Android Question B4XPages and ResumableSub

RB Smissaert · Dec 31, 2022

Just starting with B4XPages and noticed that ResumableSub is not behaving the same as in a non B4XPages project.
In an activity based project I can run this from Main with no problem:

B4X:

    Dim rs As ResumableSub = CSV2List(File.DirRootExternal & "/PhonePats", "menu_props2.csv", True, 44, 34, True, 10, -1)
    Wait For (rs) Complete (lstCSV As List)
    
    Log(lstCSV.Size)

and I can use the produced list fine.

In a B4XPages project though I get this error:
java.lang.ClassCastException: java.util.ArrayList cannot be cast to anywheresoftware.b4a.BA$ResumableSub

If I run this not as a ResumableSub:

B4X:

    Dim lstCSV As List
    
    lstCSV = CSV2List(File.DirRootExternal & "/PhonePats", "menu_props2.csv", True, 44, 34, True, 10, -1)

    Log(lstCSV.Size)

There is no problem.
Is this a known limitation of B4XPages or am I doing something wrong?

RBS

RB Smissaert · Jan 1, 2023

Sagenut said:
Correct me if I am wrong.
In this part of your code

B4X:

If bDone Then '---------- 'this works '---------- Dim rs As ResumableSub = MakeMenuArray Wait For (rs) Complete (dDoneMenuArray As Boolean) '----------------- 'this doesn't work '----------------- ' MakeMenuArray For i = iButtonStartIndex To arrMenuButtons.Length - 1 'overflow button has no bitmap arrMenuButtons(i).SetBitmap(arrMenu(i).bmpIconBitMap1) '<<<<< java.lang.ArrayIndexOutOfBoundsException: length=0; index=0 Next End If

after the MakeMenuArray you have a For cycle that need

B4X:

arrMenu(i).bmpIconBitMap1

to be ready. This is done by MakeMenuArray.
Calling MakeMenuArray as a normal Sub seems not to leave enough time to the Sub to complete its job before the next operations.
This is why using it as a Resumable Sub solve the problem.
As a confirmation, if you put a Sleep to let it complete

B4X:

If bDone Then '---------- 'this works '---------- ' Dim rs As ResumableSub = MakeMenuArray ' Wait For (rs) Complete (dDoneMenuArray As Boolean) '----------------- 'this doesn't work '----------------- MakeMenuArray Sleep(1000) 'Let us give time to MakeMenuArray to complete (exagerated value) For i = iButtonStartIndex To arrMenuButtons.Length - 1 'overflow button has no bitmap arrMenuButtons(i).SetBitmap(arrMenu(i).bmpIconBitMap1) '<<<<< java.lang.ArrayIndexOutOfBoundsException: length=0; index=0 Next End If

then you can have your Sub like this

B4X:

Sub MakeMenuArray 'Do things 'More things 'Yet more things End Sub

But honestly I would prefer a Resumable Sub that just wait for the exact time needed by the Sub to complete.

Yes, thanks, that might be the problem.
Will try with the sleep, but as you say, a RemableSub seems better.

RBS

rraswisak · Jan 2, 2023

I would prefer using CallSubDelayed approach...

B4X:

    If bDone Then
        '...
        '...
        MakeMenuArray
        Wait For MakeMenuArray_Done Complete
        '...
        '...
    End If

B4X:

Private Sub MakeMenuArray
    'do all your code here and end with CallSubDelayed
    'If you want to return value, use CallSubDelayed2 or CallSubDelayed3 depend on your situation

    '...
    CallSubDelayed(Me,"MakeMenuArray_Done")
End Sub

RB Smissaert · Jan 2, 2023

rraswisak said:

I would prefer using CallSubDelayed approach...

B4X:

    If bDone Then
        '...
        '...
        MakeMenuArray
        Wait For MakeMenuArray_Done Complete
        '...
        '...
    End If

B4X:

Private Sub MakeMenuArray
    'do all your code here and end with CallSubDelayed
    'If you want to return value, use CallSubDelayed2 or CallSubDelayed3 depend on your situation

    '...
    CallSubDelayed(Me,"MakeMenuArray_Done")
End Sub

Where in your suggested code is the Boolean bDone coming from?
Did you mean:

B4X:

Private Sub MakeMenuArray() As Boolean

or does MakeMenuArray remain a ResumableSub?

