Starting a Specified Page

When the launch type of a PageAbility is set to singleton (default), the onNewWant() callback is triggered if the PageAbility is not started for the first time. For details about the launch type, see PageAbility Launch Type. In this case, you can use the want parameter to transfer startup information. For example, if you want to start a PageAbility with a specified page, pass the pages information in parameters of want.

In app.ets or page of the caller PageAbility, use startAbility() to start the PageAbility again, with the page information passed in the uri parameter in want.

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}`);
  });
})()

Obtain the want parameter that contains the page information from the onNewWant() callback of the target PageAbility.

// Construct a singleton object in GlobalContext.ts.
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();

Obtain the want parameter that contains the page information from the custom component of the target PageAbility and process the route based on the URI.

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'))
  }
}

When a PageAbility in multiton mode is started or when the PageAbility in singleton mode is started for the first time, you can use the parameters parameter in want to transfer the pages information and use the startAbility() method to start the PageAbility. For details about the launch type, see PageAbility Launch Type. The target PageAbility can use the featureAbility.getWant() method in onCreate to obtain the want parameter, and then call router.pushUrl to start a specified page.

When a user touches the button on the page of the caller PageAbility, the startAbility() method is called to start the target PageAbility. The want parameter in startAbility() carries the specified page information.

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'))
  }
}

In the onCreate() callback of the target PageAbility, use the featureAbility.getWant() method to obtain the want parameter, parse the parameter, and start the specified page.

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();