JSON parsing with Gson/Moshi in Android Kotlin - Cheat Sheet & Quick Revision

Recall & Review

beginner

What is Gson in Android development?

Gson is a library that helps convert JSON strings into Kotlin objects and vice versa. It makes handling JSON easy and automatic.

beginner

What is Moshi and how is it different from Gson?

Moshi is another JSON library for Android that is modern and supports Kotlin features better, like null safety and Kotlin data classes. It is often preferred for Kotlin projects.

beginner

How do you parse a JSON string into a Kotlin data class using Gson?

You create a Gson object and call fromJson(jsonString, YourDataClass::class.java). This converts the JSON string into your Kotlin object.

intermediate

What annotation does Moshi use to map JSON keys to Kotlin properties?

Moshi uses the @Json(name = "json_key") annotation to map JSON keys to Kotlin properties when the names differ.

beginner

Why is it important to use data classes with Moshi or Gson?

Data classes automatically provide useful functions like equals(), hashCode(), and toString(), and they work well with JSON libraries for easy parsing and serialization.

Which library is known for better Kotlin support and null safety in JSON parsing?

A Moshi

B Retrofit

C Jackson

D Gson

Moshi is designed with Kotlin in mind and supports Kotlin features like null safety better than Gson.

How do you convert a JSON string to a Kotlin object using Gson?

A Moshi().fromJson(jsonString, DataClass::class.java)

B Gson().toJson(jsonString, DataClass::class.java)

C Gson().fromJson(jsonString, DataClass::class.java)

D JsonParser.parse(jsonString)

The fromJson() method of Gson converts JSON string to Kotlin object.

Which annotation is used in Moshi to rename JSON keys?

A @SerializedName

B @Json(name = "key")

C @JsonKey

D @JsonProperty

Moshi uses @Json(name = "key") to map JSON keys to Kotlin properties.

What Kotlin feature helps Moshi parse JSON easily?

A Extension functions

B Sealed classes

C Companion objects

D Data classes

Data classes provide a simple structure that Moshi can easily map JSON data into.

Which of these is NOT a function provided automatically by Kotlin data classes?

A parseJson()

B equals()

C toString()

D hashCode()

parseJson() is not automatically provided by data classes; it's a function from JSON libraries.

Explain how to parse a JSON string into a Kotlin object using Gson.

Think about the method that converts JSON text to an object.

Describe the advantages of using Moshi over Gson in Kotlin projects.

Focus on Kotlin-specific features and annotations.