android - NullPointerException while trying to insert records -

i trying insert records db .the problem when click save button getting exception.so firstly have checked logcat , filtered out theese messages .

    03-21 18:07:00.820: e/androidruntime(4756): fatal exception: main     03-21 18:07:00.820: e/androidruntime(4756): java.lang.nullpointerexception     03-21 18:07:00.820: e/androidruntime(4756):     @ com.example.kjk.mainactivity$1.onclick(mainactivity.java:51)     03-21 18:07:00.820: e/androidruntime(4756):     @ android.view.view.performclick(view.java:4240)     03-21 18:07:00.820: e/androidruntime(4756):     @ android.view.view$performclick.run(view.java:17721)     03-21 18:07:00.820: e/androidruntime(4756):     @ android.os.handler.handlecallback(handler.java:730)     03-21 18:07:00.820: e/androidruntime(4756):     @ android.os.handler.dispatchmessage(handler.java:92)     03-21 18:07:00.820: e/androidruntime(4756):     @ android.os.looper.loop(looper.java:137)     03-21 18:07:00.820: e/androidruntime(4756):     @ android.app.activitythread.main(activitythread.java:5103)     03-21 18:07:00.820: e/androidruntime(4756):     @ java.lang.reflect.method.invokenative(native method)     03-21 18:07:00.820: e/androidruntime(4756):     @ java.lang.reflect.method.invoke(method.java:525)     03-21 18:07:00.820: e/androidruntime(4756):     @ com.android.internal.os.zygoteinit$methodandargscaller.run(zygoteinit.java:737)     03-21 18:07:00.820: e/androidruntime(4756):     @ com.android.internal.os.zygoteinit.main(zygoteinit.java:553)     03-21 18:07:00.820: e/androidruntime(4756):     @ dalvik.system.nativestart.main(native method) 

i think exception comes here couldnt fin solution fix problem

adddata(name.gettext().tostring(), surname.gettext().tostring());

protected void oncreate(bundle savedinstancestate) {     super.oncreate(savedinstancestate);     setcontentview(r.layout.activity_main);     name=(edittext)findviewbyid(r.id.edtname);     surname=(edittext)findviewbyid(r.id.edtsurname);     btnsave=(button)findviewbyid(r.id.btnsave);     btnfetch=(button)findviewbyid(r.id.btnfetch);     tvname=(textview)findviewbyid(r.id.tvnmae);     tvsurname=(textview)findviewbyid(r.id.tvsurname);      btnsave.setonclicklistener(new view.onclicklistener() {           @override         public void onclick(view v) {         try {              adddata(name.gettext().tostring(), surname.gettext().tostring());          } catch (exception e) {              log.e("error ", e.getmessage());         }         finally{              v1.close();          }          }     });       btnfetch.setonclicklistener(new view.onclicklistener() {          @override         public void onclick(view v) {         sqlitedatabase db=v1.getreadabledatabase();         cursor cursor=db.query( "info", columns, null, null, null, null, null);          while(cursor.movetonext()){              string name=cursor.getstring(cursor.getcolumnindex("name"));             string surname=cursor.getstring(cursor.getcolumnindex("surname"));             tvname.settext(name);             tvsurname.settext(surname);            }         }     });  }  private void adddata(string name,string sur) { sqlitedatabase db=v1.getwritabledatabase(); contentvalues cv=new contentvalues(); cv.put(name, sur); db.insertorthrow("info", null, cv);  } 

here database class

private static final string db_name="mydb"; private static final int ver=1;   public veritabani(context context, string name, cursorfactory factory,         int version) {     super(context, db_name, null, ver);     // todo auto-generated constructor stub }  @override public void oncreate(sqlitedatabase db) {     // todo auto-generated method stub     db.execsql("create table info(name text,surname text);");  }  @override public void onupgrade(sqlitedatabase db, int oldversion, int newversion) {     // todo auto-generated method stub     db.execsql("drop table if exist info");     oncreate(db); } 

your stacktrace says

java.lang.nullpointerexception  03-21 18:07:00.820: e/androidruntime(4756):at com.example.kjk.mainactivity$1.onclick(mainactivity.java:51) 

from comments

so v1 instance of database , line 51 indicated logcat v1.close();

this indicates v1 null , have not initialized properly.

try

protected void oncreate(bundle savedinstancestate) { super.oncreate(savedinstancestate); setcontentview(r.layout.activity_main); v1 = new veritabani(this);