1# Touch Event 2 3A touch event is triggered when a finger is pressed against, swipes on, or is lifted from a component. 4 5> **NOTE** 6> 7> This event is supported since API version 7. Updates will be marked with a superscript to indicate their earliest API version. 8 9## onTouch 10 11onTouch(event: (event: TouchEvent) => void): T 12 13Invoked when a touch event is triggered. 14 15**Atomic service API**: This API can be used in atomic services since API version 11. 16 17**System capability**: SystemCapability.ArkUI.ArkUI.Full 18 19**Parameters** 20 21| Name| Type | Mandatory| Description | 22| ------ | --------------------------------- | ---- | -------------------- | 23| event | [TouchEvent](#touchevent) | Yes | **TouchEvent** object.| 24 25**Return value** 26 27| Type| Description| 28| -------- | -------- | 29| T | Current component.| 30 31## TouchEvent 32 33Inherits from [BaseEvent](ts-gesture-customize-judge.md#baseevent). 34 35**System capability**: SystemCapability.ArkUI.ArkUI.Full 36 37| Name | Type | Description | 38| ------------------- | ---------------------------------------- | ------------ | 39| type | [TouchType](ts-appendix-enums.md#touchtype) | Type of the touch event.<br>**Atomic service API**: This API can be used in atomic services since API version 11. | 40| touches | Array<[TouchObject](#touchobject)> | All finger information.<br>**Atomic service API**: This API can be used in atomic services since API version 11. | 41| changedTouches | Array<[TouchObject](#touchobject)> | Finger information changed.<br>**Atomic service API**: This API can be used in atomic services since API version 11.| 42| stopPropagation | () => void | Stops the event from bubbling upwards or downwards.<br>**Atomic service API**: This API can be used in atomic services since API version 11.| 43| preventDefault<sup>12+</sup> | () => void | Blocks the default event.<br> **NOTE**<br>This API can only be used by certain components; currently there are no supported components.<br>**Atomic service API**: This API can be used in atomic services since API version 12.| 44 45 46### getHistoricalPoints<sup>10+</sup> 47 48getHistoricalPoints(): Array<HistoricalPoint> 49 50Obtains all historical points of the current frame. The touch event frequency of a frame varies by device, and all touch events of the current frame are referred to as its historical points. This API can be called only in [TouchEvent](#touchevent). You can use this API to obtain the historical points of the current frame when [onTouch](#ontouch) is invoked. [onTouch](#ontouch) is invoked only once for a frame. If the value of [TouchEvent](#touchevent) received by the current frame is greater than 1, the last point of the frame is returned through [onTouch](#ontouch). The remaining points are regarded as historical points. 51 52**Atomic service API**: This API can be used in atomic services since API version 11. 53 54**System capability**: SystemCapability.ArkUI.ArkUI.Full 55 56**Return value** 57 58| Type | Description | 59| ------ | ----------------------- | 60| Array<[HistoricalPoint](#historicalpoint10)>| Array of historical points.| 61 62 63## TouchObject 64 65**System capability**: SystemCapability.ArkUI.ArkUI.Full 66 67| Name | Type | Description | 68| ------- | ------------------------------------------- | ------------------------------------- | 69| type | [TouchType](ts-appendix-enums.md#touchtype) | Type of the touch event.<br>**Atomic service API**: This API can be used in atomic services since API version 11. | 70| id | number | Unique identifier of a finger.<br>**Atomic service API**: This API can be used in atomic services since API version 11. | 71| x | number | X coordinate of the touch point relative to the upper left corner of the event responding component.<br>Unit: vp<br>**Atomic service API**: This API can be used in atomic services since API version 11.| 72| y | number | Y coordinate of the touch point relative to the upper left corner of the event responding component.