Android Question java.lang.NullPointerException: null receiver

[peacemaker]

What this error mean ?

Line 192 is the latest line "End Sub" of
Private Sub JobDone (Job As HttpJob) in the class that downloads by OKHttputils2 built-in lib v.2.20 (not a class). B4A v.6.

Job is successful, but error in the end of the sub. And error only in DEBUG mode at first start, if to restart "running previous successful shell app" - NO ERROR ! Release looks OK, but sometimes the black screen and app is closed.
Job result is

StartActivity(Client)
CallSub2(Client, "Refresh_tab", m)

where m is Map, Client is the activity to be started.

** Service (httputils2service) Start **
job_received=GetToken
Received Token for Session = 45f5304463dada979933ca3506d80f79033839cf
Error occurred on line: 192 (clsBallovnet)
java.lang.NullPointerException: null receiver
    at java.lang.reflect.Field.get(Native Method)
    at java.lang.reflect.Field.get(Field.java:279)
    at anywheresoftware.b4a.shell.Shell.getStateAfterUserSubHelper(Shell.java:513)
    at anywheresoftware.b4a.shell.Shell.getStateAfterUserSub(Shell.java:496)
    at anywheresoftware.b4a.shell.Shell.raiseEventImpl(Shell.java:403)
    at anywheresoftware.b4a.shell.Shell.raiseEvent(Shell.java:247)
    at java.lang.reflect.Method.invoke(Native Method)
    at java.lang.reflect.Method.invoke(Method.java:372)
    at anywheresoftware.b4a.ShellBA.raiseEvent2(ShellBA.java:134)
    at anywheresoftware.b4a.BA$2.run(BA.java:328)
    at android.os.Handler.handleCallback(Handler.java:815)
    at android.os.Handler.dispatchMessage(Handler.java:104)
    at android.os.Looper.loop(Looper.java:194)
    at android.app.ActivityThread.main(ActivityThread.java:5552)
    at java.lang.reflect.Method.invoke(Native Method)
    at java.lang.reflect.Method.invoke(Method.java:372)
    at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:964)
    at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:759)
** Activity (main) Pause, UserClosed = true **

 

[peacemaker]

"Client" activity is null, if to break point. But activity is on the screen ! How can it be null ?

 

[DonManfred]

Have you tried to use CallSubDelayed?

 

[peacemaker]

I thought i tried...
But did now - and works OK ! THanks !

 

[peacemaker]

Now

java.lang.NullPointerException: expected receiver of type activty.client, but got null

at the same place.
But the activity CLIENT was started before, after first login Http job. And Activity_Resume sub of this CLIENT activity - has started this second HTTP job with error.

 

[Erel]

1. Can you post the full error message?
2. Try it with CallSubDelayed and without the StartActivity call. CallSubDelayed will start the activity for you (if the application is not in the background).

 

[peacemaker]

Erel, yes - i have tried, the same error "null receiver" under Android5, or "
expected receiver of type %packagename%.client, but got null" under Android 4.2
:

LogCat connected to: YSEIFMEM99999999
--------- beginning of system
--------- beginning of main
** Service (starter) Create **
** Service (starter) Start **
** Activity (main) Create, isFirst = true **
** Activity (main) Resume **
No partial wakelock.
** Service (httputils2service) Create **
** Service (httputils2service) Start **
Received Token for Session = 2bb2c71c14465a318c75d09d6cd0551960b3ec3a
Error occurred on line: 188 (clsBallovnet)
java.lang.NullPointerException: null receiver
    at java.lang.reflect.Field.get(Native Method)
    at java.lang.reflect.Field.get(Field.java:279)
    at anywheresoftware.b4a.shell.Shell.getStateAfterUserSubHelper(Shell.java:513)
    at anywheresoftware.b4a.shell.Shell.getStateAfterUserSub(Shell.java:496)
    at anywheresoftware.b4a.shell.Shell.raiseEventImpl(Shell.java:403)
    at anywheresoftware.b4a.shell.Shell.raiseEvent(Shell.java:247)
    at java.lang.reflect.Method.invoke(Native Method)
    at java.lang.reflect.Method.invoke(Method.java:372)
    at anywheresoftware.b4a.ShellBA.raiseEvent2(ShellBA.java:134)
    at anywheresoftware.b4a.BA$2.run(BA.java:328)
    at android.os.Handler.handleCallback(Handler.java:815)
    at android.os.Handler.dispatchMessage(Handler.java:104)
    at android.os.Looper.loop(Looper.java:194)
    at android.app.ActivityThread.main(ActivityThread.java:5552)
    at java.lang.reflect.Method.invoke(Native Method)
    at java.lang.reflect.Method.invoke(Method.java:372)
    at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:964)
    at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:759)
** Activity (main) Pause, UserClosed = true **

The line number is "End Sub".

 

[Erel]

This is a debugger error. What happens in release mode?

Can you send me your project?

 

[peacemaker]

In release-mode all looks OK, but the customer reports that sometimes after start - just black screen (Job is failed, data is not received\parsed), the same in the debug mode at this error.
Erel, emailed the project to [email protected]

 

[Erel]

Thank you. It is fixed for the next version. You can workaround it by adding this code to the end of the JobDone event:

 If False Then
   Log("") '<--- put a breakpoint here
 End If

 

[peacemaker]

Thanks ! Very strange code