Kotlin Quiz Engines: Category-Safe Question Loading

Kotlin Quiz Engines: Category-Safe Question Loading

Quiz apps feel easy until category filters, localization, and randomization collide. Then users report seeing wrong questions in the wrong section. Here’s a safer architecture.

Step 1: Model category and question contracts explicitly

data class Question(
    val id: String,
    val categoryId: String,
    val prompt: String,
    val options: List<String>,
    val answerIndex: Int
)

Step 2: Filter first, randomize second

fun pickQuestions(all: List<Question>, categoryId: String, limit: Int): List<Question> {
    return all
        .asSequence()
        .filter { it.categoryId == categoryId }
        .shuffled()
        .take(limit)
        .toList()
}

Step 3: Detect malformed question sets before runtime

fun validate(questions: List<Question>) {
    require(questions.none { it.options.isEmpty() })
    require(questions.all { it.answerIndex in it.options.indices })
}

Pitfalls to avoid

• Applying randomization before category filter.
• Question IDs duplicated across packs.
• No startup validation for malformed options.

Validation checklist

• Category pages only show category-owned questions.
• Malformed question packs fail during validation, not during quizzes.
• Randomization stays stable under seeded test mode.