B4J Question Problem working with B4XCustomDialogs: Numberformatexception: empty String

[GuyBooth]

I'm new to B4X Dialogs and I'm having problems with my first attempt.
My Dialog box has two text fields and two combo boxes. I want to disable the "OK" button until the combo box results are acceptable - for purposes of this test, both of them must have any value other than the first one in the list selected.

The relevant subs are:

Sub btnCustom_Click
''' some code
dialog.setbuttonState(-1, False)    ' to set the ok button to disabled
dialog.setbuttonState(-3, True)        ' to set the Cancel button enabled
End sub

Sub fieldcbx1_SelectedIndexChanged (Index As Int)
    Check_CBXChanged
    Log("CBX1 Index")
End Sub
Sub fieldcbx2_SelectedIndexChanged (Index As Int)
    Check_CBXChanged
    Log("CBX1 Index")
End Sub

Sub Check_CBXChanged
    Dim index1 As Int = fieldcbx1.SelectedIndex
    Dim index2 As Int = fieldcbx2.SelectedIndex
    dialog.SetButtonState(-1, (index1 > 0 And index2 > 0))
End Sub

When I click on the combo box to select and item, the dialog.setbuttonstate(-1, (index1 > 0 and Index2 > 0)) throws this error:

b4xdialog._getbutton (java line: 340)
java.lang.NumberFormatException: empty String
    at java.base/jdk.internal.math.FloatingDecimal.readJavaFormatString(FloatingDecimal.java:1842)
    at java.base/jdk.internal.math.FloatingDecimal.parseDouble(FloatingDecimal.java:110)
    at java.base/java.lang.Double.parseDouble(Double.java:549)
    at anywheresoftware.b4a.BA.ObjectToNumber(BA.java:395)
    at b4j.example.b4xdialog._getbutton(b4xdialog.java:340)
    at b4j.example.b4xdialog._setbuttonstate(b4xdialog.java:493)
    at b4j.example.main._check_cbxchanged(main.java:580)
    at b4j.example.main._fieldcbx1_selectedindexchanged(main.java:587)
    at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
    at java.base/jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
    at java.base/java.lang.reflect.Method.invoke(Method.java:564)
    at anywheresoftware.b4a.BA.raiseEvent2(BA.java:91)
    at anywheresoftware.b4a.keywords.Common.CallSub4(Common.java:487)
    at anywheresoftware.b4a.keywords.Common.CallSubNew2(Common.java:442)
    at b4j.example.b4xcombobox$ResumableSub_RaiseEvent.resume(b4xcombobox.java:271)
    at anywheresoftware.b4a.keywords.Common$2$1.run(Common.java:1018)
    at javafx.graphics/com.sun.javafx.application.PlatformImpl.lambda$runLater$10(PlatformImpl.java:428)
    at java.base/java.security.AccessController.doPrivileged(AccessController.java:391)
    at javafx.graphics/com.sun.javafx.application.PlatformImpl.lambda$runLater$11(PlatformImpl.java:427)
    at javafx.graphics/com.sun.glass.ui.InvokeLaterDispatcher$Future.run(InvokeLaterDispatcher.java:96)
    at javafx.graphics/com.sun.glass.ui.win.WinApplication._runLoop(Native Method)
    at javafx.graphics/com.sun.glass.ui.win.WinApplication.lambda$runLoop$3(WinApplication.java:174)
    at java.base/java.lang.Thread.run(Thread.java:832)

How should I be doing this? Can anyone see an error here?
I have attached an example with my code, it is based on the example on this forum.

 

[Erel]

It is related to a bug in XUI Views v2.31. Update to v2.32.