state of the X-ray imaging device, wherein the first interface includes a first key corresponding to the second operating state; obtaining, via the first interface of the terminal, a first input from a user, the first input being associated with the second operating state of the X-ray imaging device; determining whether the first input satisfies a switch condition;and upon a determination that the first input satisfies the switch condition, transmitting, to the X-ray imaging device, a first instruction to switch the X-ray imaging device from the first operating state to the second operating state; and transmitting, to the terminal, a second instruction to switch the terminal from the first interface to a second interface corresponding to a third operating state of the X-ray imaging device, wherein the second interface includes a further key corresponding to the third operating state, and wherein the first key is marked inactive or disappears in the second interface,the first operating state is an exposure pending state in which the X-ray imaging device waits for a scan, the second operating state is an exposure preparation state in which one or more parameters of the X-ray imaging device are adjusted to prepare for the scan, and the third operating state is an exposure state in which X-rays are emitted to an object to be scanned.