EventBus注册与解注册逻辑封装

@MainThread
public void toggleEvent(boolean enabled) {
    final boolean hasRegistered = EventBus.getDefault().isRegistered(this);
    if (hasRegistered && !enabled) {
      EventBus.getDefault().unregister(this);
    } else if (!hasRegistered && enabled) {
      EventBus.getDefault().register(this);
    }
  }