Input Monitor Development (for System Applications Only)

When to Use

The inputMonitor module provides capabilities such as listening for key events and touchpad gestures. For example, if your application needs to implement a dedicated function when a three-finger swipe-up gesture occurs on the touchpad, you can listen for three-finger swipe-up events to serve that purpose.

Modules to Import

import { inputMonitor } from '@kit.InputKit';

Available APIs

The following table lists common APIs for input monitor. For details, see @ohos.multimodalInput.inputMonitor (Input Monitor) (System API).

API	Description
on(type: 'mouse', receiver: Callback<MouseEvent>): void	Listens for mouse events.
on(type: 'touch', receiver: TouchEventReceiver): void	Enables listening for touchscreen events.
on(type: 'pinch', receiver: TouchEventReceiver): void	Listens for pinch events.
on(type: 'threeFingersSwipe', receiver: Callback<ThreeFingersSwipe>): void	Listens for three-finger swipe-up events.
on(type: 'threeFingersTap', receiver: Callback<ThreeFingersSwipe>): void	Listens for three-finger tap events.
on(type: 'fourFingersSwipe', receiver: Callback<FourFingersSwipe>): void	Listens for four-finger swipe events.
on(type: 'rotate', fingers: number, receiver: Callback<Rotate>): void	Listens for rotation events.
off(type: 'mouse', receiver: Callback<MouseEvent>): void	Cancels listening for mouse events.
off(type: 'touch', receiver: TouchEventReceiver): void	Disables listening for touchscreen events.
off(type: 'pinch', receiver: TouchEventReceiver): void	Cancels listening for pinch events.
off(type: 'threeFingersSwipe', receiver: Callback<ThreeFingersSwipe>): void	Cancels listening for three-finger swipe-up events.
off(type: 'threeFingersTap', receiver: Callback<ThreeFingersSwipe>): void	Cancels listening for three-finger tap events.
off(type: 'fourFingersSwipe', receiver: Callback<FourFingersSwipe>): void	Cancels listening for four-finger swipe events.
off(type: 'rotate', fingers: number, receiver: Callback<Rotate>): void	Cancels listening for rotation events.

How to Develop

This example assumes that the application needs to change the style based on the mouse button pressing status. Specifically, listen for mouse button events by calling on, and cancel listening for mouse button events by calling off.

import { inputMonitor } from '@kit.InputKit';
import { MouseEvent } from '@kit.InputKit';

@Entry
@Component
struct Index {
  build() {
    RelativeContainer() {
      Text()
        .onClick(() => {
          let BUTTON_DOWN = 2;
          let callback = (mouseEvent: MouseEvent) => {
            console.info(`Monitor on success ${JSON.stringify(mouseEvent)}`);
            if (mouseEvent.action = BUTTON_DOWN) {
              return true; // Callback triggered when the mouse button is pressed.
            }
            return false;
          };

          try {
            inputMonitor.on('mouse', (mouseEvent: MouseEvent) => { // Enable listening for mouse events.
              console.info(`Monitor on success ${JSON.stringify(mouseEvent)}`);
              return false;
            });
          } catch (error) {
            console.error(`Monitor on failed, error: ${JSON.stringify(error, ["code", "message"])}`);
          }
          // Callback triggered when the mouse button is pressed.
          try {
            inputMonitor.off('mouse', callback); // Cancel listening for mouse events.
            console.info(`Monitor off success`);
          } catch (error) {
            console.error(`Monitor off failed, error: ${JSON.stringify(error, ["code", "message"])}`);
          }
        })
    }
  }
}