鴻蒙開發(fā)實戰(zhàn)系列之一：鴻蒙開發(fā)實戰(zhàn)系列之一：圓角
前言
上一篇跟大家分享了如何在鴻蒙系統(tǒng)中實現(xiàn)圓角，這一期我們來跟大家分享一下如何實現(xiàn)發(fā)布/訂閱的事件總線，也就是我們在Android開發(fā)中常用的EventBus、RxBus等框架晒衩。
開始之前饿这，我們先回顧下Android里面的事件發(fā)布/訂閱是個什么東西怜浅？
像EventBus凡蚜、RxBus是我們在Android應(yīng)用開發(fā)中常選用的發(fā)布/訂閱事件框架，用來代替?zhèn)鹘y(tǒng)的Intent披泪，Handler，Broadcast搬瑰，在Activity款票，F(xiàn)ragment，Service線程之間傳遞數(shù)據(jù)泽论，執(zhí)行方法艾少。
它有很多優(yōu)點：簡化應(yīng)用組件間的通信；解耦事件的發(fā)送者和接收者翼悴；避免復雜和容易出錯的依賴和生命周期的問題缚够；速度快，專門為高性能優(yōu)化過等等鹦赎。
主要工作原理：事件源將產(chǎn)生的消息發(fā)送到事件總線的特定通道之上谍椅，然后監(jiān)聽器在事先會訂閱事務(wù)總線之中不同的通道以區(qū)分消息的響應(yīng)，然后當消息被發(fā)送到事務(wù)總線的特定通道之中時古话，所對應(yīng)的監(jiān)聽器會監(jiān)聽到消息雏吭，然后監(jiān)聽器根據(jù)程序中設(shè)置的響應(yīng)函數(shù)進行執(zhí)行。
rxbus.jpg
那在鴻蒙系統(tǒng)中陪踩，肯定是沒有現(xiàn)成的EventBus或者RxBus給我們直接用的杖们，那么我們?nèi)绾卧邙櫭上到y(tǒng)中的Slice，Ability膊毁，Service胀莹，線程之間傳遞消息，執(zhí)行方法呢婚温？
磨刀不誤砍柴工啊描焰，兄dei，要是不先把這個工具庫寫出來，這么幾周的時間怎么完成一個鴻蒙App呢荆秦，產(chǎn)品手中的30m大刀可不是鬧著玩的啊篱竭。
由于鴻蒙只能使用Java代碼，所以我們看上了RxJava這個小兄弟步绸，何不像在Android中一樣掺逼，在rxjava的基礎(chǔ)上封裝一個RxBus呢？跟Android大哥看齊不香么瓤介？
好的吕喘，說干就干，我們來手lu一個鴻蒙版的RxBus刑桑。
實現(xiàn)鴻蒙Rxbus
1氯质、先引入Rxjava庫
implementation 'io.reactivex.rxjava3:rxjava:3.0.4'
2、創(chuàng)建鴻蒙線程調(diào)度HarmonySchedulers
import io.reactivex.rxjava3.annotations.NonNull;
import io.reactivex.rxjava3.core.Scheduler;
import io.reactivex.rxjava3.schedulers.Schedulers;
import java.util.concurrent.Executor;
public class HarmonySchedulers implements Executor {
private static HarmonySchedulers instance;
private final Scheduler mMainScheduler;
private TaskDispatcher uiTaskDispatcher;
private HarmonySchedulers() {
mMainScheduler = Schedulers.from(this);
}
public static synchronized Scheduler mainThread() {
if (instance == null) {
instance = new HarmonySchedulers();
}
return instance.mMainScheduler;
}
@Override
public void execute(@NonNull Runnable command) {
if (uiTaskDispatcher == null) {
uiTaskDispatcher = getMainAbility().getUITaskDispatcher();//注意祠斧，這里要用Ability來獲取UI線程的任務(wù)發(fā)射器闻察，Ability自己想辦法獲取
}
uiTaskDispatcher.delayDispatch(runnable, delayTime);
}
}
3、創(chuàng)建RxBus類琢锋，實現(xiàn)訂閱辕漂、注冊、取消注冊等功能
@SuppressWarnings("unused")
public class RxBus {
public static final String LOG_BUS = "RXBUS_LOG";
private static volatile RxBus defaultInstance;
private Map<Class, List<Disposable>> subscriptionsByEventType = new HashMap<>();
private Map<Object, List<Class>> eventTypesBySubscriber = new HashMap<>();
private Map<Class, List<SubscriberMethod>> subscriberMethodByEventType = new HashMap<>();
private final Subject<Object> bus;
private RxBus() {
this.bus = PublishSubject.create().toSerialized();
}
public static RxBus get() {
RxBus rxBus = defaultInstance;
if (defaultInstance == null) {
synchronized (RxBus.class) {
rxBus = defaultInstance;
if (defaultInstance == null) {
rxBus = new RxBus();
defaultInstance = rxBus;
}
}
}
return rxBus;
}
/**
* 根據(jù)傳遞的 eventType 類型返回特定類型(eventType)的 被觀察者
*
* @param eventType 事件類型
* @return return
*/
private <T> Flowable<T> toObservable(Class<T> eventType) {
return bus.toFlowable(BackpressureStrategy.BUFFER).ofType(eventType);
}
/**
* 根據(jù)傳遞的code和 eventType 類型返回特定類型(eventType)的 被觀察者
*
