Cách lọc RecyclerView với SearchView trên Android

Giới thiệu

Ví dụ này minh họa cách triển khai tìm kiếm/lọc dữ liệu trên RecyclerView sử dụng SearchView trên Action Bar/Toolbar. Adapter implements Filterable để xử lý logic lọc.

Các bước thực hiện

Bước 1: Tạo dự án mới

Mở Android Studio, chọn File → New Project.

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

<?xml version="1.0" encoding="utf-8"?>
<androidx.constraintlayout.widget.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="match_parent"
    tools:context=".MainActivity">

    <androidx.recyclerview.widget.RecyclerView
        android:id="@+id/recyclerView"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:padding="4dp"
        android:scrollbars="vertical"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toTopOf="parent" />

</androidx.constraintlayout.widget.ConstraintLayout>

Bước 3: Model Item (src/ExampleItem.java)

package com.app.sample;

public class ExampleItem {
    private int imageResource;
    private String text1;
    private String text2;

    public ExampleItem(int imageResource, String text1, String text2) {
        this.imageResource = imageResource;
        this.text1 = text1;
        this.text2 = text2;
    }

    public int getImageResource() { return imageResource; }
    public String getText1() { return text1; }
    public String getText2() { return text2; }
}

Bước 4: Adapter có Filter (src/ExampleAdapter.java)

package com.app.sample;

import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.Filter;
import android.widget.Filterable;
import android.widget.ImageView;
import android.widget.TextView;
import androidx.annotation.NonNull;
import androidx.recyclerview.widget.RecyclerView;
import java.util.ArrayList;
import java.util.List;

public class ExampleAdapter extends RecyclerView.Adapter<ExampleAdapter.ExampleViewHolder> implements Filterable {
    private List<ExampleItem> exampleList;
    private List<ExampleItem> exampleListFull;

    static class ExampleViewHolder extends RecyclerView.ViewHolder {
        ImageView imageView;
        TextView textView1, textView2;

        ExampleViewHolder(View itemView) {
            super(itemView);
            imageView = itemView.findViewById(R.id.image_view);
            textView1 = itemView.findViewById(R.id.text_view1);
            textView2 = itemView.findViewById(R.id.text_view2);
        }
    }

    ExampleAdapter(List<ExampleItem> exampleList) {
        this.exampleList = exampleList;
        this.exampleListFull = new ArrayList<>(exampleList);
    }

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

    @Override
    public void onBindViewHolder(@NonNull ExampleViewHolder holder, int position) {
        ExampleItem currentItem = exampleList.get(position);
        holder.imageView.setImageResource(currentItem.getImageResource());
        holder.textView1.setText(currentItem.getText1());
        holder.textView2.setText(currentItem.getText2());
    }

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

    @Override
    public Filter getFilter() { return exampleFilter; }

    private Filter exampleFilter = new Filter() {
        @Override
        protected FilterResults performFiltering(CharSequence constraint) {
            List<ExampleItem> filteredList = new ArrayList<>();
            if (constraint == null || constraint.length() == 0) {
                filteredList.addAll(exampleListFull);
            } else {
                String filterPattern = constraint.toString().toLowerCase().trim();
                for (ExampleItem item : exampleListFull) {
                    if (item.getText2().toLowerCase().contains(filterPattern)) {
                        filteredList.add(item);
                    }
                }
            }
            FilterResults results = new FilterResults();
            results.values = filteredList;
            return results;
        }

        @Override
        protected void publishResults(CharSequence constraint, FilterResults results) {
            exampleList.clear();
            exampleList.addAll((List) results.values);
            notifyDataSetChanged();
        }
    };
}

Bước 5: Layout item (res/layout/example_item.xml)

<?xml version="1.0" encoding="utf-8"?>
<androidx.cardview.widget.CardView
    xmlns:android="https://schemas.android.com/apk/res/android"
    xmlns:app="https://schemas.android.com/apk/res-auto"
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:layout_marginBottom="4dp"
    app:cardCornerRadius="4dp">

    <RelativeLayout
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:layout_margin="4dp">

        <ImageView
            android:id="@+id/image_view"
            android:layout_width="50dp"
            android:layout_height="50dp"
            android:padding="2dp" />

