RecyclerView-এ ConstraintLayout ব্যবহারের পদ্ধতি

ConstraintLayout ব্যবহার করে RecyclerView আইটেম লেআউট তৈরি করা

এই উদাহরণটি দেখাবে কীভাবে RecyclerView-এর প্রতিটি আইটেমে ConstraintLayout ব্যবহার 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"?>
<android.support.design.widget.CoordinatorLayout
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    xmlns:android="https://schemas.android.com/apk/res/android"
    xmlns:app="https://schemas.android.com/apk/res-auto">
    <android.support.design.widget.AppBarLayout
        android:layout_width="match_parent"
        android:layout_height="wrap_content">
        <android.support.v7.widget.Toolbar
            android:id="@+id/appbarlayout_tool_bar"
            android:background="@color/colorPrimary"
            android:layout_width="match_parent"
            android:layout_height="?attr/actionBarSize"
            app:layout_scrollFlags="scroll|snap|enterAlways"
            app:theme="@style/ThemeOverlay.AppCompat.Dark.ActionBar"
            app:popupTheme="@style/ThemeOverlay.AppCompat.Light" />
    </android.support.design.widget.AppBarLayout>
    <android.support.v7.widget.RecyclerView
        android:id="@+id/recycler_view"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        app:layout_behavior="@string/appbar_scrolling_view_behavior"/>
</android.support.design.widget.CoordinatorLayout>

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

package com.example.myapplication;

import android.annotation.TargetApi;
import android.os.Build;
import android.os.Bundle;
import android.support.v7.app.AppCompatActivity;
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.support.v7.widget.Toolbar;
import java.util.ArrayList;

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

    @TargetApi(Build.VERSION_CODES.LOLLIPOP)
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        Toolbar toolbar = findViewById(R.id.appbarlayout_tool_bar);
        toolbar.setTitle("This is toolbar.");
        setSupportActionBar(toolbar);
        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));
        // ডেটা যোগ
        for (int i = 0; i < 20; i++) {
            list.add("Item " + i);
        }
    }
}

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) - ConstraintLayout

<?xml version="1.0" encoding="utf-8"?>
<android.support.constraint.ConstraintLayout 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="wrap_content"
    android:background="@color/colorAccent"
    tools:context=".MainActivity">
    <ImageView
        android:id="@+id/imageView2"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:src="@drawable/logo"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toTopOf="parent"
        app:layout_constraintVertical_bias="0.209" />
    <TextView
        android:id="@+id/title"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_marginTop="35dp"
        android:gravity="center"
        android:textSize="30sp"
        app:layout_constraintTop_toBottomOf="@+id/imageView2"
        tools:layout_editor_absoluteX="0dp" />
    <TextView
        android:id="@+id/textview2"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_marginTop="16dp"
        android:layout_marginBottom="8dp"
        android:gravity="center"
        android:text="Sairamkrishan"
        android:textSize="30sp"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintTop_toBottomOf="@+id/title"
        app:layout_constraintVertical_bias="0.0"
        tools:layout_editor_absoluteX="0dp" />
</android.support.constraint.ConstraintLayout>

অ্যাপ্লিকেশন চালানোর পদ্ধতি

অ্যাপ চালু করলে RecyclerView-এ ConstraintLayout-ভিত্তিক আইটেম দেখাবে।