HarmonyOS应用开发-FA调用PA能力学习分享 - HarmonyOS技术社区 - 电子技术论坛

李洋水蛟龙

2021-11-03 10:52:44

在鸿蒙开发中，页面交互时有时候需要调用后台PA的能力，比如数据获取、控制后台等，下面介绍如何做到上述情况。

相关接口：

FA端提供以下三个JS接口：

FeatureAbility.callAbility(OBJECT)：调用PA能力。

FeatureAbility.subscribeAbilityEvent(OBJECT, Function)：订阅PA能力。

FeatureAbility.unsubscribeAbilityEvent(OBJECT)：取消订阅PA能力。

PA端提供以下两类接口：

IRemoteObject.onRemoteRequest(int, MessageParcel, MessageParcel, MessageOption)：Ability调用方式，FA使用远端进程通信拉起并请求PA服务。

AceInternalAbility.AceInternalAbilityHandler.onRemoteRequest(int, MessageParcel, MessageParcel, MessageOption)：Internal Ability调用方式，采用内部函数调用的方式和FA进行通信。

使用演示：

FA：

// abilityType: 0-Ability; 1-Internal Ability
const ABILITY_TYPE_EXTERNAL = 0;
const ABILITY_TYPE_INTERNAL = 1;
// syncOption(Optional, default sync): 0-Sync; 1-Async
const ACTION_SYNC = 0;
const ACTION_ASYNC = 1;
const ACTION_MESSAGE_CODE_PLUS = 1001;
export default {
plus: async function() {
var actionData = {};
actionData.firstNum = 1024;
actionData.secondNum = 2048;
var action = {};
action.bundleName = 'com.example.hiaceservice';
action.abilityName = 'com.example.hiaceservice.ComputeServiceAbility';
action.messageCode = ACTION_MESSAGE_CODE_PLUS;
action.data = actionData;
action.abilityType = ABILITY_TYPE_EXTERNAL;
action.syncOption = ACTION_SYNC;
var result = await FeatureAbility.callAbility(action);
var ret = JSON.parse(result);
if (ret.code == 0) {
console.info('plus result is:' + JSON.stringify(ret.abilityResult));
} else {
console.error('plus error code:' + JSON.stringify(ret.code));
}
}
}

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PA:

package com.example.hiaceservice;
// ohos相关接口包
import ohos.aafwk.ability.Ability;
import ohos.aafwk.content.Intent;
import ohos.hiviewdfx.HiLog;
import ohos.hiviewdfx.HiLogLabel;
import ohos.rpc.IRemoteBroker;
import ohos.rpc.IRemoteObject;
import ohos.rpc.RemoteObject;
import ohos.rpc.MessageParcel;
import ohos.rpc.MessageOption;
import ohos.utils.zson.ZSONObject;
import java.util.HashMap;
import java.util.Map;
public class ComputeServiceAbility extends Ability {
// 定义日志标签
private static final HiLogLabel LABEL = new HiLogLabel(HiLog.LOG_APP, 0, "MY_TAG");
private MyRemote remote = new MyRemote();
// FA在请求PA服务时会调用Ability.connectAbility连接PA，连接成功后，需要在onConnect返回一个remote对象，供FA向PA发送消息
@Override
protected IRemoteObject onConnect(Intent intent) {
super.onConnect(intent);
return remote.asObject();
}
class MyRemote extends RemoteObject implements IRemoteBroker {
private static final int SUCCESS = 0;
private static final int ERROR = 1;
private static final int PLUS = 1001;
MyRemote() {
super("MyService_MyRemote");
}
@Override
public boolean onRemoteRequest(int code, MessageParcel data, MessageParcel reply, MessageOption option) {
switch (code) {
case PLUS: {
String dataStr = data.readString();
RequestParam param = new RequestParam();
try {
param = ZSONObject.stringToClass(dataStr, RequestParam.class);
} catch (RuntimeException e) {
HiLog.error(LABEL, "convert failed.");
}
// 返回结果当前仅支持String，对于复杂结构可以序列化为ZSON字符串上报
Map<String, Object> result = new HashMap<String, Object>();
result.put("code", SUCCESS);
result.put("abilityResult", param.getFirstNum() + param.getSecondNum());
reply.writeString(ZSONObject.toZSONString(result));
break;
}
default: {
Map<String, Object> result = new HashMap<String, Object>();
result.put("abilityError", ERROR);
reply.writeString(ZSONObject.toZSONString(result));
return false;
}
}
return true;
}
@Override
public IRemoteObject asObject() {
return this;
}
}
}

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[文章]HarmonyOS应用开发-FA调用PA能力学习分享

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