class SomeObject {
final List list;
final int integer;
SomeObject({required this.integer, required this.list});
@override
bool operator ==(Object other) {
if (other is SomeObject && integer == other.integer) {
  if (other.list.length != list.length) {
    return false;
  }
  for (int i = 0; i < list.length; i  ) {
    if (list[i] == other.list[i]) {
      return true;
    }
  }
  return false;
}
return false;

}

@override
// TODO: implement hashCode
int get hashCode => Object.hashAll(list);

}

void main(){
var b = SomeObject(integer: 4, list: [5, 6, 7]);
var c = SomeObject(integer: 4, list: [5, 6, 8]);
print(b == c);

Here equality operator returns true while it should return false .I think there is some problem in comparing individual list elements.

}

CodePudding user response：

Consider using != and return false in this part:

for (int i = 0; i < list.length; i  ) {
  if (list[i] == other.list[i]) {
    return true;
  }
}

If we look carefully why it is failing:

var b = SomeObject(integer: 4, list: [5, 6, 7]);
var c = SomeObject(integer: 4, list: [5, 6, 8]);

First loop: i = 0

if (list[0] == other.list[0]) { // 5 == 5
  return true; // it stops and immediately returns true 
}

If we use != and return false, it will break the loop as soon as the elements at index i are not equal.

for (int i = 0; i < list.length; i  ) {
  if (list[i] != other.list[i]) {
    return false;
  }
}

Last loop: i = 2

if (list[2] != other.list[2]) { // 7 == 8 
  return false; 
}

But if you want a shorter way to do this:

import 'package:flutter/foundation.dart';

class SomeObject {
  final List list;
  final int integer;

  SomeObject({
    required this.list,
    required this.integer,
  });


  @override
  bool operator ==(Object other) {
    if (identical(this, other)) return true;

    return other is SomeObject &&
        listEquals(other.list, list) &&
        other.integer == integer;
  }

  @override
  int get hashCode => list.hashCode ^ integer.hashCode;
}