VolleyExample.java.xml

#######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:layout_width="match_parent"
    android:layout_height="match_parent"
    tools:context="abhiandroid.com.volleybasicexample.MainActivity">


    <Button
        android:id="@+id/buttonRequest"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:background="#414af4"
        android:text="Click Here To Send HTTP Request To Server And See Response Displayed As Toast"
        android:textColor="#ffffff"
        android:layout_alignParentTop="true"
        android:layout_marginTop="50dp" />
</RelativeLayout>


dependency file
################

apply plugin: 'com.android.application'

android {
    compileSdkVersion 25
    buildToolsVersion "25.0.3"
    defaultConfig {
        applicationId "abhiandroid.com.volleybasicexample"
        minSdkVersion 15
        targetSdkVersion 25
        versionCode 1
        versionName "1.0"
        testInstrumentationRunner "android.support.test.runner.AndroidJUnitRunner"
    }
    buildTypes {
        release {
            minifyEnabled false
            proguardFiles getDefaultProguardFile('proguard-android.txt'), 'proguard-rules.pro'
        }
    }
}

dependencies {
    compile fileTree(dir: 'libs', include: ['*.jar'])
    androidTestCompile('com.android.support.test.espresso:espresso-core:2.2.2', {
        exclude group: 'com.android.support', module: 'support-annotations'
    })
    compile 'com.android.support:appcompat-v7:25.3.1'
    testCompile 'junit:junit:4.12'
    compile 'com.android.volley:volley:1.0.0' // dependency file for Volley
}
********************************************************************************************************
Manifest.xml code:

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
    package="abhiandroid.com.volleybasicexample">

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

    <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>






First we will need sample JSON code. Below is the code I am using:


{
    "users": [
        {
                "id": "1087",
                "name": ram",
                "email": "we@gmail.com",
                "gender" : "male",
                "contact": {
                    "mobile": "9886588523",
                    "home": "00 000000",
                    "office": "00 000000"
                }
        },
        {
                "id": "1088",
                "name": "raki",
                "email": "dd@gmail.com",
                "gender" : "male",
                "contact": {
                    "mobile": "+91 0000000000",
                    "home": "00 000000",
                    "office": "00 000000"
                }
        }
  ]
}




Now we will open the mocky.io and put the JSON code in it.

Generate HTTP Response For Volley




c) Now click on the Generate My HTTP Response




d) It will generate the link url which we will use in next step for sending request and getting HTTP response.
HTTP Request URL For Volley




Step 6: Now open app -> java -> package -> MainActivity.java and add the below code.




In this step we will initialize the button and set on click listener on it. When the button is click, it will send HTTP request to the url that we generated in the previous step and display the response as Toast on the screen.

Here we have used simple StringRequest and default RequestQueue that volley provide us.

package caseior.com.volleybasicexample;

import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.util.Log;
import android.view.View;
import android.widget.Button;
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;

public class MainActivity extends AppCompatActivity {

    private static final String TAG = MainActivity.class.getName();
    private Button btnRequest;

    private RequestQueue mRequestQueue;
    private StringRequest mStringRequest;
    private String url = "http://www.mocky.io/v2/597c41390f0000d002f4dbd1";

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

        btnRequest = (Button) findViewById(R.id.buttonRequest);

        btnRequest.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v){

                sendAndRequestResponse();

            }
        }

        );

    }

    private void sendAndRequestResponse() {

        //RequestQueue initialized
        mRequestQueue = Volley.newRequestQueue(this);

        //String Request initialized
        mStringRequest = new StringRequest(Request.Method.GET, url, new Response.Listener<String>() {
            @Override
            public void onResponse(String response) {

                Toast.makeText(getApplicationContext(),"Response :" + response.toString(), Toast.LENGTH_LONG).show();//display the response on screen

            }
        }, new Response.ErrorListener() {
            @Override
            public void onErrorResponse(VolleyError error) {

                Log.i(TAG,"Error :" + error.toString());
            }
        });

        mRequestQueue.add(mStringRequest);
    }
}


Output:

Now run the App and click on the button. You will see HTTP response from server on click of it.

