I am getting Null pointer exception when i run my app 2nd time

Question

java.lang.NullPointerException: Attempt to invoke virtual method 'java.lang.String java.lang.String.trim()' on a null object reference

This is the line where the exception is pointing to

  String tot=avg[i+2];
             total=Float.parseFloat(tot);

and

 adapter=new VivaAdapter(Attendance.this,gedata());

I am recieving data in form of string and then converting it into float ,but the app runs fine first time but second time it throws exception

I tried to change avg[i+2].trim() but dint worked

App crashes every alternative time

Eception log:

/AndroidRuntime: FATAL EXCEPTION: main
                                                                                      Process: com.example.rushabh123453.attendancepict, PID: 643
                                                                                      java.lang.NullPointerException: Attempt to invoke virtual method 'java.lang.String java.lang.String.trim()' on a null object reference
                                                                                          at java.lang.StringToReal.parseFloat(StringToReal.java:304)
                                                                                          at java.lang.Float.parseFloat(Float.java:306)
                                                                                          at com.example.rushabh123453.attendancepict.Attendance$Networking1.onPostExecute(Attendance.java:189)
                                                                                          at android.os.AsyncTask.finish(AsyncTask.java:636)
                                                                                          at android.os.AsyncTask.access$500(AsyncTask.java:177)
                                                                                          at android.os.AsyncTask$InternalHandler.handleMessage(AsyncTask.java:653)
                                                                                          at android.os.Handler.dispatchMessage(Handler.java:102)
                                                                                          at android.os.Looper.loop(Looper.java:211)
                                                                                          at android.app.ActivityThread.main(ActivityThread.java:5389)
                                                                                          at java.lang.reflect.Method.invoke(Native Method)
                                                                                          at java.lang.reflect.Method.invoke(Method.java:372)
                                                                                          at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1020)
                                                                                          at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:815)

The exception seems pretty clear there; – Eenvincible May 05 '17 at 11:22 — Eenvincible, May 05 '17 at 11:22

score 0 · Answer 1 · answered May 05 '17 at 11:23

0

You should check if String is null. You can't call method trim() String with null value.

answered May 05 '17 at 11:23

kostyabakay

1,649
2
21
32

i am requesting data from html page and data is not empty,it is crashing every alternative time only – Rushabh Oswal May 05 '17 at 11:25
Its tricky,see i have a login that takes user id and password and then post in on html page,and response is stored in string array and showed in textview,now when we press back button and again press login,it crashes with null exception – Rushabh Oswal May 05 '17 at 12:00
Problem solved:- actually i was having a counter which was static , it counts the number of subject and then stores data,so if 12 subjects where there it ws showing 24 eventhough i pressed the back button and hence this error, so here i got a point that static variables store data even if we close that intent – Rushabh Oswal May 05 '17 at 12:11

score 0 · Accepted Answer · answered May 05 '17 at 11:26

0

Add a null check before parsing into float

if(!TextUtils.isEmpty(tot)){
   total=Float.parseFloat(tot);
}

answered May 05 '17 at 11:26

Vijay Pal Vishwakarma

721
3
9

still it is giving same exception,y is it crashing on every alternative attempts only?when we press back button in android does android clear all data ? – Rushabh Oswal May 05 '17 at 11:40
can you share exception log? – Vijay Pal Vishwakarma May 05 '17 at 11:41
i take userid and password from login screen and gice http post request and response is set to textview now when user press back buttons something happens here? – Rushabh Oswal May 05 '17 at 11:42
i have added exception log – Rushabh Oswal May 05 '17 at 11:43
Code block of line no 189? – Vijay Pal Vishwakarma May 05 '17 at 11:46
String tot=total[l]; float total=Float.parseFloat(tot); – Rushabh Oswal May 05 '17 at 11:51

I am getting Null pointer exception when i run my app 2nd time

2 Answers2