[SOLVED] Failed notifying listener

Add-ons Bindings
1

I have this error message:

2018-12-22 15:10:22.119 [WARN ] [pse.smarthome.core.items.GenericItem] - failed notifying listener 'avgTemps (Type=GroupItem, BaseType=NumberItem, Members=1, State=15.900390, Label=null, Category=null)' about state update of item avgTemps: null

Reading on the forum I think I understand that it is a Null value that is not correctly interpreted.
I tried to disable every single sensor from the group to understand if one of the values ​​created a problem, but nothing.
Should I debug, but I do not know what bindings, to better understand if there is an error, or is a rule better that eliminates the Null value problem?
this is the sitemap:

Text item = avgTemps

item file:

Group: Number: AVG avgTemps "average temperature [% .1f ° C]" <temperature> (avgTemps)

Number Temperature_day "daytime temperature [% .1f ° C]" <temperature> (avgTemps, TechnicView_Node3) {souliss = "T52: 3: 18"}
Number Temperature_corridor "corridor temperature [% .1f ° C]" <temperature> (avgTemps, TechnicView_Node1) {souliss = "T52: 5: 0"}
Number Temperature_camera "room temperature [% .1f ° C]" <temperature> (avgTemps, TechnicView_Node2) {souliss = "T52: 2: 3"}
Number Temperature_studio "studio temperature [% .1f ° C]" <temperature> (avgTemps, TechnicView_Node12) {souliss = "T52: 12: 9"}

Thanks for your suggestions

2

NULL and null are two different things,

NULL - indicates an Item is not yet initialized
null - part of the language, indicates that a variable does not have a value

Do you get the temp reading if using just one item without groups and trying to average?

3

thanks for the explanation on the differency of the definition NULL.
To answer your question, do you mean if I have a reading in the average value by inserting only one sensor in the group?
If this is the question, the answer is yes, and they are the same

4

Members=1
Shouldn’t it be 4??

Change the item definition:
Remove the space between Number: and AVG
And remove the group at the end (A group can’t belong to itself!)

Number:AVG avgTemps "average temperature [% .1f ° C]" <temperature>
5

now the mistake is gone. Thank you
So my mistake was to have put (avgTemps)
in Group: Number: AVG avgTemps
and any writing errors
I got it

6

.:+1:

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Thanks