鸿蒙开发相关知识（四）【数据持久化（用户首选项、关系型数据库）、通知（基础通知、进度条通知、通知意图）】

本文主要是介绍鸿蒙开发相关知识（四）【数据持久化（用户首选项、关系型数据库）、通知（基础通知、进度条通知、通知意图）】，希望对大家解决编程问题提供一定的参考价值，需要的开发者们随着小编来一起学习吧！

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一、数据持久化

1、用户首选项

（1）语法说明

• 为应用提供Key-Value键值型的数据处理能力，支持应用持久化轻量级数据，并对其修改和查询。
• Key键为string类型，要求非空且长度不超过80个字节。
• 如果Value值为string类型，可以为空，不为空时长度不超过8192个字节。
• 建议存储的数据不超过一万条。
• 导入用户首选项模块

import dataPreferences from '@ohos.data.preferences';

• 要获取Preferences实例，读取指定文件

 dataPreferences.getPreferences(this.context, 'mystore', (err, preferences) => {if (err) {console.error(`Failed to get preferences. Code:${err.code},message:${err.message}`);return;}console.info('Succeeded in getting preferences.');// 进行相关数据操作})

• 数据操作
• 写入数据，如果已经存在则会覆盖，可利用.has() 判断是否存在

 preferences.put('startup', 'auto', (err) => {if (err) {console.error(`Failed to put data. Code:${err.code}, message:${err.message}`);return;}console.info('Succeeded in putting data.');})

• 读取数据，如果值为null或者非默认值类型，则返回默认数据。

 preferences.get('startup', 'default', (err, val) => {if (err) {console.error(`Failed to get value of 'startup'. Code:${err.code}, message:${err.message}`);return;}console.info(`Succeeded in getting value of 'startup'. val: ${val}.`);})

• 删除数据

  preferences.delete('startup', (err) => {if (err) {console.error(`Failed to delete the key 'startup'. Code:${err.code}, message:${err.message}`);return;}console.info("Succeeded in deleting the key 'startup'.");})

• 数据持久化，应用存入数据到Preferences实例后，可以使用flush()方法实现数据持久化

preferences.flush((err) => {if (err) {console.error(`Failed to flush. Code:${err.code}, message:${err.message}`);return;}console.info('Succeeded in flushing.');})

（2）完整代码示例

• ets/common/util/PreferencesUtil.ts
• 加载实例、写入、获取、删除方法

import preferences from '@ohos.data.preferences';class PreferencesUtil{prefMap: Map<string, preferences.Preferences> = new Map()async loadPreference(context, name: string){try { // 加载preferenceslet pref = await preferences.getPreferences(context, name)this.prefMap.set(name, pref)console.log('testTag', `加载Preferences[${name}]成功`)} catch (e) {console.log('testTag', `加载Preferences[${name}]失败`, JSON.stringify(e))}}async putPreferenceValue(name: string, key: string, value: preferences.ValueType){if (!this.prefMap.has(name)) {console.log('testTag', `Preferences[${name}]尚未初始化！`)return}try {let pref = this.prefMap.get(name)// 写入数据await pref.put(key, value)// 刷盘await pref.flush()console.log('testTag', `保存Preferences[${name}.${key} = ${value}]成功`)} catch (e) {console.log('testTag', `保存Preferences[${name}.${key} = ${value}]失败`, JSON.stringify(e))}}async getPreferenceValue(name: string, key: string, defaultValue: preferences.ValueType){if (!this.prefMap.has(name)) {console.log('testTag', `Preferences[${name}]尚未初始化！`)return}try {let pref = this.prefMap.get(name)// 读数据let value = await pref.get(key, defaultValue)console.log('testTag', `读取Preferences[${name}.${key} = ${value}]成功`)return value} catch (e) {console.log('testTag', `读取Preferences[${name}.${key} ]失败`, JSON.stringify(e))}}
}const preferencesUtil = new PreferencesUtil()export default preferencesUtil as PreferencesUtil

