How to Fillter item in Recyclerview Android example

RecyclerView makes it easy to efficiently display large sets of data. You supply the data and define how each item looks, and the RecyclerView library dynamically creates the elements when they're needed.

As the name implies, RecyclerView recycles those individual elements. When an item scrolls off the screen, RecyclerView doesn't destroy its view. Instead, RecyclerView reuses the view for new items that have scrolled onscreen. This reuse vastly improves performance, improving your app's responsiveness and reducing power consumption.

In this example we will implement a search functionality for our RecyclerView so we can filter it’s items by their text. For this we will use an EditText, the setTextChangedListener method, a TextWatcher and the afterTextChanged method.

How to Step Fillter item in recyclerview android

Step1. Create example_item.xml

<?xml version="1.0" encoding="utf-8"?>

<android.support.v7.widget.CardView xmlns:android="http://schemas.android.com/apk/res/android"

    xmlns:app="http://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/imageView"

            android:layout_width="50dp"

            android:layout_height="50dp"

            android:padding="2dp" />

        <TextView

            android:id="@+id/textView"

            android:layout_width="wrap_content"

            android:layout_height="wrap_content"

            android:layout_alignParentTop="true"

            android:layout_toEndOf="@+id/imageView"

            android:text="Line 1"

            android:textColor="@android:color/black"

            android:textSize="20sp"

            android:textStyle="bold" />

        <TextView

            android:id="@+id/textView2"

            android:layout_width="wrap_content"

            android:layout_height="wrap_content"

            android:layout_below="@+id/textView"

            android:layout_marginStart="8dp"

            android:layout_toEndOf="@+id/imageView"

            android:text="Line 2"

            android:textSize="15sp" />

    </RelativeLayout>

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

Step 2. Create model class ExampleItem.java

public class ExampleItem {

    private int mImageResource;

    private String mText1;

    private String mText2;

    public ExampleItem(int imageResource, String text1, String text2) {

        mImageResource = imageResource;

        mText1 = text1;

        mText2 = text2;

    }

    public int getImageResource() {

        return mImageResource;

    }

    public String getText1() {

        return mText1;

    }

    public String getText2() {

        return mText2;

    }

}

Step 3. Create adapter class ExampleAdapter .java

public class ExampleAdapter extends RecyclerView.Adapter<ExampleAdapter.ExampleViewHolder> {

    private ArrayList<ExampleItem> mExampleList;

    public static class ExampleViewHolder extends RecyclerView.ViewHolder {

        public ImageView mImageView;

        public TextView mTextView1;

        public TextView mTextView2;

        public ExampleViewHolder(View itemView) {

            super(itemView);

            mImageView = itemView.findViewById(R.id.imageView);

            mTextView1 = itemView.findViewById(R.id.textView);

            mTextView2 = itemView.findViewById(R.id.textView2);

        }

    }

    public ExampleAdapter(ArrayList<ExampleItem> exampleList) {

        mExampleList = exampleList;

    }

    @Override

    public ExampleViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {

        View v = LayoutInflater.from(parent.getContext()).inflate(R.layout.example_item, 

                parent, false);

        ExampleViewHolder evh = new ExampleViewHolder(v);

        return evh;

    }

    @Override

    public void onBindViewHolder(ExampleViewHolder holder, int position) {

        ExampleItem currentItem = mExampleList.get(position);

        holder.mImageView.setImageResource(currentItem.getImageResource());

        holder.mTextView1.setText(currentItem.getText1());

        holder.mTextView2.setText(currentItem.getText2());

    }

    @Override

    public int getItemCount() {

        return mExampleList.size();

    }

    public void filterList(ArrayList<ExampleItem> filteredList) {

        mExampleList = filteredList;

        notifyDataSetChanged();

    }

}

Step 4. Create layout  activity_main.xml

<?xml version="1.0" encoding="utf-8"?>

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"

    xmlns:app="http://schemas.android.com/apk/res-auto"

    xmlns:tools="http://schemas.android.com/tools"

    android:layout_width="match_parent"

    android:layout_height="match_parent"

    android:orientation="vertical"

    tools:context="com.codinginflow.searchfunctionalityexample.MainActivity">

    <EditText

        android:id="@+id/edittext"

        android:layout_width="match_parent"

        android:layout_height="wrap_content"

        android:layout_margin="16dp"/>

    <android.support.v7.widget.RecyclerView

        android:id="@+id/recyclerView"

        android:layout_width="match_parent"

        android:layout_height="match_parent"

        android:background="@android:color/darker_gray"

        android:padding="4dp"

        android:scrollbars="vertical" />

</LinearLayout>

Step 5. Create class  MainActivity.java

public class MainActivity extends AppCompatActivity {

    private ArrayList<ExampleItem> mExampleList;

    private RecyclerView mRecyclerView;

    private ExampleAdapter mAdapter;

    private RecyclerView.LayoutManager mLayoutManager;

    @Override

    protected void onCreate(Bundle savedInstanceState) {

        super.onCreate(savedInstanceState);

        setContentView(R.layout.activity_main);

        createExampleList();

        buildRecyclerView();

        EditText editText = findViewById(R.id.edittext);

        editText.addTextChangedListener(new TextWatcher() {

            @Override

            public void beforeTextChanged(CharSequence s, int start, int count, int after) {

            }

            @Override

            public void onTextChanged(CharSequence s, int start, int before, int count) {

            }

            @Override

            public void afterTextChanged(Editable s) {

                filter(s.toString());

            }

        });

    }

    private void filter(String text) {

        ArrayList<ExampleItem> filteredList = new ArrayList<>();

        for (ExampleItem item : mExampleList) {

            if (item.getText1().toLowerCase().contains(text.toLowerCase())) {

                filteredList.add(item);

            }

        }

        mAdapter.filterList(filteredList);

    }

    private void createExampleList() {

        mExampleList = new ArrayList<>();

        mExampleList.add(new ExampleItem(R.drawable.ic_android, "One", "Line 2"));

        mExampleList.add(new ExampleItem(R.drawable.ic_audio, "Two", "Line 2"));

        mExampleList.add(new ExampleItem(R.drawable.ic_sun, "Three", "Line 2"));

        mExampleList.add(new ExampleItem(R.drawable.ic_android, "Four", "Line 2"));

        mExampleList.add(new ExampleItem(R.drawable.ic_audio, "Five", "Line 2"));

        mExampleList.add(new ExampleItem(R.drawable.ic_sun, "Six", "Line 2"));

        mExampleList.add(new ExampleItem(R.drawable.ic_android, "Seven", "Line 2"));

        mExampleList.add(new ExampleItem(R.drawable.ic_audio, "Eight", "Line 2"));

        mExampleList.add(new ExampleItem(R.drawable.ic_sun, "Nine", "Line 2"));

    }

    private void buildRecyclerView() {

        mRecyclerView = findViewById(R.id.recyclerView);

        mRecyclerView.setHasFixedSize(true);

        mLayoutManager = new LinearLayoutManager(this);

        mAdapter = new ExampleAdapter(mExampleList);

        mRecyclerView.setLayoutManager(mLayoutManager);

        mRecyclerView.setAdapter(mAdapter);

    }

}