অ্যান্ড্রয়েডে JSON অবজেক্ট পার্স করার পদ্ধতি

অ্যান্ড্রয়েডে JSON ডেটা পার্স করে RecyclerView-এ দেখানো

এই টিউটোরিয়ালটি দেখাবে কীভাবে অ্যাসেট ফোল্ডার থেকে JSON ফাইল পড়ে, ডেটা এক্সট্র্যাক্ট করে RecyclerView-এ কার্ড ভিউ ফরম্যাটে প্রদর্শন করা যায়।

ধাপ ১: প্রজেক্ট তৈরি করুন

Android Studio-তে File → New Project নির্বাচন করুন।

ধাপ ২: Gradle নির্ভরতা যোগ করুন (build.gradle)

dependencies {
    implementation fileTree(dir: 'libs', include: ['*.jar'])
    implementation 'com.android.support:appcompat-v7:28.0.0'
    implementation 'com.android.support.constraint:constraint-layout:1.1.3'
    implementation 'com.android.support:recyclerview-v7:28.0.0'
    implementation 'com.android.support:cardview-v7:28.0.0'
    // RecyclerView এবং CardView-এর জন্য অতিরিক্ত
    implementation "com.android.support:recyclerview-v7:23.0.1"
    implementation 'com.android.support:cardview-v7:23.0.1'
}

ধাপ ৩: মূল লেআউট (res/layout/activity_main.xml)

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="https://schemas.android.com/apk/res/android"
    xmlns:app="https://schemas.android.com/apk/res-auto"
    xmlns:tools="https://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    tools:context=".MainActivity">

    <android.support.v7.widget.RecyclerView
        android:id="@+id/recyclerView"
        android:layout_width="match_parent"
        android:layout_height="match_parent" />

</RelativeLayout>

ধাপ ৪: সারি লেআউট (res/layout/rowlayout_main.xml)

<?xml version="1.0" encoding="utf-8"?>
<android.support.v7.widget.CardView xmlns:android="https://schemas.android.com/apk/res/android"
    xmlns:card_view="https://schemas.android.com/apk/res-auto"
    android:id="@+id/cardView"
    android:layout_width="match_parent"
    android:layout_margin="5dp"
    android:layout_height="wrap_content">

    <LinearLayout
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:orientation="vertical"
        android:padding="10dp">

        <TextView
            android:id="@+id/tvName"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:text="Name"
            android:textColor="#000"
            android:textSize="20sp" />

        <TextView
            android:id="@+id/tvEmail"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:text="email@email.com"
            android:textColor="#000"
            android:textSize="15sp" />

        <TextView
            android:id="@+id/tvMobile"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:text="e9999999999"
            android:textColor="#000"
            android:textSize="15sp" />

    </LinearLayout>
</android.support.v7.widget.CardView>

ধাপ ৫: মেইন এক্টিভিটি (src/MainActivity.java)

package com.example.sample;

import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.support.v7.widget.LinearLayoutManager;
import android.support.v7.widget.RecyclerView;
import android.util.Log;
import org.json.JSONArray;
import org.json.JSONException;
import org.json.JSONObject;
import java.io.IOException;
import java.io.InputStream;
import java.util.ArrayList;
import java.util.Arrays;

public class MainActivity extends AppCompatActivity {
    ArrayList<String> personNames = new ArrayList<>();
    ArrayList<String> emailIds = new ArrayList<>();
    ArrayList<String> mobileNumbers = new ArrayList<>();

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

        RecyclerView recyclerView = findViewById(R.id.recyclerView);
        LinearLayoutManager linearLayoutManager = new LinearLayoutManager(getApplicationContext());
        recyclerView.setLayoutManager(linearLayoutManager);

        try {
            // JSON ফাইল থেকে ডেটা লোড
            JSONObject obj = new JSONObject(loadJSONFromAsset());
            JSONArray userArray = obj.getJSONArray("users");

            for (int i = 0; i < userArray.length(); i++) {
                JSONObject userDetail = userArray.getJSONObject(i);
                personNames.add(userDetail.getString("name"));
                emailIds.add(userDetail.getString("email"));