• ets/entryability/EntryAbility.ets
• 应用启动时调用加载实例方法

import UIAbility from '@ohos.app.ability.UIAbility';
import PreferencesUtil from '../common/util/PreferencesUtil'export default class EntryAbility extends UIAbility {async onCreate(want, launchParam) {hilog.info(0x0000, 'testTag', '%{public}s', 'Ability onCreate running');// 加载Preferencesawait PreferencesUtil.loadPreference(this.context, 'MyPreferences')}
}

• ets/pages/Index.ets
• 页面出现前（aboutToAppear()）获取实例并赋值

import IndexFontSizePanel from '../views/IndexFontSizePanel'
import PreferencesUtil from '../common/util/PreferencesUtil'@Entry
@Component
struct Index {@State message: string = '页面列表'@State showPanel: boolean = false@Provide fontSize: number = 16async aboutToAppear(){this.fontSize = await PreferencesUtil.getPreferenceValue('MyPreferences', 'IndexFontSize', 16) as number}build() {Column() {// 字体修改面板if(this.showPanel){IndexFontSizePanel().transition({translate: { y: 115 }})}}.width('100%').height('100%')}}

• views/IndexFontSizePanel.ets
• onChange 方法中修改实例值

import PreferencesUtil from '../common/util/PreferencesUtil'@Component
export default struct IndexFontSizePanel {@Consume fontSize: numberfontSizLabel: object = {14: '小',16: '标准',18: '大',20: '特大',}build() {Column() {Text(this.fontSizLabel[this.fontSize]).fontSize(20)Row({ space: 5 }) {Text('A').fontSize(14).fontWeight(FontWeight.Bold)Slider({min: 14,max: 20,step: 2,value: this.fontSize}).showSteps(true).trackThickness(6).layoutWeight(1).onChange(val => {// 修改字体大小this.fontSize = val// 写入PreferencesPreferencesUtil.putPreferenceValue('MyPreferences', 'IndexFontSize', val)})Text('A').fontSize(20).fontWeight(FontWeight.Bold)}.width('100%')}.width('100%').padding(15).backgroundColor('#fff1f0f0').borderRadius(20)}
}

2、关系型数据库

（1）初始化数据库

• a、导入关系型数据库模块

import relationalStore from '@ohos.data.relationalStore';

• b、初始化数据库表
• rdb配置

const STORE_CONFIG = {name: 'RdbTest.db', // 数据库文件名securityLevel: relationalStore.SecurityLevel.S1 // 数据库安全级别
};

• 初始化表的SQL

// 建表Sql语句
const SQL_CREATE_TABLE = 'CREATE TABLE IF NOT EXISTS EMPLOYEE (ID INTEGER PRIMARY KEY AUTOINCREMENT, NAME TEXT NOT NULL, AGE INTEGER, SALARY REAL, CODES BLOB)';

• 获取rdb,执行SQL,后续的所有增删改查都是使用rdbStore对象

relationalStore.getRdbStore(this.context, STORE_CONFIG, (err, store) => {if (err) {console.error(`Failed to get RdbStore. Code:${err.code}, message:${err.message}`);return;}console.info(`Succeeded in getting RdbStore.`);store.executeSql(SQL_CREATE_TABLE); // 创建数据表// 这里执行数据库的增、删、改、查等操作});

（2）增删改数据

• a.新增数据

const valueBucket = {'NAME': 'Lisa','AGE': 18,'SALARY': 100.5,'CODES': new Uint8Array([1, 2, 3, 4, 5])
};
//EMPLOYEE 数据表名
store.insert('EMPLOYEE', valueBucket, (err, rowId) => {if (err) {console.error(`Failed to insert data. Code:${err.code}, message:${err.message}`);return;}console.info(`Succeeded in inserting data. rowId:${rowId}`);
})

• b.修改数据

const valueBucket = {'NAME': 'Rose','AGE': 22,
};
// 创建表'EMPLOYEE'的predicates
let predicates = new relationalStore.RdbPredicates('EMPLOYEE');
// 匹配表'EMPLOYEE'中'NAME'为'Lisa'的字段
predicates.equalTo('NAME', 'Lisa'); 
store.update(valueBucket, predicates, (err, rows) => {if (err) {console.error(`Failed to update data. Code:${err.code}, message:${err.message}`);return;}console.info(`Succeeded in updating data. row count: ${rows}`);
})

