How to parse a String to int and not get the next errors?

Question

Withvar pinU = int.parse(pin.text); I get this error:

E/flutter (16045): [ERROR:flutter/runtime/dart_vm_initializer.cc(41)] Unhandled Exception: FormatException: Invalid number (at character 1)
E/flutter (16045):
E/flutter (16045): ^

With var pinU = pin as int; I get this error:

E/flutter (16045): [ERROR:flutter/runtime/dart_vm_initializer.cc(41)] Unhandled Exception: type 'String' is not a subtype of type 'int' in type cast

I'm trying to pass a PIN to the database helper function to get the results. Here is my complete function:

login2() async {
    var usernameU = username.text;
    var pinU = int.parse(pin.text);

    await DBProvider.db.getUser(usernameU, pinU).then((tempUser) {
      Navigator.push(context as BuildContext,
          MaterialPageRoute(builder: (context) => const WelcomePage()));
    }).catchError((err) {
      // ignore: avoid_print
      print('Error: $err');
    });
  }

I need to pass a int, but this error is persistent.

1. Don't try to parse empty strings. 2. If you're parsing untrusted input from a user, use [`int.tryParse`](https://api.dart.dev/stable/dart-core/int/tryParse.html) instead. — jamesdlin, Mar 19 '23 at 01:57
@AndreiVolgin it is declared here: final TextEditingController pin = TextEditingController(); — Andres Rodriguez, Mar 20 '23 at 11:02

score 0 · Accepted Answer · answered Mar 19 '23 at 07:24

0

Instead of var use int as datatype.

int pinU = int.parse(pin.text ?? "0");

answered Mar 19 '23 at 07:24

Fahmida

1,050
8
19

with your solution I'm getting this error: 'The left operand can't be null, so the right operand is never executed. Try removing the operator and the right operand.' – Andres Rodriguez Mar 20 '23 at 11:08

score 0 · Answer 2 · answered Mar 20 '23 at 14:14

0

Try this:

if (pin.text.isEmpty) {
   // tell a user that this field is required or do something else
   return;
}

final pinU = int.parse(pin.text);

You also need to set your TextField to accept only numbers, or you should use tryParse instead.

answered Mar 20 '23 at 14:14

Andrei Volgin

40,755
6
49
58

How to parse a String to int and not get the next errors?

2 Answers2