HarmonyOS 相对布局（RelativeContainer）

1. HarmonyOS 相对布局（RelativeContainer）

  文档中心:https://developer.huawei.com/consumer/cn/doc/harmonyos-guides-V5/arkts-layout-development-relative-layout-V5
  RelativeContainer为采用相对布局的容器，支持容器内部的子元素设置相对位置关系。子元素支持指定兄弟元素作为锚点，也支持指定父容器作为锚点，基于锚点做相对位置布局。下图是一个RelativeContainer的概念图，图中的虚线表示位置的依赖关系。

import { TitleBar } from '../../components/common/TitleBar'
import { router } from '@kit.ArkUI'
import { RouterParams } from 'zzslib'//子组件相对父组件位置
let sonRule1: Record<string,
Record<string, string | VerticalAlign | HorizontalAlign>> = {'top': {'anchor': '__container__','align': VerticalAlign.Top},'left': {'anchor': '__container__','align': HorizontalAlign.Start}
}
let sonRule2: Record<string,
Record<string, string | VerticalAlign | HorizontalAlign>> = {'top': {'anchor': '__container__','align': VerticalAlign.Top},'right': {'anchor': '__container__','align': HorizontalAlign.End}
}
let sonRule3: Record<string,
Record<string, string | VerticalAlign | HorizontalAlign>> = {'bottom': {'anchor': '__container__','align': VerticalAlign.Bottom},'right': {'anchor': '__container__','align': HorizontalAlign.End},
}//父组件样式
@Extend(RelativeContainer)
function extendFather() {.width(300).height(300).margin({ 'left': 20 }).border({'width': 2,'color': '#6699FF'})
}//子组件样式
@Extend(Row)
function extendSon() {.justifyContent(FlexAlign.Center).width(100).height(100).backgroundColor("#FF3333")
}//子组件样式
@Extend(Row)
function extendSon3() {.width('100%').padding({top:10,bottom:10}).justifyContent(FlexAlign.Center).backgroundColor("#FF66FF")
}@Entry
@Component
struct RelativePage {@State pageTitle: string = "RelativeContainer"aboutToAppear() {try {this.pageTitle = (router.getParams() as RouterParams).title} catch (e) {}}build() {Column() {TitleBar({ pageTitle: $pageTitle })Text('相对布局 (RelativeContainer)')RelativeContainer() {Row() {Text('son1')}.id("row1").alignRules(sonRule1).extendSon()Row() {Text('son2')}.id("row2").alignRules(sonRule2).extendSon()Row() {Text('son3')}.id("row3").alignRules(sonRule3).extendSon3()}.id("father_id").extendFather()}}
}

1.1. 相对布局示意图

  子元素并不完全是上图中的依赖关系。比如，Item4可以以Item2为依赖锚点，也可以以RelativeContainer父容器为依赖锚点。

1.2. 基本概念

  （1）锚点：通过锚点设置当前元素基于哪个元素确定位置。
  （2）对齐方式：通过对齐方式，设置当前元素是基于锚点的上中下对齐，还是基于锚点的左中右对齐。

1.3. 锚点设置

  锚点设置是指设置子元素相对于父元素或兄弟元素的位置依赖关系。在水平方向上，可以设置left、middle、right的锚点。在竖直方向上，可以设置top、center、bottom的锚点。为了明确定义锚点，必须为RelativeContainer及其子元素设置ID，用于指定锚点信息。ID默认为“container”，其余子元素的ID通过id属性设置。未设置ID的子元素在RelativeContainer中不会显示。
  说明：在使用锚点时要注意子元素的相对位置关系，避免出现错位或遮挡的情况。

1.3.1. RelativeContainer父组件为锚点，__container__代表父容器的ID。

let AlignRus:Record<string,Record<string,string|VerticalAlign|HorizontalAlign>> = {'top': { 'anchor': '__container__', 'align': VerticalAlign.Top },'left': { 'anchor': '__container__', 'align': HorizontalAlign.Start }
}
let AlignRue:Record<string,Record<string,string|VerticalAlign|HorizontalAlign>> = {'top': { 'anchor': '__container__', 'align': VerticalAlign.Top },'right': { 'anchor': '__container__', 'align': HorizontalAlign.End }
}
let Mleft:Record<string,number> = { 'left': 20 }
let BWC:Record<string,number|string> = { 'width': 2, 'color': '#6699FF' }
RelativeContainer() {Row().width(100).height(100).backgroundColor("#FF3333").alignRules(AlignRus).id("row1")Row().width(100).height(100).backgroundColor("#FFCC00").alignRules(AlignRue).id("row2")
}.width(300).height(300)
.margin(Mleft)
.border(BWC)

