List

The <List> component provides a list container that presents a series of list items arranged in a column with the same width. It supports presentations of the same type of data in a multiple and coherent row style, for example, images or text.

NOTE

• This component is supported since API version 7. Updates will be marked with a superscript to indicate their earliest API version.
• This component can produce a bounce effect only when there is more than one screen of content.

Child Components

This component supports the <ListItem> and <ListItemGroup> child components.

NOTE

Below are the rules for calculating the indexes of the child components of <List>:

The index increases in ascending order of child components.

In the if/else statement, only the child components in the branch where the condition is met participate in the index calculation.

In the ForEach or LazyForEach statement, the indexes of all expanded subnodes are calculated.

If the values of if/else, ForEach, and LazyForEach change, the indexes of subnodes are updated.

Each <ListItemGroup> component is taken as a whole and assigned an index, and the indexes of the list items within are not included in the index calculation.

Child components of <List> whose visibility attribute is set to Hidden or None are included in the index calculation.

Child components of <List> whose visibility attribute is set to None are not displayed, but the spacing above and below them still takes effect.

APIs

List(value?:{space?: number|string, initialIndex?: number, scroller?: Scroller})

Since API version 9, this API is supported in ArkTS widgets.

Parameters

Attributes

In addition to the universal attributes, the following attributes are supported.

ListItemAlign⁹⁺

This API is supported in ArkTS widgets.

StickyStyle⁹⁺

This API is supported in ArkTS widgets.

ChainEdgeEffect¹⁰⁺

Describes the chained animation edge scrolling effect.

System API: This is a system API.

chainAnimationOptions¹⁰⁺

Provides the chained animation settings, which cover the maximum spacing, minimum spacing, intensity, conductivity, and edge scrolling effect.

System API: This is a system API.

NOTE

The default value of the universal attribute clip is true for the <List> component.

ScrollSnapAlign¹⁰⁺

Enumerates the alignment modes of list items when scrolling ends.

Since API version 10, this API is supported in ArkTS widgets.

When list items are left-, right-, top-, or bottom-aligned, the items at the end must be completely displayed, without exposure of any blank area of the boundary; the items at the other end can be out of alignment.

This API is available only when the heights of list items are the same.

Events

ScrollState

Since API version 9, this API is supported in ArkTS widgets.

The table below lists the changes in the ScrollState enums.

NOTE

To enable the editable mode for a list, the following conditions must be met: (This feature is deprecated since API version 9.)

• editMode is set to true.

• The list is bound to the onItemDelete event and the event returns true in the event callback.

• The editable attribute of ListItem is set to true.

To enable dragging for a list item, the following conditions must be met:

• editMode is set to true. (This is not required since API version 9.)

• The list item is bound to the onDragStart event and the event returns a floating UI during event callback.

Example

Example 1

// xxx.ets
@Entry
@Component
struct ListExample {
  private arr: number[] = [0, 1, 2, 3, 4, 5, 6, 7, 8, 9]

  build() {
    Column() {
      List({ space: 20, initialIndex: 0 }) {
        ForEach(this.arr, (item: number) => {
          ListItem() {
            Text('' + item)
              .width('100%').height(100).fontSize(16)
              .textAlign(TextAlign.Center).borderRadius(10).backgroundColor(0xFFFFFF)
          }
        }, (item: string) => item)
      }
      .listDirection(Axis.Vertical) // Arrangement direction
      .scrollBar(BarState.Off)
      .friction(0.6)
      .divider({ strokeWidth: 2, color: 0xFFFFFF, startMargin: 20, endMargin: 20 }) // Divider
      .edgeEffect(EdgeEffect.Spring) // Set the edge scrolling effect to Spring.
      .onScrollIndex((firstIndex: number, lastIndex: number, centerIndex: number) => {
        console.info('first' + firstIndex)
        console.info('last' + lastIndex)
        console.info('center' + centerIndex)
      })
      .onScroll((scrollOffset: number, scrollState: ScrollState) => {
        console.info(`onScroll scrollState = ScrollState` + scrollState + `, scrollOffset = ` + scrollOffset)
      })
      .width('90%')
    }
    .width('100%')
    .height('100%')
    .backgroundColor(0xDCDCDC)
    .padding({ top: 5 })
  }
}