RBS

RB Smissaert · Jan 2, 2023

RB Smissaert said:
Where in your suggested code is the Boolean bDone coming from?
Did you mean:

B4X:

Private Sub MakeMenuArray() As Boolean

or does MakeMenuArray remain a ResumableSub?

RBS

Sorry, ignore that, I thought that in my code the bDone came from MakeMenuArray.

RBS

rraswisak · Jan 2, 2023

RB Smissaert said:
does MakeMenuArray remain a ResumableSub?

No, just a normal sub.

Same approach for CSV2List sub too...

RB Smissaert · Jan 2, 2023

rraswisak said:
No, just a normal sub.

Same approach for CSV2List sub too...

Just to make sure.
So, the end of CSV2List will be:

B4X:

    CallSubDelayed(Me, "CSV2List_Done")
    
    Return lstRows

End Sub

And that CSV2List will be called like this:

B4X:

    lstCSV = CSV2List(File.DirRootExternal & "/PhonePats", "menu_props2.csv", True, 44, 34, True, 10, -1)
    Wait For CSV2List_Done Complete

I am asking as it looks a bit strange to have the list before the Sub is done.

Also, could you tell why you prefer this approach?

RBS

rraswisak · Jan 2, 2023

B4X:

'...
'...
CSV2List(File.DirRootExternal & "/PhonePats", "menu_props2.csv", True, 44, 34, True, 10, -1)
Wait For CSV2List_Done Complete (lstCSV As List)
'...
'...

B4X:

Sub CSV2List(strFolder As String, _
             strFile As String, _
             bFileHasFieldNames As Boolean, _
             btSeparatorByte As Byte, _
             btEncloserByte As Byte, _
             bLookForEncloserByte As Boolean, _
             btEndOfLineByte As Byte, _
             lRows As Long)
     '...
     '...
     CallSubDelayed2(Me, "CSV2List_Done", lstRows)
End Sub

RB Smissaert said:
tell why you prefer this approach?

For me, its easier to define and controlled

RB Smissaert · Jan 2, 2023

rraswisak said:

B4X:

'...
'...
CSV2List(File.DirRootExternal & "/PhonePats", "menu_props2.csv", True, 44, 34, True, 10, -1)
Wait For CSV2List_Done Complete (lstCSV As List)
'...
'...

B4X:

Sub CSV2List(strFolder As String, _
             strFile As String, _
             bFileHasFieldNames As Boolean, _
             btSeparatorByte As Byte, _
             btEncloserByte As Byte, _
             bLookForEncloserByte As Boolean, _
             btEndOfLineByte As Byte, _
             lRows As Long)
     '...
     '...
     CallSubDelayed2(Me, "CSV2List_Done", lstRows)
End Sub

For me, its easier to define and controlled

OK, thanks.

BTW:

B4X:

Wait For CSV2List_Done Complete (lstCSV As List)

Should be:

B4X:

Wait For CSV2List_Done(lstCSV As List)

RBS

rraswisak · Jan 2, 2023

RB Smissaert said:
Should be:

That was correct... (sorry just copy-paste)

RB Smissaert · Jan 2, 2023

rraswisak said:
That was correct... (sorry just copy-paste)

No worry, figured it out quick enough.

RBS

Android Question B4XPages and ResumableSub

RB Smissaert

Well-Known Member

RB Smissaert

Well-Known Member

rraswisak

Active Member

RB Smissaert

Well-Known Member

RB Smissaert

Well-Known Member

rraswisak

Active Member

RB Smissaert

Well-Known Member

rraswisak

Active Member

RB Smissaert

Well-Known Member

rraswisak

Active Member

RB Smissaert

Well-Known Member

Similar Threads

Android Question B4XPages and ResumableSub

Well-Known Member

Well-Known Member

Active Member

Well-Known Member

Well-Known Member

Active Member

Well-Known Member

Active Member

Well-Known Member

Active Member

Well-Known Member

Similar Threads

Privacy & Transparency

Privacy & Transparency