[UIAbility]是系统调度的最小单元。在设备内的功能模块之间跳转时,会涉及到启动特定的UIAbility,包括应用内的其他UIAbility、或者其他应用的UIAbility(例如启动三方支付UIAbility)。

本文主要介绍启动应用内的UIAbility组件的方式。

  • [启动应用内的UIAbility]
  • [启动应用内的UIAbility并获取返回结果]
  • [启动UIAbility的指定页面]

启动应用内的UIAbility

当一个应用内包含多个[UIAbility]时,存在应用内启动UIAbility的场景。例如在支付应用中从入口UIAbility启动收付款UIAbility。

假设应用中有两个UIAbility:EntryAbility和FuncAbility(可以在同一个Module中,也可以在不同的Module中),需要从EntryAbility的页面中启动FuncAbility。

  1. 在EntryAbility中,通过调用[startAbility()]方法启动UIAbility,[want]为UIAbility实例启动的入口参数,其中bundleName为待启动应用的Bundle名称,abilityName为待启动的Ability名称,moduleName在待启动的UIAbility属于不同的Module时添加,parameters为自定义信息参数。
import { common, Want } from '@kit.AbilityKit';
import { hilog } from '@kit.PerformanceAnalysisKit';
import { BusinessError } from '@kit.BasicServicesKit';

const TAG: string = '[Page_UIAbilityComponentsInteractive]';
const DOMAIN_NUMBER: number = 0xFF00;

@Entry
@Component
struct Page_UIAbilityComponentsInteractive {
  private context = getContext(this) as common.UIAbilityContext;

  build() {
    Column() {
      //...
      List({ initialIndex: 0 }) {
        ListItem() {
          Row() {
            //...
          }
          .onClick(() => {
            // context为Ability对象的成员,在非Ability对象内部调用需要
            // 将Context对象传递过去
            let wantInfo: Want = {
              deviceId: '', // deviceId为空表示本设备
              bundleName: 'com.samples.stagemodelabilitydevelop',
              moduleName: 'entry', // moduleName非必选
              abilityName: 'FuncAbilityA',
              parameters: {
                // 自定义信息
                info: '来自EntryAbility Page_UIAbilityComponentsInteractive页面'
              },
            };
            // context为调用方UIAbility的UIAbilityContext
            this.context.startAbility(wantInfo).then(() => {
              hilog.info(DOMAIN_NUMBER, TAG, 'startAbility success.');
            }).catch((error: BusinessError) => {
              hilog.error(DOMAIN_NUMBER, TAG, 'startAbility failed.');
            });
          })
        }
        //...
      }
      //...
    }
    //...
  }
}
  1. 在FuncAbility的[onCreate()]或者[onNewWant()]生命周期回调文件中接收EntryAbility传递过来的参数。
import { AbilityConstant, UIAbility, Want } from '@kit.AbilityKit';

export default class FuncAbilityA extends UIAbility {
  onCreate(want: Want, launchParam: AbilityConstant.LaunchParam): void {
    // 接收调用方UIAbility传过来的参数
    let funcAbilityWant = want;
    let info = funcAbilityWant?.parameters?.info;
  }
  //...
}

说明

在被拉起的FuncAbility中,可以通过获取传递过来的[want]参数的parameters来获取拉起方[UIAbility]的PID、Bundle Name等信息。

  1. 在FuncAbility业务完成之后,如需要停止当前[UIAbility]实例,在FuncAbility中通过调用[terminateSelf()]方法实现。
import { common } from '@kit.AbilityKit';
import { hilog } from '@kit.PerformanceAnalysisKit';

const TAG: string = '[Page_FromStageModel]';
const DOMAIN_NUMBER: number = 0xFF00;

@Entry
@Component
struct Page_FromStageModel {
  build() {
    Column() {
      //...
      Button('FuncAbilityB')
        .onClick(() => {
          let context: common.UIAbilityContext = getContext(this) as common.UIAbilityContext; // UIAbilityContext
          // context为需要停止的UIAbility实例的AbilityContext
          context.terminateSelf((err) => {
            if (err.code) {
              hilog.error(DOMAIN_NUMBER, TAG, `Failed to terminate self. Code is ${err.code}, message is ${err.message}`);
              return;
            }
          });
        })
    }
    //...
  }
}

说明

调用terminateSelf()方法停止当前UIAbility实例时,默认会保留该实例的快照(Snapshot),即在最近任务列表中仍然能查看到该实例对应的任务。如不需要保留该实例的快照,可以在其对应UIAbility的[module.json5配置文件]中,将[abilities标签]的removeMissionAfterTerminate字段配置为true。

  1. 如需要关闭应用所有的[UIAbility]实例,可以调用[ApplicationContext]的[killAllProcesses()]方法实现关闭应用所有的进程。

