java.lang.NullPointerException: Attempt to invoke virtual method 'int java.lang.String.length()' on a null object reference
        at org.json.JSONTokener.nextCleanInternal(JSONTokener.java:116)
        at org.json.JSONTokener.nextValue(JSONTokener.java:94)
        at org.json.JSONObject.<init>(JSONObject.java:159)
        at org.json.JSONObject.<init>(JSONObject.java:176)
        at com.anlyn.project.MailContentsFragment$BackgroundTaskDeleteMail.onPostExecute(MailContentsFragment.java:294)
        at com.anlyn.project.MailContentsFragment$BackgroundTaskDeleteMail.onPostExecute(MailContentsFragment.java:253)

이런 에러가 나온다면
닝겐이여  .. php에서 받아오는 값이 이상하다네
php 등짝을 찾아보자 ..

DB dateTime로 어떻게 파라미터를 넘겨 줘야할까

https://wwwi.tistory.com/82

링크쟁이 ..

AppCompatActivity Activity 차이 , android context란 //링크

AppCompatActivity 

https://hashcode.co.kr/questions/1487/%EC%9D%BC%EB%B0%98-activity%EC%99%80-appcompatactivity%EC%9D%98-%EC%B0%A8%EC%9D%B4%EA%B0%80-%EB%AC%B4%EC%97%87%EC%9D%B8%EA%B0%80%EC%9A%94

android context란 

https://hmgirl.tistory.com/217

어떤 Activity 혹은 어떤 application 인가에 대해서 구별하는 정보가 context

라고 하는군엽 
출처: https://zxcv5500.tistory.com/258 [샤핀의 blog]

새 물리 , 새 실루엣, 안개효과

https://github.com/brihernandez/ArcadeSpaceFlightExample

https://www.google.com/search?q=%EC%83%88+%EC%9D%BC%EB%9F%AC%EC%8A%A4%ED%8A%B8&safe=active&rlz=1C1WPZB_koKR824KR824&source=lnms&tbm=isch&sa=X&ved=0ahUKEwizv4mT94HhAhUdyYsBHQGxDhcQ_AUIDigB&biw=1920&bih=969#imgrc=-2419i5nv_NeDM:

https://www.google.com/imgres?imgurl=https%3A%2F%2Fi.ytimg.com%2Fvi%2FK4uNfxq-zEc%2Fmaxresdefault.jpg&imgrefurl=https%3A%2F%2Fwww.youtube.com%2Fwatch%3Fv%3DK4uNfxq-zEc&docid=iCtmzhWkRmy8LM&tbnid=hIHcPUYsTvRRZM%3A&vet=10ahUKEwi79qDn94HhAhVQUd4KHVMmAgwQMwiCASg4MDg..i&w=1280&h=720&safe=active&bih=969&biw=1920&q=unity%202d%20smoke%20background&ved=0ahUKEwi79qDn94HhAhVQUd4KHVMmAgwQMwiCASg4MDg&iact=mrc&uact=8

https://alinecosta.artstation.com/projects/vKEWd

https://alinecosta.artstation.com/projects/vKEWd

https://docs.microsoft.com/ko-kr/dotnet/csharp/programming-guide/types/casting-and-type-conversions

https://docs.microsoft.com/ko-kr/dotnet/csharp/programming-guide/types/casting-and-type-conversions

https://sdev.tistory.com/96

https://sdev.tistory.com/96

https://www.pinterest.co.kr/pin/480900066445702374/
https://www.behance.net/gallery/29386097/Video-game-character-design-collection
https://www.slideshare.net/seokholee5454/ndc-48341874
https://www.polygon.com/features/2018/10/10/17952674/the-12-best-indie-metroidvania-games
https://www.ign.com/articles/2018/01/02/39-awesome-indie-games-to-keep-on-your-radar-in-2018
https://www.webstagram.biz/tag/GAMEART

https://blog.naver.com/dksdlsrbs/221465159165

at in on //Time

on days, the weekend
at time(o'clock) , night
in months ,seasons ,morning ,evening ,afternoon ,period of time
none this~ +weekend this morning this evening // 전치사와 쓰이지 않는다

IF 절 , Main 절

If 절 상태를 표현, Main 절 질문, 결과, recommadation

If it's sunny tomorrow ,I will go to the beach
If I hired you for the job, you would get ~~~ a year
If I had studied a little more, I would have passed the test . == might