EventBus - 4 源码解析-2 subscribe注解／threadMode

最新推荐文章于 2023-03-09 10:08:37 发布

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最新推荐文章于 2023-03-09 10:08:37 发布 · 1.4k 阅读

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CC 4.0 BY-SA版权

本文深入探讨了EventBus库中@Subscribe注解的源码，重点关注线程模式，包括POSTING、MAIN、BACKGROUND和ASYNC。POSTING默认在事件发布线程执行，MAIN确保在主线程处理，BACKGROUND在后台线程，而ASYNC使用独立线程。此外，文章还介绍了粘性事件的概念，即事件消费者即使在事件发布后注册也能接收，以及方法优先级的设定。

接下来看下@Subscribe的源码，

@Documented
@Retention(RetentionPolicy.RUNTIME)
@Target({ElementType.METHOD})
public @interface Subscribe {
    ThreadMode threadMode() default ThreadMode.POSTING;

    /**
     * If true, delivers the most recent sticky event (posted with
     * {@link EventBus#postSticky(Object)}) to this subscriber (if event available).
     */
    boolean sticky() default false;

    /** Subscriber priority to influence the order of event delivery.
     * Within the same delivery thread ({@link ThreadMode}), higher priority subscribers will receive events before
     * others with a lower priority. The default priority is 0. Note: the priority does *NOT* affect the order of
     * delivery among subscribers with different {@link ThreadMode}s! */
    int priority() default 0;
}