harmony 鸿蒙GridRow

2022-10-28
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GridRow

The responsive grid layout provides rules for layout design and resolves issues of dynamic layout across devices with different sizes, thereby ensuring layout consistency across layouts on different devices.

The <GridRow> component is used in a grid layout, together with its child component <GridCol>.

NOTE

This component is supported since API version 9. Updates will be marked with a superscript to indicate their earliest API version.

Child Components

This component can contain the <GridCol> child component.

APIs

GridRow(option?: {columns?: number|GridRowColumnOption, gutter?: Length|GutterOption, breakpoints?: BreakPoints, direction?: GridRowDirection})

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

Parameters

Name	Type	Mandatory	Description
gutter	Length \|GutterOption	No	Gutter of the grid layout.
columns	number \|GridRowColumnOption	No	Number of columns in the grid layout.
breakpoints	BreakPoints	No	Array of breakpoints for the breakpoint value and the corresponding reference based on the window or container size.
direction	GridRowDirection	No	Arrangement direction of the grid layout.

GutterOption

Provides the gutter options for the grid layout to define the spacing between child components in different directions.

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

Name	Type	Mandatory	Description
x	Length \|GridRowSizeOption	No	Horizontal spacing between grid child components.
y	Length \|GridRowSizeOption	No	Vertical spacing between grid child components.

GridRowColumnOption

Describes the numbers of grid columns for different device width types.

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

Name	Type	Mandatory	Description
xs	number	No	Number of grid columns for minimum device width.
sm	number	No	Number of grid columns for small device width.
md	number	No	Number of grid columns for medium device width.
lg	number	No	Number of grid columns for large device width.
xl	number	No	Number of grid columns for extra large device width.
xxl	number	No	Number of grid columns for extra extra large device width.

GridRowSizeOption

Describes the gutter sizes for different device width types.

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

Name	Type	Mandatory	Description
xs	Length	No	Gutter size for minimum device width.
sm	Length	No	Gutter size for small device width.
md	Length	No	Gutter size for medium device width.
lg	Length	No	Gutter size for large device width.
xl	Length	No	Gutter size for extra large device width.
xxl	Length	No	Gutter size for extra extra large device width.

BreakPoints

Sets breakpoints for the responsive grid container.

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

Name	Type	Mandatory	Description
value	Array<string>	No	Array of monotonically increasing breakpoints. Default value: [“320vp”, “600vp”, “840vp”]
reference	BreakpointsReference	No	Breakpoint switching reference. Default value: BreakpointsReference.WindowSize

  // Enable the xs, sm, and md breakpoints.
  breakpoints: {value: ["100vp", "200vp"]}
  // Enable four breakpoints: xs, sm, md, and lg. The breakpoint range must be monotonically increasing.
  breakpoints: {value: ["320vp", "600vp", "840vp"]}
  // Enable five breakpoints: xs, sm, md, lg, and xl. The number of breakpoint ranges cannot exceed the number of breakpoints minus 1.
  breakpoints: {value: ["320vp", "600vp", "840vp", "1080vp"]}

BreakpointsReference

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

Name	Description
WindowSize	The window is used as a reference.
ComponentSize	The container is used as a reference.

GridRowDirection

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

Name	Description
Row	Grid elements are arranged in the row direction.
RowReverse	Grid elements are arranged in the reverse row direction.

A grid supports a maximum of six breakpoints: xs, sm, md, lg, xl and xxl, whose names cannot be changed. Assume that the input array is [n0, n1, n2, n3, n4], then the value ranges of breakpoints are as follows.

Breakpoint	Value Range
xs	[0, n0)
sm	[n0, n1)
md	[n1, n2)
lg	[n2, n3)
xl	[n3, n4)
xxl	[n4, INF)

NOTE * Grid elements can be arranged only in the Row or RowReverse direction, but not in the Column or ColumnReverse direction. * The location and size of a grid child component can be calculated only based on span and offset. If the span values of child components add up to a number greater than the allowed number of columns, the grid will automatically wraps lines. * If the span value of a single child component exceeds the maximum number of columns, the maximum number of columns is used. * If a child component takes up more than the total number of columns according to its offset and span settings, it will be placed in a new row. * Below is the display effect of Item1: GridCol({span: 6}), Item2: GridCol({ span: 8, offset:11}).

1	2	3	4	5	6	7	8	9	10	11	12
$\circ$	$\circ$	$\circ$	$\circ$	$\circ$	$\circ$	-	-	-	-	-	-
-	-	-	-	-
$\circ$	$\circ$	$\circ$	$\circ$	$\circ$	$\circ$	$\circ$	$\circ$

Attributes

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

Name	Type	Description
alignItems¹⁰⁺	ItemAlign	Alignment mode of the <GridCol> cross axis. Default value: ItemAlign.Start NOTE ItemAlign supports the following enums: ItemAlign.Start, ItemAlign.Center, ItemAlign.End, and ItemAlign.Stretch. The alignment mode of the <GridCol> component can also be set using alignSelf(ItemAlign). If both of the preceding methods are used, the setting of alignSelf(ItemAlign) prevails. Since API version 10, this API is supported in ArkTS widgets.

Events

onBreakpointChange

onBreakpointChange(callback: (breakpoints: string) => void)

Triggered when the breakpoint changes.

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

Parameters

Name	Type	Mandatory	Description
breakpoints	string	Yes	Breakpoint change. The value can be “xs”, “sm”, “md”, “lg”, “xl”, or “xxl”.

Example

// xxx.ets
@Entry
@Component
struct GridRowExample {
  @State bgColors: Color[] = [Color.Red, Color.Orange, Color.Yellow, Color.Green, Color.Pink, Color.Grey, Color.Blue, Color.Brown]
  @State currentBp: string = 'unknown'

  build() {
    Column() {
      GridRow({
        columns: 5,
        gutter: { x: 5, y: 10 },
        breakpoints: { value: ["400vp", "600vp", "800vp"],
          reference: BreakpointsReference.WindowSize },
        direction: GridRowDirection.Row
      }) {
        ForEach(this.bgColors, (color: Color) => {
          GridCol({ span: { xs: 1, sm: 2, md: 3, lg: 4 }, offset: 0, order: 0 }) {
            Row().width("100%").height("20vp")
          }.borderColor(color).borderWidth(2)
        })
      }.width("100%").height("100%")
      .onBreakpointChange((breakpoint) => {
        this.currentBp = breakpoint
      })
    }.width('80%').margin({ left: 10, top: 5, bottom: 5 }).height(200)
    .border({ color: '#880606', width: 2 })
  }
}