• c.删除数据

let predicates = new relationalStore.RdbPredicates('EMPLOYEE');
predicates.equalTo('NAME', 'Lisa');
store.delete(predicates, (err, rows) => {if (err) {console.error(`Failed to delete data. Code:${err.code}, message:${err.message}`);return;}console.info(`Delete rows: ${rows}`);
})

（3）查询数据

• a.查询数据、返回一个ResultSet结果集

let predicates = new relationalStore.RdbPredicates('EMPLOYEE');
predicates.equalTo('NAME', 'Rose');
let result = await store.query(predicates, ['ID', 'NAME', 'AGE', 'SALARY', 'CODES'])

• b.解析结果

// 准备数组保存结果
let tasks:any[]=[]
//循环遍历结果集，判断结果是否遍历到最后一行
while(!result.isAtLastRow){//指针移动到下一行数据result.goToNextRow()//根据字段名获取字段index，从而获取字段值let id = result.getLong(result.getColumnIndex('ID'));let name = result.getString(result.getColumnIndex('NAME'));tasks.push({id,name})
}

（4）完整代码示例

• ets/model/TaskModel.ets

import relationalStore from '@ohos.data.relationalStore';
import TaskInfo from '../viewmodel/TaskInfo';class TaskModel {private rdbStore: relationalStore.RdbStoreprivate tableName: string = 'TASK'/*** 初始化任务表*/initTaskDB(context){// 1.rdb配置const config = {name: 'MyApplication.db',securityLevel: relationalStore.SecurityLevel.S1}// 2.初始化SQL语句const sql = `CREATE TABLE IF NOT EXISTS TASK (ID INTEGER PRIMARY KEY AUTOINCREMENT,NAME TEXT NOT NULL,FINISHED bit)`// 3.获取rdbrelationalStore.getRdbStore(context, config, (err, rdbStore) => {if(err){console.log('testTag', '获取rdbStore失败！')return}// 执行SqlrdbStore.executeSql(sql)console.log('testTag', '创建task表成功！')// 保存rdbStorethis.rdbStore = rdbStore})}/*** 查询任务列表*/async getTaskList(){// 1.构建查询条件let predicates = new relationalStore.RdbPredicates(this.tableName)// 2.查询let result = await this.rdbStore.query(predicates, ['ID', 'NAME', 'FINISHED'])// 3.解析查询结果// 3.1.定义一个数组，组装最终的查询结果let tasks: TaskInfo[] = []// 3.2.遍历封装while(!result.isAtLastRow){// 3.3.指针移动到下一行result.goToNextRow()// 3.4.获取数据let id = result.getLong(result.getColumnIndex('ID'))let name = result.getString(result.getColumnIndex('NAME'))let finished = result.getLong(result.getColumnIndex('FINISHED'))// 3.5.封装到数组tasks.push({id, name, finished: !!finished})}console.log('testTag', '查询到数据：', JSON.stringify(tasks))return tasks}/*** 添加一个新的任务* @param name 任务名称* @returns 任务id*/addTask(name: string): Promise<number>{return this.rdbStore.insert(this.tableName, {name, finished: false})}/*** 根据id更新任务状态* @param id 任务id* @param finished 任务是否完成*/updateTaskStatus(id: number, finished: boolean) {// 1.要更新的数据let data = {finished}// 2.更新的条件let predicates = new relationalStore.RdbPredicates(this.tableName)predicates.equalTo('ID', id)// 3.更新操作return this.rdbStore.update(data, predicates)}/*** 根据id删除任务* @param id 任务id*/deleteTaskById(id: number){// 1.删除的条件let predicates = new relationalStore.RdbPredicates(this.tableName)predicates.equalTo('ID', id)// 2.删除操作return this.rdbStore.delete(predicates)}
}let taskModel = new TaskModel();export default taskModel as TaskModel;

• ets/entryability/EntryAbility.ets
• 应用启动时调用初始化

import UIAbility from '@ohos.app.ability.UIAbility';
import hilog from '@ohos.hilog';
import window from '@ohos.window';
import TaskModel from '../model/TaskModel';export default class EntryAbility extends UIAbility {async onCreate(want, launchParam) {// 初始化任务表TaskModel.initTaskDB(this.context)}
}

