JSON parsing (jsonDecode) in Flutter - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to parse a JSON string into a Dart map using jsonDecode.

Flutter

import 'dart:convert';

void main() {
  String jsonString = '{"name": "Alice", "age": 30}';
  var user = [1](jsonString);
  print(user['name']);
}

Drag options to blanks, or click blank then click option'

AjsonDecode

BjsonEncode

CjsonParse

DjsonStringify

Attempts:

3 left

💡 Hint

Common Mistakes

Using jsonEncode instead of jsonDecode

Trying to parse JSON without importing dart:convert

The jsonDecode function converts a JSON string into a Dart object, such as a Map.

2fill in blank

medium

Complete the code to access the 'age' value from the parsed JSON map.

Flutter

import 'dart:convert';

void main() {
  String jsonString = '{"name": "Bob", "age": 25}';
  var user = jsonDecode(jsonString);
  int age = user[1];
  print(age);
}

Drag options to blanks, or click blank then click option'

A{'age'}

B.age

C(age)

D['age']

Attempts:

3 left

💡 Hint

Common Mistakes

Using dot notation to access map keys

Using parentheses or curly braces instead of square brackets

To get a value from a Map in Dart, use square brackets with the key as a string.

3fill in blank

hard

Fix the error in the code to correctly parse a JSON list of strings.

Flutter

import 'dart:convert';

void main() {
  String jsonString = '["apple", "banana", "cherry"]';
  List<String> fruits = List<String>.from([1](jsonString));
  print(fruits[1]);
}

Drag options to blanks, or click blank then click option'

AjsonEncode

BjsonParse

CjsonDecode

DjsonStringify

Attempts:

3 left

💡 Hint

Common Mistakes

Using jsonEncode instead of jsonDecode

Not converting the decoded object to List

Use jsonDecode to convert the JSON string into a Dart List, then convert it to List<String>.

4fill in blank

hard

Fill both blanks to parse a JSON string and access the first user's email.

Flutter

import 'dart:convert';

void main() {
  String jsonString = '{"users": [{"email": "[e-mail]"}, {"email": "[e-mail]"}]}';
  var data = [1](jsonString);
  String email = data['users'][2]['email'];
  print(email);
}

Drag options to blanks, or click blank then click option'

AjsonDecode

BjsonEncode

C[0]

D.0

Attempts:

3 left

💡 Hint

Common Mistakes

Using dot notation to access list elements

Using jsonEncode instead of jsonDecode

First, decode the JSON string with jsonDecode. Then access the first element of the 'users' list with [0].

5fill in blank

hard

Fill all three blanks to parse a JSON string and create a map of user names to ages for users older than 20.

Flutter

import 'dart:convert';

void main() {
  String jsonString = '{"users": [{"name": "Anna", "age": 22}, {"name": "Ben", "age": 19}]}';
  var data = jsonDecode(jsonString);
  var result = {user[1]: user[2] for user in data['users'] if user['age'] [3] 20};
  print(result);
}

Drag options to blanks, or click blank then click option'

A['name']

B['age']

C>

D<

Attempts:

3 left

💡 Hint

Common Mistakes

Using dot notation instead of square brackets for map keys

Using less than operator instead of greater than

Mixing up keys and values in the map comprehension

Use user['name'] as the key and user['age'] as the value. Filter users with age greater than 20 using >.