harmony 鸿蒙RotationGesture

2022-08-09
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RotationGesture

RotationGesture is used to trigger a rotation gesture, which requires two to five fingers with a minimum 1-degree rotation angle.

NOTE

This gesture is supported since API version 7. Updates will be marked with a superscript to indicate their earliest API version.

APIs

RotationGesture(value?: { fingers?: number, angle?: number })

Parameters

Name	Type	Mandatory	Description
fingers	number	No	Minimum number of fingers to trigger a rotation. The value ranges from 2 to 5. Default value: 2
angle	number	No	Minimum degree that can trigger the rotation gesture. Default value: 1 NOTE If the value is less than or equal to 0, it will be converted to the default value.

Events

Parameter	Description
onActionStart(event:(event?: GestureEvent) => void)	Triggered when a rotation gesture is recognized.
onActionUpdate(event:(event?: GestureEvent) => void)	Triggered when the user moves the finger in a rotation gesture on the screen.
onActionEnd(event:(event?: GestureEvent) => void)	Triggered when the finger used for the rotation gesture is lift.
onActionCancel(event: () => void)	Triggered when a tap cancellation event is received after the rotation gesture is recognized.

Example

// xxx.ets
@Entry
@Component
struct RotationGestureExample {
  @State angle: number = 0
  @State rotateValue: number = 0

  build() {
    Column() {
      Column() {
        Text('RotationGesture angle:' + this.angle)
      }
      .height(200)
      .width(300)
      .padding(20)
      .border({ width: 3 })
      .margin(80)
      .rotate({ angle: this.angle })
      // The gesture event is triggered by rotating with two fingers.
      .gesture(
      RotationGesture()
        .onActionStart((event?: GestureEvent) => {
          console.info('Rotation start')
        })
        .onActionUpdate((event?: GestureEvent) => {
          if (event) {
            this.angle = this.rotateValue + event.angle
          }
        })
        .onActionEnd(() => {
          this.rotateValue = this.angle
          console.info('Rotation end')
        })
      )
    }.width('100%')
  }
}

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