启动应用内的UIAbility并获取返回结果

在一个EntryAbility启动另外一个FuncAbility时,希望在被启动的FuncAbility完成相关业务后,能将结果返回给调用方。例如在应用中将入口功能和账号登录功能分别设计为两个独立的[UIAbility],在账号登录UIAbility中完成登录操作后,需要将登录的结果返回给入口UIAbility。

  1. 在EntryAbility中,调用[startAbilityForResult()]接口启动FuncAbility,异步回调中的data用于接收FuncAbility停止自身后返回给EntryAbility的信息。
import { common, Want } from '@kit.AbilityKit';
import { hilog } from '@kit.PerformanceAnalysisKit';
import { promptAction } from '@kit.ArkUI';
import { BusinessError } from '@kit.BasicServicesKit';

const TAG: string = '[Page_UIAbilityComponentsInteractive]';
const DOMAIN_NUMBER: number = 0xFF00;

@Entry
@Component
struct Page_UIAbilityComponentsInteractive {
  build() {
    Column() {
      //...
      List({ initialIndex: 0 }) {
        ListItem() {
          Row() {
            //...
          }
          .onClick(() => {
            let context: common.UIAbilityContext = getContext(this) as common.UIAbilityContext; // UIAbilityContext
            const RESULT_CODE: number = 1001;
            let want: Want = {
              deviceId: '', // deviceId为空表示本设备
              bundleName: 'com.samples.stagemodelabilitydevelop',
              moduleName: 'entry', // moduleName非必选
              abilityName: 'FuncAbilityA',
              parameters: {
                // 自定义信息
                info: '来自EntryAbility UIAbilityComponentsInteractive页面'
              }
            };
            context.startAbilityForResult(want).then((data) => {
              if (data?.resultCode === RESULT_CODE) {
                // 解析被调用方UIAbility返回的信息
                let info = data.want?.parameters?.info;
                hilog.info(DOMAIN_NUMBER, TAG, JSON.stringify(info) ?? '');
                if (info !== null) {
                  promptAction.showToast({
                    message: JSON.stringify(info)
                  });
                }
              }
              hilog.info(DOMAIN_NUMBER, TAG, JSON.stringify(data.resultCode) ?? '');
            }).catch((err: BusinessError) => {
              hilog.error(DOMAIN_NUMBER, TAG, `Failed to start ability for result. Code is ${err.code}, message is ${err.message}`);
            });
          })
        }
        //...
      }
      //...
    }
    //...
  }
}
  1. 在FuncAbility停止自身时,需要调用[terminateSelfWithResult()]=方法,入参[abilityResult]=为FuncAbility需要返回给EntryAbility的信息。
import { common } from '@kit.AbilityKit';
import { hilog } from '@kit.PerformanceAnalysisKit';

const TAG: string = '[Page_FuncAbilityA]';
const DOMAIN_NUMBER: number = 0xFF00;

@Entry
@Component
struct Page_FuncAbilityA {
  build() {
    Column() {
      //...
      List({ initialIndex: 0 }) {
        ListItem() {
          Row() {
            //...
          }
          .onClick(() => {
            let context: common.UIAbilityContext = getContext(this) as common.UIAbilityContext; // UIAbilityContext
            const RESULT_CODE: number = 1001;
            let abilityResult: common.AbilityResult = {
              resultCode: RESULT_CODE,
              want: {
                bundleName: 'com.samples.stagemodelabilitydevelop',
                moduleName: 'entry', // moduleName非必选
                abilityName: 'FuncAbilityB',
                parameters: {
                  info: '来自FuncAbility Index页面'
                },
              },
            };
            context.terminateSelfWithResult(abilityResult, (err) => {
              if (err.code) {
                hilog.error(DOMAIN_NUMBER, TAG, `Failed to terminate self with result. Code is ${err.code}, message is ${err.message}`);
                return;
              }
            });
          })
        }
        //...
      }
      //...
    }
    //...
  }
}
  1. FuncAbility停止自身后,EntryAbility通过[startAbilityForResult()]=方法回调接收被FuncAbility返回的信息,RESULT_CODE需要与前面的数值保持一致。
import { common, Want } from '@kit.AbilityKit';
import { hilog } from '@kit.PerformanceAnalysisKit';
import { promptAction } from '@kit.ArkUI';
import { BusinessError } from '@kit.BasicServicesKit';

const TAG: string = '[Page_UIAbilityComponentsInteractive]';
const DOMAIN_NUMBER: number = 0xFF00;

