walorwang / EventBus

Event bus for Android and Java that simplifies communication between Activities, Fragments, Threads, Services, etc. Less code, better quality.

Hey, do have a minute for a quick survey on how we are doing with EventBus?

EventBus

EventBus is a publish/subscribe event bus for Android and Java.

EventBus...

• simplifies the communication between components
  • decouples event senders and receivers
  • performs well with Activities, Fragments, and background threads
  • avoids complex and error-prone dependencies and life cycle issues
• makes your code simpler
• is fast
• is tiny (~50k jar)
• is proven in practice by apps with 100,000,000+ installs
• has advanced features like delivery threads, subscriber priorities, etc.

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.

Add EventBus to your project

Via Gradle:

implementation 'org.greenrobot:eventbus:3.1.1'

Via Maven:

<dependency>
    <groupId>org.greenrobot</groupId>
    <artifactId>eventbus</artifactId>
    <version>3.1.1</version>
</dependency>

Or download the latest JAR from Maven Central.

Homepage, Documentation, Links

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

Features

Documentation

ProGuard

Changelog

FAQ

How does EventBus compare to other solutions, like Otto from Square? Check this comparison.

License

Copyright (C) 2012-2017 Markus Junginger, greenrobot (http://greenrobot.org)

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

More Open Source by greenrobot

ObjectBox (GitHub) is a new superfast object-oriented database for mobile.

Essentials (GitHub) is a set of utility classes and hash functions for Android & Java projects.

greenDAO (GitHub) is an ORM optimized for Android: it maps database tables to Java objects and uses code generation for optimal speed.

Check our homepage to stay up to date.