• 页面调用方法查询、添加数据

import TaskModel from '../../model/TaskModel'// 总任务数量@Link totalTask: number@Link finishTask: number// 任务数组@State tasks: TaskInfo[] = []aboutToAppear(){// 查询任务列表console.log('testTag', '初始化组件，查询任务列表')TaskModel.getTaskList().then(tasks => {this.tasks = tasks// 更新任务状态this.handleTaskChange()})}handleTaskChange(){// 1.更新任务总数量this.totalTask = this.tasks.length// 2.更新已完成任务数量this.finishTask = this.tasks.filter(item => item.finished).length}

  handleAddTask(name: string){// 1.新增任务TaskModel.addTask(name).then(id => {console.log('testTag', '处理新增任务: ', name)// 回显到数组页面this.tasks.push(new TaskInfo(id, name))// 2.更新任务完成状态this.handleTaskChange()// 3.关闭对话框this.dialogController.close()}).catch(error => console.log('testTag', '新增任务失败：', name, JSON.stringify(error)))}

@Builder DeleteButton(index: number, id: number){Button(){Image($r('app.media.ic_public_delete_filled')).fillColor(Color.White).width(20)}.width(40).height(40).type(ButtonType.Circle).backgroundColor(Color.Red).margin(5).onClick(() => {// 删除任务TaskModel.deleteTaskById(id).then(() => {this.tasks.splice(index, 1)console.log('testTag', `尝试删除任务，index: ${index}`)this.handleTaskChange()}).catch(error => console.log('testTag', '删除任务失败，id = ', id, JSON.stringify(error)))})}

二、通知

1、基础通知

• 应用可以通过通知接口发送通知消息，提醒用户关注应用中变化。
• 用户可以在通知栏查看和操作通知内容

（1）基础使用

• 导入notification模块

import notificationManager from '@ohos.notificationManager';

• 构建通知请求

let request: notificationManager.NotificationRequest = {id: 1, content: {// 通知内容：...}},showDeliveryTime: true, // 是否显示分发时间deliveryTime: new Date().getTime(), // 通知发送时间groupName: 'wechat', // 组通知名称slotType: notify.SlotType.SOCIAL_COMMUNICATION  // 通道类型...   //其它属性查看相关文档
}

• 发布通知

notificationManager.publish(request, (err) => {if (err) {console.error(`Failed to publish notification. Code is ${err.code}, message is ${err.message}`);return;}console.info('Succeeded in publishing notification.');
});

• 取消通知

// 取消 id=10 的通知
notificationManager.cancel(10)
// 取消当前应用所有通知
notificationManager.cancelAll()

（2）通知内容类型

• 普通文本类型

let notificationRequest = {id: 1,content: {contentType: notificationManager.ContentType.NOTIFICATION_CONTENT_BASIC_TEXT, // 普通文本类型通知normal: {title: '通知标题',text: '通知内容详情',additionalText: '通知附加内容',}}
}

• 长文本类型

let notificationRequest = {id: 1,content: {contentType: notificationManager.ContentType.NOTIFICATION_CONTENT_LONG_TEXT, // 长文本类型通知longText: {title: '通知标题',text: '通知内容详情',additionalText: '通知附加内容',longText: '通知中的长文本、很长很长。。。',briefText: '通知概要总结',expandedTitle: '通知展开时的标题',}}
}

• 多行文本类型

let notificationRequest = {id: 1,content: {contentType: NotificationManager.ContentType.NOTIFICATION_CONTENT_MULTILINE, // 多行文本类型通知multiLine: {title: '通知标题',text: '通知内容详情',additionalText: '通知附加内容',briefText: '通知概要总结',longTitle: '展开时的标题，有多行，我很宽',lines: ['第一行', '第二行', '第三行', '第四行'],}}
}

• 图片类型

// 需要获取图片PixelMap信息
let imagePixelMap: PixelMap = undefined; 
let notificationRequest: notificationManager.NotificationRequest = {id: 1,content: {contentType: notificationManager.ContentType.NOTIFICATION_CONTENT_PICTURE,picture: {title: '通知标题',text: '通知内容详情',additionalText: '通知附加内容',briefText: '通知概要总结',expandedTitle: '通知展开时的标题',picture: imagePixelMap}}
};

