How to serialize Kotlin objects to JSON using GSON in Kotlin Android

How to serialize Kotlin objects to JSON using GSON in Kotlin Android.

Here's a step-by-step tutorial on how to serialize Kotlin objects to JSON using GSON in Kotlin Android.

Step 1: Add GSON Dependency

First, you need to add the GSON dependency to your project. Open your project's build.gradle file and add the following line to the dependencies block:

implementation 'com.google.code.gson:gson:2.8.6'

Sync your project to download the GSON library.

Step 2: Create a Kotlin data class

Next, create a Kotlin data class representing the object you want to serialize. For example, let's say you want to serialize a user object with name and email fields. You can create the data class as follows:

data class User(val name: String, val email: String)

Step 3: Serialize the object to JSON

To serialize the user object to JSON using GSON, follow these steps:

a. Create an instance of the Gson class:

val gson = Gson()

b. Convert the object to a JSON string using the toJson() method:

val user = User("John Doe", "[email protected]")
val json = gson.toJson(user)

The json variable now contains the JSON representation of the user object.

Step 4: Deserialize JSON back to object (optional)

If you want to deserialize the JSON back to an object, you can follow these steps:

a. Create an instance of the Gson class (if you haven't already):

val gson = Gson()

b. Use the fromJson() method to convert the JSON string back to an object:

val user = gson.fromJson(json, User::class.java)

The user variable now contains the deserialized object.

Step 5: Handle nested objects (optional)

If your object contains nested objects, you can handle them by creating data classes for each nested object and nesting them accordingly. For example, if your user object has an address field, you can define an Address data class and include it in the User data class:

data class User(val name: String, val email: String, val address: Address)

data class Address(val street: String, val city: String, val state: String)

You can then serialize and deserialize the user object as before.

Step 6: Customize serialization (optional)

GSON provides various options to customize serialization, such as excluding specific fields, renaming fields, or providing custom serializers. You can refer to the GSON documentation for more details on customization options.

That's it! You've learned how to serialize Kotlin objects to JSON using GSON in Kotlin Android.