Input device and electronic device input system

An input device, comprising:

• a device body,
• a touchpad (400),
• a first key (300), and
• a second key (500);
• wherein the device body comprises a handheld part, the first key (300) and the touchpad (400) are arranged on the device body and located on the same side of the device body, and in a case that the handheld part is in a first state, a curvature of the handheld part is a first curvature;
• and in a case that the handheld part is in a second state, the curvature of the handheld part is a second curvature, and the first curvature is greater than the second curvature;
• the second key (500) is arranged on the device body;
• the second key (500) and the touchpad (400) are located on the same side of the device body or the second key (500) and the touchpad (400) are located on adjacent two sides of the device body;
• wherein
• in a case that the handheld part is in the first state, the first key (300) is in an active state and the second key (500) is in an inactive state;
• and in a case that the handheld part is in the second state, the second key (500) is in the active state and the touchpad (400) is in the active state.