【HarmonyOS 5】鴻蒙中的UIAbility詳解（二）

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一、前言

今天我們繼續(xù)深入講解UIAbility，根據(jù)下圖可知，在鴻蒙中UIAbility繼承于Ability，開發(fā)者無法直接繼承Ability。只能使用其兩個(gè)子類：UIAbility和ExtensionAbility。

本文將對(duì)UIAbility的三種啟動(dòng)模式，數(shù)據(jù)如何傳遞，訂閱UIAbility生命周期變化，訂閱設(shè)備的信息變化進(jìn)行講解。

二、UIAbility的三種啟動(dòng)模式

singleton（單實(shí)例模式），說人話就是單例模式，App任務(wù)進(jìn)度中該UIAbilty只能存在一個(gè)。

multiton（多實(shí)例模式），說人話就是單例模式，App任務(wù)進(jìn)度中該UIAbilty能存在多個(gè)。

specified（指定實(shí)例模式），這玩意就有點(diǎn)復(fù)雜了，參見下圖，主要通過唯一標(biāo)識(shí)key來作為判斷量，看該UIAbility是創(chuàng)建新的，還是使用已創(chuàng)建的。

在module.json5配置文件中的launchType字段配置為singleton，multiton，specified即可。

{
  "module": {
    // ...
    "abilities": [
      {
        "launchType": "singleton",
        // ...
      }
    ]
  }
}

三、UIAbility的數(shù)據(jù)如何傳遞

一般而言，UIAbility的數(shù)據(jù)傳遞有兩種場(chǎng)景：
1、A UIAbility數(shù)據(jù)傳遞給 B UIAbility。
2、A UIAbility數(shù)據(jù)傳給內(nèi)部的page或者自定義view。

同樣通用數(shù)據(jù)傳遞的方式有以下三種方式進(jìn)行：
1. 單例對(duì)象維護(hù)數(shù)據(jù)
通過單例對(duì)象和注冊(cè)回調(diào)的機(jī)制，將數(shù)據(jù)進(jìn)行傳導(dǎo)：

export class EventDataMgr {

  private static mEventDataMgr : EventDataMgr  | null = null;

  // 需要處理的數(shù)據(jù)
  public mData: XXX | null = null;

  /**
   * 獲取實(shí)例
   * @returns
   */
  public static Ins(){

    if(!EventDataMgr .mEventDataMgr ){
      EventDataMgr .mEventDataMgr = new EventDataMgr();
    }
    return EventDataMgr .mEventDataMgr;
  }
}

2. EventHub，Emitter
我是不建議使用Emitter作為數(shù)據(jù)傳遞方案，因?yàn)樗亓耍褂闷饋硪矝]有EventHub方便。

而EventHub是從context中獲取，所以在多Ability數(shù)據(jù)共享場(chǎng)景中，需要對(duì)EventHub做唯一性處理

import { common } from '@kit.AbilityKit';

export class EventHubUtils {

  private static mEventHub: common.EventHub | null = null;

  /**
   * 獲取事件通知實(shí)例
   * @returns
   */
  public static getEventHub(){
    // 封裝唯一性。因?yàn)樵诓煌瑆indow中會(huì)導(dǎo)致獲取的eventhub 不是一個(gè)。
    if(!EventHubUtils.mEventHub){
      let context = getContext() as common.UIAbilityContext;
      EventHubUtils.mEventHub = context.eventHub;
      console.log("EventHubUtils", "EventIns mEventHub done !");
    }
    return EventHubUtils.mEventHub;
  }
}

3. AppStroage或者LocalStroage
AppStroage主要用于多UIAbility共享數(shù)據(jù)進(jìn)行傳遞的業(yè)務(wù)場(chǎng)景。
LocalStroage用于UIAbility內(nèi)部到page或者自定義view進(jìn)行傳遞傳遞的業(yè)務(wù)場(chǎng)景。

import { UIAbility } from '@kit.AbilityKit';
import { hilog } from '@kit.PerformanceAnalysisKit';
import { window } from '@kit.ArkUI';

export default class EntryAbility extends UIAbility {

  storage: LocalStorage = new LocalStorage();

  onWindowStageCreate(windowStage: window.WindowStage): void {
    windowStage.loadContent('pages/Index', this.storage, (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.');
    });
  }

