Volley Library in Android

What is Volley Library In Android 

Volley is used to call REST API under android application with better security and performance as compared to normal web requests.

Volley is also used to call multiple web services simultaneously using asynchronous call operation.

1)  Add volley library in  Project

implementation 'com.android.volley:volley:1.1.1'

2)  Mainfest internet permission

<uses-permission android:name="android.permission.INTERNET" />

3)  Create POJO CLASS or Property Class

package com.example.webviewexample;

public class Hero {
    String name, imageUrl;

    public Hero(String name, String imageUrl) {
        this.name = name;
        this.imageUrl = imageUrl;
    }

    public String getName() {
        return name;
    }

    public String getImageUrl() {
        return imageUrl;
    }
}


4)  Create CustomAdapter using LisViewAdapter

package com.example.webviewexample;

import android.content.Context;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.ArrayAdapter;
import android.widget.TextView;

import java.util.List;

public class ListViewAdapter extends ArrayAdapter<Hero> {

    //the hero list that will be displayed
    private List<Hero> heroList;

    //the context object
    private Context mCtx;

    //here we are getting the herolist and context
    //so while creating the object of this adapter class we need to give herolist and context
    public ListViewAdapter(List<Hero> heroList, Context mCtx) {
        super(mCtx, R.layout.list_items, heroList);
        this.heroList = heroList;
        this.mCtx = mCtx;
    }

    //this method will return the list item
    @Override
    public View getView(int position, View convertView, ViewGroup parent) {
        //getting the layoutinflater
        LayoutInflater inflater = LayoutInflater.from(mCtx);

        //creating a view with our xml layout
        View listViewItem = inflater.inflate(R.layout.list_items, null, true);

        //getting text views
        TextView textViewName = listViewItem.findViewById(R.id.textViewName);
        TextView textViewImageUrl = listViewItem.findViewById(R.id.textViewImageUrl);

        //Getting the hero for the specified position
        Hero hero = heroList.get(position);

        //setting hero values to textviews
        textViewName.setText(hero.getName());
        textViewImageUrl.setText(hero.getImageUrl());

        //returning the listitem
        return listViewItem;
    }
}


5)

package com.example.webviewexample;

import androidx.appcompat.app.AppCompatActivity;

import android.os.Bundle;
import android.view.View;
import android.widget.ListView;
import android.widget.ProgressBar;
import android.widget.Toast;

import com.android.volley.Request;
import com.android.volley.RequestQueue;
import com.android.volley.Response;
import com.android.volley.VolleyError;
import com.android.volley.toolbox.StringRequest;
import com.android.volley.toolbox.Volley;

import org.json.JSONArray;
import org.json.JSONException;
import org.json.JSONObject;

import java.util.ArrayList;
import java.util.List;

public class VolleyExample extends AppCompatActivity {

    private static final String JSON_URL = "https://simplifiedcoding.net/demos/view-flipper/heroes.php";

   

    //the hero list where we will store all the hero objects after parsing json
    List<Hero> heroList;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_volley_example);
        listView = (ListView) findViewById(R.id.listView);
        heroList = new ArrayList<>();

        //this method will fetch and parse the data
        loadHeroList();
    }

    private void loadHeroList() {
        //getting the progressbar
        final ProgressBar progressBar = (ProgressBar) findViewById(R.id.progressBar);

        //making the progressbar visible
        progressBar.setVisibility(View.VISIBLE);

        //creating a string request to send request to the url
        StringRequest stringRequest = new StringRequest(Request.Method.GET, JSON_URL,
                new Response.Listener<String>() {
                    @Override
                    public void onResponse(String response) {
                        //hiding the progressbar after completion
                        progressBar.setVisibility(View.INVISIBLE);


                        try {
                            //getting the whole json object from the response
                            JSONObject obj = new JSONObject(response);

                            //we have the array named hero inside the object
                            //so here we are getting that json array
                            JSONArray heroArray = obj.getJSONArray("heroes");

                            //now looping through all the elements of the json array
                            for (int i = 0; i < heroArray.length(); i++) {
                                //getting the json object of the particular index inside the array
                                JSONObject heroObject = heroArray.getJSONObject(i);

                                //creating a hero object and giving them the values from json object
                                Hero hero = new Hero(heroObject.getString("name"), heroObject.getString("imageurl"));

