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一、使用方法：
0、初始化实例：一般在EntryAbility.ts的onWindowStageCreate中初始化；（可忽略）
1、将数据写入Preferences实例
function() {let arrayNum: number[] = [1, 2, 3];let arrayStr: string[] = ["5", "2", "3"];let arrayBoo: boolean[] = [true, false, true];var fruit: Fruit;fruit = new Fruit();fruit.fruitName = "Name";fruit.fruitNum = "Num";PFUtils.put("number", 10);PFUtils.put("string", "22");PFUtils.put("boolean", true);PFUtils.put("arrayNum", arrayNum);PFUtils.put("arrayStr", arrayStr);PFUtils.put("arrayBoo", arrayBoo);PFUtils.put("fruit", fruit) // 自定义实体this.breakpointSystem.register();this.intervalId = setInterval(this.countdown, 1000);
}
2、获取键对应的值
function() {PFUtils.get("number").then((value: number) => {Logger.error(Constants.TAG, "number：" + value)})PFUtils.get("string").then((value: string) => {Logger.error(Constants.TAG, "string：" + value)})PFUtils.get("boolean").then((value: boolean) => {Logger.error(Constants.TAG, "boolean：" + value)})PFUtils.get("arrayNum").then((value: Array<number>) => {Logger.error(Constants.TAG, "Array<number>：" + value)})PFUtils.get("arrayStr").then((value: Array<string>) => {Logger.error(Constants.TAG, "Array<string>：" + value)})PFUtils.get("arrayBoo").then((value: Array<boolean>) => {Logger.error(Constants.TAG, "Array<boolean>：" + value)})PFUtils.getEntity("fruit").then((value: Fruit) => {Logger.error(Constants.TAG, "Fruit：" + value)Logger.error(Constants.TAG, "FruitName：" + value.fruitName)Logger.error(Constants.TAG, "FruitNum：" + value.fruitNum)})
}
3、其他方法：
1、getAll：获取含有所有键值的Object对象。
2、has：检查Preferences实例是否包含名为给定Key的存储键值对
3、delete：从Preferences实例中删除名为给定Key的存储键值对
4、flush：将当前Preferences实例的数据异步存储到用户首选项的持久化文件中（put中已生效）
5、clear：清除此Preferences实例中的所有存储
二、完整代码：
import dataPreferences from '@ohos.data.preferences';
import { Constants, Logger } from '@ohos/common';let preference: dataPreferences.Preferences;
let preferenceTemp: dataPreferences.Preferences;
let context = getContext(this);export class PFUtils {/*** Read the specified Preferences persistence file and load the data into the Preferences instance.*/static async getPreferences(context: Context) {try {preference = await dataPreferences.getPreferences(context, Constants.PREFERENCES_NAME);} catch (err) {Logger.error(Constants.TAG, `Failed to get preferences, Cause: ${err}`);}}/*** Deletes the specified Preferences persistence file from memory and removes the Preferences instance.*/static async deletePreferences() {try {await dataPreferences.deletePreferences(context, Constants.PREFERENCES_NAME);} catch (err) {Logger.error(Constants.TAG, `Failed to delete preferences, Cause: ${err}`);}preference = preferenceTemp;}/*** Save the data to the Preferences.** @param data.*/static async put(key: string, value: unknown) {if (!preference) {await this.getPreferences(getContext(this));}try {if (typeof value === "number") {await preference.put(key, value);}if (typeof value === "string") {await preference.put(key, value);}if (typeof value === "boolean") {await preference.put(key, value);}if (typeof value === "object") {if (Array.isArray(value)) {await preference.put(key, value);} else {await preference.put(key, JSON.stringify(value));}}} catch (err) {Logger.error(Constants.TAG, `Failed to put value, Cause: ${err}`);}// Store the Preference instance in the preference persistence fileawait preference.flush();}/*** Get preference data.*/static async get(key: string) {let value: unknown;if (!preference) {await this.getPreferences(getContext(this));}try {value = await preference.get(key, undefined).then();} catch (err) {Logger.error(Constants.TAG, `Failed to get value, Cause: ${err}`);}return value;}/*** Get custom entity data.*/static async getEntity(key: string) {let value: string = '';if (!preference) {await this.getPreferences(getContext(this));}try {value = (await preference.get(key, '')).toString();} catch (err) {Logger.error(Constants.TAG, `Failed to get value, Cause: ${err}`);}return JSON.parse(value);}/*** Get an Object object that contains all key values.*/static async getAll() {let value: unknown;if (!preference) {await this.getPreferences(getContext(this));}try {value = await preference.getAll().then();} catch (err) {Logger.error(Constants.TAG, `Failed to get value, Cause: ${err}`);}return value;}/*** Check if the Preferences instance contains a stored key value pair named the given Key*/static async has(key: string) {let value: boolean = false;if (!preference) {await this.getPreferences(getContext(this));}try {value = await preference.has(key).then();} catch (err) {Logger.error(Constants.TAG, `Failed to get value, Cause: ${err}`);}return value;}/*** Delete a stored key value pair named the given Key from the Preferences instance*/static async delete(key: string) {if (!preference) {await this.getPreferences(getContext(this));}try {await preference.delete(key).then();} catch (err) {Logger.error(Constants.TAG, `Failed to get value, Cause: ${err}`);}}/*** Clear all storage in this Preferences instance*/static async clear() {if (!preference) {await this.getPreferences(getContext(this));}try {await preference.clear().then();} catch (err) {Logger.error(Constants.TAG, `Failed to get value, Cause: ${err}`);}}/***Asynchronous storage of data from the current Preferences instance to the persistent file of user preferences*/static async flush() {if (!preference) {await this.getPreferences(getContext(this));}try {await preference.flush().then();} catch (err) {Logger.error(Constants.TAG, `Failed to get value, Cause: ${err}`);}}
}
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