【高心星出品】

Ability与Page数据传递

基于当前的应用模型，可以通过以下几种方式来实现UIAbility组件与UI之间的数据同步。

• 使用EventHub进行数据通信：在基类Context中提供了EventHub对象，可以通过发布订阅方式来实现事件的传递。在事件传递前，订阅者需要先进行订阅，当发布者发布事件时，订阅者将接收到事件并进行相应处理。
• 使用AppStorage/LocalStorage进行数据同步：ArkUI提供了AppStorage和LocalStorage两种应用级别的状态管理方案，可用于实现应用级别和UIAbility级别的数据同步。

Page向Ability传递数据

EventHub为UIAbility组件提供了事件机制，使它们能够进行订阅、取消订阅和触发事件等数据通信能力。

在基类Context中，提供了EventHub对象，可用于在UIAbility组件实例内通信。使用EventHub实现UIAbility与UI之间的数据通信需要先获取EventHub对象，本章节将以此为例进行说明。

下面案例实现：页面点击按钮发送颜色给ability，从而修改ability的窗口背景色。

EntryAbility代码

import { AbilityConstant, UIAbility, Want } from '@kit.AbilityKit';
import { hilog } from '@kit.PerformanceAnalysisKit';
import { window } from '@kit.ArkUI';export default class EntryAbility extends UIAbility {onCreate(want: Want, launchParam: AbilityConstant.LaunchParam): void {hilog.info(0x0000, 'testTag', '%{public}s', 'Ability onCreate');// 注册event_01事件监听this.context.eventHub.on('event_01',(data:Record<string,Object>)=>{// 获取页面传递的数据  设置窗口背景颜色this.context.windowStage.getMainWindowSync().setWindowBackgroundColor(data!.color as string)})}onDestroy(): void {//关闭监听this.context.eventHub.off('event_01')hilog.info(0x0000, 'testTag', '%{public}s', 'Ability onDestroy');}onWindowStageCreate(windowStage: window.WindowStage): void {// Main window is created, set main page for this abilityhilog.info(0x0000, 'testTag', '%{public}s', 'Ability onWindowStageCreate');windowStage.loadContent('pages/eventpage', (err) => {if (err.code) {hilog.error(0x0000, 'testTag', 'Failed to load the content. Cause: %{public}s', JSON.stringify(err) ?? '');return;}hilog.info(0x0000, 'testTag', 'Succeeded in loading the content.');});}onWindowStageDestroy(): void {// Main window is destroyed, release UI related resourceshilog.info(0x0000, 'testTag', '%{public}s', 'Ability onWindowStageDestroy');}onForeground(): void {// Ability has brought to foregroundhilog.info(0x0000, 'testTag', '%{public}s', 'Ability onForeground');}onBackground(): void {// Ability has back to backgroundhilog.info(0x0000, 'testTag', '%{public}s', 'Ability onBackground');}
}

eventpage页面代码

import { common } from '@kit.AbilityKit';@Entry
@Component
struct Eventpage {@State message: string = 'Hello World';private context:common.UIAbilityContext=getContext(this) as common.UIAbilityContextbuild() {Column(){Button('向EntryAbility发送数据更改背景颜色').width('60%').onClick(()=>{// 提交数据this.context.eventHub.emit('event_01',{color:'#ff0000'})})}.width('100%').height('100%').justifyContent(FlexAlign.Center)}
}

Ability向Page传递数据

ArkUI提供了AppStorage和LocalStorage两种应用级别的状态管理方案，可用于实现应用级别和UIAbility级别的数据同步。使用这些方案可以方便地管理应用状态，提高应用性能和用户体验。其中，AppStorage是一个全局的状态管理器，适用于多个UIAbility共享同一状态数据的情况；而LocalStorage则是一个局部的状态管理器，适用于单个UIAbility内部使用的状态数据。

下面一个案例：在ability获取窗口可布局界面的宽度和高度（窗口高度-通知栏高度）

EntryAbility代码

import { AbilityConstant, UIAbility, Want } from '@kit.AbilityKit';
import { hilog } from '@kit.PerformanceAnalysisKit';
import { AppStorageV2, window } from '@kit.ArkUI';export default class EntryAbility extends UIAbility {onCreate(want: Want, launchParam: AbilityConstant.LaunchParam): void {hilog.info(0x0000, 'testTag', '%{public}s', 'Ability onCreate');// 注册event_01事件监听this.context.eventHub.on('event_01',(data:Record<string,Object>)=>{// 获取页面传递的数据  设置窗口背景颜色this.context.windowStage.getMainWindowSync().setWindowBackgroundColor(data!.color as string)})}onDestroy(): void {//关闭监听this.context.eventHub.off('event_01')hilog.info(0x0000, 'testTag', '%{public}s', 'Ability onDestroy');}onWindowStageCreate(windowStage: window.WindowStage): void {// Main window is created, set main page for this abilityhilog.info(0x0000, 'testTag', '%{public}s', 'Ability onWindowStageCreate');// 获取窗口可布局的宽度和高度let win=windowStage.getMainWindowSync()// 获得通知栏区域let notifybar=win.getWindowAvoidArea(window.AvoidAreaType.TYPE_SYSTEM).topRectlet width=win.getWindowProperties().windowRect.widthlet height=win.getWindowProperties().windowRect.height-notifybar.height// 保存到appstorage中AppStorage.setOrCreate('width', width);AppStorage.setOrCreate('height', height);windowStage.loadContent('pages/eventpage', (err) => {if (err.code) {hilog.error(0x0000, 'testTag', 'Failed to load the content. Cause: %{public}s', JSON.stringify(err) ?? '');return;}hilog.info(0x0000, 'testTag', 'Succeeded in loading the content.');});}onWindowStageDestroy(): void {// Main window is destroyed, release UI related resourceshilog.info(0x0000, 'testTag', '%{public}s', 'Ability onWindowStageDestroy');}onForeground(): void {// Ability has brought to foregroundhilog.info(0x0000, 'testTag', '%{public}s', 'Ability onForeground');}onBackground(): void {// Ability has back to backgroundhilog.info(0x0000, 'testTag', '%{public}s', 'Ability onBackground');}
}

eventpage页面代码

import { common } from '@kit.AbilityKit';@Entry
@Component
struct Eventpage {@State message: string = 'Hello World';// 获取ability传过来的宽度和高度 单位是px@StorageProp('width') wd: number = 0@StorageProp('height') ht: number = 0private context: common.UIAbilityContext = getContext(this) as common.UIAbilityContextbuild() {Column() {Button('向EntryAbility发送数据更改背景颜色').width('60%').onClick(() => {// 提交数据this.context.eventHub.emit('event_01', { color: '#ff0000' })})Column() {Text('宽度为： ' + this.wd).width('100%').fontSize(20)Text('高度为： ' + this.ht).width('100%').fontSize(20)}// 设置组件的宽和高.width(this.wd / 2 + 'px').height(this.ht / 3 + 'px').border({ width: 3, color: Color.Red, style: BorderStyle.Dashed }).justifyContent(FlexAlign.Center).margin(20)}.width('100%').height('100%').justifyContent(FlexAlign.Center)}
}
order({ width: 3, color: Color.Red, style: BorderStyle.Dashed }).justifyContent(FlexAlign.Center).margin(20)}.width('100%').height('100%').justifyContent(FlexAlign.Center)}
}