How to convert ArrayList to String using GSON

GSON is java library, It is used to convert OBJECT to JSON and JSON to Object. Internally it going to work based on serialization and de- serialization.

This example demonstrate about how to convert ArrayList to string using GSON library.

Add the following code in build.gradle.

apply plugin: 'com.android.application'

android {

   compileSdkVersion 28

   defaultConfig {

      applicationId "com.example.andy.myapplication"

      minSdkVersion 15

      targetSdkVersion 28

      versionCode 1

      versionName "1.0"

      testInstrumentationRunner "android.support.test.runner.AndroidJUnitRunner"

   }

   buildTypes {

      release {

         minifyEnabled false

         proguardFiles getDefaultProguardFile('proguard-android.txt'), 'proguard-rules.pro'

      }

   }

}

dependencies {

   implementation fileTree(dir: 'libs', include: ['*.jar'])

   implementation 'com.android.support:appcompat-v7:28.0.0'

   implementation 'com.google.code.gson:gson:2.8.5'

   implementation 'com.android.support.constraint:constraint-layout:1.1.3'

   testImplementation 'junit:junit:4.12'

   androidTestImplementation 'com.android.support.test:runner:1.0.2'

   androidTestImplementation 'com.android.support.test.espresso:espresso-core:3.0.2'

}

Add the following code to res/layout/activity_main.xml

<?xml version = "1.0" encoding = "utf-8"?>

<android.support.constraint.ConstraintLayout xmlns:android = "http://schemas.android.com/apk/res/android"

   xmlns:app = "http://schemas.android.com/apk/res-auto"

   xmlns:tools = "http://schemas.android.com/tools"

   android:layout_width = "match_parent"

   android:layout_height = "match_parent"

   tools:context = ".MainActivity">

   <TextView

      android:id = "@+id/result"

      android:layout_width = "wrap_content"

      android:layout_height = "wrap_content"

      android:text = "Result Data"

      app:layout_constraintBottom_toBottomOf = "parent"

      app:layout_constraintLeft_toLeftOf = "parent"

      app:layout_constraintRight_toRightOf = "parent"

      app:layout_constraintTop_toTopOf = "parent" />

</android.support.constraint.ConstraintLayout>

Add the following code to src/MainActivity.java

public class MainActivity extends AppCompatActivity {

   @Override

   protected void onCreate(Bundle savedInstanceState) {

      super.onCreate(savedInstanceState);

      setContentView(R.layout.activity_main);

      TextView result = findViewById(R.id.result);

      ArrayList<String> list = new ArrayList<String>();

      list.add("JAVA");

      list.add("Android");

      list.add("Kotlin");

      list.add("C programing Language");

      list.add("C plus plus");

      Gson gson = new Gson();

      String arrayData = gson.toJson(list);

      result.setText(arrayData);

   }

}