Json Implemetation(Fetch Values)

activity_json_list_item.xml

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:id="@+id/relativeLayout"
    android:layout_width="match_parent"
    android:layout_height="?android:attr/listPreferredItemHeightLarge"
    >

    <ImageView
        android:id="@+id/imageView"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_centerVertical="true"
        android:layout_alignParentStart="true"
        android:layout_alignParentLeft="true"
        android:layout_marginStart="@dimen/activity_horizontal_margin"
        android:layout_marginEnd="@dimen/activity_horizontal_margin"
        android:contentDescription="Icon" />

    <TextView
        android:id="@+id/textView"
        android:layout_width="wrap_content"
        android:layout_height="match_parent"
        android:layout_toEndOf="@id/imageView"
        android:layout_toRightOf="@id/imageView"
        android:gravity="center_vertical"
        android:textSize="16sp"/>

</RelativeLayout>

activity_json_parser.xml

<?xml version="1.0" encoding="utf-8"?>
<androidx.constraintlayout.widget.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=".JsonParser">

</androidx.constraintlayout.widget.ConstraintLayout>

activity_json_recycler_view.xml

<?xml version="1.0" encoding="utf-8"?>
<androidx.constraintlayout.widget.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"
    android:scrollbars="vertical"
    tools:context=".RecyclerViewExample2">

    <androidx.recyclerview.widget.RecyclerView
        android:id="@+id/recyclerView2"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toTopOf="parent" />
</androidx.constraintlayout.widget.ConstraintLayout>

CustomAdapter.java

package com.example.myapplication;


import android.content.Context;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.TextView;

import androidx.annotation.NonNull;
import androidx.recyclerview.widget.RecyclerView;

import java.util.ArrayList;

public class CustomAdapter extends RecyclerView.Adapter<CustomAdapter.ViewHolder> {

    ArrayList<JsonModel> list;
    Context context;

    public CustomAdapter(ArrayList<JsonModel> list, Context context) {
        this.list = list;
        this.context = context;
    }

    @NonNull
    @Override
    public ViewHolder onCreateViewHolder(@NonNull ViewGroup parent, int viewType) {
        LayoutInflater layoutInflater = LayoutInflater.from(parent.getContext());
        View listItem= layoutInflater.inflate(R.layout.jsonlist, parent, false);
        ViewHolder viewHolder = new ViewHolder(listItem);
        return viewHolder;

    }


    @Override
    public void onBindViewHolder(@NonNull ViewHolder holder, int position) {

        JsonModel jsonModel = list.get(position);
        holder.userid.setText(jsonModel.getId());
        holder.name.setText(jsonModel.getName());

    }

    @Override
    public int getItemCount() {
        return list.size();
    }

    public class ViewHolder extends RecyclerView.ViewHolder {


        TextView userid, name;

        public ViewHolder(@NonNull View itemView) {
            super(itemView);

            userid=itemView.findViewById(R.id.textview10);
            name=itemView.findViewById(R.id.textview11);
        }
    }
}

data.json

{
  "users": [
    {
      "name": "Anand",
      "id": "1"
    },
    {
      "name": "Ankit",
      "id": "2"
    },
    {
      "name":"abhishek",
      "id": "3"

    }

  ]
}

JsonModel.java

package com.example.myapplication;

import androidx.appcompat.app.AppCompatActivity;

import android.os.Bundle;

public class JsonModel {

    private String name;
    private String id;

    public JsonModel(String name, String id) {
        this.name = name;
        this.id = id;
    }



    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }

    public String getId() {
        return id;
    }

    public void setId(String id) {
        this.id = id;
    }



}

JsonRecyclerView.java

package com.example.myapplication;

import androidx.appcompat.app.AppCompatActivity;
import androidx.recyclerview.widget.LinearLayoutManager;
import androidx.recyclerview.widget.RecyclerView;

import android.os.Bundle;

import com.google.gson.Gson;

import org.json.JSONArray;
import org.json.JSONException;
import org.json.JSONObject;

import java.io.IOException;
import java.io.InputStream;
import java.util.ArrayList;

public class JsonRecyclerView extends AppCompatActivity {

    RecyclerView recyclerView;
    ArrayList<String> personNames = new ArrayList<>();
    ArrayList<String> userId = new ArrayList<>();
    ArrayList<JsonModel> list = new ArrayList<>();


    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_json_recycler_view);
        recyclerView = findViewById(R.id.recyclerView2);




        recyclerView.setLayoutManager(new LinearLayoutManager(getApplicationContext()));
        CustomAdapter customAdapter = new CustomAdapter(list, this);
        recyclerView.setAdapter(customAdapter);


        try {
            JSONObject obj = new JSONObject(loadJSONfromAssets());
            JSONArray userArray = obj.getJSONArray("users");

