안드로이드 오류 코드 내용 및 오류확인해봐야 되는 곳 확인하는 방법을 알려주세요

Question

동영상파일을 업로드 ftp에 업로드 하는 앱을 제작중인데 실행아이콘을 누르면 실행화면으로 가야되는데 까만화면으로 변하다가 중단됩니다. 아래 오류코드를 어떻게 봐야하는지좀 알려주시길 부탁드립니다.  

Process: com.dodo.dodori, PID: 12484
    java.lang.RuntimeException: An error occurred while executing doInBackground()
        at android.os.AsyncTask$3.done(AsyncTask.java:318)
        at java.util.concurrent.FutureTask.finishCompletion(FutureTask.java:354)
        at java.util.concurrent.FutureTask.setException(FutureTask.java:223)
        at java.util.concurrent.FutureTask.run(FutureTask.java:242)
        at android.os.AsyncTask$SerialExecutor$1.run(AsyncTask.java:243)
        at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1133)
        at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:607)
        at java.lang.Thread.run(Thread.java:761)
     Caused by: java.lang.NullPointerException: Attempt to invoke interface method 'java.sql.Statement java.sql.Connection.createStatement()' on a null object reference
        at com.dodo.dodori.task.DownloadTask.getFileItemList(DownloadTask.java:174)
        at com.dodo.dodori.task.DownloadTask.doInBackground(DownloadTask.java:109)
        at com.dodo.dodori.task.DownloadTask.doInBackground(DownloadTask.java:39)
        at android.os.AsyncTask$2.call(AsyncTask.java:304)
        at java.util.concurrent.FutureTask.run(FutureTask.java:237)
        at android.os.AsyncTask$SerialExecutor$1.run(AsyncTask.java:243)
        at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1133)
        at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:607)
        at java.lang.Thread.run(Thread.java:761)
07-27 00:46:11.536 12484-12484/com.dodo.dodori E/WindowManager: android.view.WindowLeaked: Activity com.dodo.dodori.activity.VideoActivity has leaked window DecorView@226dbf5[] that was originally added here
        at android.view.ViewRootImpl.<init>(ViewRootImpl.java:417)
        at android.view.WindowManagerGlobal.addView(WindowManagerGlobal.java:331)
        at android.view.WindowManagerImpl.addView(WindowManagerImpl.java:93)
        at android.app.Dialog.show(Dialog.java:316)
        at com.dodo.dodori.task.DownloadTask.<init>(DownloadTask.java:79)
        at com.dodo.dodori.activity.VideoActivity.onCreate(VideoActivity.java:74)
        at android.app.Activity.performCreate(Activity.java:6662)
        at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1118)
        at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2599)
        at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2707)
        at android.app.ActivityThread.-wrap12(ActivityThread.java)
        at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1460)
        at android.os.Handler.dispatchMessage(Handler.java:102)
        at android.os.Looper.loop(Looper.java:154)
        at android.app.ActivityThread.main(ActivityThread.java:6077)
        at java.lang.reflect.Method.invoke(Native Method)
        at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:866)
        at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:756)

Answer 1

java.lang.NullPointerException: Attempt to invoke interface method 'java.sql.Statement java.sql.Connection.createStatement()' on a null object reference
        at com.dodo.dodori.task.DownloadTask.getFileItemList(DownloadTask.java:174)
        at com.dodo.dodori.task.DownloadTask.doInBackground(DownloadTask.java:109)
        at com.dodo.dodori.task.DownloadTask.doInBackground(DownloadTask.java:39)

 

DownloadTask클래스의 getFileItemList 메소드에서 null point exception이 발생했네요.

DownloadTask.java 파일의 174줄 입니다.

 

내용을 보니 db접근하려고 한 것 같은데 Android 에서 직접 DB서버 접근 못합니다.

중간에 서버 하나 두셔서

앱에서 서버로 요청. -> 서버에서 요청 확인 후 DB서버에 작업 -> 서버에서 결과 앱으로 응답 -> 앱에서 응답에 따라 처리하기

형태로 작업하셔야 합니다.