There is no such thing as posting an array. It is up to you to convert the array to a string (or raw bytes).
For example:
B4X:
Dim sb As StringBuilder
sb.Initialize
If listCodes.Length > 0 Then
For Each code As String In listCodes
sb.Append(code).Append(",")
Next
sb.Remove(sb.Length - 1, sb.Length)
End If
httpJob.PostString("http://url, "listCodes=" & sb.ToString)