            JsonModel object;
            JSONObject userDetails;
            Gson gson = new Gson();


            for ( int i=0 ; i<userArray.length(); i++){

                userDetails = userArray.getJSONObject(i);
                object = gson.fromJson(userDetails.toString(), JsonModel.class);
//                personNames.add(userDetails.getString("name"));
//                userId.add(userDetails.getString("id"));
                list.add(object);


            }
        } catch (JSONException e) {
            e.printStackTrace();
        }

    }

    private String loadJSONfromAssets() {

        String json = null;
        try {

            InputStream is = getAssets().open("data.json");
            int size = is.available();

            byte[] buffer = new byte[size];
            is.read(buffer);
            is.getClass();


            json = new String(buffer, "UTF-8");


        } catch (IOException e) {
            e.printStackTrace();
            return null;
        }
    return json;
    }


}

MainActivity.java

package com.example.myapplication;

import androidx.appcompat.app.AppCompatActivity;
import androidx.appcompat.widget.Toolbar;
import androidx.fragment.app.FragmentManager;

import android.content.Intent;
import android.content.SharedPreferences;
import android.graphics.Color;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import android.widget.TextView;
import android.widget.Toast;

public class MainActivity extends AppCompatActivity {
    Button button1,buttonn;
    private Bundle args;
    private Toolbar toolbar;



    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

//        toolbar =findViewById(R.id.myToolBar);
//        setSupportActionBar(toolbar);


        buttonn = findViewById(R.id.buttonn);
        buttonn.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                Intent intent = new Intent(MainActivity.this, JsonRecyclerView.class);
                startActivity(intent);

            }
        });
        FragmentManager fragmentManager = getSupportFragmentManager();
        fragmentManager.beginTransaction()
                .replace(R.id.fragmentContainerView,new MainFragment()).commit();

        FragmentManager fragmentManager1 = getSupportFragmentManager();
        fragmentManager1.beginTransaction()
                .replace(R.id.abc,new MainFragment2()).commit();




    }
}

//Switch Button to Activity
//        Log.v("activity_lifestyle","OnCreate1 called");
//        button = (Button) findViewById(R.id.button);
//      button.setOnClickListener(new View.OnClickListener() {

//            @Override
//            public void onClick(View view) {
//
//
//            }
//    }

//    @Override
//    protected void onStart() {
//        super.onStart();
//        Log.v("activity_lifestyle","OnStart1 called");
//    }
//
//    @Override
//    protected void onResume() {
//        super.onResume();
//        Log.v("activity_lifestyle","OnResume1 called");
//    }
//
//    @Override
//    protected void onPause() {
//        super.onPause();
//        Log.v("activity_lifestyle","OnPause1 called");
//    }
//
//    @Override
//    protected void onStop() {
//        super.onStop();
//        Log.v("activity_lifestyle","OnStop1 called");
//    }
//
//    @Override
//    protected void onDestroy() {
//        super.onDestroy();
//        Log.v("activity_lifestyle","OnDestroy1 called");


// printLinkedList();















        //Parcelable
//        Animals obj2=new Animals();
//          obj2.setName1("Lion");
//          obj2.setFunctinalities("Hunt");
//
//          Intent intent = new Intent(MainActivity.this,ThirdActivity.class);
//          intent.putExtra("Mammals",obj2);
//          startActivity(intent);





//Serializable
//        Employees model = new Employees();
//        model.setId(755);
//        model.setName("Anand");
//
//        Intent intent= new Intent(MainActivity.this,SecondActivity.class);
//        intent.putExtra("Human", model);
//        startActivity(intent);







        //PrintAbstractionClass();

        //MultilevelInheritanceClass();
        //HierarchicalInheritanceClass();
        //SingleInheritanceClass();
        //HybridInheritanceClass();
        //PolymorphimClass();
        //OverRidingClass();
        //OverloadingClass();
        //EncapsulationClass();
        //InterafaceClass();
        //ConstructorClass();
        //DefaulConstructorClass();
        //ParameterizedConstructorClass();
        //printArrayList();
        //printArray();
        //printStringBuffer();
        //printStringBuilder();





//    private void printLinkedList() {
//
//        LinkedList<String> al = new LinkedList<String>();
//        al.add("Ravi");
//        al.add("Vijay");
//        al.add("Ravi");
//        al.add("Ajay");
//
//        Iterator<String> itr = al.iterator();
//        while (itr.hasNext()) {
//            Toast.makeText(this, "" + itr.next(), Toast.LENGTH_SHORT).show();
//        }
//    }

//    private void printStringBuilder() {
//        StringBuilder builder=new StringBuilder("Welcome");
//        builder.append("User");
//        Toast.makeText(this, ""+builder, Toast.LENGTH_SHORT).show();
//    }