<br>Unit: vp<br>**Atomic service API**: This API can be used in atomic services since API version 11.| 73| windowX<sup>10+</sup> | number | X coordinate of the touch point relative to the upper left corner of the application window.<br>Unit: vp<br>**Atomic service API**: This API can be used in atomic services since API version 11. | 74| windowY<sup>10+</sup> | number | Y coordinate of the touch point relative to the upper left corner of the application window.<br>Unit: vp<br>**Atomic service API**: This API can be used in atomic services since API version 11. | 75| displayX<sup>10+</sup> | number | X coordinate of the touch point relative to the upper left corner of the application screen.<br>Unit: vp<br>**Atomic service API**: This API can be used in atomic services since API version 11. | 76| displayY<sup>10+</sup> | number | Y coordinate of the touch point relative to the upper left corner of the application screen.<br>Unit: vp<br>**Atomic service API**: This API can be used in atomic services since API version 11. | 77| screenX<sup>(deprecated)</sup> | number | X coordinate of the touch point relative to the upper left corner of the application window.<br>Unit: vp<br>This API is deprecated since API version 10. You are advised to use **windowX** instead. | 78| screenY<sup>(deprecated)</sup> | number | Y coordinate of the touch point relative to the upper left corner of the application window.<br>Unit: vp<br>This API is deprecated since API version 10. You are advised to use **windowY** instead. | 79 80## HistoricalPoint<sup>10+</sup> 81 82**Atomic service API**: This API can be used in atomic services since API version 11. 83 84**System capability**: SystemCapability.ArkUI.ArkUI.Full 85 86| Name | Type | Description | 87| ----------- | ----------------------------------- | ----------------------------------------------------------------------------- | 88| touchObject | [TouchObject](#touchobject) | Basic information of the historical point. | 89| size | number | Size of the contact area between the finger and screen for the historical point.<br>Default value: **0** | 90| force | number | Touch force of the historical point.<br>Default value: **0**<br>Value range: [0, 65535). The greater the pressure, the larger the value.| 91| timestamp | number | Timestamp of the historical point. It is the interval between the time when the event is triggered and the time when the system starts.<br>Unit: ns | 92## Example 93 94```ts 95// xxx.ets 96@Entry 97@Component 98struct TouchExample { 99 @State text: string = '' 100 @State eventType: string = '' 101 102 build() { 103 Column() { 104 Button('Touch').height(40).width(100) 105 .onTouch((event?: TouchEvent) => { 106 if(event){ 107 if (event.type === TouchType.Down) { 108 this.eventType = 'Down' 109 } 110 if (event.type === TouchType.Up) { 111 this.eventType = 'Up' 112 } 113 if (event.type === TouchType.Move) { 114 this.eventType = 'Move' 115 } 116 this.text = 'TouchType:' + this.eventType + '\nDistance between touch point and touch element:\nx: ' 117 + event.touches[0].x + '\n' + 'y: ' + event.touches[0].y + '\nComponent globalPos:(' 118 + event.target.area.globalPosition.x + ',' + event.target.area.globalPosition.y + ')\nwidth:' 119 + event.target.area.width + '\nheight:' + event.target.area.height 120 } 121 }) 122 Button('Touch').height(50).width(200).margin(20) 123 .onTouch((event?: TouchEvent) => { 124 if(event){ 125 if (event.type === TouchType.Down) { 126 this.eventType = 'Down' 127 } 128 if (event.type === TouchType.Up) { 129 this.eventType = 'Up' 130 } 131 if (event.type === TouchType.Move) { 132 this.eventType = 'Move' 133 } 134 this.text = 'TouchType:' + this.eventType + '\nDistance between touch point and touch element:\nx: ' 135 + event.touches[0].x + '\n' + 'y: ' + event.touches[0].y + '\nComponent globalPos:(' 136 + event.target.area.globalPosition.x + ',' + event.target.area.globalPosition.y + ')\nwidth:' 137 + event.target.area.width + '\nheight:' + event.target.area.height 138 } 139 }) 140 Text(this.text) 141 }.width('100%').padding(30) 142 } 143} 144``` 145 146 147
