根据卡片状态刷新不同内容
相同的卡片可以添加到桌面上实现不同的功能，比如添加两张桌面的卡片，一张显示杭州的天气，一张显示北京的天气，设置每天早上7点触发定时刷新，卡片需要感知当前的配置是杭州还是北京，然后将对应城市的天气信息刷新到卡片上，以下示例介绍了如何根据卡片的状态动态选择需要刷新的内容。
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卡片配置文件：配置每天早上7点触发定时刷新。
{ "forms": [ { "name": "widget", "description": "This is a service widget.", "src": "./ets/widget/pages/WidgetCard.ets", "uiSyntax": "arkts", "window": { "designWidth": 720, "autoDesignWidth": true }, "colorMode": "auto", "isDefault": true, "updateEnabled": true, "scheduledUpdateTime": "07:00", "updateDuration": 0, "defaultDimension": "2*2", "supportDimensions": ["2*2"] } ] } -
卡片页面：卡片具备不同的状态选择，在不同的状态下需要刷新不同的内容，因此在状态发生变化时通过postCardAction通知EntryFormAbility。
let storage = new LocalStorage(); @Entry(storage) @Component struct WidgetCard { @LocalStorageProp('textA') textA: string = '待刷新...'; @LocalStorageProp('textB') textB: string = '待刷新...'; @State selectA: boolean = false; @State selectB: boolean = false; build() { Column() { Row() { Checkbox({ name: 'checkbox1', group: 'checkboxGroup' }) .select(false) .onChange((value: boolean) => { this.selectA = value; postCardAction(this, { action: 'message', params: { selectA: JSON.stringify(value) } }); }) Text('状态A') } Row() { Checkbox({ name: 'checkbox2', group: 'checkboxGroup' }) .select(false) .onChange((value: boolean) => { this.selectB = value; postCardAction(this, { action: 'message', params: { selectB: JSON.stringify(value) } }); }) Text('状态B') } Row() { // 选中状态A才会进行刷新的内容 Text('状态A: ') Text(this.textA) } Row() { // 选中状态B才会进行刷新的内容 Text('状态B: ') Text(this.textB) } }.padding('10%') } } -
EntryFormAbility：将卡片的状态存储在本地数据库中，在刷新事件回调触发时，通过formId获取当前卡片的状态，然后根据卡片的状态选择不同的刷新内容。
import formInfo from '@ohos.app.form.formInfo' import formProvider from '@ohos.app.form.formProvider'; import formBindingData from '@ohos.app.form.formBindingData'; import FormExtensionAbility from '@ohos.app.form.FormExtensionAbility'; import dataPreferences from '@ohos.data.preferences'; import Want from '@ohos.app.ability.Want'; import Base from '@ohos.base'; export default class EntryFormAbility extends FormExtensionAbility { onAddForm(want: Want) { let formId: string = ''; let isTempCard: boolean; if (want.parameters) { formId = JSON.stringify(want.parameters[formInfo.FormParam.IDENTITY_KEY]); isTempCard = want.parameters[formInfo.FormParam.TEMPORARY_KEY] as boolean; if (isTempCard === false) { // 如果为常态卡片，直接进行信息持久化 console.info('Not temp card, init db for:' + formId); let promise: Promise<dataPreferences.Preferences> = dataPreferences.getPreferences(this.context, 'myStore'); promise.then(async (storeDB: dataPreferences.Preferences) => { console.info("Succeeded to get preferences."); await storeDB.put('A' + formId, 'false'); await storeDB.put('B' + formId, 'false'); await storeDB.flush(); }).catch((err: Base.BusinessError) => { console.info(`Failed to get preferences. ${JSON.stringify(err)}`); }) } } let formData: Record<string, Object | string> = {}; return formBindingData.createFormBindingData(formData); } onRemoveForm(formId: string) { console.info('onRemoveForm, formId:' + formId); let promise = dataPreferences.getPreferences(this.context, 'myStore'); promise.then(async (storeDB) => { console.info("Succeeded to get preferences."); await storeDB.delete('A' + formId); await storeDB.delete('B' + formId); await storeDB.flush(); }).catch((err: Base.BusinessError) => { console.info(`Failed to get preferences. ${JSON.stringify(err)}`); }) } // 如果在添加时为临时卡片，则建议转为常态卡片时进行信息持久化 onCastToNormalForm(formId: string) { console.info('onCastToNormalForm, formId:' + formId); let promise: Promise<dataPreferences.Preferences> = dataPreferences.getPreferences(this.context, 'myStore'); promise.then(async (storeDB: dataPreferences.Preferences) => { console.info("Succeeded to get preferences."); await storeDB.put('A' + formId, 'false'); await storeDB.put('B' + formId, 'false'); await storeDB.flush(); }).catch((err: Base.BusinessError) => { console.info(`Failed to get preferences. ${JSON.stringify(err)}`); }) } onUpdateForm(formId: string) { let promise: Promise<dataPreferences.Preferences> = dataPreferences.getPreferences(this.context, 'myStore'); promise.then(async (storeDB: dataPreferences.Preferences) => { console.info("Succeeded to get preferences."); let stateA = await storeDB.get('A' + formId, 'false'); let stateB = await storeDB.get('B' + formId, 'false'); // A状态选中则更新textA if (stateA === 'true') { let param: Record<string, string> = { 'textA': 'AAA' }; let formInfo: formBindingData.FormBindingData = formBindingData.createFormBindingData(param); await formProvider.updateForm(formId, formInfo); } // B状态选中则更新textB if (stateB === 'true') { let param: Record<string, string> = { 'textB': 'BBB' }; let formInfo: formBindingData.FormBindingData = formBindingData.createFormBindingData(param); await formProvider.updateForm(formId, formInfo); } console.info(`Update form success stateA:${stateA} stateB:${stateB}.`); }).catch((err: Base.BusinessError) => { console.info(`Failed to get preferences. ${JSON.stringify(err)}`); }) } onFormEvent(formId: string, message: string) { // 存放卡片状态 console.info('onFormEvent formId:' + formId + 'msg:' + message); let promise: Promise<dataPreferences.Preferences> = dataPreferences.getPreferences(this.context, 'myStore'); promise.then(async (storeDB: dataPreferences.Preferences) => { console.info("Succeeded to get preferences."); let msg: Record<string, string> = JSON.parse(message); if (msg.selectA != undefined) { console.info('onFormEvent selectA info:' + msg.selectA); await storeDB.put('A' + formId, msg.selectA); } if (msg.selectB != undefined) { console.info('onFormEvent selectB info:' + msg.selectB); await storeDB.put('B' + formId, msg.selectB); } await storeDB.flush(); }).catch((err: Base.BusinessError) => { console.info(`Failed to get preferences. ${JSON.stringify(err)}`); }) } };
说明：
通过本地数据库进行卡片信息的持久化时，建议先在onAddForm生命周期中通过TEMPORARY_KEY判断当前添加的卡片是否为常态卡片：如果是常态卡片，则直接进行卡片信息持久化；如果为临时卡片，则可以在卡片转为常态卡片(onCastToNormalForm)时进行持久化；同时需要在卡片销毁(onRemoveForm)时删除当前卡片存储的持久化信息，避免反复添加删除卡片导致数据库文件持续变大。