//    //printStringBuffer();
//    private void printStringBuffer() {
//        StringBuffer buffer=new StringBuffer("Welcome");
//        buffer.append("User");
//        Toast.makeText(this, ""+buffer, Toast.LENGTH_SHORT).show();
//    }


//    //array
//    private void printArray() {
//
//        int[] arr = new int[3];
//        arr[0] = 5;
//        arr[1] = 6;
//        arr[2] = 10;
//
//        Toast.makeText(this, ""+ Arrays.toString(arr), Toast.LENGTH_SHORT).show();
//    }


//    //ArrayList
//    private void printArrayList() {
//        ArrayList<Integer> arr = new ArrayList<Integer>();
//        arr.add(5);
//        arr.add(9);
//        arr.add(11);
//
//        Toast.makeText(this, ""+arr, Toast.LENGTH_SHORT).show();
//
//    }


//    //Parameterized Constructor
//    private void ParameterizedConstructorClass() {
//        Main2 myObj = new Main2(5);
//        Log.v(Main2.class.getSimpleName(), "myObj" + (myObj.x));
//    }
//
//
//    public class Main2 {
//        int x;
//
//        public Main2(int y) {
//            x = y;
//        }
//
//    }
//
//
//    //Default Constructor
//    private void DefaulConstructorClass() {
//        new Demo();
//    }
//
//    class Demo {
//        public Demo() {
//            Log.v(Demo.class.getSimpleName(), "This is a no argument constructor");
//        }
//
//    }
//
//
//    //constructor
//
//    private void ConstructorClass() {
//        Hello obj = new Hello();
//        Log.v(Hello.class.getSimpleName(), "Hello Google");
//    }
//
//    public class Hello {
//        String name;
//
//        //Constructor
//        Hello() {
//            this.name = "Google.com";
//        }
//    }
//
//
//    //Interface
//    private void InterafaceClass() {
//
//        Mammals i = new Mammals();
//        i.eat();
//        i.travel();
//    }
//
//
//    //overiding
//    private void OverloadingClass() {
//        Adder adder = new Adder();
//        Toast.makeText(MainActivity.this, "" + adder.add(10, 20), Toast.LENGTH_SHORT).show();
//        Toast.makeText(this, "" + adder.add(12.3, 12.6), Toast.LENGTH_SHORT).show();
//    }
//
//    class Adder {
//        int add(int a, int b) {
//            return a + b;
//        }
//
//        double add(double a, double b) {
//            return a + b;
//        }
//    }
//
//
//    //overiding
//    private void OverRidingClass() {
//        Car b = new Audi();//upcasting
//        b.run();
//    }
//
//    class Car {
//        void run() {
//            System.out.println("running");
//        }
//    }
//
//    class Audi extends Car {
//        void run() {
//            Toast.makeText(MainActivity.this, "running safely with 200km", Toast.LENGTH_SHORT).show();
//        }
//    }
//
//
//    //polymorphism
//    private void PolymorphimClass() {
//        Animal myAnimal = new Animal();  // Create a Animal object
//        Animal myPig = new Pig();  // Create a Pig object
//        Animal myDog = new Dog();  // Create a Dog object
//        myAnimal.animalSound();
//        myPig.animalSound();
//        myDog.animalSound();
//    }
//
//    class Animal {
//        public void animalSound() {
//            Toast.makeText(MainActivity.this, "The animal makes a sound", Toast.LENGTH_SHORT).show();
//        }
//    }
//
//    class Pig extends Animal {
//        public void animalSound() {
//            Toast.makeText(MainActivity.this, "The pig says: wee wee", Toast.LENGTH_SHORT).show();
//        }
//    }
//
//    class Dog extends Animal {
//        public void animalSound() {
//            Toast.makeText(MainActivity.this, "The dog says: bow wow\"", Toast.LENGTH_SHORT).show();
//        }
//    }
//
//    class Main1 {
//    }
//
//
//    //hybrid
//    private void HybridInheritanceClass() {
//        Daughter1 obj = new Daughter1();
//        obj.show();
//    }
//
//    class GrandFather {
//        public void show() {
//            Toast.makeText(MainActivity.this, "I am grandfather.", Toast.LENGTH_SHORT).show();
//        }
//    }
//
//    //inherits GrandFather properties
//    class Father extends GrandFather {
//        public void show() {
//            Toast.makeText(MainActivity.this, "I am father.", Toast.LENGTH_SHORT).show();
//        }
//    }
//
//    //inherits Father properties
//    class Son extends Father {
//        public void show() {
//            Toast.makeText(MainActivity.this, "I am son.", Toast.LENGTH_SHORT).show();
//        }
//    }
//
//    //inherits Father properties
//    public class Daughter1 extends Father {
//        public void show() {
//            Toast.makeText(MainActivity.this, "I am a daughter.", Toast.LENGTH_SHORT).show();
//        }
//
//
//        //Hierarchical
//        private void HierarchicalInheritanceClass() {
//            Son s = new Son();
//            Daughter1 d = new Daughter1();
//        }
//
//        class Father1 {
//            String familyName;
//            String houseaddress;
//
//            Father1() {
//                familyName = "Programmer";
//                houseaddress = "Delhi";
//            }
//        }
//
//        class Son extends Father1 {
//            Son() {
//                Toast.makeText(MainActivity.this, "I am the Son", Toast.LENGTH_SHORT).show();
//                Toast.makeText(MainActivity.this, "My family name is \" + this.familyName + \" and I am from \" + this.houseaddress", Toast.LENGTH_SHORT).show();
//            }
//        }
//
//        class Daughter extends Father1 {
//            Daughter() {
//                Toast.makeText(MainActivity.this, "I am the Daughter", Toast.LENGTH_SHORT).show();
//                Toast.makeText(MainActivity.this, "My family name is \" + this.familyName + \" and I am from \" + this.houseaddress", Toast.LENGTH_SHORT).show();
//            }
//        }
//
//
//        //single inheritance
//        private void SingleInheritanceClass() {
//            Rectangle rect = new Rectangle();
//            rect.display();
//            rect.area();
//        }
//
//        class Shape {
//            public void display() {
//                Toast.makeText(MainActivity.this, "Inside display", Toast.LENGTH_SHORT).show();
//            }
//        }
//
//        class Rectangle extends Shape {
//            public void area() {
//                Toast.makeText(MainActivity.this, "Inside area", Toast.LENGTH_SHORT).show();
//            }
//        }
//
//        public class Tester {
//        }
//
//
//        //Multilevel
//        private void MultilevelInheritanceClass() {
//            Son1 s1 = new Son1();
//        }
//
//        class GrandFather {
//            GrandFather() {
//                Toast.makeText(MainActivity.this, "I am the grandfather!", Toast.LENGTH_SHORT).show();
//            }
//        }
//
//        class Father extends GrandFather {
//            String familyName;
//            String houseaddress;
//
//            Father() {
//                Toast.makeText(MainActivity.this, "I am the father! I inherit from Grandfather", Toast.LENGTH_SHORT).show();
//            }
//        }
//
//        public class Son1 extends Father {
//            Son1() {
//                Toast.makeText(MainActivity.this, "I am the son and I inherit from my father.", Toast.LENGTH_SHORT).show();
//            }
//
//
//            //Abstraction
//            private void PrintAbstractionClass() {
//                Dog d1 = new Dog();
//
//                d1.makeSound();
//                d1.eat();
//            }
//
//            abstract class Animal {
//                abstract void makeSound();
//
//                public void eat() {
//                    Toast.makeText(MainActivity.this, "Bark bark", Toast.LENGTH_SHORT).show();
//                }
//            }
//
//            class Dog extends Animal {
//
//                // provide implementation of abstract method
//                public void makeSound() {
//                    Toast.makeText(MainActivity.this, "My name is Anand", Toast.LENGTH_SHORT).show();
//                }
//            }
//
//        }
//
//    }
//}

