CODEWITHSUNDEEP
kotlin
SK1dev
SK1dev

Reputation: 1139

Map with multiple keys and values

I'm making a quiz app in Kotlin where there is a question with between 2 and 5 answer options together with scores. So there is the question number, question, answers and points for each answer. I have made the app in flutter where I used Map with one key (question number: question) and another key (answer option: score). The answer used a list for the multiple options. What would be the best way to do it in Kotlin?

Flutter code

{
      'Question 1': 'Do you ...?',
      'answers': [
        {'text': 'Not at all', 'score': 0},
        {'text': 'Partly', 'score': 50},
        {'text': 'Mostly', 'score': 280},
        {'text': 'Completely', 'score': 500},
      ],
    },

Upvotes: 0

Views: 2612

Answers (2)

Matthijs van den Bos
Matthijs van den Bos

Reputation: 1179

With thanks to Lena Bru for the original answer, which unfortunately had a few bugs in it. This should be a working version that addresses your question:

data classes:

data class Answer(
    @SerializedName("text") val text: String = "",
    @SerializedName("score") val score: Int = 0
)

data class Question(
    @SerializedName("Question") val questionText: String = "",
    val answers: List<Answer> = listOf()
)

json data:

val json = """
[
    {
        "Question": "Why?",
        "answers": [
            {
                "text": "Because I said so",
                "score": 10
            },
            {
                "text": "Dunno",
                "score": 20
            }
        ]
    }
]
"""

And finally, parsing the json and displaying it:

val gson = Gson()
val questions: List<Question> = gson.fromJson(json, object : TypeToken<List<Question?>?>() {}.type)


questions.forEach { question ->
    println("The question is: ${question.questionText}")
    println("The answers are:")
    question.answers.forEach {answer ->
        println("    Text: ${answer.text}, score: ${answer.score}")
    }
}

The main differences with the previous answer:

  • changed json to match data classes
  • json is now a string
  • Fixed display code

Hope this helps and is still relevant.

Upvotes: 1

Lena Bru
Lena Bru

Reputation: 13937

data class Answer(@SerializedName("text") val text: String = "", @SerializedName("score") score: Int = 0)

data class Question(@SerializedName("Question") val questionText: String = "", answers: List<Answer> = listOf())

In my opinion your json structure is not good, because you have a number inside the question key, i.e "Question 1"

I would structure it the following way:

json = [
   { "Question": "why is blabla a blabla?",
     "answers": ["because I said so", "who knows?", "It doesnt matter"]
    },
    { "Question": "Is this a second question because it is an array of questions?",
      "answers": ["Yes", "No", "White", "Black"]
    }
]

When you put that json through gson for example (the common google json parser)

val questions: List<Question> = gson.fromJson(json,TypeToken<List<Question>(){}.type)


 questions.forEach { question ->
    Log.d("TAG","The question is:${question.questionText}"
    Log.d("TAG","The answers are: ${question.answers.contentToString()}"
 }

Upvotes: 1

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