• 获取图片PixelMap信息

async aboutToAppear() {// 获取资源管理器let rm = getContext(this).resourceManager;// 读取图片let file = await rm.getMediaContent($r('app.media.watchGT4'))// 创建PixelMapimage.createImageSource(file.buffer).createPixelMap().then(value => this.pixel = value).catch(reason => console.log('testTag', '加载图片异常', JSON.stringify(reason)))
}

（3）完整代码示例

import notify from '@ohos.notificationManager'
import image from '@ohos.multimedia.image'@Entry
@Component
struct NotificationPage {// 全局任务ididx: number = 100// 图象pixel: PixelMapasync aboutToAppear() {// 获取资源管理器let rm = getContext(this).resourceManager;// 读取图片let file = await rm.getMediaContent($r('app.media.watchGT4'))// 创建PixelMapimage.createImageSource(file.buffer).createPixelMap().then(value => this.pixel = value).catch(reason => console.log('testTag', '加载图片异常', JSON.stringify(reason)))}build() {Column({space: 20}) {Button(`发送normalText通知`).onClick(() => this.publishNormalTextNotification())Button(`发送longText通知`).onClick(() => this.publishLongTextNotification())Button(`发送multiLine通知`).onClick(() => this.publishMultiLineNotification())Button(`发送Picture通知`).onClick(() => this.publishPictureNotification())}.width('100%').height('100%').padding(5).backgroundColor('#f1f2f3')}//通知普通文本publishNormalTextNotification() {let request: notify.NotificationRequest = {id: this.idx++,content: {contentType: notify.ContentType.NOTIFICATION_CONTENT_BASIC_TEXT,normal: {title: '通知标题' + this.idx,text: '通知内容详情',additionalText: '通知附加内容'}},showDeliveryTime: true,deliveryTime: new Date().getTime(),groupName: 'wechat',slotType: notify.SlotType.SOCIAL_COMMUNICATION}this.publish(request)}//通知长文本publishLongTextNotification() {let request: notify.NotificationRequest = {id: this.idx++,content: {contentType: notify.ContentType.NOTIFICATION_CONTENT_LONG_TEXT,longText: {title: '通知标题' + this.idx,text: '通知内容详情',additionalText: '通知附加内容',longText: '通知中的长文本，我很长，我很长，我很长，我很长，我很长，我很长，我很长',briefText: '通知概要和总结',expandedTitle: '通知展开时的标题' + this.idx}}}this.publish(request)}//通知多行文本publishMultiLineNotification() {let request: notify.NotificationRequest = {id: this.idx++,content: {contentType: notify.ContentType.NOTIFICATION_CONTENT_MULTILINE,multiLine: {title: '通知标题' + this.idx,text: '通知内容详情',additionalText: '通知附加内容',briefText: '通知概要和总结',longTitle: '展开时的标题，我很宽，我很宽，我很宽',lines: ['第一行','第二行','第三行','第四行',]}}}this.publish(request)}//通知图片类型publishPictureNotification() {let request: notify.NotificationRequest = {id: this.idx++,content: {contentType: notify.ContentType.NOTIFICATION_CONTENT_PICTURE,picture: {title: '通知标题' + this.idx,text: '通知内容详情',additionalText: '通知附加内容',briefText: '通知概要和总结',expandedTitle: '展开后标题' + this.idx,picture: this.pixel}}}this.publish(request)}// 发送文本private publish(request: notify.NotificationRequest) {notify.publish(request).then(() => console.log('notify test', '发送通知成功')).then(reason => console.log('notify test', '发送通知失败', JSON.stringify(reason)))}
}

2、进度条通知

• 进度条通知会展示一个动态的进度条，主要用于文件下载、长任务处理的进度显示。

（1）基础使用

• 判断当前系统是否支持进度条模板

NotificationManager.isSupportTemplate('downloadTemplate').then((data) => {console.info(`[ANS] isSupportTemplate success`);let isSupportTpl: boolean = data; // isSupportTpl的值为true表示支持支持downloadTemplate模板类通知，false表示不支持// ...
}).catch((err) => {console.error(`[ANS] isSupportTemplate failed, error[${err}]`);
});

