Android Question Doevents and Sleep(0)

Sorry, but without seeing your it's impossible to give a concrete advice.

I did not post code because project is 13,000 lines. I see that I also have some undeclared variables and a warning: Return type (in Sub signature) should be set explicitly, However I was surprised when it compiles and runs fine with DoEvents but not with Sleep(0). I have used DoEvents in code many times (100+). The first part of code in sub with error is:

Sub Filter_Overlay_Touch(Action As Int, X As Float,Y As Float)
'Msgbox("overlay",Y)
X=X/WS: Y=Y/HS
'Msgbox(X,Y)
Dim Z,ZZ As String
Dim V As Float
Dim PR As String

Select Action
Case Activity.ACTION_DOWN

Z=File.ReadString(File.DirRootExternal,"/JVJ/download/stocktmp")
J=1: 'pointer to first entry in list
H=0: V=0
'CC=Z.Length*.05: '5%
ZZ=""

If X<150 And Y>210 And Y<270 Then
'from price
PriceRangeList.Visible=True
Return True

Else If X<150 And Y>300 And Y<360 Then
'to price
PriceRangeList2.Visible=True
Return True

Else If X<150 And Y>100 And Y<175 Then
'reset
Filter_Overlay.SetBackgroundImage(LoadBitmap(File.DirRootExternal, "/JVJ/images/page/wait.jpg"))
DoEvents
If Instr(SUMMARY.Text&" ","CLEARANCE ITEMS:")>0 Then
Z=File.ReadString(File.DirRootExternal,"/JVJ/download/clear")
tabs(1).Tag="CLEARANCE ITEMS:"
Else
Z=File.ReadString(File.DirRootExternal,"/JVJ/download/stock")
tabs(1).Tag="INVENTORY ITEMS:"
End If

plus many more else if statements.
I wanted to use Return True to exit Sub so code below if statement would not run.

Try this:
instead of this:

You should use code tags when post code:

Sleep(0) is not identical to DoEvents.
In this case I don't think that the DoEvents call does anything useful. Just remove it.

Resumable subs tutorial: https://www.b4x.com/android/forum/threads/78601/#content