启动指定页面

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 hilog from '@ohos.hilog';const TAG: string = 'PagePageAbilityFirst';
const domain: number = 0xFF00;

(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) => {hilog.debug(domain, 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.pushUrl({ 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.pushUrl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 hilog from '@ohos.hilog';const TAG: string = 'PagePageAbilityFirst';
const domain: number = 0xFF00;@Entry
@Component
struct PagePageAbilityFirst {build() {Column() {//...List({ initialIndex: 0 }) {//...ListItem() {Flex({ justifyContent: FlexAlign.SpaceBetween, alignContent: FlexAlign.Center }) {//...}.onClick(() => {let want: Want = {bundleName: 'com.samples.famodelabilitydevelop',abilityName: 'com.samples.famodelabilitydevelop.PageAbilityStandard',parameters: { page: 'pages/first' }};featureAbility.startAbility({ want: want }).then((data) => {hilog.info(domain, TAG, `startAbility finish:${data}`);}).catch((err: BusinessError) => {hilog.info(domain, TAG, `startAbility failed errcode:${err.code}`);})})}//...ListItem() {Flex({ justifyContent: FlexAlign.SpaceBetween, alignContent: FlexAlign.Center }) {//...}.onClick(() => {let want: Want = {bundleName: 'com.samples.famodelabilitydevelop',abilityName: 'com.samples.famodelabilitydevelop.PageAbilityStandard',parameters: { page: 'pages/second' }};featureAbility.startAbility({ want: want }).then((data) => {hilog.info(domain, TAG, `startAbility finish:${data}`);}).catch((err: BusinessError) => {hilog.info(domain, TAG, `startAbility failed errcode:${err.code}`);})})}//...}//...}//...}
}

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.pushUrl({ url: want.parameters.page as string });}}})}
}export default new PageAbilityStandard();