Bug? XCLV Index out of bounds exception when removing the last item (or is it me?)

[walt61]

See title; the attached demo project shows what happens, and this exception occurs (only when removing the last item, removing any others works fine):

Spoiler

Call B4XPages.GetManager.LogEvents = True to enable logging B4XPages events.
customlistview._getrawlistitem (java line: 449)
java.lang.IndexOutOfBoundsException: Index 0 out of bounds for length 0
at java.base/jdk.internal.util.Preconditions.outOfBounds(Preconditions.java:100)
at java.base/jdk.internal.util.Preconditions.outOfBoundsCheckIndex(Preconditions.java:106)
at java.base/jdk.internal.util.Preconditions.checkIndex(Preconditions.java:302)
at java.base/java.util.Objects.checkIndex(Objects.java:385)
at java.base/java.util.ArrayList.get(ArrayList.java:427)
at anywheresoftware.b4a.objects.collections.List.Get(List.java:122)
at b4j.example.customlistview._getrawlistitem(customlistview.java:449)
at b4j.example.customlistview$ResumableSub_PanelClickHandler.resume(customlistview.java:775)
at b4j.example.customlistview._panelclickhandler(customlistview.java:751)
at b4j.example.customlistview._panel_mouseclicked(customlistview.java:742)
at java.base/jdk.internal.reflect.DirectMethodHandleAccessor.invoke(DirectMethodHandleAccessor.java:104)
at java.base/java.lang.reflect.Method.invoke(Method.java:578)
at anywheresoftware.b4a.BA.raiseEvent2(BA.java:117)
at anywheresoftware.b4a.BA.raiseEvent(BA.java:104)
at anywheresoftware.b4j.objects.NodeWrapper$1.handle(NodeWrapper.java:109)
at anywheresoftware.b4j.objects.NodeWrapper$1.handle(NodeWrapper.java:1)
at javafx.base/com.sun.javafx.event.CompositeEventHandler.dispatchBubblingEvent(CompositeEventHandler.java:86)
at javafx.base/com.sun.javafx.event.EventHandlerManager.dispatchBubblingEvent(EventHandlerManager.java:234)
at javafx.base/com.sun.javafx.event.EventHandlerManager.dispatchBubblingEvent(EventHandlerManager.java:191)
at javafx.base/com.sun.javafx.event.CompositeEventDispatcher.dispatchBubblingEvent(CompositeEventDispatcher.java:59)
at javafx.base/com.sun.javafx.event.BasicEventDispatcher.dispatchEvent(BasicEventDispatcher.java:58)
at javafx.base/com.sun.javafx.event.EventDispatchChainImpl.dispatchEvent(EventDispatchChainImpl.java:114)
at javafx.base/com.sun.javafx.event.BasicEventDispatcher.dispatchEvent(BasicEventDispatcher.java:56)
at javafx.base/com.sun.javafx.event.EventDispatchChainImpl.dispatchEvent(EventDispatchChainImpl.java:114)
at javafx.base/com.sun.javafx.event.BasicEventDispatcher.dispatchEvent(BasicEventDispatcher.java:56)
at javafx.base/com.sun.javafx.event.EventDispatchChainImpl.dispatchEvent(EventDispatchChainImpl.java:114)
at javafx.base/com.sun.javafx.event.BasicEventDispatcher.dispatchEvent(BasicEventDispatcher.java:56)
at javafx.base/com.sun.javafx.event.EventDispatchChainImpl.dispatchEvent(EventDispatchChainImpl.java:114)
at javafx.base/com.sun.javafx.event.BasicEventDispatcher.dispatchEvent(BasicEventDispatcher.java:56)
at javafx.base/com.sun.javafx.event.EventDispatchChainImpl.dispatchEvent(EventDispatchChainImpl.java:114)
at javafx.base/com.sun.javafx.event.EventUtil.fireEventImpl(EventUtil.java:74)
at javafx.base/com.sun.javafx.event.EventUtil.fireEvent(EventUtil.java:54)
at javafx.base/javafx.event.Event.fireEvent(Event.java:198)
at javafx.graphics/javafx.scene.Scene$ClickGenerator.postProcess(Scene.java:3602)
at javafx.graphics/javafx.scene.Scene$MouseHandler.process(Scene.java:3906)
at javafx.graphics/javafx.scene.Scene.processMouseEvent(Scene.java:1878)
at javafx.graphics/javafx.scene.Scene$ScenePeerListener.mouseEvent(Scene.java:2623)
at javafx.graphics/com.sun.javafx.tk.quantum.GlassViewEventHandler$MouseEventNotification.run(GlassViewEventHandler.java:411)
at javafx.graphics/com.sun.javafx.tk.quantum.GlassViewEventHandler$MouseEventNotification.run(GlassViewEventHandler.java:301)
at java.base/java.security.AccessController.doPrivileged(AccessController.java:399)
at javafx.graphics/com.sun.javafx.tk.quantum.GlassViewEventHandler.lambda$handleMouseEvent$2(GlassViewEventHandler.java:450)
at javafx.graphics/com.sun.javafx.tk.quantum.QuantumToolkit.runWithoutRenderLock(QuantumToolkit.java:424)
at javafx.graphics/com.sun.javafx.tk.quantum.GlassViewEventHandler.handleMouseEvent(GlassViewEventHandler.java:449)
at javafx.graphics/com.sun.glass.ui.View.handleMouseEvent(View.java:557)
at javafx.graphics/com.sun.glass.ui.View.notifyMouse(View.java:943)
at javafx.graphics/com.sun.glass.ui.win.WinApplication._runLoop(Native Method)
at javafx.graphics/com.sun.glass.ui.win.WinApplication.lambda$runLoop$3(WinApplication.java:184)
at java.base/java.lang.Thread.run(Thread.java:1589)