                JSONObject contact = userDetail.getJSONObject("contact");
                mobileNumbers.add(contact.getString("mobile"));
            }
        } catch (JSONException e) {
            e.printStackTrace();
        }

        CustomAdapter customAdapter = new CustomAdapter(this, personNames, emailIds, mobileNumbers);
        recyclerView.setAdapter(customAdapter);
    }

    public String loadJSONFromAsset() {
        String json = null;
        try {
            InputStream is = getAssets().open("users_list.json");
            int size = is.available();
            byte[] buffer = new byte[size];
            is.read(buffer);
            is.close();
            json = new String(buffer, "UTF-8");
        } catch (IOException ex) {
            ex.printStackTrace();
            return null;
        }
        return json;
    }
}

ধাপ ৬: কাস্টম অ্যাডাপ্টার (src/CustomAdapter.java)

package com.example.sample;

import android.content.Context;
import android.support.v7.widget.RecyclerView;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.TextView;
import android.widget.Toast;
import java.util.ArrayList;

public class CustomAdapter extends RecyclerView.Adapter<CustomAdapter.MyViewHolder> {
    ArrayList<String> personNames;
    ArrayList<String> emailIds;
    ArrayList<String> mobileNumbers;
    Context context;

    public CustomAdapter(Context context, ArrayList<String> personNames,
                         ArrayList<String> emailIds, ArrayList<String> mobileNumbers) {
        this.context = context;
        this.personNames = personNames;
        this.emailIds = emailIds;
        this.mobileNumbers = mobileNumbers;
    }

    @Override
    public MyViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
        View v = LayoutInflater.from(parent.getContext()).inflate(R.layout.rowlayout, parent, false);
        return new MyViewHolder(v);
    }

    @Override
    public void onBindViewHolder(MyViewHolder holder, final int position) {
        holder.name.setText(personNames.get(position));
        holder.email.setText(emailIds.get(position));
        holder.mobileNo.setText(mobileNumbers.get(position));

        holder.itemView.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                Toast.makeText(context, personNames.get(position), Toast.LENGTH_SHORT).show();
            }
        });
    }

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

    public class MyViewHolder extends RecyclerView.ViewHolder {
        TextView name, email, mobileNo;

        public MyViewHolder(View itemView) {
            super(itemView);
            name = itemView.findViewById(R.id.tvName);
            email = itemView.findViewById(R.id.tvEmail);
            mobileNo = itemView.findViewById(R.id.tvMobile);
        }
    }
}

ধাপ ৭: মেনিফেস্ট (app/manifests/AndroidManifest.xml)

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="https://schemas.android.com/apk/res/android"
    package="com.example.sample">

    <application
        android:allowBackup="true"
        android:icon="@mipmap/ic_launcher"
        android:label="@string/app_name"
        android:roundIcon="@mipmap/ic_launcher_round"
        android:supportsRtl="true"
        android:theme="@style/AppTheme">

        <activity android:name=".MainActivity">
            <intent-filter>
                <action android:name="android.intent.action.MAIN" />
                <category android:name="android.intent.category.LAUNCHER" />
            </intent-filter>
        </activity>
    </application>
</manifest>

অতিরিক্ত সেটআপ

assets/users_list.json ফাইল তৈরি করুন নিচের কন্টেন্টসহ:

{
  "users": [
    {
      "name": "John Doe",
      "email": "john@example.com",
      "contact": { "mobile": "1234567890" }
    },
    {
      "name": "Jane Smith",
      "email": "jane@example.com",
      "contact": { "mobile": "0987654321" }
    }
  ]
}

ফলাফল

অ্যাপ্লিকেশন চালানোর পর RecyclerView-এ কার্ড ভিউতে নাম, ইমেইল এবং মোবাইল নম্বর দেখাবে।