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EventBus is a publish/subscribe event bus for Android and Java.<br/> <img src="EventBus-Publish-Subscribe.png" width="500" height="187"/>

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EventBus...

EventBus in 3 steps

  1. Define events:

    public static class MessageEvent { /* Additional fields if needed */ }
    
  2. Prepare subscribers: Declare and annotate your subscribing method, optionally specify a thread mode:

    @Subscribe(threadMode = ThreadMode.MAIN)  
    public void onMessageEvent(MessageEvent event) {/* Do something */};
    

    Register and unregister your subscriber. For example on Android, activities and fragments should usually register according to their life cycle:

     @Override
     public void onStart() {
         super.onStart();
         EventBus.getDefault().register(this);
     }
    
     @Override
     public void onStop() {
         super.onStop();
         EventBus.getDefault().unregister(this);
     }
    
  3. Post events:

     EventBus.getDefault().post(new MessageEvent());
    

Read the full getting started guide.

There are also some examples.

Note: we highly recommend the EventBus annotation processor with its subscriber index. This will avoid some reflection related problems seen in the wild.

Add EventBus to your project

<a href="https://search.maven.org/search?q=g:org.greenrobot%20AND%20a:eventbus"><img src="https://img.shields.io/maven-central/v/org.greenrobot/eventbus.svg"></a>

Available on <a href="https://search.maven.org/search?q=g:org.greenrobot%20AND%20a:eventbus">Maven Central</a>.

Android projects:

implementation("org.greenrobot:eventbus:3.3.0")

Java projects:

implementation("org.greenrobot:eventbus-java:3.3.0")
<dependency>
    <groupId>org.greenrobot</groupId>
    <artifactId>eventbus-java</artifactId>
    <version>3.3.0</version>
</dependency>

R8, ProGuard

If your project uses R8 or ProGuard this library ships with embedded rules.

Homepage, Documentation, Links

For more details please check the EventBus website. Here are some direct links you may find useful:

Features

Documentation

Changelog

FAQ

License

Copyright (C) 2012-2020 Markus Junginger, greenrobot (https://greenrobot.org)

EventBus binaries and source code can be used according to the Apache License, Version 2.0.

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