RecyclerView

RecyclerView

The RecyclerView widget is a more advanced and flexible version of ListView . This widget is a container for displaying large data sets that can be scrolled very efficiently by maintaining a limited number of views.

Will see simple example how to display country name and population using RecyclerView.

1. For recyclerview we need to add support library inside the

build.gradla(module:app),and then Syc project. 

compile 'com.android.support:recyclerview-v7:24.1.1'

2.Add RecyclerView in the activity_main.xml 

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:id="@+id/activity_main"
    android:layout_width="match_parent"
    android:layout_height="match_parent"

    tools:context="com.falgee.recycler.MainActivity">

    <android.support.v7.widget.RecyclerView
        android:id="@+id/recycler_view"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:scrollbars="vertical"/>
</RelativeLayout>

3.Create java class with 2 variables country and population.

public class Country {
    protected String name;
    protected double population;

    public Country(String name, double population) {
        this.name = name;
        this.population = population;
    }
} 

4.Create Adapter class for set the value to each item.

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

    private ArrayList<Country> countryList;

    /**     * View holder class     * */    public class MyViewHolder extends RecyclerView.ViewHolder {
        public TextView countryText;
        public TextView popText;

        public MyViewHolder(View view) {
            super(view);
            countryText = (TextView) view.findViewById(R.id.countryName);
            popText = (TextView) view.findViewById(R.id.pop);
        }
    }

    public CountryAdapter(ArrayList<Country> countryList) {
        this.countryList = countryList;
    }

    @Override    public void onBindViewHolder(MyViewHolder holder, int position) {
        Country c = countryList.get(position);
        holder.countryText.setText(c.name);
        holder.popText.setText(String.valueOf(c.population));
    }

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

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

5.We need to create item layout with 2 TextView for Display name and population.

row.xml 

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:orientation="vertical" android:layout_width="wrap_content"
    android:layout_height="wrap_content">

    <TextView
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:id="@+id/countryName"
        android:textStyle="bold"
        />
    <TextView
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:id="@+id/pop"/>
</LinearLayout> 

6.Go to MainActivity and we have to initialize RecyclerView.

And set the value for country and population. And set value to recycleview.

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

import java.util.ArrayList;

public class MainActivity extends Activity {
    ArrayList<Country> countryList;


    @Override    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        RecyclerView rv = (RecyclerView) findViewById(R.id.recycler_view);
        Country c=new Country("India","1,210,193,422");
        Country c1=new Country("China","1,354,040,000");
        Country c2=new Country("United States","315,761,000");
        Country c3=new Country("Indonesia","237,641,326");
        countryList=new ArrayList<Country>();
        countryList.add(c);
        countryList.add(c1);
        countryList.add(c2);
        countryList.add(c3);
        CountryAdapter ca = new CountryAdapter(countryList);
        rv.setAdapter(ca);
        LinearLayoutManager llm = new LinearLayoutManager(this);
        llm.setOrientation(LinearLayoutManager.VERTICAL);
        rv.setLayoutManager(llm);
    }
}

7.Run and see the result in your Screen.