Add dependencies --

build.gridle file-

plugins {
id 'com.android.application'
}

android {
compileSdk 32

defaultConfig {
    applicationId "com.example.myapplication"
    minSdk 21
    targetSdk 32
    versionCode 1
    versionName "1.0"

    testInstrumentationRunner "androidx.test.runner.AndroidJUnitRunner"
}

buildTypes {
    release {
        minifyEnabled false
        proguardFiles getDefaultProguardFile('proguard-android-optimize.txt'), 'proguard-rules.pro'
    }
}
compileOptions {
    sourceCompatibility JavaVersion.VERSION_1_8
    targetCompatibility JavaVersion.VERSION_1_8
}

}

dependencies {

implementation 'androidx.appcompat:appcompat:1.4.1'
implementation 'com.google.android.material:material:1.5.0'
implementation 'androidx.constraintlayout:constraintlayout:2.1.3'
implementation 'androidx.legacy:legacy-support-v4:1.0.0'
implementation 'androidx.fragment:fragment:1.3.5'
testImplementation 'junit:junit:4.13.2'
androidTestImplementation 'androidx.test.ext:junit:1.1.3'
androidTestImplementation 'androidx.test.espresso:espresso-core:3.4.0'
implementation 'de.hdodenhof:circleimageview:3.1.0'
implementation "androidx.cardview:cardview:1.0.0"
implementation "androidx.recyclerview:recyclerview:1.2.1"
implementation 'com.google.code.gson:gson:2.8.7'

}