Serialize and Deserialize JSON using GSON Library in Android
When we need to send some data from one activity to another, we can use intents with putExtra() function. But we putExtra supports primitive data types. So if we need to pass and the user defines the object, we need to serialize it first, then send it to the destination. While receiving the data we need to deserialize it. We will serialize and deserialize objects to JSON using the Gson library.
Step by step Implementation
Step 1: Create a new project in android studio using kotlin.
Step 2: Create a user-defined data class
Kotlin
package com.ayush.serialize_deserialize data class StudentInfo(val id: Int, val Name :String, val RollNo : Int) |
Step 3: Create a new activity where we will send the data
XML
<?xml version="1.0" encoding="utf-8"?><LinearLayout android:layout_width="match_parent" android:gravity="center" android:orientation="vertical" android:layout_height="match_parent" tools:context=".SecondActivity"> <TextView android:id="@+id/tvId" android:layout_width="wrap_content" android:layout_height="wrap_content" android:text="ID" android:textStyle="bold" android:textColor="#7CB342" android:textSize="22sp"/> <TextView android:id="@+id/tvName" android:layout_width="wrap_content" android:layout_height="wrap_content" android:text="NAME" android:textStyle="bold" android:textColor="#7CB342" android:layout_margin="4dp" android:textSize="22sp"/> <TextView android:id="@+id/tvRoll" android:layout_width="wrap_content" android:layout_height="wrap_content" android:text="ROLL" android:textStyle="bold" android:textColor="#7CB342" android:textSize="22sp"/></LinearLayout> |
Step 4: Now we will create an object of user define class, and convert it into JSON data using Gson().toJson() function and send it to the intent.
Kotlin
package com.ayush.serialize_deserialize import android.content.Intentimport androidx.appcompat.app.AppCompatActivityimport android.os.Bundleimport com.google.gson.Gson class MainActivity : AppCompatActivity() { override fun onCreate(savedInstanceState: Bundle?) { super.onCreate(savedInstanceState) setContentView(R.layout.activity_main) val stu01 = StudentInfo(1,"AMAN",10) val json = Gson().toJson(stu01) val intent = Intent(this,SecondActivity::class.java) intent.putExtra("data",json) startActivity(intent) }} |
Step 5: We will extract data from intent using getExtra() method and deserialize it using Gson().fromJson().
Kotlin
package com.ayush.serialize_deserialize import android.content.Intentimport androidx.appcompat.app.AppCompatActivityimport android.os.Bundleimport android.widget.TextViewimport com.google.gson.Gson class SecondActivity : AppCompatActivity() { lateinit var data : StudentInfo lateinit var tvId : TextView lateinit var tvName : TextView lateinit var tvRoll : TextView override fun onCreate(savedInstanceState: Bundle?) { super.onCreate(savedInstanceState) setContentView(R.layout.activity_second) tvId = findViewById(R.id.tvId) tvName = findViewById(R.id.tvName) tvRoll= findViewById(R.id.tvRoll) val json = intent.getStringExtra("data") data = Gson().fromJson(json,StudentInfo::class.java) tvId.text = data.id.toString() tvName.text = data.Name tvRoll.text = data.RollNo.toString() }} |
So, our app is ready and we can see the output.
Output:
Output
.png)