• 通知模板
• 模板名称，必须是 downloadTemplate

let template = {name:'downloadTemplate',data: {title: '标题：',fileName: 'music.mp4', // 文件名progressValue: 30, //进度条当前值progressMaxValue:100, // 进度条最大值}
}

• 通知请求

let notificationRquest = {id: 1,slotType: notify.SlotType.OTHER_TYPES,template: template, //进度条模板content: {contentType: notify.ContentType.NOTIFICATION_CONTENT_BASIC_TEXT,normal: {title: template.data.title + template.data.fileName,text: "sendTemplate",additionalText: "30%"}},deliveryTime: new Date().getTime(),showDeliveryTime: true
}

• 发送通知，与基础通知相同

（3）完整代码示例

import notify from '@ohos.notificationManager'
import promptAction from '@ohos.promptAction'enum DownloadState {NOT_BEGIN = '未开始',DOWNLOADING = '下载中',PAUSE = '已暂停',FINISHED = '已完成',
}@Component
export default struct DownloadCard {// 下载进度@State progressValue: number = 0progressMaxValue: number = 100// 任务状态@State state: DownloadState = DownloadState.NOT_BEGIN// 下载的文件名filename: string = '圣诞星.mp4'// 模拟下载的任务的idtaskId: number = -1// 通知idnotificationId: number = 999isSupport: boolean = falseasync aboutToAppear(){// 1.判断当前系统是否支持进度条模板this.isSupport = await notify.isSupportTemplate('downloadTemplate')}build() {Row({ space: 10 }) {Image($r('app.media.ic_files_video')).width(50)Column({ space: 5 }) {Row() {Text(this.filename)Text(`${this.progressValue}%`).fontColor('#c1c2c1')}.width('100%').justifyContent(FlexAlign.SpaceBetween)Progress({value: this.progressValue,total: this.progressMaxValue,})Row({ space: 5 }) {Text(`${(this.progressValue * 0.43).toFixed(2)}MB`).fontSize(14).fontColor('#c1c2c1')Blank()if (this.state === DownloadState.NOT_BEGIN) {Button('开始').downloadButton().onClick(() => this.download())} else if (this.state === DownloadState.DOWNLOADING) {Button('取消').downloadButton().backgroundColor('#d1d2d3').onClick(() => this.cancel())Button('暂停').downloadButton().onClick(() => this.pause())} else if (this.state === DownloadState.PAUSE) {Button('取消').downloadButton().backgroundColor('#d1d2d3').onClick(() => this.cancel())Button('继续').downloadButton().onClick(() => this.download())} else {Button('打开').downloadButton().onClick(() => this.open())}}.width('100%')}.layoutWeight(1)}.width('100%').borderRadius(20).padding(15).backgroundColor(Color.White)}cancel() {// 取消定时任务if(this.taskId > 0){clearInterval(this.taskId);this.taskId = -1}// 清理下载任务进度this.progressValue = 0// 标记任务状态：未开始this.state = DownloadState.NOT_BEGIN// 取消通知notify.cancel(this.notificationId)}download() {// 清理旧任务if(this.taskId > 0){clearInterval(this.taskId);}// 开启定时任务，模拟下载this.taskId = setInterval(() => {// 判断任务进度是否达到100if(this.progressValue >= 100){// 任务完成了，应该取消定时任务clearInterval(this.taskId)this.taskId = -1// 并且标记任务状态为已完成this.state = DownloadState.FINISHED// 发送通知this.publishDownloadNotification()return}// 模拟任务进度变更this.progressValue += 2// 发送通知this.publishDownloadNotification()}, 500)// 标记任务状态：下载中this.state = DownloadState.DOWNLOADING}pause() {// 取消定时任务if(this.taskId > 0){clearInterval(this.taskId);this.taskId = -1}// 标记任务状态：已暂停this.state = DownloadState.PAUSE// 发送通知this.publishDownloadNotification()}open() {promptAction.showToast({message: '功能未实现'})}publishDownloadNotification(){// 1.判断当前系统是否支持进度条模板if(!this.isSupport){// 当前系统不支持进度条模板return}// 2.准备进度条模板的参数let template = {name: 'downloadTemplate',data: {progressValue: this.progressValue,progressMaxValue: this.progressMaxValue}}let request: notify.NotificationRequest = {id: this.notificationId,template: template,content: {contentType: notify.ContentType.NOTIFICATION_CONTENT_BASIC_TEXT,normal: {title: this.filename + ':  ' + this.state,text: '',additionalText: this.progressValue + '%'}}}// 3.发送通知notify.publish(request).then(() => console.log('test', '通知发送成功')).catch(reason => console.log('test', '通知发送失败！', JSON.stringify(reason)))}
}@Extend(Button) function downloadButton() {.width(75).height(28).fontSize(14)
}

