使用RxJava和RxAndroid封装RxBus，实现EventBus功能

使用RxJava和RxAndroid封装RxBus，实现EventBus功能

依赖第三方库：RxJava和RxAndroid

compile 'io.reactivex:rxjava:1.1.5'
compile 'io.reactivex:rxandroid:1.2.0'

RxBus的具体代码：

public class RxBus {
    private HashMap> maps = new HashMap<>();
    private static RxBus instance;

    private RxBus() {
    }

    public static RxBus get() {
        if (instance == null) {
            synchronized (RxBus.class) {
                if (instance == null) {
                    instance = new RxBus();
                }
            }
        }
        return instance;
    }

    @SuppressWarnings("unchecked")
    public  Observable register(@NonNull Object tag, @NonNull Class clazz) {
        List subjects = maps.get(tag);
        if (subjects == null) {
            subjects = new ArrayList<>();
            maps.put(tag, subjects);
        }
        Subject subject = PublishSubject.create();
        subjects.add(subject);
        return subject;
    }

    @SuppressWarnings("unchecked")
    public void unregister(@NonNull Object tag, @NonNull Observable observable) {
        List subjects = maps.get(tag);
        if (subjects != null) {
            subjects.remove((Subject) observable);
            if (subjects.isEmpty()) {
                maps.remove(tag);
            }
        }
    }

    @SuppressWarnings("unchecked")
    public void post(@NonNull Object o) {
        post(o.getClass().getSimpleName(), o);
    }

    @SuppressWarnings("unchecked")
    public void post(@NonNull Object tag, @NonNull Object o) {
        List subjects = maps.get(tag);
        if (subjects != null && !subjects.isEmpty()) {
            for (Subject s : subjects) {
                s.onNext(o);
            }
        }
    }
}

在MianActivity中注册，接收消息，在SecondActivity页面中发送消息

public class MainActivity extends AppCompatActivity {

    private Observable zhang;
    private Button btn;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        btn = (Button) findViewById(R.id.main);
        btn.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                startActivity(new Intent(MainActivity.this, SecondActivity.class));
            }
        });
        zhang = RxBus.get().register("zhang", String.class);
        zhang.subscribe(new Action1() {
            @Override
            public void call(String s) {
                Log.e("zhang", "+++++++++++++++++++++++++++++++"+s);
            }
        });
    }

    @Override
    protected void onDestroy() {
        super.onDestroy();
        RxBus.get().unregister("zhang", zhang);
    }
}

public class SecondActivity extends AppCompatActivity {

    private Button btn;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_second);
        btn = (Button) findViewById(R.id.second);
        btn.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                new Thread() {
                    @Override
                    public void run() {
                        super.run();
                        RxBus.get().post("zhang", "传递数据++++++");
                    }
                }.start();
            }
        });
    }
}

参考：++基于RxJava、RxAndroid的EventBus实现++