Android Recycler View Example

    Android RecyclerView is more advanced version of ListView with improved performance and other benefits. In this tutorial we are going to learn how to render a simple RecyclerView with a custom layout. We’ll also learn writing a adapter class and row click listener.

    Open build.gradle and add recycler view and card view dependency. Then after rebuild the project.

build.gradle

dependencies {
    compile fileTree(include: ['*.jar'], dir: 'libs')
    compile 'com.android.support:appcompat-v7:25.0.1'
    compile 'com.android.support:design:25.0.1'
    compile 'com.android.support:cardview-v7:25.0.1'
    compile 'com.android.support:recyclerview-v7:25.0.1'
}

    Open res->values->styles.xml and added this below card view style into your styles file.

styles.xml

<resources>

    <style name="AppTheme" parent="Theme.AppCompat.Light.DarkActionBar">
        <item name="colorPrimary">@color/colorPrimary</item>
        <item name="colorPrimaryDark">@color/colorPrimaryDark</item>
        <item name="colorAccent">@color/colorAccent</item>
    </style>

    <style name="CardViewDefault" parent="CardView">
        <item name="cardElevation">3dp</item>
        <item name="contentPadding">5dp</item>
        <item name="android:layout_width">match_parent</item>
        <item name="android:layout_height">wrap_content</item>
        <item name="android:layout_marginTop">5dp</item>
        <item name="android:layout_marginLeft">5dp</item>
        <item name="android:layout_marginRight">5dp</item>
        <item name="android:layout_marginBottom">5dp</item>
    </style>

</resources>

    Open res->layout->activity_main.xml then after added this below line of code into your activity_main.xml file. here main componet is recycler view.

activity_main.xml

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="vertical"
    android:background="#e7e7e7"
    tools:context="com.androidsimplifycodes.example.RecyclerView.RecyclerActivity">

    <android.support.v7.widget.RecyclerView
        android:id="@+id/rvSelectItem"
        android:layout_width="match_parent"
        android:layout_height="match_parent"/>

</LinearLayout>

    Create an layout xml named list_item.xml with the below line of code. This layout file renders a single row in recycler view by displaying images into card view.

list_item.xml

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:orientation="vertical"
    android:padding="10dp">

    <android.support.v7.widget.CardView
        style="@style/CardViewDefault">

        <ImageView
            android:id="@+id/ivImage"
            android:layout_width="wrap_content"
            android:layout_height="300dp"
            android:contentDescription="@null"
            android:scaleType="fitXY"
            android:src="@drawable/img2" />

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

</LinearLayout>

    RecyclerModel is class use for the data storage. For example here stored scale bitmap into this model class.

RecyclerModel.java

package com.androidsimplifycodes.example.RecyclerView;

import android.content.Context;
import android.graphics.Bitmap;
import android.graphics.BitmapFactory;

public class RecyclerModel {

    private Bitmap bitmapResource;

    public Bitmap getBitmapResource() {
        return bitmapResource;
    }

    public void setGetBitmapResource(Context context, int getBitmapResource) {
        this.bitmapResource = Bitmap.createScaledBitmap(
                BitmapFactory.decodeResource(context.getResources(), getBitmapResource),
                500,
                500,
                false);
    }
}

RecyclerAdapter.java

package com.androidsimplifycodes.example.RecyclerView;

import android.content.Context;
import android.support.v7.widget.RecyclerView;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.ImageView;
import android.widget.Toast;

import com.androidsimplifycodes.example.R;

import java.util.ArrayList;

public class RecyclerAdapter extends RecyclerView.Adapter<RecyclerAdapter.ViewHolder> {

    private Context context;
    private ArrayList<RecyclerModel> list;

    RecyclerAdapter(Context context, ArrayList<RecyclerModel> list) {
        // give reference to the Activity context and list into the adapter
        this.context = context;
        this.list = list;
    }

    @Override
    public RecyclerAdapter.ViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
        return new ViewHolder(LayoutInflater.from(context).inflate(R.layout.list_item, parent, false));
    }

    @Override
    public void onBindViewHolder(final RecyclerAdapter.ViewHolder holder, int position) {
        holder.ivImage.setImageBitmap(list.get(position).getBitmapResource());

        holder.ivImage.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                // for the displaying the current item position when click.
                Toast.makeText(context, String.valueOf(holder.getAdapterPosition()), Toast.LENGTH_SHORT).show();
            }
        });
    }

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

    class ViewHolder extends RecyclerView.ViewHolder {

        ImageView ivImage;

        ViewHolder(View itemView) {
            super(itemView);
            initView(itemView);
        }

        private void initView(View rootView) {
            ivImage = (ImageView) rootView.findViewById(R.id.ivImage);
        }
    }
}

RecyclerActivity.java

package com.androidsimplifycodes.example.RecyclerView;

import android.os.Bundle;
import android.support.v7.app.AppCompatActivity;
import android.support.v7.widget.LinearLayoutManager;
import android.support.v7.widget.RecyclerView;

import com.androidsimplifycodes.example.R;

import java.util.ArrayList;

public class RecyclerActivity extends AppCompatActivity {

    protected RecyclerView rvSelectItem;
    protected ArrayList<RecyclerModel> list;
    protected RecyclerModel recyclerModel;

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

        // initialize array list
        list = new ArrayList<>();

        recyclerModel = new RecyclerModel();
        recyclerModel.setGetBitmapResource(this, R.drawable.img2);
        list.add(recyclerModel);

        recyclerModel = new RecyclerModel();
        recyclerModel.setGetBitmapResource(this, R.drawable.img5);
        list.add(recyclerModel);

        recyclerModel = new RecyclerModel();
        recyclerModel.setGetBitmapResource(this, R.drawable.img4);
        list.add(recyclerModel);

        recyclerModel = new RecyclerModel();
        recyclerModel.setGetBitmapResource(this, R.drawable.img5);
        list.add(recyclerModel);

        recyclerModel = new RecyclerModel();
        recyclerModel.setGetBitmapResource(this, R.drawable.img2);
        list.add(recyclerModel);

        recyclerModel = new RecyclerModel();
        recyclerModel.setGetBitmapResource(this, R.drawable.img4);
        list.add(recyclerModel);

        // LinearLayoutManager user for set Recycler View HORIZONTAL Or VERTICAL
        // for example LinearLayoutManager.VERTICAL Or LinearLayoutManager.HORIZONTAL
        LinearLayoutManager manager = new LinearLayoutManager(RecyclerActivity.this, LinearLayoutManager.HORIZONTAL, false);
        rvSelectItem.setLayoutManager(manager);
        // set Our RecyclerAdapter into setAdapter() method.
        rvSelectItem.setAdapter(new RecyclerAdapter(this, list));
    }

    private void initView() {
        rvSelectItem = (RecyclerView) findViewById(R.id.rvSelectItem);
    }
}

Output :