***************************************************************************************************

Volley-Example-2-


In-Android-Studio
Creating New Project: Create a new Project  File -> New ->Android Application Project

 

Step 1: Open your layout file of main activity and add a ListView element.




###########
actvity_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:layout_width="match_parent"
 android:layout_height="match_parent"
 tools:context=".MainActivity" >

<ListView
 android:id="@+id/list"
 android:layout_width="fill_parent"
 android:layout_height="wrap_content"
 android:dividerHeight="1dp"
 />

</RelativeLayout>





Step 2: We will now create another layout file for ListView row and name this file as list_row.xml

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

<!-- Title -->
 <TextView
 android:id="@+id/title"
 android:layout_width="match_parent"
 android:layout_height="wrap_content"
 android:textSize="@dimen/title"
 android:layout_marginTop="10dp"
 android:layout_marginBottom="20dp"
 android:textColor="@color/title"/>

<!-- category-->
 <TextView
 android:id="@+id/category"
 android:layout_width="fill_parent"
 android:layout_height="wrap_content"
 android:textColor="@color/category"
 android:textSize="@dimen/category"
 android:textStyle="bold"
 android:layout_below="@+id/title"
 android:layout_marginTop="20dp"
 android:layout_marginLeft="1dp" />

<!-- Thumbnail Image -->
 <com.android.volley.toolbox.NetworkImageView
 android:id="@+id/thumbnail"
 android:layout_width="280dp"
 android:layout_height="280dp"
 android:layout_below="@+id/category"
 />
</RelativeLayout>







Step 3: Create a ImageClass.java and add the following code:

This class takes care of caching images on disk. A memory and disk cache allow   components to quickly reload processed images.

A memory cache offers fast access to bitmaps at the cost of taking up valuable application memory. The LruCache class is particularly well suited to the task of caching bitmaps.

package com.caseior.volley.json;

import android.graphics.Bitmap;
import android.support.v4.util.LruCache;

import com.android.volley.toolbox.ImageLoader.ImageCache;

public class ImageClass extends LruCache<String, Bitmap> implements
        ImageCache {
    public static int getDefaultLruCacheSize() {
        final int maxMemory = (int) (Runtime.getRuntime().maxMemory() / 1024);
        final int cacheSize = maxMemory / 8;

        return cacheSize;
    }

    public ImageClass() {
        this(getDefaultLruCacheSize());
    }

    public ImageClass(int sizeInKiloBytes) {
        super(sizeInKiloBytes);
    }

    @Override
    protected int sizeOf(String key, Bitmap value) {
        return value.getRowBytes() * value.getHeight() / 1024;
    }

    @Override
    public Bitmap getBitmap(String url) {
        return get(url);
    }

    @Override
    public void putBitmap(String url, Bitmap bitmap) {
        put(url, bitmap);
    }
}
Step 4: Next create a AppController class and add it in the AndroidManifest.xml to your <application> using name property to execute this class on starting of the application. Also add INTERNET permission as we are going to make network calls.

AppController.java

 package com.caseior.volley.json;

 import android.app.Application;
 import android.text.TextUtils;

 import com.android.volley.Request;
 import com.android.volley.RequestQueue;
 import com.android.volley.toolbox.ImageLoader;
 import com.android.volley.toolbox.Volley;

 public class AppController extends Application {

 public static final String TAG = AppController.class.getSimpleName();

 private RequestQueue mRequestQueue;
 private ImageLoader mImageLoader;

 private static AppController mInstance;

 @Override
 public void onCreate() {
 super.onCreate();
 mInstance = this;
 }

public static synchronized AppController getInstance() {
 return mInstance;
 }

public RequestQueue getRequestQueue() {
 if (mRequestQueue == null) {
 mRequestQueue = Volley.newRequestQueue(getApplicationContext());
 }

return mRequestQueue;
 }

public ImageLoader getImageLoader() {
 getRequestQueue();
 if (mImageLoader == null) {
 mImageLoader = new ImageLoader(this.mRequestQueue,
 new ImageClass());
 }
 return this.mImageLoader;
 }

public  void addToRequestQueue(Request req, String tag) {
 // set the default tag if tag is empty
 req.setTag(TextUtils.isEmpty(tag) ? TAG : tag);
 getRequestQueue().add(req);
 }

public  void addToRequestQueue(Request req) {
 req.setTag(TAG);
 getRequestQueue().add(req);
 }

public void cancelPendingRequests(Object tag) {
 if (mRequestQueue != null) {
 mRequestQueue.cancelAll(tag);
 }
 }
 }
 
