HarmonyOS 应用开发之启动指定页面_业界新闻

发布时间:2024-08-03 09:15

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当PageAbility的启动模式设置为单例时（具体设置方法和典型场景示例见 PageAbility的启动模式，缺省情况下是单实例模式），若PageAbility已被拉起，再次启动PageAbility会触发onNewWant回调（即非首次拉起）。应用开发者可以通过want传递启动参数，例如开发者希望指定页面启动PageAbility，可以通过want中的parameters参数传递pages信息，具体示例代码如下：

调用方PageAbility的app.ets中或者page中，使用startAbility再次拉起PageAbility，通过want中的uri参数传递页面信息：

import featureAbility from '@ohos.ability.featureAbility'; import Want from '@ohos.app.ability.Want'; import Logger from '../../utils/Logger';  const TAG: string = 'PagePageAbilityFirst';

(async (): Promise<void> => {   let wantInfo: Want = {     bundleName: 'com.samples.famodelabilitydevelop',     abilityName: 'com.samples.famodelabilitydevelop.PageAbilitySingleton',     parameters: { page: 'pages/second' }   };   featureAbility.startAbility({ want: wantInfo }).then((data) => {     Logger.debug(TAG, `restartAbility success : ${data}`);   }); })()

在目标端PageAbility的onNewWant回调中获取包含页面信息的want参数：

// GlobalContext.ts 构造单例对象 export class GlobalContext {   private constructor() {   }    private static instance: GlobalContext;   private _objects = new Map<string, Object>();    public static getContext(): GlobalContext {     if (!GlobalContext.instance) {       GlobalContext.instance = new GlobalContext();     }     return GlobalContext.instance;   }    getObject(value: string): Object | undefined {     return this._objects.get(value);   }    setObject(key: string, objectClass: Object): void {     this._objects.set(key, objectClass);   } }

import Want from '@ohos.app.ability.Want'; import featureAbility from '@ohos.ability.featureAbility'; import { GlobalContext } from '../utils/GlobalContext';  class PageAbilitySingleton {   onNewWant(want: Want) {     featureAbility.getWant().then((want) => {       GlobalContext.getContext().setObject('newWant', want);     })   } }  export default new PageAbilitySingleton();

在目标端页面的自定义组件中获取包含页面信息的want参数并根据uri做路由处理：

import Want from '@ohos.app.ability.Want'; import router from '@ohos.router'; import { GlobalContext } from '../../utils/GlobalContext';  @Entry @Component struct First {   onPageShow() {     let newWant = GlobalContext.getContext().getObject('newWant') as Want;     if (newWant) {       if (newWant.parameters) {         if (newWant.parameters.page) {           router.push({ url: newWant.parameters.page as string});           GlobalContext.getContext().setObject("newWant", undefined)         }       }     }   }    build() {     Column() {       Row() {         Text($r('app.string.singleton_first_title'))           .fontSize(24)           .fontWeight(FontWeight.Bold)           .textAlign(TextAlign.Start)           .margin({ top: 12, bottom: 11, right: 24, left: 24 })       }       .width('100%')       .height(56)       .justifyContent(FlexAlign.Start)        Image($r('app.media.pic_empty'))         .width(120)         .height(120)         .margin({ top: 224 })        Text($r('app.string.no_content'))         .fontSize(14)         .margin({ top: 8, bottom: 317, right: 152, left: 152 })         .fontColor($r('app.color.text_color'))         .opacity(0.4)     }     .width('100%')     .height('100%')     .backgroundColor($r('app.color.backGrounding'))   } }

当PageAbility的启动模式设置为多实例模式或为首次启动单例模式的PageAbility时（具体设置方法和典型场景示例见 PageAbility的启动模式），在调用方PageAbility中，通过want中的parameters参数传递要启动的指定页面的pages信息，调用startAbility()方法启动PageAbility。被调用方可以在onCreate中使用featureAbility的getWant方法获取want，再通过调用router.push实现启动指定页面。

