HarmonyOS 鸿蒙Next用户选择服务卡片并创建后是否能通知到 App

参考以下案例：

先存储卡片id，在主应用或者元服务页面中，首先从首选项中获取卡片id，然后调用formProvider.updateForm(formId，data) 给卡片发送数据。

参考代码如下：

1、存储卡片id：

在卡片添加到页面时，我们可以在FormExtensionAbility中的onAddForm生命周期中将卡片id存储到首选项中，在应用或者元服务页面中就可以通过首选项来获取卡片id了。

import formInfo from '@ohos.app.form.formInfo';
import formBindingData from '@ohos.app.form.formBindingData';
import { FormExtensionAbility } from '@ohos.app.form.FormExtensionAbility';
import { PreferencesUtil } from '../common/PreferencesUtil';

export default class EntryFormAbility extends FormExtensionAbility {

onAddForm(want) {
let formData = {
    title:'鸿蒙雄起',
    desc:'鸿蒙千帆起，我要当舵手'
};

// 1. 获取卡片id
let formId = want.parameters[formInfo.FormParam.IDENTITY_KEY];

//2. 将卡片id保存到首选项
PreferencesUtil.getInstance().addFormId(this.context,formId);

// 2. 将数据转为卡片识别的对象返回
return formBindingData.createFormBindingData(formData);
}
};

在上面的代码中，用到了PreferencesUtil这个工具类，其实现如下：

import dataPreferences from '@ohos.data.preferences';
import { Logger } from '@ohos.hilog';

const TAG = 1;
const MY_STORE = 'myStore';
const FORM_ID = 'formIds';

type ValueType = number | string | boolean | Array<number> | Array<string> | Array<boolean>;

export class PreferencesUtil {

private static preferencesUtil: PreferencesUtil;

public static getInstance(): PreferencesUtil {
if (!PreferencesUtil.preferencesUtil) {
    PreferencesUtil.preferencesUtil = new PreferencesUtil();
}

return PreferencesUtil.preferencesUtil;
}

getPreferences(context: Context): Promise<dataPreferences.Preferences> {
return new Promise((resolve, reject) => {
dataPreferences.getPreferences(context, MY_STORE, (err, pref: dataPreferences.Preferences) => {
    if (err) {
        Logger.error(TAG, `Failed to get preferences. Code:${err.code},message:${err.message}`);
        reject(err);
        return;
    }

    resolve(pref);
})
})
}

preferencesFlush(preferences: dataPreferences.Preferences) {
preferences.flush((err) => {
    if (err) {
        Logger.error(TAG, `Failed to flush. Code:${err.code}, message:${err.message}`);
    }
})
}

preferencesPut(preferences: dataPreferences.Preferences, formIds: Array<string>): Promise<boolean> {
return new Promise((resolve, reject) => {
try {
    preferences.put(FORM_ID, formIds, (err) => {
        if (err) {
            reject(err);
            Logger.error(TAG, `Failed to put data. Code:${err.code}, message:${err.message}`);
            return;
        }

        Logger.info(TAG, `preferencesPut succeed,formIds: ${JSON.stringify(formIds)}`);
        resolve(true);
    })
} catch (error) {
    Logger.error(TAG, `Failed to put data. Code: ${error.code},
message:${error.message}`);
}
});

}

async preferencesHas(preferences: dataPreferences.Preferences): Promise<boolean> {
return new Promise((resolve, reject) => {
preferences.has(FORM_ID, (err, value) => {
    if (err) {
        reject(err);
        Logger.error(TAG, `WANG to check the key 'formIds'. Code:${err.code}, message:${err.message}`);
        return;
    }

    resolve(value);
});
})

}

removePreferencesFromCache(context: Context): void {
dataPreferences.removePreferencesFromCache(context, MY_STORE);
}

async getFormIds(context: Context): Promise<Array<string>> {
try {
    let preferences = await this.getPreferences(context);

    return new Promise((resolve, reject) => {
        if (preferences === null) {
            Logger.error(TAG, `preferences is null`);
            return;
        }

        preferences.get(FORM_ID, [''], (err, value: ValueType) => {
            if (err) {
                reject(err);
                Logger.error(TAG, `Failed to get value of 'formIds'. Code:${err.code}, message:${err.message}`);
                return;
            }

            resolve(value as Array<string>);
            Logger.info(TAG, `Succeeded in getting value of 'formIds'. val: ${value}.`);
        })
    })
} catch (error) {
    Logger.error(TAG, `WANG Failed to get value of 'formIds'. Code:${error.code},
message:${error.message}`);
}

return new Promise((resolve, reject) => {});

}

async addFormId(context: Context, formId: string) {
try {
    let preferences = await this.getPreferences(context);

    if (preferences === null) {
        Logger.error(TAG, `preferences is null`);
        return;
    }

    if (await this.preferencesHas(preferences)) {
        let formIds = await this.getFormIds(context);

        console.log('formIds:',formIds)

        if (formIds.indexOf(formId) === -1) {
            formIds.push(formId);

            if (!await this.preferencesPut(preferences, formIds)) {
                return;
            }

            this.preferencesFlush(preferences);
        }
    } else {
        if (!await this.preferencesPut(preferences, [formId])) {
            return;
        }

        this.preferencesFlush(preferences);
    }
} catch (error) {
    Logger.error(TAG, `Failed to check the key 'formIds'. Code:${error.code},
message:${error.message}`);
}

}

async removeFormId(context: Context, formId: string) {
try {
    let preferences = await this.getPreferences(context);

    if (preferences === null) {
        Logger.error(TAG, `preferences is null`);
        return;
    }

    if (await this.preferencesHas(preferences)) {
        let formIds = await this.getFormIds(context);

        let index = formIds.indexOf(formId);

        if (index !== -1) {
            formIds.splice(index, 1);
        }

        if (!await this.preferencesPut(preferences, formIds)) {
            return;
        }

        this.preferencesFlush(preferences);
    }
} catch (error) {
    Logger.error(TAG, `WANG Failed to get preferences. Code:${error.code},
message:${error.message}`);
}

}
}

2、应用/元服务页面中发送数据

在主应用或者元服务页面中，首先从首选项中获取卡片id，然后调用formProvider.updateForm(formId，data) 给卡片发送数据。

async aboutToAppear() {
// 1. 从首选项获取卡片id
let cardids = await PreferencesUtil.getInstance().getFormIds(getContext(this));

// 2. 遍历卡片id，更新卡片数据
let data = {
    title: '鸿蒙雄起- 主应用推送刷新'+Math.random(),
    desc: '鸿蒙千帆起，我要当舵手-主应用推送刷新'+Math.random()
};

cardids.forEach(cardid => {
    let bindData = formBindingData.createFormBindingData(data);
    formProvider.updateForm(cardid, bindData)
    .then(res => {
        console.log('mylog',JSON.stringify(res))
    })
    .catch(err => {
        console.log('mylog','err',JSON.stringify(err))
    })
})
}

3、卡片页面接收数据

在卡片WidgetCard.ets中通过localStorageProp接收数据。首先在WidgetCard.ets文件的最上面创建一个LocalStorage的实例，然后将实例传递给@Entry，在页面中就可以使用LocalStorageProp修饰符来接收数据了。