Android Question Entering an amount of money with B4XFloatTextField

Sub B4XFloatTextField1_TextChanged (Old As String, New As String)
        If IsValid(New) =False Then
            B4XFloatTextField1.Text=Old
            Dim et As EditText =B4XFloatTextField1.TextField
            et.SelectionStart=et.Text.Length
            B4XFloatTextField1.TextField.SetColorAndBorder(Colors.cyan,10dip,Colors.Red,5dip)  'line optional
        End If        
End Sub
Sub IsValid(entry As Double) As Boolean  'allows only  digits with max 2 decimals
    Return Regex.IsMatch("^\d+\.?\d{0,2}$", entry) 'allows max 2 decimals
End Sub