* @param code 事件code
* @param eventType 事件類型
*/
private <T> Flowable<T> toObservable(final int code, final Class<T> eventType) {
return bus.toFlowable(BackpressureStrategy.BUFFER).ofType(Message.class)
.filter(new Predicate<Message>() {
@Override
public boolean test(Message o) throws Exception {
return o.getCode() == code && eventType.isInstance(o.getObject());
}
}).map(new Function<Message, Object>() {
@Override
public Object apply(Message o) throws Exception {
return o.getObject();
}
}).cast(eventType);
}
/**
* 注冊
*
* @param subscriber 訂閱者
*/
public void register(Object subscriber) {
Class<?> subClass = subscriber.getClass();
Method[] methods = subClass.getDeclaredMethods();
for (Method method : methods) {
if (method.isAnnotationPresent(Subscribe.class)) {
//獲得參數(shù)類型
Class[] parameterType = method.getParameterTypes();
//參數(shù)不為空 且參數(shù)個數(shù)為1
if (parameterType != null && parameterType.length == 1) {
Class eventType = parameterType[0];
addEventTypeToMap(subscriber, eventType);
Subscribe sub = method.getAnnotation(Subscribe.class);
int code = sub.code();
ThreadMode threadMode = sub.threadMode();
SubscriberMethod subscriberMethod = new SubscriberMethod(subscriber, method, eventType, code, threadMode);
addSubscriberToMap(eventType, subscriberMethod);
addSubscriber(subscriberMethod);
} else if (parameterType == null || parameterType.length == 0) {
Class eventType = BusData.class;
addEventTypeToMap(subscriber, eventType);
Subscribe sub = method.getAnnotation(Subscribe.class);
int code = sub.code();
ThreadMode threadMode = sub.threadMode();
SubscriberMethod subscriberMethod = new SubscriberMethod(subscriber, method, eventType, code, threadMode);
addSubscriberToMap(eventType, subscriberMethod);
addSubscriber(subscriberMethod);
}
}
}
}
/**
* 將event的類型以訂閱中subscriber為key保存到map里
*
* @param subscriber 訂閱者
* @param eventType event類型
*/
private void addEventTypeToMap(Object subscriber, Class eventType) {
List<Class> eventTypes = eventTypesBySubscriber.get(subscriber);
if (eventTypes == null) {
eventTypes = new ArrayList<>();
eventTypesBySubscriber.put(subscriber, eventTypes);
}
if (!eventTypes.contains(eventType)) {
eventTypes.add(eventType);
}
}
/**
* 將注解方法信息以event類型為key保存到map中
*
* @param eventType event類型
* @param subscriberMethod 注解方法信息
*/
private void addSubscriberToMap(Class eventType, SubscriberMethod subscriberMethod) {
List<SubscriberMethod> subscriberMethods = subscriberMethodByEventType.get(eventType);
if (subscriberMethods == null) {
subscriberMethods = new ArrayList<>();
subscriberMethodByEventType.put(eventType, subscriberMethods);
}
if (!subscriberMethods.contains(subscriberMethod)) {
subscriberMethods.add(subscriberMethod);
}
}
/**
* 將訂閱事件以event類型為key保存到map,用于取消訂閱時用
*
* @param eventType event類型
* @param disposable 訂閱事件
*/
private void addSubscriptionToMap(Class eventType, Disposable disposable) {
List<Disposable> disposables = subscriptionsByEventType.get(eventType);
if (disposables == null) {
disposables = new ArrayList<>();
subscriptionsByEventType.put(eventType, disposables);
}
if (!disposables.contains(disposable)) {