3、通知意图

• 我们可以给通知或其中的按钮设置的行为意图（Want）
• 从而实现拉起应用组件或发布公共事件等能力。

（1）基础使用

• 导入模块

import NotificationManager from '@ohos.notificationManager';
import wantAgent from '@ohos.app.ability.wantAgent';

• 意图行为信息

let wantAgentInfo = {wants: [{deviceId: '',bundleName: 'com.example.test',abilityName: 'com.example.test.MainAbility',action: '',entities: [],uri: '',parameters: {}}],operationType: wantAgent.OperationType.START_ABILITY,requestCode: 0,wantAgentFlags:[wantAgent.WantAgentFlags.CONSTANT_FLAG]
}

• 创建wantAgent实例

 // 用于保存创建成功的WantAgent对象，后续使用其完成触发的动作。
let wantAgentObj = null;wantAgent.getWantAgent(wantAgentInfo, (err, data) => {if (err) {console.error('[WantAgent]getWantAgent err=' + JSON.stringify(err));} else {console.info('[WantAgent]getWantAgent success');wantAgentObj = data;}
});

• 通知请求

let notificationRequest = {content: {// ....},id: 1,label: 'TEST',wantAgent: wantAgentObj,
}

（2）完整代码示例

import wantAgent, { WantAgent } from '@ohos.app.ability.wantAgent'
import promptAction from '@ohos.promptAction'@Component
export default struct DownloadCard {// 存放wantAgent实例wantAgentInstance: WantAgentasync aboutToAppear(){// 1.判断当前系统是否支持进度条模板this.isSupport = await notify.isSupportTemplate('downloadTemplate')// 2.创建拉取当前应用的行为意图// 2.1.创建wantInfo信息let wantInfo: wantAgent.WantAgentInfo = {wants: [{bundleName: 'com.example.myapplication',abilityName: 'EntryAbility',}],requestCode: 0,operationType: wantAgent.OperationType.START_ABILITY,wantAgentFlags: [wantAgent.WantAgentFlags.CONSTANT_FLAG]}// 2.2.创建wantAgent实例this.wantAgentInstance = await wantAgent.getWantAgent(wantInfo)}build() {···· // 同进度条通知代码示例}open() {promptAction.showToast({message: '功能未实现'})}publishDownloadNotification(){// 1.判断当前系统是否支持进度条模板if(!this.isSupport){// 当前系统不支持进度条模板return}// 2.准备进度条模板的参数let template = {name: 'downloadTemplate',data: {progressValue: this.progressValue,progressMaxValue: this.progressMaxValue}}let request: notify.NotificationRequest = {id: this.notificationId,template: template,// 通知意图wantAgent: this.wantAgentInstance,content: {contentType: notify.ContentType.NOTIFICATION_CONTENT_BASIC_TEXT,normal: {title: this.filename + ':  ' + this.state,text: '',additionalText: this.progressValue + '%'}}}// 3.发送通知notify.publish(request).then(() => console.log('test', '通知发送成功')).catch(reason => console.log('test', '通知发送失败！', JSON.stringify(reason)))}
}@Extend(Button) function downloadButton() {.width(75).height(28).fontSize(14)
}

这篇关于鸿蒙开发相关知识（四）【数据持久化（用户首选项、关系型数据库）、通知（基础通知、进度条通知、通知意图）】的文章就介绍到这儿，希望我们推荐的文章对编程师们有所帮助！

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