 
 
Step 5: Define internet permission and add AppController class in AndroidManifest.xml



<?xml version="1.0" encoding="utf-8"?>
 <manifest xmlns:android="http://schemas.android.com/apk/res/android"
 package="com.example.abhishek.json">
 <uses-permission android:name="android.permission.INTERNET" />
 <application
 android:allowBackup="true"
 android:name=".AppController"
 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>





Step 6: Open build.gradle and add Volley library dependency.


compile ‘com.android.volley:volley:1.0.0’

 apply plugin: 'com.android.application'
 android {
 compileSdkVersion 26
 buildToolsVersion "26.0.2"
 defaultConfig {
 applicationId "com.example.abhishek.jsonvolleyexample"
 minSdkVersion 15
 targetSdkVersion 26
 versionCode 1
 versionName "1.0"
 testInstrumentationRunner "android.support.test.runner.AndroidJUnitRunner"
 }
 buildTypes {
 release {
 minifyEnabled false
 proguardFiles getDefaultProguardFile('proguard-android.txt'), 'proguard-rules.pro'
 }
 }
 }

dependencies {
 compile fileTree(dir: 'libs', include: ['*.jar'])
 androidTestCompile('com.android.support.test.espresso:espresso-core:2.2.2', {
 exclude group: 'com.android.support', module: 'support-annotations'
 })
 compile 'com.android.support:appcompat-v7:26.+'
 compile 'com.android.support.constraint:constraint-layout:1.0.2'
 testCompile 'junit:junit:4.12'
 compile 'com.android.volley:volley:1.0.0'
 }
 
 
 
 
 
 
Step 7: Create Model.java. This model class will be used to provide data to list view after parsing the json.

 package com.caseior.volley.json;

 public class Model {
 private String title, category ,thumbnailUrl;

 public Model() {
 }
 public Model(String title, String category, String thumbnailUrl) {
 this.title=title;
 this.category=category;
 this.thumbnailUrl = thumbnailUrl;
 }

 public String getTitle() {
 return title;
 }

 public void setTitle(String title) {
 this.title = title;
 }

 public String getCategory() {
 return category;
 }

 public void setCategory(String category) {
 this.category = category;
 }

 public String getThumbnailUrl() {
 return thumbnailUrl;
 }

 public void setThumbnailUrl(String thumbnailUrl) {
 this.thumbnailUrl = thumbnailUrl;
 }
 }
 
 
 
 
Step 8: Create a class CustomAdapter.java with below code. This is a custom adapter class which provides data to ListView

 package com.caseior.volley.json;
 import android.app.Activity;
 import android.content.Context;
 import android.view.LayoutInflater;
 import android.view.View;
 import android.view.ViewGroup;
 import android.widget.BaseAdapter;
 import android.widget.TextView;

 import com.android.volley.toolbox.ImageLoader;
 import com.android.volley.toolbox.NetworkImageView;
 import java.util.List;

 public class CustomAdapter extends BaseAdapter {
 private Activity activity;
 private LayoutInflater inflater;
 private List modelItems;
 ImageLoader imageLoader = AppController.getInstance().getImageLoader();

 public CustomAdapter(Activity activity, List modelItems) {
 this.activity = activity;
 this.modelItems = modelItems;
 }

 @Override
 public int getCount() {
 return modelItems.size();
 }

 @Override
 public Object getItem(int location) {
 return modelItems.get(location);
 }

 @Override
 public long getItemId(int position) {
 return position;
 }

 @Override
 public View getView(int position, View convertView, ViewGroup parent) {

 if (inflater == null)
 inflater = (LayoutInflater) activity
 .getSystemService(Context.LAYOUT_INFLATER_SERVICE);
 if (convertView == null)
 convertView = inflater.inflate(R.layout.list_row, null);

 if (imageLoader == null)
 imageLoader = AppController.getInstance().getImageLoader();