                                //adding the hero to herolist
                                heroList.add(hero);
                            }

                            //creating custom adapter object
                            ListViewAdapter adapter = new ListViewAdapter(heroList, getApplicationContext());

                            //adding the adapter to listview
                            listView.setAdapter(adapter);

                        } catch (JSONException e) {
                            e.printStackTrace();
                        }
                    }
                },
                new Response.ErrorListener() {
                    @Override
                    public void onErrorResponse(VolleyError error) {
                        //displaying the error in toast if occurrs
                        Toast.makeText(getApplicationContext(), error.getMessage(), Toast.LENGTH_SHORT).show();
                    }
                });

        //creating a request queue
        RequestQueue requestQueue = Volley.newRequestQueue(this);

        //adding the string request to request queue
        requestQueue.add(stringRequest);
    }
}





Layout File


<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout 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"
    tools:context=".VolleyExample">

    <ListView
        android:id="@+id/listView"
        android:layout_width="match_parent"
        android:layout_height="match_parent" />

    <ProgressBar
        android:visibility="gone"
        android:id="@+id/progressBar"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_centerHorizontal="true"
        android:layout_centerVertical="true" />

</RelativeLayout>


7)   Design File
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:padding="16dp"
    android:orientation="vertical">

    <TextView
        android:id="@+id/textViewName"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:textAppearance="@style/Base.TextAppearance.AppCompat.Large" />

    <TextView
        android:id="@+id/textViewImageUrl"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:autoLink="web"
        android:textColor="#08308e" />

</LinearLayout>


Call Registration API using Volley Library?

Volley library provide simple approach to registartion page?

package com.example.webviewexample;

import androidx.appcompat.app.AppCompatActivity;

import android.os.Bundle;
import android.view.View;
import android.widget.ListView;
import android.widget.ProgressBar;
import android.widget.Toast;

import com.android.volley.Request;
import com.android.volley.RequestQueue;
import com.android.volley.Response;
import com.android.volley.VolleyError;
import com.android.volley.toolbox.StringRequest;
import com.android.volley.toolbox.Volley;

import org.json.JSONArray;
import org.json.JSONException;
import org.json.JSONObject;

import java.util.ArrayList;
import java.util.List;

public class VolleyExample extends AppCompatActivity {

    private static  String JSON_URL = "https://shivaconceptsolution.com/webservices/reg.php";

    //listview object
    ListView listView;

    //the hero list where we will store all the hero objects after parsing json
    List<Hero> heroList;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_volley_example);
        listView = (ListView) findViewById(R.id.listView);
        heroList = new ArrayList<>();

        //this method will fetch and parse the data
        loadHeroList();
    }

    private void loadHeroList() {
        //getting the progressbar
        final ProgressBar progressBar = (ProgressBar) findViewById(R.id.progressBar);

        //making the progressbar visible
        progressBar.setVisibility(View.VISIBLE);

        //creating a string request to send request to the url
        StringRequest stringRequest = new StringRequest(Request.Method.POST, JSON_URL+= "?name="+"check"+"&pwd="+"chk123"+"&email="+"chk@gmail.com",
                new Response.Listener<String>() {
                    @Override
                    public void onResponse(String response) {
                        //hiding the progressbar after completion
                        progressBar.setVisibility(View.INVISIBLE);


                        try {
                            //getting the whole json object from the response
                            JSONObject obj = new JSONObject(response);

                            //we have the array named hero inside the object
                            //so here we are getting that json array
                            int st = obj.getInt("status");
                           if(st!=0)
                           {
                               Toast.makeText(getApplicationContext(),"Success", Toast.LENGTH_SHORT).show();
                           }
                          else
                           {
                               Toast.makeText(getApplicationContext(),"Fail", Toast.LENGTH_SHORT).show();
                           }

                        } catch (JSONException e) {
                            e.printStackTrace();
                        }
                    }
                },
                new Response.ErrorListener() {
                    @Override
                    public void onErrorResponse(VolleyError error) {
                        //displaying the error in toast if occurrs
                        Toast.makeText(getApplicationContext(), error.getMessage(), Toast.LENGTH_SHORT).show();
                    }
                });

        //creating a request queue
        RequestQueue requestQueue = Volley.newRequestQueue(this);

        //adding the string request to request queue
        requestQueue.add(stringRequest);
    }
}