@Entry
@Component
struct Page_UIAbilityComponentsInteractive {
  build() {
    Column() {
      //...
      List({ initialIndex: 0 }) {
        ListItem() {
          Row() {
            //...
          }
          .onClick(() => {
            let context: common.UIAbilityContext = getContext(this) as common.UIAbilityContext; // UIAbilityContext
            const RESULT_CODE: number = 1001;

            let want: Want = {
              deviceId: '', // deviceId为空表示本设备
              bundleName: 'com.samples.stagemodelabilitydevelop',
              moduleName: 'entry', // moduleName非必选
              abilityName: 'FuncAbilityA',
              parameters: {
                // 自定义信息
                info: '来自EntryAbility UIAbilityComponentsInteractive页面'
              }
            };
            context.startAbilityForResult(want).then((data) => {
              if (data?.resultCode === RESULT_CODE) {
                // 解析被调用方UIAbility返回的信息
                let info = data.want?.parameters?.info;
                hilog.info(DOMAIN_NUMBER, TAG, JSON.stringify(info) ?? '');
                if (info !== null) {
                  promptAction.showToast({
                    message: JSON.stringify(info)
                  });
                }
              }
              hilog.info(DOMAIN_NUMBER, TAG, JSON.stringify(data.resultCode) ?? '');
            }).catch((err: BusinessError) => {
              hilog.error(DOMAIN_NUMBER, TAG, `Failed to start ability for result. Code is ${err.code}, message is ${err.message}`);
            });
          })
        }
        //...
      }
      //...
    }
    //...
  }
}

启动UIAbility的指定页面

概述

一个[UIAbility]可以对应多个页面,在不同的场景下启动该UIAbility时需要展示不同的页面,例如从一个UIAbility的页面中跳转到另外一个UIAbility时,希望启动目标UIAbility的指定页面。

UIAbility的启动分为两种情况:UIAbility冷启动和UIAbility热启动。

  • UIAbility冷启动:指的是UIAbility实例处于完全关闭状态下被启动,这需要完整地加载和初始化UIAbility实例的代码、资源等。
  • UIAbility热启动:指的是UIAbility实例已经启动并在前台运行过,由于某些原因切换到后台,再次启动该UIAbility实例,这种情况下可以快速恢复UIAbility实例的状态。

调用方UIAbility指定启动页面

调用方[UIAbility]启动另外一个UIAbility时,通常需要跳转到指定的页面。例如FuncAbility包含两个页面(Index对应首页,Second对应功能A页面),此时需要在传入的[want]参数中配置指定的页面路径信息,可以通过want中的parameters参数增加一个自定义参数传递页面跳转信息。

import { common, Want } from '@kit.AbilityKit';
import { hilog } from '@kit.PerformanceAnalysisKit';
import { BusinessError } from '@kit.BasicServicesKit';

const TAG: string = '[Page_UIAbilityComponentsInteractive]';
const DOMAIN_NUMBER: number = 0xFF00;

@Entry
@Component
struct Page_UIAbilityComponentsInteractive {
  build() {
    Column() {
      //...
      List({ initialIndex: 0 }) {
        ListItem() {
          Row() {
            //...
          }
          .onClick(() => {
            let context: common.UIAbilityContext = getContext(this) as common.UIAbilityContext; // UIAbilityContext
            let want: Want = {
              deviceId: '', // deviceId为空表示本设备
              bundleName: 'com.samples.stagemodelabilityinteraction',
              moduleName: 'entry', // moduleName非必选
              abilityName: 'FuncAbility',
              parameters: { // 自定义参数传递页面信息
                router: 'funcA'
              }
            };
            // context为调用方UIAbility的UIAbilityContext
            context.startAbility(want).then(() => {
              hilog.info(DOMAIN_NUMBER, TAG, 'Succeeded in starting ability.');
            }).catch((err: BusinessError) => {
              hilog.error(DOMAIN_NUMBER, TAG, `Failed to start ability. Code is ${err.code}, message is ${err.message}`);
            });
          })
        }
        //...
      }
      //...
    }
    //...
  }
}

目标UIAbility冷启动

目标[UIAbility]冷启动时,在目标UIAbility的[onCreate()]生命周期回调中,接收调用方传过来的参数。然后在目标UIAbility的[onWindowStageCreate()]生命周期回调中,解析调用方传递过来的[want]参数,获取到需要加载的页面信息url,传入[windowStage.loadContent()]方法。

import { AbilityConstant, Want, UIAbility } from '@kit.AbilityKit';
import { hilog } from '@kit.PerformanceAnalysisKit';
import { window, UIContext } from '@kit.ArkUI';

const DOMAIN_NUMBER: number = 0xFF00;
const TAG: string = '[EntryAbility]';

export default class EntryAbility extends UIAbility {
  funcAbilityWant: Want | undefined = undefined;
  uiContext: UIContext | undefined = undefined;

  onCreate(want: Want, launchParam: AbilityConstant.LaunchParam): void {
    // 接收调用方UIAbility传过来的参数
    this.funcAbilityWant = want;
  }

  onWindowStageCreate(windowStage: window.WindowStage): void {
    // Main window is created, set main page for this ability
    hilog.info(DOMAIN_NUMBER, TAG, '%{public}s', 'Ability onWindowStageCreate');
    // Main window is created, set main page for this ability
    let url = 'pages/Index';
    if (this.funcAbilityWant?.parameters?.router && this.funcAbilityWant.parameters.router === 'funcA') {
      url = 'pages/Page_ColdStartUp';
    }
    windowStage.loadContent(url, (err, data) => {
      // ...
    });
  }
}