disposables.add(disposable);
}
}
/**
* 用RxJava添加訂閱者
*
* @param subscriberMethod d
*/
@SuppressWarnings("unchecked")
private void addSubscriber(final SubscriberMethod subscriberMethod) {
Flowable flowable;
if (subscriberMethod.code == -1) {
flowable = toObservable(subscriberMethod.eventType);
} else {
flowable = toObservable(subscriberMethod.code, subscriberMethod.eventType);
}
Disposable subscription = postToObservable(flowable, subscriberMethod)
.subscribe(new Consumer<Object>() {
@Override
public void accept(Object o) throws Exception {
callEvent(subscriberMethod, o);
}
});
addSubscriptionToMap(subscriberMethod.subscriber.getClass(), subscription);
}
/**
* 用于處理訂閱事件在那個線程中執(zhí)行
*
* @param observable d
* @param subscriberMethod d
* @return Observable
*/
private Flowable postToObservable(Flowable observable, SubscriberMethod subscriberMethod) {
Scheduler scheduler;
switch (subscriberMethod.threadMode) {
case MAIN:
scheduler = HarmonySchedulers.mainThread();
break;
case NEW_THREAD:
scheduler = Schedulers.newThread();
break;
case CURRENT_THREAD:
scheduler = Schedulers.trampoline();
break;
default:
throw new IllegalStateException("Unknown thread mode: " + subscriberMethod.threadMode);
}
return observable.observeOn(scheduler);
}
/**
* 回調(diào)到訂閱者的方法中
*
* @param method code
* @param object obj
*/
private void callEvent(SubscriberMethod method, Object object) {
Class eventClass = object.getClass();
List<SubscriberMethod> methods = subscriberMethodByEventType.get(eventClass);
if (methods != null && methods.size() > 0) {
for (SubscriberMethod subscriberMethod : methods) {
Subscribe sub = subscriberMethod.method.getAnnotation(Subscribe.class);
int c = sub.code();
if (c == method.code && method.subscriber.equals(subscriberMethod.subscriber) && method.method.equals(subscriberMethod.method)) {
subscriberMethod.invoke(object);
}
}
}
}
/**
* 取消注冊
*
* @param subscriber object
*/
public void unRegister(Object subscriber) {
List<Class> subscribedTypes = eventTypesBySubscriber.get(subscriber);
if (subscribedTypes != null) {
for (Class<?> eventType : subscribedTypes) {
unSubscribeByEventType(subscriber.getClass());
unSubscribeMethodByEventType(subscriber, eventType);
}
eventTypesBySubscriber.remove(subscriber);
}
}
/**
* subscriptions unsubscribe
*
* @param eventType eventType
*/
private void unSubscribeByEventType(Class eventType) {
List<Disposable> disposables = subscriptionsByEventType.get(eventType);
if (disposables != null) {
Iterator<Disposable> iterator = disposables.iterator();
while (iterator.hasNext()) {
Disposable disposable = iterator.next();
if (disposable != null && !disposable.isDisposed()) {
disposable.dispose();
iterator.remove();
}
}
}
}
/**
* 移除subscriber對應(yīng)的subscriberMethods
*
* @param subscriber subscriber
* @param eventType eventType
*/
private void unSubscribeMethodByEventType(Object subscriber, Class eventType) {
List<SubscriberMethod> subscriberMethods = subscriberMethodByEventType.get(eventType);
if (subscriberMethods != null) {
Iterator<SubscriberMethod> iterator = subscriberMethods.iterator();
while (iterator.hasNext()) {
