JS UI 框架提供了 JS FA（Feature Ability）调用 Java PA（Particle Ability）的机制，该机制提供了一种通道来传递方法调用、数据返回以及订阅事件上报。
当前提供 Ability 和 Internal Ability 两种调用方式，开发者可以根据业务场景选择合适的调用方式进行开发。
JS 端与 Java 端通过 bundleName 和 abilityName 来进行关联。在系统收到 JS 调用请求后，根据开发者在 JS 接口中设置的参数来选择对应的处理方式。开发者在 onRemoteRequest() 中实现 PA 提供的业务逻辑。详细信息请参考 JS FA调用Java PA机制。
FA 端提供以下三个 JS 接口：
PA 端提供以下两类接口：
返回该错误说明 JS 接口调用请求未在系统中找到对应的 InternalAbilityHandler 进行处理，因此需要检查以下几点是否正确执行：
Ability 和 Internal Ability 是两种不同的 FA 调用 PA 的方式。 [表1]列举了在开发时各方面的差异，供开发者参考，避免开发时将两者混淆使用：
| 差异项 | Ability | InternalAbility |
|---|---|---|
| JS端（abilityType） | 0 | 1 |
| 是否需要在 config.json 的 abilities 中为 PA 添加声明 | 需要（有独立的生命周期） | 不需要（和FA共生命周期） |
| 是否需要在FA中注册 | 不需要 | 需要 |
| 继承的类 | ohos.aafwk.ability.Ability | ohos.ace.ability.AceInternalAbility |
| 是否允许被其他FA访问调用 | 是 | 否 |
// 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.huawei.hiaceservice';
action.abilityName = 'CalcServiceAbility';
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 && ret.code == 0) {
console.info('plus result is:' + JSON.stringify(ret.abilityResult));
} else {
if (ret.code) {
console.error('plus error code:' + JSON.stringify(ret.code));
} else {
console.error('plus error undefined.');
}
}
}
}功能代码实现：
CalcServiceAbility.java
// ohos相关接口包
import ohos.aafwk.ability.Ability;
import ohos.aafwk.content.Intent;
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 CalcServiceAbility extends Ability {
private static final String TAG = "CalcServiceAbility";
private MyRemote remote = new MyRemote();
// FA在请求PA服务时会调用AbilityconnectAbility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 ERROR = -1;
private static final int SUCCESS = 0;
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 zsonStr = data.readString();
RequestParam param = ZSONObject.stringToClass(zsonStr, RequestParam.class);
// 返回结果仅支持可序列化的Object类型
Map<String, Object> zsonResult = new HashMap<String, Object>();
zsonResult.put("code", SUCCESS);
zsonResult.put("abilityResult", param.getFirstNum() + param.getSecondNum());
reply.writeString(ZSONObject.toZSONString(zsonResult));
break;
}
default: {
Map<String, Object> zsonResult = new HashMap<String, Object>();
zsonResult.put("abilityError", ERROR);
reply.writeString(ZSONObject.toZSONString(zsonResult));
return false;
}
}
return true;
}
@Override
public IRemoteObject asObject() {
return this;
}
}
}请求参数代码：
RequestParam.java
public class RequestParam {
private int firstNum;
private int secondNum;
public int getFirstNum() {
return firstNum;
}
public void setFirstNum(int firstNum) {
this.firstNum = firstNum;
}
public int getSecondNum() {
return secondNum;
}
public void setSecondNum(int secondNum) {
this.secondNum = secondNum;
}
}功能代码实现：
CalcInternalAbility.java
// ohos相关接口包
import ohos.ace.ability.AceInternalAbility;
import ohos.app.AbilityContext;
import ohos.rpc.IRemoteObject;
import ohos.rpc.MessageOption;
import ohos.rpc.MessageParcel;
import ohos.rpc.RemoteException;
import ohos.utils.zson.ZSONObject;
import java.util.HashMap;
import java.util.Map;
public class CalcInternalAbility extends AceInternalAbility {
private static final String TAG = CalcInternalAbility.class.getSimpleName();
private static final String BUNDLE_NAME = "com.huawei.hiaceservice";
private static final String ABILITY_NAME = "CalcInternalAbility";
private static final int ERROR = -1;
private static final int SUCCESS = 0;
private static final int PLUS = 1001;
private static CalcInternalAbility instance;
private AbilityContext abilityContext;
// 如果多个Ability实例都需要注册当前InternalAbility实例，需要更改构造函数，设定自己的bundleName和abilityName
public CalcInternalAbility() {
super(BUNDLE_NAME, ABILITY_NAME);
}
public boolean onRemoteRequest(int code, MessageParcel data, MessageParcel reply, MessageOption option) {
switch (code) {
case PLUS: {
String zsonStr = data.readString();
RequestParam param = ZSONObject.stringToClass(zsonStr, RequestParam.class);
// 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> zsonResult = new HashMap<String, Object>();
zsonResult.put("code", SUCCESS);
zsonResult.put("abilityResult", param.getFirstNum() + param.getSecondNum());
// SYNC
if (option.getFlags() == MessageOption.TF_SYNC) {
reply.writeString(ZSONObject.toZSONString(zsonResult));
} else {
// ASYNC
MessageParcel reponseData = MessageParcel.obtain();
reponseData.writeString(ZSONObject.toZSONString(zsonResult));
IRemoteObject remoteReply = reply.readRemoteObject();
try {
remoteReply.sendRequest(0, reponseData, MessageParcel.obtain(), new MessageOption());
reponseData.reclaim();
} catch (RemoteException exception) {
return false;
}
}
break;
}
default: {
Map<String, Object> zsonResult = new HashMap<String, Object>();
zsonResult.put("abilityError", ERROR);
reply.writeString(ZSONObject.toZSONString(zsonResult));
return false;
}
}
return true;
}
/**
* Internal ability registration.
*/
public static void register(AbilityContext abilityContext) {
instance = new CalcInternalAbility();
instance.onRegister(abilityContext);
}
private void onRegister(AbilityContext abilityContext) {
this.abilityContext = abilityContext;
this.setInternalAbilityHandler((code, data, reply, option) -> {
return this.onRemoteRequest(code, data, reply, option);
});
}
/**
* Internal ability deregistration.
*/
public static void deregister() {
instance.onDeregister();
}
private void onDeregister() {
abilityContext = null;
this.setInternalAbilityHandler(null);
}
}Internal Ability 注册：修改继承 AceAbility 工程中的代码
public class HiAceInternalAbility extends AceAbility {
@Override
public void onStart(Intent intent) {
super.onStart(intent);
// 注册
CalcInternalAbility.register(this);
...
}
@Override
public void onStop() {
// 去注册
CalcInternalAbility.deregister();
super.onStop();
}
}