HarmonyOS4.0系统性深入开发11通过message事件刷新卡片内容-编程知识

通过message事件刷新卡片内容

在卡片页面中可以通过postCardAction接口触发message事件拉起FormExtensionAbility，然后由FormExtensionAbility刷新卡片内容，下面是这种刷新方式的简单示例。

在卡片页面通过注册Button的onClick点击事件回调，并在回调中调用

postCardAction

接口触发message事件拉起FormExtensionAbility。

let storage = new LocalStorage();@Entry(storage)
@Component
struct WidgetCard {@LocalStorageProp('title') title: string = 'init';@LocalStorageProp('detail') detail: string = 'init';build() {Column() {Button('刷新').onClick(() => {postCardAction(this, {'action': 'message','params': {'msgTest': 'messageEvent'}});})Text(`${this.title}`)Text(`${this.detail}`)}.width('100%').height('100%')}
}

在FormExtensionAbility的onFormEvent生命周期中调用updateForm接口刷新卡片。

import formBindingData from '@ohos.app.form.formBindingData';
import FormExtensionAbility from '@ohos.app.form.FormExtensionAbility';
import formProvider from '@ohos.app.form.formProvider';export default class EntryFormAbility extends FormExtensionAbility {onFormEvent(formId, message) {// Called when a specified message event defined by the form provider is triggered.console.info(`FormAbility onEvent, formId = ${formId}, message: ${JSON.stringify(message)}`);let formData = {'title': 'Title Update Success.', // 和卡片布局中对应'detail': 'Detail Update Success.', // 和卡片布局中对应};let formInfo = formBindingData.createFormBindingData(formData)formProvider.updateForm(formId, formInfo).then((data) => {console.info('FormAbility updateForm success.' + JSON.stringify(data));}).catch((error) => {console.error('FormAbility updateForm failed: ' + JSON.stringify(error));})}...
}

运行效果如下图所示。

点击放大

通过router或call事件刷新卡片内容

在卡片页面中可以通过postCardAction接口触发router或call事件拉起UIAbility，然后由UIAbility刷新卡片内容，下面是这种刷新方式的简单示例。

通过router事件刷新卡片内容

在卡片页面通过注册Button的onClick点击事件回调，并在回调中调用

postCardAction

接口触发router事件拉起UIAbility。

let storage = new LocalStorage();@Entry(storage)
@Component
struct WidgetCard {@LocalStorageProp('detail') detail: string = 'init';build() {Column() {Button('跳转').margin('20%').onClick(() => {console.info('postCardAction to EntryAbility');postCardAction(this, {'action': 'router','abilityName': 'EntryAbility', // 只能跳转到当前应用下的UIAbility'params': {'detail': 'RouterFromCard'}});})Text(`${this.detail}`).margin('20%')}.width('100%').height('100%')}
}

在UIAbility的onCreate()或者onNewWant()生命周期中可以通过入参want获取卡片的formID和传递过来的参数信息，然后调用updateForm接口刷新卡片。

import UIAbility from '@ohos.app.ability.UIAbility';
import formBindingData from '@ohos.app.form.formBindingData';
import formProvider from '@ohos.app.form.formProvider';
import formInfo from '@ohos.app.form.formInfo';export default class EntryAbility extends UIAbility {// 如果UIAbility第一次启动，在收到Router事件后会触发onCreate生命周期回调onCreate(want, launchParam) {console.info('Want:' + JSON.stringify(want));if (want.parameters[formInfo.FormParam.IDENTITY_KEY] !== undefined) {let curFormId = want.parameters[formInfo.FormParam.IDENTITY_KEY];let message = JSON.parse(want.parameters.params).detail;console.info(`UpdateForm formId: ${curFormId}, message: ${message}`);let formData = {"detail": message + ': onCreate UIAbility.', // 和卡片布局中对应};let formMsg = formBindingData.createFormBindingData(formData)formProvider.updateForm(curFormId, formMsg).then((data) => {console.info('updateForm success.' + JSON.stringify(data));}).catch((error) => {console.error('updateForm failed:' + JSON.stringify(error));})}}// 如果UIAbility已在后台运行，在收到Router事件后会触发onNewWant生命周期回调onNewWant(want, launchParam) {console.info('onNewWant Want:' + JSON.stringify(want));if (want.parameters[formInfo.FormParam.IDENTITY_KEY] !== undefined) {let curFormId = want.parameters[formInfo.FormParam.IDENTITY_KEY];let message = JSON.parse(want.parameters.params).detail;console.info(`UpdateForm formId: ${curFormId}, message: ${message}`);let formData = {"detail": message + ': onNewWant UIAbility.', // 和卡片布局中对应};let formMsg = formBindingData.createFormBindingData(formData)formProvider.updateForm(curFormId, formMsg).then((data) => {console.info('updateForm success.' + JSON.stringify(data));}).catch((error) => {console.error('updateForm failed:' + JSON.stringify(error));})}}...
}

通过call事件刷新卡片内容

在使用

postCardAction

接口的call事件时，需要在FormExtensionAbility中的onAddForm生命周期回调中更新formId。

import formBindingData from '@ohos.app.form.formBindingData'; 
import FormExtensionAbility from '@ohos.app.form.FormExtensionAbility';export default class EntryFormAbility extends FormExtensionAbility {onAddForm(want) {let formId = want.parameters["ohos.extra.param.key.form_identity"];let dataObj1 = {"formId": formId};let obj1 = formBindingData.createFormBindingData(dataObj1);return obj1;}...
};

在卡片页面通过注册Button的onClick点击事件回调，并在回调中调用

postCardAction

接口触发call事件拉起UIAbility。

let storage = new LocalStorage();@Entry(storage)
@Component
struct WidgetCard {@LocalStorageProp('detail') detail: string = 'init';@LocalStorageProp('formId') formId: string = '0';build() {Column() {Button('拉至后台').margin('20%').onClick(() => {console.info('postCardAction to EntryAbility');postCardAction(this, {'action': 'call','abilityName': 'EntryAbility', // 只能跳转到当前应用下的UIAbility'params': {'method': 'funA','formId': this.formId,'detail': 'CallFromCard'}});})Text(`${this.detail}`).margin('20%')}.width('100%').height('100%')}
}

在UIAbility的onCreate生命周期中监听call事件所需的方法，然后调用updateForm接口刷新卡片。

import UIAbility from '@ohos.app.ability.UIAbility';
import formBindingData from '@ohos.app.form.formBindingData';
import formProvider from '@ohos.app.form.formProvider';
import formInfo from '@ohos.app.form.formInfo';
const MSG_SEND_METHOD: string = 'funA'// 在收到call事件后会触发callee监听的方法
function FunACall(data) {// 获取call事件中传递的所有参数let params = JSON.parse(data.readString())if (params.formId !== undefined) {let curFormId = params.formId;let message = params.detail;console.info(`UpdateForm formId: ${curFormId}, message: ${message}`);let formData = {"detail": message};let formMsg = formBindingData.createFormBindingData(formData)formProvider.updateForm(curFormId, formMsg).then((data) => {console.info('updateForm success.' + JSON.stringify(data));}).catch((error) => {console.error('updateForm failed:' + JSON.stringify(error));})}return null;
}
export default class EntryAbility extends UIAbility {// 如果UIAbility第一次启动，call事件后会触发onCreate生命周期回调onCreate(want, launchParam) {console.info('Want:' + JSON.stringify(want));try {// 监听call事件所需的方法this.callee.on(MSG_SEND_METHOD, FunACall);} catch (error) {console.log(`${MSG_SEND_METHOD} register failed with error ${JSON.stringify(error)}`)}}...
}