1.3.2. 以兄弟元素为锚点。

let AlignRus:Record<string,Record<string,string|VerticalAlign|HorizontalAlign>> = {'top': { 'anchor': '__container__', 'align': VerticalAlign.Top },'left': { 'anchor': '__container__', 'align': HorizontalAlign.Start }
}
let RelConB:Record<string,Record<string,string|VerticalAlign|HorizontalAlign>> = {'top': { 'anchor': 'row1', 'align': VerticalAlign.Bottom },'left' : { 'anchor': 'row1', 'align': HorizontalAlign.Start }
}
let Mleft:Record<string,number> = { 'left': 20 }
let BWC:Record<string,number|string> = { 'width': 2, 'color': '#6699FF' }
RelativeContainer() {Row().width(100).height(100).backgroundColor("#FF3333").alignRules(AlignRus).id("row1")Row().width(100).height(100).backgroundColor("#FFCC00").alignRules(RelConB).id("row2")
}.width(300).height(300)
.margin(Mleft)
.border(BWC)

1.3.3. 子组件锚点可以任意选择，但需注意不要相互依赖。

子组件锚点可以任意选择，但需注意不要相互依赖。

@Entry
@Component
struct Index {build() {Row() {RelativeContainer() {Row(){Text('row1')}.justifyContent(FlexAlign.Center).width(100).height(100).backgroundColor('#ff3339ff').alignRules({top: {anchor: "__container__", align: VerticalAlign.Top},left: {anchor: "__container__", align: HorizontalAlign.Start}}).id("row1")Row(){Text('row2')}.justifyContent(FlexAlign.Center).width(100).backgroundColor('#ff298e1e').alignRules({top: {anchor: "__container__", align: VerticalAlign.Top},right: {anchor: "__container__", align: HorizontalAlign.End},bottom: {anchor: "row1", align: VerticalAlign.Center},}).id("row2")Row(){Text('row3')}.justifyContent(FlexAlign.Center).height(100).backgroundColor('#ffff6a33').alignRules({top: {anchor: "row1", align: VerticalAlign.Bottom},left: {anchor: "row1", align: HorizontalAlign.Start},right: {anchor: "row2", align: HorizontalAlign.Start}}).id("row3")Row(){Text('row4')}.justifyContent(FlexAlign.Center).backgroundColor('#ffff33fd').alignRules({top: {anchor: "row3", align: VerticalAlign.Bottom},left: {anchor: "row1", align: HorizontalAlign.Center},right: {anchor: "row2", align: HorizontalAlign.End},bottom: {anchor: "__container__", align: VerticalAlign.Bottom}}).id("row4")}.width(300).height(300).margin({left: 50}).border({width:2, color: "#6699FF"})}.height('100%')}
}

1.4. 设置相对于锚点的对齐位置

  设置了锚点之后，可以通过align设置相对于锚点的对齐位置。
  在水平方向上，对齐位置可以设置为HorizontalAlign.Start、HorizontalAlign.Center、HorizontalAlign.End。

