harmony 鸿蒙Mouse Event

2022-08-09
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Mouse Event

If a mouse action triggers multiple events, the order of these events is fixed. By default, mouse events are transmitted transparently.

NOTE

The APIs of this module are supported since API version 8. Updates will be marked with a superscript to indicate their earliest API version.

For the time being, a mouse event can be triggered only by an external mouse.

Events

Name	Bubbling Supported	Description
onHover(event: (isHover?: boolean, event¹⁰⁺?: HoverEvent) => void)	Yes	Triggered when the mouse pointer enters or leaves the component. isHover: whether the mouse pointer hovers over the component. The value true means that the mouse pointer enters the component, and the value false means that the mouse pointer leaves the component. event: bubbling blocking of the event.
onMouse(event: (event?: MouseEvent) => void)	Yes	Triggered when the component is clicked by a mouse button or the mouse pointer moves on the component. The event parameter indicates the timestamp, mouse button, action, coordinates of the clicked point on the entire screen, and coordinates of the clicked point relative to the component when the event is triggered.

MouseEvent

Name	Type	Description
x	number	X coordinate of the mouse pointer relative to the upper left corner of the component being clicked.
y	number	Y coordinate of the mouse pointer relative to the upper left corner of the component being clicked.
button	MouseButton	Mouse button.
action	MouseAction	Mouse action.
stopPropagation	() => void	Stops the event from bubbling upwards or downwards.
timestamp⁸⁺	number	Timestamp of the event. It is interval between the time when the event is triggered and the time when the system starts, in nanoseconds.
target⁸⁺	EventTarget	Display area of the component that triggers the event.
source⁸⁺	SourceType	Event input device.
windowX¹⁰⁺	number	X coordinate of the mouse pointer relative to the upper left corner of the application window.
windowY¹⁰⁺	number	Y coordinate of the mouse pointer relative to the upper left corner of the application window.
displayX¹⁰⁺	number	X coordinate of the mouse pointer relative to the upper left corner of the application screen.
displayY¹⁰⁺	number	Y coordinate of the mouse pointer relative to the upper left corner of the application screen.
screenX^(deprecated)	number	X coordinate of the mouse pointer relative to the upper left corner of the application window. This API is deprecated since API version 10. You are advised to use windowX instead.
screenY^(deprecated)	number	Y coordinate of the mouse pointer relative to the upper left corner of the application window. This API is deprecated since API version 10. You are advised to use windowY instead.

HoverEvent¹⁰⁺

Name	Type	Description
stopPropagation	() => void	Stops the event from bubbling upwards or downwards.

Example

// xxx.ets
@Entry
@Component
struct MouseEventExample {
  @State hoverText: string = 'no hover';
  @State mouseText: string = '';
  @State action: string = '';
  @State mouseBtn: string = '';
  @State color: Color = Color.Blue;

  build() {
    Column({ space: 20 }) {
      Button(this.hoverText)
        .width(180).height(80)
        .backgroundColor(this.color)
        .onHover((isHover?: boolean, event?: HoverEvent):void => {
          // Use the onHover event to dynamically change the text content and background color of a button when the mouse pointer is hovered on it.
          if (isHover) {
            this.hoverText = 'hover';
            this.color = Color.Pink;
          } else {
            this.hoverText = 'no hover';
            this.color = Color.Blue;
          }
        })
      Button('onMouse')
        .width(180).height(80)
        .onMouse((event?: MouseEvent):void => {
          if(event){
            switch (event.button) {
              case MouseButton.None:
                this.mouseBtn = 'None';
                break;
              case MouseButton.Left:
                this.mouseBtn = 'Left';
                break;
              case MouseButton.Right:
                this.mouseBtn = 'Right';
                break;
              case MouseButton.Back:
                this.mouseBtn = 'Back';
                break;
              case MouseButton.Forward:
                this.mouseBtn = 'Forward';
                break;
              case MouseButton.Middle:
                this.mouseBtn = 'Middle';
                break;
            }
            switch (event.action) {
              case MouseAction.Hover:
                this.action = 'Hover';
                break;
              case MouseAction.Press:
                this.action = 'Press';
                break;
              case MouseAction.Move:
                this.action = 'Move';
                break;
              case MouseAction.Release:
                this.action = 'Release';
                break;
            }
            this.mouseText = 'onMouse:\nButton = ' + this.mouseBtn +
            '\nAction = ' + this.action + '\nXY=(' + event.x + ',' + event.y + ')' +
            '\nwindowXY=(' + event.windowX + ',' + event.windowY + ')';
          }
        })
      Text(this.mouseText)
    }.padding({ top: 30 }).width('100%')
  }
}

The figure below shows how the button looks like when hovered on.

mouse