SubscriberMethod subscriberMethod = iterator.next();
if (subscriberMethod.subscriber.equals(subscriber)) {
iterator.remove();
}
}
}
}
public void send(int code, Object o) {
bus.onNext(new Message(code, o));
}
public void send(Object o) {
bus.onNext(o);
}
public void send(int code) {
bus.onNext(new Message(code, new BusData()));
}
private class Message {
private int code;
private Object object;
public Message() {
}
private Message(int code, Object o) {
this.code = code;
this.object = o;
}
private int getCode() {
return code;
}
public void setCode(int code) {
this.code = code;
}
private Object getObject() {
return object;
}
public void setObject(Object object) {
this.object = object;
}
}
}
4吴超、添加其他附加類
BusData.java 事件數(shù)據(jù)封裝
public class BusData {
String id;
String status;
public BusData() {}
public BusData(String id, String status) {
this.id = id;
this.status = status;
}
public String getId() {
return id;
}
public void setId(String id) {
this.id = id;
}
public String getStatus() {
return status;
}
public void setStatus(String status) {
this.status = status;
}
}
Subscribe.java 注解類
@Documented
@Target(ElementType.METHOD)
@Retention(RetentionPolicy.RUNTIME)
public @interface Subscribe {
int code() default -1;
ThreadMode threadMode() default ThreadMode.CURRENT_THREAD;
}
SubscriberMethod.java 執(zhí)行注冊方法封裝
public class SubscriberMethod {
public Method method;
public ThreadMode threadMode;
public Class<?> eventType;
public Object subscriber;
public int code;
public SubscriberMethod(Object subscriber, Method method, Class<?> eventType, int code,ThreadMode threadMode) {
this.method = method;
this.threadMode = threadMode;
this.eventType = eventType;
this.subscriber = subscriber;
this.code = code;
}
/**
* 調(diào)用方法
* @param o 參數(shù)
*/
public void invoke(Object o){
try {
Class[] parameterType = method.getParameterTypes();
if(parameterType != null && parameterType.length == 1){
method.invoke(subscriber, o);
} else if(parameterType == null || parameterType.length == 0){
method.invoke(subscriber);
}
} catch (IllegalAccessException e) {
e.printStackTrace();
} catch (InvocationTargetException e) {
e.printStackTrace();
}
}
}
ThreadMode.java 線程模型钉嘹，用來標識事件運行線程
public enum ThreadMode {
/**
* current thread
*/
CURRENT_THREAD,
/**
* android main thread
*/
MAIN,
/**
* new thread
*/
NEW_THREAD
}
使用Rxbus
1、定義事件參數(shù)類
public class RxbusEvent {}
2烛芬、定義事件接收者
public class RxBusDemoAbilitySlice extends AbilitySlice {
@Override
protected void onStart(Intent intent) {
super.onStart(intent);
RxBus.get().register(this);//注測rxbus
}
@Override
protected void onStop() {
super.onStop();
RxBus.get().unRegister(this);//注銷rxbus
}
/**
* 接收事件
* @param rxbusEvent
*/
@Subscribe(threadMode = ThreadMode.MAIN)
public void rxBusRxbusEvent(RxbusEvent rxbusEvent) {
if (rxbusEvent == null) {
return;
}
//執(zhí)行對應(yīng)操作
}
}
3隧期、發(fā)送事件
RxBus.get().send(new RxbusEvent());//發(fā)送事件
總結(jié)
打完收工，最后使用起來跟Android中基本一樣赘娄，本期代碼比較多仆潮，歡迎大家使用測試并反饋bug，后期代碼整理好會一并傳到github上去遣臼。好了性置，繼續(xù)搞鴻蒙其他功能去了。
這是本系列的第二篇揍堰，后面還會為大家?guī)砀嗟镍櫭筛韶浥羟常凑埰诖?/p>
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