B4J Question File Chooser code

Sub Button1_Click
    Dim fc As FileChooser
    Dim filename As String
    fc.Initialize
    fc.InitialDirectory = File.DirApp
    filename = fc.ShowOpen(MainForm)
    Log(filename)
End Sub

fileNotes = fc.ShowOpen(B4XPages.GetNativeParent(Me))

Sub Class_Globals
    Public FilePath As String' Full directory and filename
    Public CurrentfileName As String = "*.txt"        ' --- Wanted file type
    Public CurrentDirectory As String = File.DirApp    ' --- Or default file location between ""
End Sub

    Dim fc As FileChooser
    fc.Initialize
    fc.InitialFileName = CurrentfileName
    fc.InitialDirectory = CurrentDirectory
    FilePath = fc.ShowOpen(B4XPages.GetNativeParent(Me))
    If File.Exists(FilePath,"") Then
        Log(FilePath)
        CurrentDirectory = File.GetFileParent(FilePath)
        CurrentfileName  = File.GetName(FilePath)
        Else
'        --- process empty chose
    End If   
'    --- Get the size of the selected file
    Log(lstJavaFile.Items.Size)