调用方的页面中实现按钮点击触发startAbility方法启动目标端PageAbility，startAbility方法的入参want中携带指定页面信息，示例代码如下：

import featureAbility from '@ohos.ability.featureAbility'; import Want from '@ohos.app.ability.Want'; import { BusinessError } from '@ohos.base'; import fs from '@ohos.file.fs'; import promptAction from '@ohos.promptAction'; import worker from '@ohos.worker'; import Logger from '../../utils/Logger';  const TAG: string = 'PagePageAbilityFirst';  @Entry @Component struct PagePageAbilityFirst {   build() {     Column() {       Row() {         Flex({ justifyContent: FlexAlign.Start, alignContent: FlexAlign.Center }) {           Text($r('app.string.pageAbility_first_button'))             .fontSize(24)             .fontWeight(FontWeight.Bold)             .textAlign(TextAlign.Start)             .margin({ top: 12, bottom: 11, right: 24, left: 24 })         }       }       .width('100%')       .height(56)       .justifyContent(FlexAlign.Start)       .backgroundColor($r('app.color.backGrounding'))        List({ initialIndex: 0 }) {         ...         ListItem() {           Flex({ justifyContent: FlexAlign.SpaceBetween, alignContent: FlexAlign.Center }) {             Text($r('app.string.start_standard_first_button'))               .textAlign(TextAlign.Start)               .fontWeight(FontWeight.Medium)               .margin({ top: 17, bottom: 17, left: 12, right: 92 })               .fontSize(16)               .width(232)               .height(22)               .fontColor($r('app.color.text_color'))           }           .onClick(() => {             let want: Want = {               bundleName: 'com.samples.famodelabilitydevelop',               abilityName: 'com.samples.famodelabilitydevelop.PageAbilityStandard',               parameters: { page: 'pages/first' }             };             featureAbility.startAbility({ want: want }).then((data) => {               Logger.info(TAG, `startAbility finish:${data}`);             }).catch((err: BusinessError) => {               Logger.info(TAG, `startAbility failed errcode:${err.code}`);             })           })         }         .height(56)         .backgroundColor($r('app.color.start_window_background'))         .borderRadius(24)         .margin({ top: 12, right: 12, left: 12 })          ListItem() {           Flex({ justifyContent: FlexAlign.SpaceBetween, alignContent: FlexAlign.Center }) {             Text($r('app.string.start_standard_second_button'))               .textAlign(TextAlign.Start)               .fontWeight(FontWeight.Medium)               .margin({ top: 17, bottom: 17, left: 12, right: 92 })               .fontSize(16)               .width(232)               .height(22)               .fontColor($r('app.color.text_color'))           }           .onClick(() => {             let want: Want = {               bundleName: 'com.samples.famodelabilitydevelop',               abilityName: 'com.samples.famodelabilitydevelop.PageAbilityStandard',               parameters: { page: 'pages/second' }             };             featureAbility.startAbility({ want: want }).then((data) => {               Logger.info(TAG, `startAbility finish:${data}`);             }).catch((err: BusinessError) => {               Logger.info(TAG, `startAbility failed errcode:${err.code}`);             })           })         }         .height(56)         .backgroundColor($r('app.color.start_window_background'))         .borderRadius(24)         .margin({ top: 12, right: 12, left: 12 })         ...       }       .height('100%')       .backgroundColor($r('app.color.backGrounding'))     }     .width('100%')     .margin({ top: 8 })     .backgroundColor($r('app.color.backGrounding'))   } }

目标端PageAbility的onCreate生命周期回调中通过featureAbility的getWant方法获取want，并对参数进行解析，实现指定页面拉起：

import featureAbility from '@ohos.ability.featureAbility'; import router from '@ohos.router';  class PageAbilityStandard {   onCreate() {     featureAbility.getWant().then((want) => {       if (want.parameters) {         if (want.parameters.page) {           router.push({ url: want.parameters.page as string });         }       }     })   } }  export default new PageAbilityStandard();

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