EventBus源码解析(一)——获取EventBus对象

/**
 * EventBus is a central publish/subscribe event system for Android. Events are posted ({@link #post(Object)}) to the
 * bus, which delivers it to subscribers that have a matching handler method for the event type. To receive events,
 * subscribers must register themselves to the bus using {@link #register(Object)}. Once registered, subscribers
 * receive events until {@link #unregister(Object)} is called. Event handling methods must be annotated by
 * {@link Subscribe}, must be public, return nothing (void), and have exactly one parameter
 * (the event).
 *
 * @author Markus Junginger, greenrobot
 */

implementation 'org.greenrobot:eventbus:3.1.1'

//注册，在onCrate里面
EventBus.getDefault().register(this)
//反注册，在onDestory里面
EventBus.getDefault().unregister(this)

@Subscribe
public void handle(MyClothes myClothes){
    //你的具体逻辑
}

EventBus.getDefault().post(new MyClothes())

public static EventBus getDefault() {
        if (defaultInstance == null) {
            synchronized (EventBus.class) {
                if (defaultInstance == null) {
                    defaultInstance = new EventBus();
                }
            }
        }
        return defaultInstance;
    }

public EventBus() {
        this(DEFAULT_BUILDER);
    }

private static final EventBusBuilder DEFAULT_BUILDER = new EventBusBuilder();

EventBusBuilder() {
    }

private final static ExecutorService DEFAULT_EXECUTOR_SERVICE = Executors.newCachedThreadPool();

ExecutorService executorService = DEFAULT_EXECUTOR_SERVICE;

EventBus(EventBusBuilder builder) {
        subscriptionsByEventType = new HashMap<>();
        typesBySubscriber = new HashMap<>();
        stickyEvents = new ConcurrentHashMap<>();
        mainThreadPoster = mainThreadSupport != null ? mainThreadSupport.createPoster(this) : null;
        backgroundPoster = new BackgroundPoster(this);
        asyncPoster = new AsyncPoster(this);
        ...
    }

private final Map<Class<?>, CopyOnWriteArrayList<Subscription>> subscriptionsByEventType;
private final Map<Object, List<Class<?>>> typesBySubscriber;
private final Map<Class<?>, Object> stickyEvents;
private final Poster mainThreadPoster;
private final BackgroundPoster backgroundPoster;
private final AsyncPoster asyncPoster;

EventBus build1 = EventBus.getDefault();

EventBus build2 = EventBus.builder().build();

public EventBus build() {
        return new EventBus(this);
    }