  在竖直方向上，对齐位置可以设置为VerticalAlign.Top、VerticalAlign.Center、VerticalAlign.Bottom。

1.4.1. 子组件位置偏移

  子组件经过相对位置对齐后，位置可能还不是目标位置，开发者可根据需要进行额外偏移设置offset。

@Entry
@Component
struct Index {build() {Row() {RelativeContainer() {Row(){Text('row1')}.justifyContent(FlexAlign.Center).width(100).height(100).backgroundColor("#FF3333").alignRules({top: {anchor: "__container__", align: VerticalAlign.Top},left: {anchor: "__container__", align: HorizontalAlign.Start}}).id("row1")Row(){Text('row2')}.justifyContent(FlexAlign.Center).width(100).backgroundColor("#FFCC00").alignRules({top: {anchor: "__container__", align: VerticalAlign.Top},right: {anchor: "__container__", align: HorizontalAlign.End},bottom: {anchor: "row1", align: VerticalAlign.Center},}).offset({x:-40,y:-20}).id("row2")Row(){Text('row3')}.justifyContent(FlexAlign.Center).height(100).backgroundColor("#FF6633").alignRules({top: {anchor: "row1", align: VerticalAlign.Bottom},left: {anchor: "row1", align: HorizontalAlign.End},right: {anchor: "row2", align: HorizontalAlign.Start}}).offset({x:-10,y:-20}).id("row3")Row(){Text('row4')}.justifyContent(FlexAlign.Center).backgroundColor("#FF9966").alignRules({top: {anchor: "row3", align: VerticalAlign.Bottom},bottom: {anchor: "__container__", align: VerticalAlign.Bottom},left: {anchor: "__container__", align: HorizontalAlign.Start},right: {anchor: "row1", align: HorizontalAlign.End}}).offset({x:-10,y:-30}).id("row4")Row(){Text('row5')}.justifyContent(FlexAlign.Center).backgroundColor("#FF66FF").alignRules({top: {anchor: "row3", align: VerticalAlign.Bottom},bottom: {anchor: "__container__", align: VerticalAlign.Bottom},left: {anchor: "row2", align: HorizontalAlign.Start},right: {anchor: "row2", align: HorizontalAlign.End}}).offset({x:10,y:20}).id("row5")Row(){Text('row6')}.justifyContent(FlexAlign.Center).backgroundColor('#ff33ffb5').alignRules({top: {anchor: "row3", align: VerticalAlign.Bottom},bottom: {anchor: "row4", align: VerticalAlign.Bottom},left: {anchor: "row3", align: HorizontalAlign.Start},right: {anchor: "row3", align: HorizontalAlign.End}}).offset({x:-15,y:10}).backgroundImagePosition(Alignment.Bottom).backgroundImageSize(ImageSize.Cover).id("row6")}.width(300).height(300).margin({left: 50}).border({width:2, color: "#6699FF"})}.height('100%')}
}

1.4.2. 多种组件的对齐布局

  Row、Column、Flex、Stack等多种布局组件，可按照RelativeContainer组件规则进行对其排布。

@Entry
@Component
struct Index {@State value: number = 0build() {Row() {RelativeContainer() {Row().width(100).height(100).backgroundColor('#ff33ffcc').alignRules({top: {anchor: "__container__", align: VerticalAlign.Top},left: {anchor: "__container__", align: HorizontalAlign.Start}}).id("row1")Column().width('50%').height(30).backgroundColor(0xAFEEEE).alignRules({top: {anchor: "__container__", align: VerticalAlign.Top},left: {anchor: "__container__", align: HorizontalAlign.Center}}).id("row2")Flex({ direction: FlexDirection.Row }) {Text('1').width('20%').height(50).backgroundColor(0xF5DEB3)Text('2').width('20%').height(50).backgroundColor(0xD2B48C)Text('3').width('20%').height(50).backgroundColor(0xF5DEB3)Text('4').width('20%').height(50).backgroundColor(0xD2B48C)}.padding(10).backgroundColor('#ffedafaf').alignRules({top: {anchor: "row2", align: VerticalAlign.Bottom},left: {anchor: "__container__", align: HorizontalAlign.Start},bottom: {anchor: "__container__", align: VerticalAlign.Center},right: {anchor: "row2", align: HorizontalAlign.Center}}).id("row3")Stack({ alignContent: Alignment.Bottom }) {Text('First child, show in bottom').width('90%').height('100%').backgroundColor(0xd2cab3).align(Alignment.Top)Text('Second child, show in top').width('70%').height('60%').backgroundColor(0xc1cbac).align(Alignment.Top)}.margin({ top: 5 }).alignRules({top: {anchor: "row3", align: VerticalAlign.Bottom},left: {anchor: "__container__", align: HorizontalAlign.Start},bottom: {anchor: "__container__", align: VerticalAlign.Bottom},right: {anchor: "row3", align: HorizontalAlign.End}}).id("row4")}.width(300).height(300).margin({left: 50}).border({width:2, color: "#6699FF"})}.height('100%')}
}

1.4.3. 组件尺寸

  子组件尺寸大小不会受到相对布局规则的影响。若子组件某个方向上设置两个或以上alignRules时最好不设置此方向尺寸大小，否则对齐规则确定的组件尺寸与开发者设置的尺寸可能产生冲突。

