Volley is an HTTP library that makes networking for Android apps easier and most importantly, faster. Volley is available through the open AOSP repository.
Volley offers the following benefits:
- Automatic scheduling of network requests.
- Multiple concurrent network connections.
- Transparent disk and memory response caching with standard HTTP cache coherence.
- Support for request prioritization.
- Cancellation request API. You can cancel a single request, or you can set blocks or scopes of requests to cancel.
- Ease of customization, for example, for retry and backoff.
- Strong ordering that makes it easy to correctly populate your UI with data fetched asynchronously from the network.
- Debugging and tracing tools.
First we need to download Volley framework as a library and add it to our project.
Clone the below url
git clone https://android.googlesource.com/platform/frameworks/volley
Now you will get a volley project downloaded.
I assume that you have created a Android Studio Project and opened it.
Now from that Window, Click File Menu -> New -> Import Module and Select Volley project we just downloaded.
We can see a Module Name while importing. You need to use this name in the gradle file to add the Volley library to your project.
My gradle file is looking like this.
dependencies {
compile fileTree(dir: 'libs', include: ['*.jar'])
testCompile 'junit:junit:4.12'
compile 'com.android.support:appcompat-v7:23.2.1'
compile 'com.android.support:design:23.2.1'
compile 'com.google.code.gson:gson:1.7.2'
compile project(':volley')
}
OR
Add Dependency
Add this dependency in build.gradle.
compile 'com.android.volley:volley:1.0.0'
Create a Singleton class for handling Volley requests.
package com.coderzheaven.volleydemo;
import android.content.Context;
import android.graphics.Bitmap;
import android.support.v4.util.LruCache;
import com.android.volley.Request;
import com.android.volley.RequestQueue;
import com.android.volley.toolbox.ImageLoader;
import com.android.volley.toolbox.Volley;
public class MySingleton {
private static MySingleton mInstance;
private RequestQueue mRequestQueue;
private ImageLoader mImageLoader;
private static Context mCtx;
private MySingleton(Context context) {
mCtx = context;
mRequestQueue = getRequestQueue();
mImageLoader = new ImageLoader(mRequestQueue,
new ImageLoader.ImageCache() {
private final LruCache<String, Bitmap>
cache = new LruCache<String, Bitmap>(20);
@Override
public Bitmap getBitmap(String url) {
return cache.get(url);
}
@Override
public void putBitmap(String url, Bitmap bitmap) {
cache.put(url, bitmap);
}
});
}
public static synchronized MySingleton getInstance(Context context) {
if (mInstance == null) {
mInstance = new MySingleton(context);
}
return mInstance;
}
public RequestQueue getRequestQueue() {
if (mRequestQueue == null) {
// getApplicationContext() is key, it keeps you from leaking the
// Activity or BroadcastReceiver if someone passes one in.
mRequestQueue = Volley.newRequestQueue(mCtx.getApplicationContext());
}
return mRequestQueue;
}
public <T> void addToRequestQueue(Request<T> req) {
getRequestQueue().add(req);
}
public ImageLoader getImageLoader() {
return mImageLoader;
}
}
Send a simple String request
Volley provides a convenience method Volley.newRequestQueue that sets up a RequestQueue for you, using default values, and starts the queue.
// Request a string response from the provided URL.
StringRequest stringRequest = new StringRequest(Request.Method.GET, url,
new Response.Listener<String>() {
@Override
public void onResponse(String response) {
Log.i(TAG, response.substring(0, 500));
}
}, new Response.ErrorListener() {
@Override
public void onErrorResponse(VolleyError error) {
Log.e(TAG, "Error :" + error.getLocalizedMessage());
}
});
stringRequest.setTag(queueTAG);
// Add the request to the RequestQueue.
mRequestQueue.add(stringRequest);
Simple Request With Cache
A RequestQueue needs two things to do its job: a network to perform transport of the requests, and a cache to handle caching.
// Instantiate the cache
Cache cache = new DiskBasedCache(getCacheDir(), 1024 * 1024); // 1MB cap
// Set up the network to use HttpURLConnection as the HTTP client.
Network network = new BasicNetwork(new HurlStack());
// Instantiate the RequestQueue with the cache and network.
mRequestQueue = new RequestQueue(cache, network);
// Start the queue
mRequestQueue.start();
// Formulate the request and handle the response.
StringRequest stringRequest = new StringRequest(Request.Method.GET, url,
new Response.Listener<String>() {
@Override
public void onResponse(String response) {
Log.i(TAG, "simpleRequestWithNetworkCache : " + response.substring(0, 500));
}
},
new Response.ErrorListener() {
@Override
public void onErrorResponse(VolleyError error) {
Log.e(TAG, "(simpleRequestWithNetworkCache) Error :" + error.getLocalizedMessage());
}
});
// Add the request to the RequestQueue.
mRequestQueue.add(stringRequest);
Download an Image
Method 1
// Retrieves an image specified by the URL, displays it in the UI.