The code is (I've only tested it with B4J):

Spoiler

Sub Class_Globals
Private Root As B4XView
Private xui As XUI
Private CustomListView1 As CustomListView
Private Label1 As Label ' Is from layout 'clvrow' and sits in a Pane
End Sub

Public Sub Initialize
End Sub

Private Sub B4XPage_Created (Root1 As B4XView)
Root = Root1
Root.LoadLayout("MainPage")
End Sub

Private Sub B4XPage_Appear

Dim i As Int
For i = 0 To 5
Wait For (CreateClvItem(i)) Complete(pnl As B4XView)
CustomListView1.Add(pnl, pnl.Tag)
Sleep(0)
Next

End Sub

Private Sub CreateClvItem(i As Int) As ResumableSub

Dim p As B4XView = xui.CreatePanel("")
p.SetLayoutAnimated(0, 0, 0, CustomListView1.AsView.Width, 50dip)
p.LoadLayout("clvrow")
Sleep(0)

p.Tag = i
Label1.Tag = i
Label1.Text = " Click here to delete item #" & i

Return p

End Sub

Private Sub Label1_MouseClicked (EventData As MouseEvent)

'!!!!!!!!!!!!!!!!!!!!!!!!
' The exception occurs when the label in the last item (#5) is clicked
'!!!!!!!!!!!!!!!!!!!!!!!!

Dim lbl As Label = Sender
DeleteFromCustomListView(lbl.Tag)
'EventData.Consume ' <---- If this is added, the exception does NOT occur
End Sub

Private Sub DeleteFromCustomListView(id As Int)

Dim i As Int

For i = (CustomListView1.Size - 1) To 0 Step -1
Dim p As B4XView = CustomListView1.GetPanel(i)
Dim tagId As Int = p.Tag
If tagId = id Then
CustomListView1.RemoveAt(i)
Return
End If
Next

End Sub

EDIT:
1. In B4A, the exception doesn't occur
2. If 'EventData.Consume' is added to the Label's MouseClicked event sub, the exception doesn't occur

 

[josejad]

Why don't you just do:

Private Sub CustomListView1_ItemClick (Index As Int, Value As Object)
    CustomListView1.RemoveAt(Index)
End Sub

 

[walt61]

Thanks for trying @josejad , but this is just minimal demo code to show the issue. My real code is way more complex