目标UIAbility热启动

在应用开发中,会遇到目标[UIAbility]实例之前已经启动过的场景,这时再次启动目标UIAbility时,不会重新走初始化逻辑,只会直接触发[onNewWant()]生命周期方法。为了实现跳转到指定页面,需要在onNewWant()中解析参数进行处理。

例如短信应用和联系人应用配合使用的场景。

  1. 用户先打开短信应用,短信应用的UIAbility实例启动,显示短信应用的主页。
  2. 用户将设备回到桌面界面,短信应用进入后台运行状态。
  3. 用户打开联系人应用,找到联系人张三。
  4. 用户点击联系人张三的短信按钮,会重新启动短信应用的UIAbility实例。
  5. 由于短信应用的UIAbility实例已经启动过了,此时会触发该UIAbility的onNewWant()回调,而不会再走[onCreate()]和[onWindowStageCreate()]等初始化逻辑。

图1 目标UIAbility热启动

外链图片转存失败,源站可能有防盗链机制,建议将图片保存下来直接上传

开发步骤如下所示。

  1. 冷启动短信应用的UIAbility实例时,在[onWindowStageCreate()]生命周期回调中,通过调用[getUIContext()]接口获取UI上下文实例[UIContext]对象。
import { hilog } from '@kit.PerformanceAnalysisKit';
import { Want, UIAbility } from '@kit.AbilityKit';
import { window, UIContext } from '@kit.ArkUI';

const DOMAIN_NUMBER: number = 0xFF00;
const TAG: string = '[EntryAbility]';

export default class EntryAbility extends UIAbility {
  funcAbilityWant: Want | undefined = undefined;
  uiContext: UIContext | undefined = undefined;

  // ...

  onWindowStageCreate(windowStage: window.WindowStage): void {
    // Main window is created, set main page for this ability
    hilog.info(DOMAIN_NUMBER, TAG, '%{public}s', 'Ability onWindowStageCreate');
    let url = 'pages/Index';
    if (this.funcAbilityWant?.parameters?.router && this.funcAbilityWant.parameters.router === 'funcA') {
      url = 'pages/Page_ColdStartUp';
    }

    windowStage.loadContent(url, (err, data) => {
      if (err.code) {
        return;
      }

      let windowClass: window.Window;
      windowStage.getMainWindow((err, data) => {
        if (err.code) {
          hilog.error(DOMAIN_NUMBER, TAG, `Failed to obtain the main window. Code is ${err.code}, message is ${err.message}`);
          return;
        }
        windowClass = data;
        this.uiContext = windowClass.getUIContext();
      });
      hilog.info(DOMAIN_NUMBER, TAG, 'Succeeded in loading the content. Data: %{public}s', JSON.stringify(data) ?? '');
    });
  }
}
  1. 在短信应用UIAbility的[onNewWant()]回调中解析调用方传递过来的[want]参数,通过调用[UIContext]中的[getRouter()]方法获取[Router]对象,并进行指定页面的跳转。此时再次启动该短信应用的UIAbility实例时,即可跳转到该短信应用的UIAbility实例的指定页面。
import { AbilityConstant, Want, UIAbility } from '@kit.AbilityKit';
import { hilog } from '@kit.PerformanceAnalysisKit';
import type { Router, UIContext } from '@kit.ArkUI';
import type { BusinessError } from '@kit.BasicServicesKit';

const DOMAIN_NUMBER: number = 0xFF00;
const TAG: string = '[EntryAbility]';

export default class EntryAbility extends UIAbility {
  funcAbilityWant: Want | undefined = undefined;
  uiContext: UIContext | undefined = undefined;
  // ...
  onNewWant(want: Want, launchParam: AbilityConstant.LaunchParam): void {
    if (want?.parameters?.router && want.parameters.router === 'funcA') {
      let funcAUrl = 'pages/Page_HotStartUp';
      if (this.uiContext) {
        let router: Router = this.uiContext.getRouter();
        router.pushUrl({
          url: funcAUrl
        }).catch((err: BusinessError) => {
          hilog.error(DOMAIN_NUMBER, TAG, `Failed to push url. Code is ${err.code}, message is ${err.message}`);
        });
      }
    }
  }
}

说明

当被调用方[UIAbility组件启动模式]设置为multiton启动模式时,每次启动都会创建一个新的实例,那么onNewWant()回调就不会被用到。

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