}

四、訂閱UIAbility生命周期變化

該場(chǎng)景主要用于統(tǒng)計(jì)SDK或者三方應(yīng)用自己進(jìn)行業(yè)務(wù)用戶時(shí)長(zhǎng)交互的數(shù)據(jù)統(tǒng)計(jì)工作。

當(dāng)進(jìn)程內(nèi)的UIAbility生命周期變化時(shí)，如創(chuàng)建、可見/不可見、獲焦/失焦、銷毀等，會(huì)觸發(fā)相應(yīng)的回調(diào)函數(shù)。每次注冊(cè)回調(diào)函數(shù)時(shí)，都會(huì)返回一個(gè)監(jiān)聽生命周期的ID，此ID會(huì)自增+1。當(dāng)超過監(jiān)聽上限數(shù)量2^63-1時(shí)，會(huì)返回-1。

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


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


export default class LifecycleAbility extends UIAbility {
  // 定義生命周期ID
  lifecycleId: number = -1;


  onCreate(want: Want, launchParam: AbilityConstant.LaunchParam): void {
    // 定義生命周期回調(diào)對(duì)象
    let abilityLifecycleCallback: AbilityLifecycleCallback = {
      // 當(dāng)UIAbility創(chuàng)建時(shí)被調(diào)用
      onAbilityCreate(uiAbility) {
        hilog.info(DOMAIN_NUMBER, TAG, `onAbilityCreate uiAbility.launchWant: ${JSON.stringify(uiAbility.launchWant)}`);
      },
      // 當(dāng)窗口創(chuàng)建時(shí)被調(diào)用
      onWindowStageCreate(uiAbility, windowStage: window.WindowStage) {
        hilog.info(DOMAIN_NUMBER, TAG, `onWindowStageCreate uiAbility.launchWant: ${JSON.stringify(uiAbility.launchWant)}`);
        hilog.info(DOMAIN_NUMBER, TAG, `onWindowStageCreate windowStage: ${JSON.stringify(windowStage)}`);
      },
      // 當(dāng)窗口處于活動(dòng)狀態(tài)時(shí)被調(diào)用
      onWindowStageActive(uiAbility, windowStage: window.WindowStage) {
        hilog.info(DOMAIN_NUMBER, TAG, `onWindowStageActive uiAbility.launchWant: ${JSON.stringify(uiAbility.launchWant)}`);
        hilog.info(DOMAIN_NUMBER, TAG, `onWindowStageActive windowStage: ${JSON.stringify(windowStage)}`);
      },
      // 當(dāng)窗口處于非活動(dòng)狀態(tài)時(shí)被調(diào)用
      onWindowStageInactive(uiAbility, windowStage: window.WindowStage) {
        hilog.info(DOMAIN_NUMBER, TAG, `onWindowStageInactive uiAbility.launchWant: ${JSON.stringify(uiAbility.launchWant)}`);
        hilog.info(DOMAIN_NUMBER, TAG, `onWindowStageInactive windowStage: ${JSON.stringify(windowStage)}`);
      },
      // 當(dāng)窗口被銷毀時(shí)被調(diào)用
      onWindowStageDestroy(uiAbility, windowStage: window.WindowStage) {
        hilog.info(DOMAIN_NUMBER, TAG, `onWindowStageDestroy uiAbility.launchWant: ${JSON.stringify(uiAbility.launchWant)}`);
        hilog.info(DOMAIN_NUMBER, TAG, `onWindowStageDestroy windowStage: ${JSON.stringify(windowStage)}`);
      },
      // 當(dāng)UIAbility被銷毀時(shí)被調(diào)用
      onAbilityDestroy(uiAbility) {
        hilog.info(DOMAIN_NUMBER, TAG, `onAbilityDestroy uiAbility.launchWant: ${JSON.stringify(uiAbility.launchWant)}`);
      },
      // 當(dāng)UIAbility從后臺(tái)轉(zhuǎn)到前臺(tái)時(shí)觸發(fā)回調(diào)
      onAbilityForeground(uiAbility) {
        hilog.info(DOMAIN_NUMBER, TAG, `onAbilityForeground uiAbility.launchWant: ${JSON.stringify(uiAbility.launchWant)}`);
      },
      // 當(dāng)UIAbility從前臺(tái)轉(zhuǎn)到后臺(tái)時(shí)觸發(fā)回調(diào)
      onAbilityBackground(uiAbility) {
        hilog.info(DOMAIN_NUMBER, TAG, `onAbilityBackground uiAbility.launchWant: ${JSON.stringify(uiAbility.launchWant)}`);
      },
      // 當(dāng)UIAbility遷移時(shí)被調(diào)用
      onAbilityContinue(uiAbility) {
        hilog.info(DOMAIN_NUMBER, TAG, `onAbilityContinue uiAbility.launchWant: ${JSON.stringify(uiAbility.launchWant)}`);
      }
    };
    // 獲取應(yīng)用上下文
    let applicationContext = this.context.getApplicationContext();
    try {
      // 注冊(cè)應(yīng)用內(nèi)生命周期回調(diào)
      this.lifecycleId = applicationContext.on('abilityLifecycle', abilityLifecycleCallback);
    } catch (err) {
      let code = (err as BusinessError).code;
      let message = (err as BusinessError).message;
      hilog.error(DOMAIN_NUMBER, TAG, `Failed to register applicationContext. Code is ${code}, message is ${message}`);
    }


