Android Question IDE warning unused variable

RB Smissaert · Mar 23, 2025

Have code that alters a variable and saves it to KVS:

B4X:

Sub UpdateSettingAndKVS(strVarKey As String, oVar As Object, oVal As Object)
    
    oVar = oVal
    cMP.UpdateKVS(strVarKey, oVal)
    
End Sub

This will give the warning:

Unused variable 'ovar'. (warning #9)
Object

Clearly the variable is used and the code works fine and I wonder if this might be a minor bug.

RBS

Daestrum · Mar 23, 2025

If you read your code - you set oVar then dont use it in the sub. That's what triggers the message.
If this code is how you want it (like you set the passed variable), just add 'ignore to the line.

B4X:

oVar = oVal'ignore

RB Smissaert · Mar 23, 2025

Daestrum said:
If you read your code - you set oVar then dont use it in the sub. That's what triggers the message.
If this code is how you want it (like you set the passed variable), just add 'ignore to the line.

B4X:

oVar = oVal'ignore

It is used though, no?
The value of the variable (oVar) is changed.

RBS

Cableguy · Mar 23, 2025

RB Smissaert said:
It is used though, no?
The value of the variable (oVar) is changed.

RBS

A value is set to the variable, like X = 30 but it is never USED like myView.height = X.
You can add #ignorewarnings: XXX were xxx is the error number, and it will ignore all similar errors

RB Smissaert · Mar 23, 2025

Cableguy said:
A value is set to the variable, like X = 30 but it is never USED like myView.height = X.
You can add #ignore XXX were xxx is the error number, and it will ignore all similar errors

>>never USED like myView.height = X
It is not used in that way, no, but it is used.

>> You can add #ignore XXX
I don't want to do that as it might be a genuine warning, that is the argument was really not used at all.

I have put:
'ignore
after the Sub declaration

Putting it after oVar = oVal doesn't work.

RBS

Cableguy · Mar 23, 2025

RB Smissaert said:
>>never USED like myView.height = X
It is not used in that way, no, but it is used.

>> You can add #ignore XXX
I don't want to do that as it might be a genuine warning, that is the argument was really not used at all.

I have put:
'ignore
after the Sub declaration

Putting it after oVar = oVal doesn't work.

RBS

Warnings are "module" dependent, meaning that if you set a variable inside main (or any other module) but only use it inside a different module, then the warning will exist in the first module!

RB Smissaert · Mar 23, 2025

Cableguy said:
Warnings are "module" dependent, meaning that if you set a variable inside main (or any other module) but only use it inside a different module, then the warning will exist in the first module!

Not sure I quite understand that one.
Either way, this still looks like a minor bug to me.

RBS

Cableguy · Mar 23, 2025

RB Smissaert said:
Not sure I quite understand that one.
Either way, this still looks like a minor bug to me.

RBS

not a bug, it's the way it works... it's like if you write a phone number in a piece of paper... but you never call the number, you never USED the info, although you SET it!!
SO the IDE just warns you that you have a variable in your code, but never used it anywhere else. The IDE makes the assumption that any variables set in the code are meant to be used as values for something else, like a height, a color, a string, etc!
You can try to use dim x as int' ignore so that the IDE doesn't take into account that variable... but then, you will not be warned if for some reason you didn't used it.
This warnings allow for 2 things: Warn you, specially in large projects, that a variable, i.e: MyColor, is not used, but somewhere you used MyColors... And also so that unused variable, that MAY not be needed for the code to work, exists, so you can decide to keep it or delete it!

RB Smissaert · Mar 23, 2025

Cableguy said:
not a bug, it's the way it works... it's like if you write a phone number in a piece of paper... but you never call the number, you never USED the info, although you SET it!!
SO the IDE just warns you that you have a variable in your code, but never used it anywhere else. The IDE makes the assumption that any variables set in the code are meant to be used as values for something else, like a height, a color, a string, etc!
You can try to use dim x as int' ignore so that the IDE doesn't take into account that variable... but then, you will not be warned if for some reason you didn't used it.
This warnings allow for 2 things: Warn you, specially in large projects, that a variable, i.e: MyColor, is not used, but somewhere you used MyColors... And also so that unused variable, that MAY not be needed for the code to work, exists, so you can decide to keep it or delete it!

This is getting a bit iffy now.
The fact is that the Sub argument oVar is used in the Sub code.
The warning seems to originate from the Sub declaration as the 'ignore needs to be put after the Sub declaration, so to say that oVar is not used
seems somewhat wrong to me. Certainly it doesn't seem helpful.

RBS

DonManfred · Mar 23, 2025

RB Smissaert said:
The fact is that the Sub argument oVar is used in the Sub code.

no, it´s not. Cableguy explains it already.

RB Smissaert · Mar 23, 2025

It all depends how you interpret the word: used.

In any case the posted code is flawed as the actual variable passed (oVar) is not changed as intended.

B4X:

Sub UpdateSettingAndKVS(strVarKey As String, oVar As Object, oVal As Object) 'ignore
    
    If strVarKey = "Enums.strDialogButtonTextColour" Then
        Log("Before, Enums.strDialogButtonTextColour: " & Enums.strDialogButtonTextColour)
        Log("Before, oVar: " & cMP.CStr(oVar))
        Log("Before, oVal: " & cMP.CStr(oVal))
    End If
    
    oVar = oVal
    cMP.UpdateKVS(strVarKey, oVal)
    
    If strVarKey = "Enums.strDialogButtonTextColour" Then
        Log("After, Enums.strDialogButtonTextColour: " & Enums.strDialogButtonTextColour)
        Log("After, oVar: " & cMP.CStr(oVar))
        Log("After, oVal: " & cMP.CStr(oVal))
    End If
    
End Sub

Used like this:

B4X:

UpdateSettingAndKVS("Enums.strDialogButtonTextColour", Enums.strDialogButtonTextColour, "255,255,165,0")

The log will show:

Before, Enums.strDialogButtonTextColour: 255,255,165,200
Before, oVar: 255,255,165,200
Before, oVal: 255,255,165,0
After, Enums.strDialogButtonTextColour: 255,255,165,200
After, oVar: 255,255,165,0
After, oVal: 255,255,165,0

So the variable I wanted to change (Enums.strDialogButtonTextColour) has not changed, so this was faulty code.

So, the warning was good, but perhaps for a different reason.

RBS

Android Question IDE warning unused variable

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