 TextView title = (TextView) convertView.findViewById(R.id.title);
 TextView category = (TextView) convertView.findViewById(R.id.category);

 NetworkImageView thumbNail = (NetworkImageView) convertView
 .findViewById(R.id.thumbnail);

 // getting model data for the row
 Model m = modelItems.get(position);

 // title
 title.setText("Title: " + String.valueOf(m.getTitle()));

 // category
 category.setText("Category: "+ String.valueOf(m.getCategory()));

 // thumbnail image
 thumbNail.setImageUrl(m.getThumbnailUrl(), imageLoader);

 return convertView;
 }}
Step 9: Now open your main activity class (MainActivity.java) and add the below code. We created volley’s JsonArrayRequest to get the json from url. Upon parsing the json, we stored all the json data into an ArrayList as Model objects.

 package com.caseior.volley.json;
 import java.util.ArrayList;
 import java.util.List;
 import org.json.JSONArray;
 import org.json.JSONException;
 import org.json.JSONObject;

 import android.app.Activity;
 import android.app.ProgressDialog;
 import android.os.Bundle;
 import android.util.Log;
 import android.view.Menu;
 import android.widget.ListView;

 import com.android.volley.Response;
 import com.android.volley.VolleyError;
 import com.android.volley.VolleyLog;
 import com.android.volley.toolbox.JsonArrayRequest;

 public class MainActivity extends Activity {
  // Log tag
 private static final String TAG = MainActivity.class.getSimpleName();

 private static final String url ="  http://mobileappdatabase.in/demo/smartnews/app_dashboard/jsonUrl/single-article.php?article-id=71";
 private ProgressDialog pDialog;

 private List modelList = new ArrayList();
 private ListView listView;
 private CustomAdapter adapter;

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

 listView = (ListView) findViewById(R.id.list);
 adapter = new CustomAdapter(this, modelList);
 listView.setAdapter(adapter);

 pDialog = new ProgressDialog(this);
 // Showing progress dialog before making http request
 pDialog.setMessage("Loading...");
 pDialog.show();

 // Creating volley request obj
 JsonArrayRequest movieReq = new JsonArrayRequest(url,
 new Response.Listener() {
 @Override
 public void onResponse(JSONArray response) {
 Log.d(TAG, response.toString());
 hidePDialog();

 // Parsing json
 for (int i = 0; i < response.length(); i++) {
 try {

 JSONObject obj = response.getJSONObject(i);
 Model model = new Model();
 model.setTitle(obj.getString("title"));
 model.setCategory(obj.getString("category"));
 model.setThumbnailUrl(obj.getString("image"));

 modelList.add(model);

} catch (JSONException e) {
 e.printStackTrace();
 }

}
 // notifying list adapter about data changes so that it renders the list view with updated data
 adapter.notifyDataSetChanged();
 }
 }, new Response.ErrorListener() {
 @Override
 public void onErrorResponse(VolleyError error) {
 VolleyLog.d(TAG, "Error: " + error.getMessage());
 hidePDialog();

}
 });

// Adding request to request queue
 AppController.getInstance().addToRequestQueue(movieReq);
 }

 @Override
 public void onDestroy() {
 super.onDestroy();
 hidePDialog();
 }

 private void hidePDialog() {
 if (pDialog != null) {
 pDialog.dismiss();
 pDialog = null;
 }
 }

 @Override
 public boolean onCreateOptionsMenu(Menu menu) {
 // Inflate the menu; this adds items to the action bar if it is present.
 getMenuInflater().inflate(R.menu.main, menu);
 return true;
 }}
Step 10: Add the following code in xml files

values  -> colors.xml

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

    <color name="category">#b932ca</color>
    <color name="title">#6b2cd9</color>

</resources>
values ->dimens.xml

<resources>

    <dimen name="title">22dp</dimen>
    <dimen name="category">20dip</dimen>

</resources>
  values -> strings.xml

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

    <string name="app_name">VolleyExample</string>

</resources>
  values -> styles.xml

<resources>

    <style name="AppBaseTheme" parent="android:Theme.Light">
    </style>
    <style name="AppTheme" parent="AppBaseTheme">
    </style>

</resources>