ImageRequest request = new ImageRequest(IMAGE_URL,
new Response.Listener<Bitmap>() {
@Override
public void onResponse(Bitmap bitmap) {
mImageView.setImageBitmap(bitmap);
}
}, 0, 0, null,
new Response.ErrorListener() {
public void onErrorResponse(VolleyError error) {
mImageView.setImageResource(R.drawable.no_image);
}
});
// Access the RequestQueue through your singleton class.
MySingleton.getInstance(this).addToRequestQueue(request);
Method 2
// Get the ImageLoader through your singleton class. mImageLoader = MySingleton.getInstance(this).getImageLoader(); // Set the URL of the image that should be loaded into this view, and // specify the ImageLoader that will be used to make the request. mNetworkImageView.setImageUrl(IMAGE_URL, mImageLoader);
Method 3 – Load Image with DiskCache
ImageLoader mImageLoader = new ImageLoader(mRequestQueue, new LruBitmapCache( LruBitmapCache.getCacheSize(getApplicationContext()))); mImgCont = mImageLoader.get(IMAGE_URL, ImageLoader.getImageListener(mImageView, R.drawable.android, R.drawable.no_image)); mImageView.setImageBitmap(mImgCont.getBitmap());
Load Local Image Without Listener
// Get the ImageLoader through your singleton class. mImageLoader = MySingleton.getInstance(this).getImageLoader(); mImgCont = mImageLoader.get(IMAGE_URL, ImageLoader.getImageListener(mImageView, R.drawable.android, R.drawable.no_image)); mImageView.setImageBitmap(mImgCont.getBitmap());
Load Local Image With Listener
// Get the ImageLoader through your singleton class.
mImageLoader = MySingleton.getInstance(this).getImageLoader();
mImgCont = mImageLoader.get(IMAGE_URL, ImageLoader.getImageListener(mImageView,
R.drawable.android, R.drawable.no_image));
mImageLoader.get(IMAGE_URL, new ImageLoader.ImageListener() {
@Override
public void onResponse(ImageLoader.ImageContainer response, boolean isImmediate) {
mImageView.setImageBitmap(response.getBitmap());
}
@Override
public void onErrorResponse(VolleyError error) {
mImageView.setImageResource(R.drawable.no_image);
}
});
Send GET Request
Volley provides the following classes for JSON requests:
- JsonArrayRequest—A request for retrieving a JSONArray response body at a given URL.
- JsonObjectRequest—A request for retrieving a JSONObject response body at a given URL, allowing for an optional JSONObject to be passed in as part of the request body.
Both classes are based on the common base class JsonRequest.
JsonObjectRequest jsObjRequest = new JsonObjectRequest
(Request.Method.GET, jsonUrl, null, new Response.Listener<JSONObject>() {
@Override
public void onResponse(JSONObject response) {
try {
Log.i(TAG, "Site : " + response.getString("Site"));
} catch (JSONException e) {
}
}
}, new Response.ErrorListener() {
@Override
public void onErrorResponse(VolleyError error) {
Log.i(TAG, "requestJSON :" + error.getLocalizedMessage());;
}
});
// Access the RequestQueue through your singleton class.
MySingleton.getInstance(this).addToRequestQueue(jsObjRequest);
Sending POST Requests
// Sending POST Request
void sendPOSTRequest(){
// Post params to be sent to the server
HashMap<String, String> params = new HashMap<String, String>();
params.put("key", "value");
JsonObjectRequest req = new JsonObjectRequest(postJsonUrl, new JSONObject(params),
new Response.Listener<JSONObject>() {
@Override
public void onResponse(JSONObject response) {
try {
VolleyLog.v("Response:%n %s", response.toString(4));
} catch (JSONException e) {
e.printStackTrace();
}
}
}, new Response.ErrorListener() {
@Override
public void onErrorResponse(VolleyError error) {
VolleyLog.e("Error: ", error.getMessage());
}
});
// Access the RequestQueue through your singleton class.
MySingleton.getInstance(this).addToRequestQueue(req);
}
Custom GSON request
You can check this post on How to Create Custom GSON request with Volley.
