Parse data to two separate lists with condition in Flutter - json

Question

[
{
"name": "ITEM-1",
"desc": "DESCRIPTION",
"listNo" :"0"
},
{
"name": "ITEM-2",
"desc": "DESCRIPTION",
"listNo" :"0"
},
{
"name": "ITEM-3",
"desc": "DESCRIPTION",
"listNo" :"0"
},
{
"name": "ITEM-4",
"desc": "DESCRIPTION",
"listNo" :"1"
},
{
"name": "ITEM-5",
"desc": "DESCRIPTION",
"listNo" :"1"
},
{
"name": "ITEM-6",
"desc": "DESCRIPTION",
"listNo" :"1"
}
]
How to implement this model in futter? I want to show the two lists as shown in and data from JSON above.
The condition for LIST-A is "listNo"="0" and for LIST-B is "listNo"="1".

Answer 1

There are multiple ways to do it but I think the most easiest to understand solution would be to do the following:
import 'dart:convert';
void main() {
const input = '''
[
{
"name": "ITEM-1",
"desc": "DESCRIPTION",
"listNo" :"0"
},
{
"name": "ITEM-2",
"desc": "DESCRIPTION",
"listNo" :"0"
},
{
"name": "ITEM-3",
"desc": "DESCRIPTION",
"listNo" :"0"
},
{
"name": "ITEM-4",
"desc": "DESCRIPTION",
"listNo" :"1"
},
{
"name": "ITEM-5",
"desc": "DESCRIPTION",
"listNo" :"1"
},
{
"name": "ITEM-6",
"desc": "DESCRIPTION",
"listNo" :"1"
}
]
''';
final list1 = <Map<String, dynamic>>[];
final list2 = <Map<String, dynamic>>[];
for (final map in json.decode(input)) {
if (map['listNo'] == '0') {
list1.add(map as Map<String, dynamic>);
} else {
list2.add(map as Map<String, dynamic>);
}
}
print(list1);
// [{name: ITEM-1, desc: DESCRIPTION, listNo: 0}, {name: ITEM-2, desc: DESCRIPTION, listNo: 0}, {name: ITEM-3, desc: DESCRIPTION, listNo: 0}]
print(list2);
// [{name: ITEM-4, desc: DESCRIPTION, listNo: 1}, {name: ITEM-5, desc: DESCRIPTION, listNo: 1}, {name: ITEM-6, desc: DESCRIPTION, listNo: 1}]
}
Alternative you could also do the following if you think that looks more clear:
final parsedJson = json.decode(input) as List<dynamic>;
final list1 = [
...parsedJson
.cast<Map<String, dynamic>>()
.where((map) => map['listNo'] == '0')
];
final list2 = [
...parsedJson
.cast<Map<String, dynamic>>()
.where((map) => map['listNo'] == '1')
];