    hilog.info(DOMAIN_NUMBER, TAG, `register callback number: ${this.lifecycleId}`);
  }
  //...
  onDestroy(): void {
    // 獲取應(yīng)用上下文
    let applicationContext = this.context.getApplicationContext();
    try {
      // 取消應(yīng)用內(nèi)生命周期回調(diào)
      applicationContext.off('abilityLifecycle', this.lifecycleId);
    } catch (err) {
      let code = (err as BusinessError).code;
      let message = (err as BusinessError).message;
      hilog.error(DOMAIN_NUMBER, TAG, `Failed to unregister applicationContext. Code is ${code}, message is ${message}`);
    }
  }
}

五、訂閱設(shè)備的信息變化

該場(chǎng)景主要是系統(tǒng)配置更新時(shí)調(diào)用。例如設(shè)備的語言環(huán)境，設(shè)備橫豎屏狀態(tài)，深淺模式等。

在UIAbility中onConfigurationUpdate()回調(diào)方法中實(shí)現(xiàn)監(jiān)測(cè)系統(tǒng)這些配置信息的變化。

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


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


let systemLanguage: string | undefined; // 系統(tǒng)當(dāng)前語言


export default class EntryAbility extends UIAbility {
  onCreate(want: Want, launchParam: AbilityConstant.LaunchParam): void {
    systemLanguage = this.context.config.language; // UIAbility實(shí)例首次加載時(shí)，獲取系統(tǒng)當(dāng)前語言
    hilog.info(DOMAIN_NUMBER, TAG, `systemLanguage is ${systemLanguage}`);
  }


  onConfigurationUpdate(newConfig: Configuration): void {
            console.info(`envCallback onConfigurationUpdated success: ${JSON.stringify(config)}`);
        // 表示應(yīng)用程序的當(dāng)前語言，例如“zh"。
        let language = config.language;
        // 表示深淺色模式，默認(rèn)為淺色。取值范圍：
        //
        // - COLOR_MODE_NOT_SET：未設(shè)置
        //
        // - COLOR_MODE_LIGHT：淺色模式
        //
        // - COLOR_MODE_DARK：深色模式
        let colorMode = config.colorMode;
        // 表示屏幕方向，取值范圍：
        //
        // - DIRECTION_NOT_SET：未設(shè)置
        //
        // - DIRECTION_HORIZONTAL：水平方向
        //
        // - DIRECTION_VERTICAL：垂直方向
        let direction = config.direction;
        let screenDensity = config.screenDensity;
        let displayId = config.displayId;
        let hasPointerDevice = config.hasPointerDevice;
        let fontId = config.fontId;
        let fontSizeScale = config.fontSizeScale;
        let fontWeightScale = config.fontWeightScale;
        let mcc = config.mcc;
        let mnc = config.mnc;
  }
  // ...
}

審核編輯 黃宇