        <TextView
            android:id="@+id/text_view1"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_alignParentTop="true"
            android:layout_toEndOf="@id/image_view"
            android:text="Line 1"
            android:textColor="@android:color/black"
            android:textSize="20sp"
            android:textStyle="bold" />

        <TextView
            android:id="@+id/text_view2"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_below="@id/text_view1"
            android:layout_marginStart="8dp"
            android:layout_toEndOf="@id/image_view"
            android:text="Line 2"
            android:textSize="15sp" />

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

Bước 6: Menu Search (res/menu/example_menu.xml)

<?xml version="1.0" encoding="utf-8"?>
<menu xmlns:android="https://schemas.android.com/apk/res/android"
    xmlns:app="https://schemas.android.com/apk/res-auto">
    <item
        android:id="@+id/action_search"
        android:title="Tìm kiếm"
        app:showAsAction="ifRoom|collapseActionView"
        app:actionViewClass="androidx.appcompat.widget.SearchView" />
</menu>

Bước 7: MainActivity (src/MainActivity.java)

package com.app.sample;

import android.os.Bundle;
import android.view.Menu;
import android.view.MenuInflater;
import android.view.MenuItem;
import android.view.inputmethod.EditorInfo;
import android.widget.SearchView;
import androidx.appcompat.app.AppCompatActivity;
import androidx.recyclerview.widget.LinearLayoutManager;
import androidx.recyclerview.widget.RecyclerView;
import java.util.ArrayList;
import java.util.List;

public class MainActivity extends AppCompatActivity {
    private ExampleAdapter adapter;
    private List<ExampleItem> exampleList;

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

    private void fillExampleList() {
        exampleList = new ArrayList<>();
        exampleList.add(new ExampleItem(R.drawable.ic_android, "One", "Ten"));
        exampleList.add(new ExampleItem(R.drawable.ic_audio, "Two", "Eleven"));
        exampleList.add(new ExampleItem(R.drawable.ic_sun, "Three", "Twelve"));
        exampleList.add(new ExampleItem(R.drawable.ic_android, "Four", "Thirteen"));
        exampleList.add(new ExampleItem(R.drawable.ic_audio, "Five", "Fourteen"));
        exampleList.add(new ExampleItem(R.drawable.ic_sun, "Six", "Fifteen"));
        exampleList.add(new ExampleItem(R.drawable.ic_android, "Seven", "Sixteen"));
        exampleList.add(new ExampleItem(R.drawable.ic_audio, "Eight", "Seventeen"));
        exampleList.add(new ExampleItem(R.drawable.ic_sun, "Nine", "Eighteen"));
    }

    private void setUpRecyclerView() {
        RecyclerView recyclerView = findViewById(R.id.recyclerView);
        recyclerView.setHasFixedSize(true);
        RecyclerView.LayoutManager layoutManager = new LinearLayoutManager(this);
        adapter = new ExampleAdapter(exampleList);
        recyclerView.setLayoutManager(layoutManager);
        recyclerView.setAdapter(adapter);
    }

    @Override
    public boolean onCreateOptionsMenu(Menu menu) {
        MenuInflater inflater = getMenuInflater();
        inflater.inflate(R.menu.example_menu, menu);
        MenuItem searchItem = menu.findItem(R.id.action_search);
        SearchView searchView = (SearchView) searchItem.getActionView();
        searchView.setImeOptions(EditorInfo.IME_ACTION_DONE);
        searchView.setOnQueryTextListener(new SearchView.OnQueryTextListener() {
            @Override
            public boolean onQueryTextSubmit(String query) { return false; }
            @Override
            public boolean onQueryTextChange(String newText) {
                adapter.getFilter().filter(newText);
                return false;
            }
        });
        return true;
    }
}

Bước 8: Manifest (Manifest/AndroidManifest.xml)

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="https://schemas.android.com/apk/res/android"
    package="com.app.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. Nhấn biểu tượng tìm kiếm trên Toolbar, gõ từ khóa để lọc RecyclerView.

Tối ưu hóa hiệu năng

• Sử dụng DiffUtil thay vì notifyDataSetChanged() trong publishResults để animation mượt mà.
• Debounce tìm kiếm (delay 300ms) tránh lọc quá nhiều khi gõ nhanh.
• Với danh sách lớn, thực hiện lọc trên background thread (RxJava, Coroutines, Executor).