Android Question [Solved]A problem about ' xui.SubExists(Component As Object ,Sub as String,NotUsed As int) As Boolean ' in B4A,B4j and B4i

Theera · Sep 12, 2025

Hi all,
I don't understand how shouId code about 'NotUsed' parameter in this as belows

B4X:

   #If B4i
            If xui.SubExists(mCallBack, mEventName & "_ResultCalculated",?) Then  '<== How to code?
                CallSubDelayed2(mCallBack, mEventName & "_ResultCalculated", result)
            End If
   #Else
            If xui.SubExists(mCallBack, mEventName & "_ResultCalculated",?) Then  '<== How to code?
                CallSubDelayed2(mCallBack, mEventName & "_ResultCalculated", result)
            End If
   #End If

stevel05 · Sep 12, 2025

From the target Sub:

S:

Sub ResultCalculated(Result as int)

End Sub

Has 1 parameter

stevel05 · Sep 12, 2025

The value is for the number of parameters the sub expects, but is only used with b4i. If you are not using b4i you can use any valid int for instance 0. It might just be easier and more consistent to put the actual number of parameters even though it does nothing:

B4X:

 #If B4i
            If xui.SubExists(mCallBack, mEventName & "_ResultCalculated",1) Then  'Correct value is required
                CallSubDelayed2(mCallBack, mEventName & "_ResultCalculated", result)
            End If
   #Else
            If xui.SubExists(mCallBack, mEventName & "_ResultCalculated",1) Then  'Value is ignored but must be an int.
                CallSubDelayed2(mCallBack, mEventName & "_ResultCalculated", result)
            End If
   #End If

Theera · Sep 12, 2025

stevel05 said:
The value is for the number of parameters the sub expects, but is only used with b4i. If you are not using b4i you can use any valid int for instance 0. It might just be easier and more consistent to put the actual number of parameters even though it does nothing:

B4X:

#If B4i If xui.SubExists(mCallBack, mEventName & "_ResultCalculated",1) Then 'Correct value is required CallSubDelayed2(mCallBack, mEventName & "_ResultCalculated", result) End If #Else If xui.SubExists(mCallBack, mEventName & "_ResultCalculated",1) Then 'Value is ignored but must be an int. CallSubDelayed2(mCallBack, mEventName & "_ResultCalculated", result) End If #End If

Thank you for your replies. How/Where to count the parameter from?

LucaMs · Sep 12, 2025

Theera said:
Thank you for your replies. How/Where to count the parameter from?

stevel05 said:
The value is for the number of parameters the sub expects

It's the number of parameters the routine you want to verify exists requires.

In this case, the routine you want to call is ResultCalculated which requires only one parameter, so that number in B4I must be one. In other cases, the routine might require two parameters, for example, and you created that routine, so you know they are two.

stevel05 · Sep 12, 2025

From the target Sub:

S:

Sub ResultCalculated(Result as int)

End Sub

Has 1 parameter

LucaMs · Sep 12, 2025

stevel05 said:
From the target Sub:

S:

Sub ResultCalculated(Result as int) End Sub

Has 1 parameter

Sorry, Steve, I replied because I saw you weren't online (a rare occurrence, as it is for me ).

You were more concise, and I bet more efficient, with that reply.

stevel05 · Sep 12, 2025

LucaMs said:
Sorry, Steve, I replied because I saw you weren't online

Not a problem, chime in whenever you feel like it

Android Question [Solved]A problem about ' xui.SubExists(Component As Object ,Sub as String,NotUsed As int) As Boolean ' in B4A,B4j and B4i

Theera

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Theera

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