RecyclerView অ্যাডাপ্টার ডেটা আপডেট করার পদ্ধতি

RecyclerView-এ ডাইনামিকভাবে ডেটা আপডেট করা

এই উদাহরণটি দেখাবে কীভাবে RecyclerView-এর অ্যাডাপ্টারে নতুন ডেটা যোগ করে notifyDataSetChanged() কল করে UI আপডেট করা যায়।

ধাপ ১: নতুন প্রজেক্ট তৈরি করুন

Android Studio-তে File → New Project নির্বাচন করুন।

ধাপ ২: লেআউট ফাইল (res/layout/activity_main.xml)

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="https://schemas.android.com/apk/res/android"
    android:orientation="vertical"
    android:layout_width="match_parent"
    android:gravity="center"
    android:layout_height="wrap_content">
    <android.support.v7.widget.RecyclerView
        android:id="@+id/recycler_view"
        android:layout_width="match_parent"
        android:layout_height="400dp"
        android:scrollbars="vertical" />
    <TextView
        android:id="@+id/text"
        android:textSize="30sp"
        android:text="Update"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content" />
</LinearLayout>

ধাপ ৩: মেইন এক্টিভিটিতে কোড (src/MainActivity.java)

package com.example.myapplication;

import android.app.Activity;
import android.os.Bundle;
import android.support.v7.widget.DefaultItemAnimator;
import android.support.v7.widget.DividerItemDecoration;
import android.support.v7.widget.LinearLayoutManager;
import android.support.v7.widget.RecyclerView;
import android.view.View;
import android.widget.TextView;
import java.util.ArrayList;

public class MainActivity extends Activity {
    private RecyclerView recyclerView;
    private customAdapter mAdapter;
    TextView text;
    ArrayList<String> list = new ArrayList<>();

    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        recyclerView = findViewById(R.id.recycler_view);
        RecyclerView.LayoutManager mLayoutManager = new LinearLayoutManager(getApplicationContext());
        recyclerView.setLayoutManager(mLayoutManager);
        recyclerView.setItemAnimator(new DefaultItemAnimator());
        mAdapter = new customAdapter(this, list);
        recyclerView.setAdapter(mAdapter);
        recyclerView.addItemDecoration(new DividerItemDecoration(recyclerView.getContext(), DividerItemDecoration.VERTICAL));
        list.add("Sairamm");
        list.add("Krishna");
        list.add("Prasad");
        text = findViewById(R.id.text);
        text.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                list.add("Mammahe");
                mAdapter.notifyDataSetChanged();
            }
        });
    }
}

ধাপ ৪: কাস্টম অ্যাডাপ্টার (src/customAdapter.java)

package com.example.myapplication;

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

public class customAdapter extends RecyclerView.Adapter<customAdapter.MyViewHolder> {
    Context context;
    ArrayList<String> list;

    public class MyViewHolder extends RecyclerView.ViewHolder {
        public TextView title;
        public MyViewHolder(View view) {
            super(view);
            title = view.findViewById(R.id.title);
        }
    }

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

    @NonNull
    @Override
    public MyViewHolder onCreateViewHolder(@NonNull ViewGroup viewGroup, int i) {
        View itemView = LayoutInflater.from(viewGroup.getContext()).inflate(R.layout.list_row, viewGroup, false);
        return new MyViewHolder(itemView);
    }

    @Override
    public void onBindViewHolder(@NonNull MyViewHolder myViewHolder, int i) {
        myViewHolder.title.setText(list.get(i));
    }

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

ধাপ ৫: লিস্ট রো লেআউট (res/layout/list_row.xml)

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="https://schemas.android.com/apk/res/android"
    android:orientation="vertical"
    android:layout_width="match_parent"
    android:layout_height="wrap_content">
    <TextView
        android:id="@+id/title"
        android:layout_width="wrap_content"
        android:textSize="30sp"
        android:layout_marginLeft="10dp"
        android:layout_height="wrap_content" />
</LinearLayout>

অ্যাপ্লিকেশন চালানোর পদ্ধতি

অ্যাপ চালু করুন। "Update" টেক্সটে ক্লিক করলে লিস্টে নতুন আইটেম যোগ হবে।