异常信息如下

java.lang.NullPointerException: Attempt to invoke virtual method 'java.lang.Class java.lang.Object.getClass()' on a null object reference at org.greenrobot.eventbus.EventBus.postSingleEvent(EventBus.java:363) at org.greenrobot.eventbus.EventBus.post(EventBus.java:251) at com.culsomusic2.coreclass.BasePlayActivity.playBaseMusic(BasePlayActivity.java:90) at com.culsomusic2.songlistmodule.ui.mactivity.activityEntity.SongContentActivity$4.onItemClick(SongContentActivity.java:252) at com.zhy.adapter.recyclerview.MultiItemTypeAdapter$1.onClick(MultiItemTypeAdapter.java:68) at android.view.View.performClick(View.java:5198) at android.view.View$PerformClick.run(View.java:21147) at android.os.Handler.handleCallback(Handler.java:739) at android.os.Handler.dispatchMessage(Handler.java:95) at android.os.Looper.loop(Looper.java:148) at android.app.ActivityThread.main(ActivityThread.java:5417) at java.lang.reflect.Method.invoke(Native Method) at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:726) at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:616)

EventBus 注册和反注册如下
@Override

protected void onCreate(@Nullable Bundle savedInstanceState) { super.onCreate(savedInstanceState); mContext = MyApplication.getContext(); Intent intent = new Intent(mContext, BaseControlService.class); startService(intent); //注册EventBus EventBus.getDefault().register(this); }

@Override

protected void onDestroy() { //反注册EventBus EventBus.getDefault().unregister(this); mContext = null; super.onDestroy(); }

调用的方法如下
public void playBaseMusic(@Nullable BaseTagBean bean) {

BaseTagBean tagBean; if (bean==null){ tagBean=new BaseTagBean(); tagBean.setTag(CONTROL_TAG_PLAY); }else { tagBean=bean; tagBean.setTag(CONTROL_TAG_PLAY); } EventBus.getDefault().post(tagBean); }

只要调用上述playBaseMusic方法它就在EventBus.getDefault().post(tagBean);这个地方报空指针错误；
请问大家如何解决。