harmony 鸿蒙Combined Gestures

2022-08-09
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Combined Gestures

Continuous recognition, parallel recognition, and exclusive recognition are supported for a group of gestures.

NOTE

The APIs of this module are supported since API version 7. Updates will be marked with a superscript to indicate their earliest API version.

APIs

GestureGroup(mode: GestureMode, …gesture: GestureType[])

Parameters

Name	Type	Mandatory	Description
mode	GestureMode	Yes	Recognition mode of combined gestures. Default value: GestureMode.Sequence
gesture	TapGesture \|LongPressGesture \|PanGesture \|PinchGesture \|RotationGesture \|SwipeGesture	Yes	Variable-length parameter, indicating one or more basic gesture types. These gestures are recognized in combination.

GestureMode

Name	Description
Sequence	Sequential recognition: Gestures are recognized in the registration sequence until all gestures are recognized successfully. When one gesture fails to be recognized, all gestures fail to be recognized. Only the last gesture in the sequential recognition gesture group can respond to onActionEnd.
Parallel	Parallel recognition. Registered gestures are recognized concurrently until all gestures are recognized. The recognition result of each gesture does not affect each other.
Exclusive	Exclusive recognition. Registered gestures are identified concurrently. If one gesture is successfully recognized, gesture recognition ends.

Events

Name	Description
onCancel(event: () => void)	Callback for the GestureMode.Sequence cancellation event.

Example

// xxx.ets
@Entry
@Component
struct GestureGroupExample {
  @State count: number = 0
  @State offsetX: number = 0
  @State offsetY: number = 0
  @State positionX: number = 0
  @State positionY: number = 0
  @State borderStyles: BorderStyle = BorderStyle.Solid

  build() {
    Column() {
      Text('sequence gesture\n' + 'LongPress onAction:' + this.count + '\nPanGesture offset:\nX: ' + this.offsetX + '\n' + 'Y: ' + this.offsetY)
        .fontSize(15)
    }
    .translate({ x: this.offsetX, y: this.offsetY, z: 0 })
    .height(150)
    .width(200)
    .padding(20)
    .margin(20)
    .border({ width: 3, style: this.borderStyles })
    .gesture(
      // The following combined gestures are recognized in sequential recognition mode. If the long press gesture event is not triggered correctly, the drag gesture event will not be triggered.
    GestureGroup(GestureMode.Sequence,
    LongPressGesture({ repeat: true })
      .onAction((event?: GestureEvent) => {
        if (event && event.repeat) {
          this.count++
        }
        console.info('LongPress onAction')
      }),
    PanGesture()
      .onActionStart(() => {
        this.borderStyles = BorderStyle.Dashed
        console.info('pan start')
      })
      .onActionUpdate((event?: GestureEvent) => {
        if (event) {
          this.offsetX = this.positionX + event.offsetX
          this.offsetY = this.positionY + event.offsetY
        }
        console.info('pan update')
      })
      .onActionEnd(() => {
        this.positionX = this.offsetX
        this.positionY = this.offsetY
        this.borderStyles = BorderStyle.Solid
        console.info('pan end')
      })
    )
      .onCancel(() => {
        console.info('sequence gesture canceled')
      })
    )
  }
}

Diagram:

In sequence recognition mode the long press gesture event is triggered first.

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