@Entry
@Component
struct Index {build() {Row() {RelativeContainer() {Row(){Text('row1')}.justifyContent(FlexAlign.Center).width(100).height(100).backgroundColor("#FF3333").alignRules({top: {anchor: "__container__", align: VerticalAlign.Top},left: {anchor: "__container__", align: HorizontalAlign.Start}}).id("row1")Row(){Text('row2')}.justifyContent(FlexAlign.Center).width(100).backgroundColor("#FFCC00").alignRules({top: {anchor: "__container__", align: VerticalAlign.Top},right: {anchor: "__container__", align: HorizontalAlign.End},bottom: {anchor: "row1", align: VerticalAlign.Center},}).id("row2")Row(){Text('row3')}.justifyContent(FlexAlign.Center).height(100).backgroundColor("#FF6633").alignRules({top: {anchor: "row1", align: VerticalAlign.Bottom},left: {anchor: "row1", align: HorizontalAlign.End},right: {anchor: "row2", align: HorizontalAlign.Start}}).id("row3")Row(){Text('row4')}.justifyContent(FlexAlign.Center).backgroundColor("#FF9966").alignRules({top: {anchor: "row3", align: VerticalAlign.Bottom},bottom: {anchor: "__container__", align: VerticalAlign.Bottom},left: {anchor: "__container__", align: HorizontalAlign.Start},right: {anchor: "row1", align: HorizontalAlign.End}}).id("row4")Row(){Text('row5')}.justifyContent(FlexAlign.Center).backgroundColor("#FF66FF").alignRules({top: {anchor: "row3", align: VerticalAlign.Bottom},bottom: {anchor: "__container__", align: VerticalAlign.Bottom},left: {anchor: "row2", align: HorizontalAlign.Start},right: {anchor: "row2", align: HorizontalAlign.End}}).id("row5")Row(){Text('row6')}.justifyContent(FlexAlign.Center).backgroundColor('#ff33ffb5').alignRules({top: {anchor: "row3", align: VerticalAlign.Bottom},bottom: {anchor: "row4", align: VerticalAlign.Bottom},left: {anchor: "row3", align: HorizontalAlign.Start},right: {anchor: "row3", align: HorizontalAlign.End}}).id("row6").backgroundImagePosition(Alignment.Bottom).backgroundImageSize(ImageSize.Cover)}.width(300).height(300).margin({left: 50}).border({width:2, color: "#6699FF"})}.height('100%')}
}

1.5. 场景实例

  相对布局内的子元素相对灵活，只要在RelativeContainer容器内，均可以通过alignRules进行相应的位置移动。

@Entry
@Component
struct Index {build() {Row() {RelativeContainer() {Row().width(100).height(100).backgroundColor('#FF3333').alignRules({top: { anchor: '__container__', align: VerticalAlign.Top },  //以父容器为锚点，竖直方向顶头对齐middle: { anchor: '__container__', align: HorizontalAlign.Center }  //以父容器为锚点，水平方向居中对齐}).id('row1')  //设置锚点为row1Row() {Image($r('app.media.icon'))}.height(100).width(100).alignRules({top: { anchor: 'row1', align: VerticalAlign.Bottom },  //以row1组件为锚点，竖直方向低端对齐left: { anchor: 'row1', align: HorizontalAlign.Start }  //以row1组件为锚点，水平方向开头对齐}).id('row2')  //设置锚点为row2Row().width(100).height(100).backgroundColor('#FFCC00').alignRules({top: { anchor: 'row2', align: VerticalAlign.Top }}).id('row3')  //设置锚点为row3Row().width(100).height(100).backgroundColor('#FF9966').alignRules({top: { anchor: 'row2', align: VerticalAlign.Top },left: { anchor: 'row2', align: HorizontalAlign.End },}).id('row4')  //设置锚点为row4Row().width(100).height(100).backgroundColor('#FF66FF').alignRules({top: { anchor: 'row2', align: VerticalAlign.Bottom },middle: { anchor: 'row2', align: HorizontalAlign.Center }}).id('row5')  //设置锚点为row5}.width(300).height(300).border({ width: 2, color: '#6699FF' })}.height('100%').margin({ left: 30 })}
}