Example 2

// xxx.ets
@Entry
@Component
struct ListLanesExample {
  @State arr: string[] = ["0", "1", "2", "3", "4", "5", "6", "7", "8", "9", "10", "11", "12", "13", "14", "15", "16", "17", "18", "19"]
  @State alignListItem: ListItemAlign = ListItemAlign.Start

  build() {
    Column() {
      List({ space: 20, initialIndex: 0 }) {
        ForEach(this.arr, (item: string) => {
          ListItem() {
            Text('' + item)
              .width('100%')
              .height(100)
              .fontSize(16)
              .textAlign(TextAlign.Center)
              .borderRadius(10)
              .backgroundColor(0xFFFFFF)
          }
          .border({ width: 2, color: Color.Green })
        }, (item: string) => item)
      }
      .height(300)
      .width("90%")
      .friction(0.6)
      .border({ width: 3, color: Color.Red })
      .lanes({ minLength: 40, maxLength: 40 })
      .alignListItem(this.alignListItem)
      .scrollBar(BarState.Off)

      Button("Change alignListItem: "+ this.alignListItem).onClick(() => {
        if (this.alignListItem == ListItemAlign.Start) {
          this.alignListItem = ListItemAlign.Center
        } else if (this.alignListItem == ListItemAlign.Center) {
          this.alignListItem = ListItemAlign.End
        } else {
          this.alignListItem = ListItemAlign.Start
        }
      })
    }.width('100%').height('100%').backgroundColor(0xDCDCDC).padding({ top: 5 })
  }
}

Example 3

// xxx.ets
@Entry
@Component
struct ListExample {
  @State arr: number[] = [0, 1, 2, 3, 4, 5, 6, 7, 8, 9]
  @State editFlag: boolean = false

  build() {
    Stack({ alignContent: Alignment.TopStart }) {
      Column() {
        List({ space: 20, initialIndex: 0 }) {
          ForEach(this.arr, (item: number, index?: number) => {
            ListItem() {
              Flex({ direction: FlexDirection.Row, alignItems: ItemAlign.Center }) {
                Text('' + item)
                  .width('100%')
                  .height(80)
                  .fontSize(20)
                  .textAlign(TextAlign.Center)
                  .borderRadius(10)
                  .backgroundColor(0xFFFFFF)
                  .flexShrink(1)
                if (this.editFlag) {
                  Button() {
                    Text("delete").fontSize(16)
                  }.width('30%').height(40)
                  .onClick(() => {
                    if (index != undefined) {
                      console.info(this.arr[index] + 'Delete')
                      this.arr.splice(index, 1)
                      console.info(JSON.stringify(this.arr))
                      this.editFlag = false
                    }
                  }).stateEffect(true)
                }
              }
            }
          }, (item: string) => item)
        }.width('90%')
        .scrollBar(BarState.Off)
        .friction(0.6)
      }.width('100%')

      Button('edit list')
        .onClick(() => {
          this.editFlag = !this.editFlag
        }).margin({ top: 5, left: 20 })
    }.width('100%').height('100%').backgroundColor(0xDCDCDC).padding({ top: 5 })
  }
}

Example 4

// xxx.ets
@Entry
@Component
struct ListExample {
  private arr: number[] = []
  private scrollerForList: Scroller = new Scroller()

  aboutToAppear() {
    for (let i = 0; i < 20; i++) {
      this.arr.push(i)
    }
  }
  build() {
    Column() {
      Row() {
        List({ space: 20, initialIndex: 3, scroller: this.scrollerForList }) {
          ForEach(this.arr, (item: number) => {
            ListItem() {
              Text('' + item)
                .width('100%').height(100).fontSize(16)
                .textAlign(TextAlign.Center)
            }
            .borderRadius(10).backgroundColor(0xFFFFFF)
            .width('60%')
            .height('80%')
          }, (item: number) => JSON.stringify(item))
        }
        .chainAnimationOptions({
          minSpace: 20,
          maxSpace: 60,
          edgeEffect: ChainEdgeEffect.STRETCH
        })
        .chainAnimation(true)
        .edgeEffect(EdgeEffect.Spring)
        .listDirection(Axis.Horizontal)
        .height('100%')
        .width('100%')
        .scrollSnapAlign(ScrollSnapAlign.CENTER)
        .borderRadius(10)
        .backgroundColor(0xDCDCDC)
        .width('100%')
      }
      .width('100%')
      .height('100%')
      .backgroundColor(0xDCDCDC)
      .padding({ top: 10 })
    }
  }
}

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