Làm việc với RecyclerView trong ứng dụng Android

Giới thiệu

RecyclerView là widget hiện đại, linh hoạt và hiệu suất cao để hiển thị danh sách lớn (list/grid) trong Android, thay thế ListView cũ. Bài viết hướng dẫn triển khai đầy đủ: Model, Adapter, ViewHolder, LayoutManager.

Các bước thực hiện

Bước 1: Tạo dự án mới

Android Studio → File → New Project → Empty Activity.

Bước 2: Layout chính (res/layout/activity_main.xml)

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="https://schemas.android.com/apk/res/android"
    android:id="@+id/rlMain"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:layout_margin="16dp"
    android:orientation="vertical">

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

</LinearLayout>

Bước 3: Model (src/MovieModel.java)

package app.com.sample;

public class MovieModel {
    private String title, genre, year;

    public MovieModel() {}

    public MovieModel(String title, String genre, String year) {
        this.title = title;
        this.genre = genre;
        this.year = year;
    }

    // Getters & Setters
    public String getTitle() { return title; }
    public void setTitle(String title) { this.title = title; }
    public String getYear() { return year; }
    public void setYear(String year) { this.year = year; }
    public String getGenre() { return genre; }
    public void setGenre(String genre) { this.genre = genre; }
}

Bước 4: Item Layout (res/layout/movies_list.xml)

<?xml version="1.0" encoding="utf-8"?>
<androidx.cardview.widget.CardView
    xmlns:android="https://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="100dp"
    android:layout_margin="8dp">

    <RelativeLayout
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:padding="8dp">

        <TextView
            android:id="@+id/title"
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:layout_alignParentStart="true"
            android:layout_toStartOf="@id/year"
            android:textColor="#222222"
            android:textSize="16sp"
            android:textStyle="bold" />

        <TextView
            android:id="@+id/year"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_alignParentEnd="true"
            android:textColor="#999999" />

        <TextView
            android:id="@+id/genre"
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:layout_alignParentBottom="true" />

    </RelativeLayout>
</androidx.cardview.widget.CardView>

Bước 5: Adapter (src/MoviesAdapter.java)

package app.com.sample;

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.List;

public class MoviesAdapter extends RecyclerView.Adapter<MoviesAdapter.MyViewHolder> {

    private List<MovieModel> moviesList;

    // ViewHolder: nắm giữ reference các View của 1 item
    static class MyViewHolder extends RecyclerView.ViewHolder {
        TextView title, year, genre;
        MyViewHolder(View view) {
            super(view);
            title = view.findViewById(R.id.title);
            genre = view.findViewById(R.id.genre);
            year = view.findViewById(R.id.year);
        }
    }

    public MoviesAdapter(List<MovieModel> moviesList) {
        this.moviesList = moviesList;
    }

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

    @Override
    public void onBindViewHolder(MyViewHolder holder, int position) {
        MovieModel movie = moviesList.get(position);
        holder.title.setText(movie.getTitle());
        holder.genre.setText(movie.getGenre());
        holder.year.setText(movie.getYear());
    }

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

Bước 6: MainActivity (src/MainActivity.java)

package app.com.sample;

import android.os.Bundle;
import androidx.appcompat.app.AppCompatActivity;
import androidx.recyclerview.widget.DefaultItemAnimator;
import androidx.recyclerview.widget.LinearLayoutManager;
import androidx.recyclerview.widget.RecyclerView;
import java.util.ArrayList;
import java.util.List;

public class MainActivity extends AppCompatActivity {

    private List<MovieModel> movieList = new ArrayList<>();
    private MoviesAdapter mAdapter;

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

        RecyclerView recyclerView = findViewById(R.id.recyclerView);
        mAdapter = new MoviesAdapter(movieList);

        // LayoutManager: LinearLayoutManager (danh sách dọc), GridLayoutManager (lưới), StaggeredGridLayoutManager
        LinearLayoutManager layoutManager = new LinearLayoutManager(getApplicationContext());
        recyclerView.setLayoutManager(layoutManager);

        // ItemAnimator: hiệu ứng thêm/xóa item
        recyclerView.setItemAnimator(new DefaultItemAnimator());

        recyclerView.setAdapter(mAdapter);

        // Chuẩn bị dữ liệu mẫu
        prepareMovieData();
    }

    private void prepareMovieData() {
        MovieModel movie = new MovieModel("Mad Max: Fury Road", "Action & Adventure", "2015");
        movieList.add(movie);
        movie = new MovieModel("Inside Out", "Animation, Kids & Family", "2015");
        movieList.add(movie);
        movie = new MovieModel("Star Wars: Episode VII - The Force Awakens", "Action", "2015");
        movieList.add(movie);
        // ... thêm nhiều phim khác ...
        movie = new MovieModel("Guardians of the Galaxy", "Science Fiction & Fantasy", "2014");
        movieList.add(movie);

        // Thông báo adapter dữ liệu đã thay đổi
        mAdapter.notifyDataSetChanged();
    }
}

Bước 7: Manifest (androidManifest.xml)

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

Chạy ứng dụng

Kết nối thiết bị, nhấn Run. Danh sách phim hiển thị trong RecyclerView cuộn mượt mà.

Dependency cần thiết (build.gradle)

dependencies {
    implementation 'androidx.recyclerview:recyclerview:1.3.2'
    implementation 'androidx.cardview:cardview:1.0.0'
}

Khái niệm cốt lõi

Mở rộng phổ biến

• Click listener: Interface callback trong Adapter → MainActivity implement.
• DiffUtil + ListAdapter: Tối ưu hiệu suất cập nhật danh sách (chỉ reload item thay đổi).
• Pagination: Load thêm dữ liệu khi cuộn gần cuối (Paging 3 library).
• Swipe to dismiss / Drag & drop: ItemTouchHelper.
• Multiple View Types: Override getItemViewType() trong Adapter.