Max range list? Dart

Question

i need some help

List<Map<String, String>> listItem = <Map<String, String>>[];

and then I have a for that adds map to map

for (int i = 0; i < items.length; i++) {
  Map<String, String> val = {
    "OrderState": "",
    "LineID": items[i].id.toString(),
    "ClientID": "idCliente!!",
    "ProductReference": items[i].ref.toString(),
    "Color": items[i].cor.toString(),
    "Size": items[i].tamanho.toString(),
    "Quantity": items[i].quantity.toString(),
    "UnitPriceWithoutTax": items[i].priceWithoutTax.toString(),
    "UnitPriceWithTax": items[i].price.toString(),
    "ShippingAmount": precoEnvio.toString(),
    "DiscountAmount": "0",
    "OrderReference": "",
    "CarrierID": idTrans.toString(),
    "Comments": coment.toString(),
    "ProductDescription": "items[i].descricao.toString()",
    "ShippingName": "envioNome!!",
    "ShippingAddress1": "envioAdr1!!",
    "ShippingAddress2": "envioAdr2!!",
    "ShippingPostalCode": "envioPostalCode!!",
    "ShippingCity": "envioCidade!!",
    "shippingPhone": "envioTele!!",
    "BillingName": "envioNome!!",
    "BillingAddress1": "envioAdr1!!",
    "BillingAddress2": "envioAdr2!!",
    "BillingPostalCode": "envioPostalCode!!",
    "BillingCity": "envioCidade!!",
    "BillingVAT": "envioNif!!",
    "BillingEmail": "envioEmail!!",
    "BillingPhone": "envioTele!!",
    "PaymentID": idPagamento.toString(),
    "PaymentInfo1": tele.toString(),
    "PaymentInfo2": "",
    "PaymentInfo3": "",
    "PaymentInfo4": "",
    "PaymentInfo5": "",
    "AF1": "",
    "AF2": "",
    "AF3": "",
    "AF4": "",
    "AF5": "",
    "AF6": "",
    "AF7": "",
    "AF8": "",
    "AF9": "",
    "AF10": ""
  };
  listItem.add(val);
}

I don't kown why my list have a limit range, he just stop when get "ShippingPo" of the second item.

Is there any way to make it infinite, since i can have 2 or 3 requests, but i can also have 20 or so i need a lot of space in the list