HarmonyOS 应用开发之创建PageAbility-编程知识

HarmonyOS 应用开发之创建PageAbility

开发者需要重写app.js/app.ets中的生命周期回调函数，开发者通过DevEco Studio开发平台创建PageAbility时，DevEco Studio会在app.js/app.ets中默认生成onCreate()和onDestroy()方法，其他方法需要开发者自行实现。接口说明参见前述章节，创建PageAbility示例如下：

import featureAbility from '@ohos.ability.featureAbility';
import Logger from '../utils/Logger';const TAG: string = 'MainAbility';class MainAbility {onCreate() {// 获取context并调用相关方法let context = featureAbility.getContext();context.getBundleName((data, bundleName) => {Logger.info(TAG, 'ability bundleName:' + bundleName);});Logger.info(TAG, 'Application onCreate');}onDestroy() {Logger.info(TAG, 'Application onDestroy');}onShow(): void {Logger.info(TAG, 'Application onShow');}onHide(): void {Logger.info(TAG, 'Application onHide');}onActive(): void {Logger.info(TAG, 'Application onActive');}onInactive(): void {Logger.info(TAG, 'Application onInactive');}onNewWant() {Logger.info(TAG, 'Application onNewWant');}
}export default new MainAbility();

PageAbility创建成功后，其abilities相关的配置项在config.json中体现，一个名字为EntryAbility的config.json配置文件示例如下：

{..."module": {..."abilities": [{"skills": [{"entities": ["entity.system.home"],"actions": ["action.system.home"]}],"orientation": "unspecified","formsEnabled": false,"name": ".MainAbility","srcLanguage": "ets","srcPath": "MainAbility","icon": "$media:icon","description": "$string:MainAbility_desc","label": "$string:MainAbility_label","type": "page","visible": true,"launchType": "singleton"},...]...}
}

FA模型中，可以通过featureAbility的getContext接口获取应用上下文，进而使用上下文提供的能力。

表1 featureAbility接口说明

通过getContext获取应用上下文并获取分布式目录的示例如下：

import featureAbility from '@ohos.ability.featureAbility';
import fs from '@ohos.file.fs';
import promptAction from '@ohos.promptAction';
import Logger from '../../utils/Logger';const TAG: string = 'PagePageAbilityFirst';

(async (): Promise<void> => {let dir: string;try {Logger.info(TAG, 'Begin to getOrCreateDistributedDir');dir = await featureAbility.getContext().getOrCreateDistributedDir();promptAction.showToast({message: dir});Logger.info(TAG, 'distribute dir is ' + dir);let fd: number;let path = dir + '/a.txt';fd = fs.openSync(path, fs.OpenMode.READ_WRITE).fd;fs.close(fd);} catch (error) {Logger.error(TAG, `getOrCreateDistributedDir failed with : ${error}`);}
})()

为了能让大家更好的学习鸿蒙（HarmonyOS NEXT）开发技术，这边特意整理了《鸿蒙开发学习手册》（共计890页），希望对大家有所帮助：https://qr21.cn/FV7h05