Here is the complete MainActivity Class.
package com.coderzheaven.volleydemo;
import android.graphics.Bitmap;
import android.os.Bundle;
import android.support.v7.app.AppCompatActivity;
import android.support.v7.widget.Toolbar;
import android.util.Log;
import android.view.View;
import android.widget.AdapterView;
import android.widget.ArrayAdapter;
import android.widget.ImageView;
import android.widget.ListView;
import android.widget.ProgressBar;
import android.widget.TextView;
import com.android.volley.Cache;
import com.android.volley.Network;
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.BasicNetwork;
import com.android.volley.toolbox.DiskBasedCache;
import com.android.volley.toolbox.HurlStack;
import com.android.volley.toolbox.ImageLoader;
import com.android.volley.toolbox.ImageRequest;
import com.android.volley.toolbox.JsonObjectRequest;
import com.android.volley.toolbox.NetworkImageView;
import com.android.volley.toolbox.StringRequest;
import org.json.JSONException;
import org.json.JSONObject;
public class MainActivity extends AppCompatActivity implements AdapterView.OnItemClickListener, View.OnClickListener {
public static final String TAG = "VolleyDemo";
public static final String queueTAG = "Req1";
ProgressBar mPb;
TextView mTextView;
ListView mListView;
ImageView mImageView;
ImageLoader mImageLoader;
NetworkImageView mNetworkImageView;
ImageLoader.ImageContainer mImgCont;
RequestQueue mRequestQueue = null;
private static final String IMAGE_URL =
"http://cdn3.pcadvisor.co.uk/cmsdata/features/3420161/Android_800_thumb800.jpg";
private static final String url = "http://www.coderzheaven.com";
private static final String jsonUrl = "http://echo.jsontest.com/Site/coderzheven.com/demo/Volley";
String[] listValues = new String[]{
"Simple Request",
"Simple Request With Network Cache",
"Download Image",
"Loading Local Image without Listener",
"Loading Local Image with Listener",
"Loading Image with Custom LRU Disk Cache",
"Request JSON",
"Custom GSON Request"
};
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
Toolbar toolbar = (Toolbar) findViewById(R.id.toolbar);
setSupportActionBar(toolbar);
mPb = (ProgressBar) findViewById(R.id.toolbar_progress_bar);
mTextView = (TextView) findViewById(R.id.tv);
mListView = (ListView) findViewById(R.id.list1);
mImageView = (ImageView) findViewById(R.id.image1);
mNetworkImageView = (NetworkImageView) findViewById(R.id.networkImageView);
mNetworkImageView.setOnClickListener(this);
mImageView.setOnClickListener(this);
// Get a RequestQueue
mRequestQueue = MySingleton.getInstance(this.getApplicationContext()).
getRequestQueue();
ArrayAdapter<String> adapter = new ArrayAdapter<String>(this,
android.R.layout.simple_list_item_1, android.R.id.text1, listValues);
// Assign adapter to ListView
mListView.setAdapter(adapter);
mListView.setOnItemClickListener(this);
//hide the progreebar initially
hidePb();
}
void showPb() {
mPb.setVisibility(View.VISIBLE);
}
void hidePb() {
mPb.setVisibility(View.GONE);
}
void simpleRequest() {
showPb();
// Request a string response from the provided URL.
StringRequest stringRequest = new StringRequest(Request.Method.GET, url,
new Response.Listener<String>() {
@Override
public void onResponse(String response) {
mTextView.setVisibility(View.VISIBLE);
Log.i(TAG, response.substring(0, 500));
mTextView.setText("SimpleRequest : Response Received");
hidePb();
}
}, new Response.ErrorListener() {
@Override
public void onErrorResponse(VolleyError error) {
mTextView.setVisibility(View.VISIBLE);
Log.e(TAG, "Error :" + error.getLocalizedMessage());
mTextView.setText("SimpleRequest : Response Error");
hidePb();
}
});
stringRequest.setTag(queueTAG);
// Add the request to the RequestQueue.
mRequestQueue.add(stringRequest);
}
void simpleRequestWithNetworkCache() {
showPb();
// Instantiate the cache
Cache cache = new DiskBasedCache(getCacheDir(), 1024 * 1024); // 1MB cap
// Set up the network to use HttpURLConnection as the HTTP client.
Network network = new BasicNetwork(new HurlStack());
// Instantiate the RequestQueue with the cache and network.
mRequestQueue = new RequestQueue(cache, network);
// Start the queue
mRequestQueue.start();
// Formulate the request and handle the response.
StringRequest stringRequest = new StringRequest(Request.Method.GET, url,
new Response.Listener<String>() {
@Override
public void onResponse(String response) {
mTextView.setVisibility(View.VISIBLE);
Log.i(TAG, "simpleRequestWithNetworkCache : " + response.substring(0, 500));
mTextView.setText("SimpleRequestWithNetworkCache : Response Received");
hidePb();
}
},
new Response.ErrorListener() {
@Override
public void onErrorResponse(VolleyError error) {
mTextView.setVisibility(View.VISIBLE);
mTextView.setText("SimpleRequestWithNetworkCache : Response Error");
Log.e(TAG, "(simpleRequestWithNetworkCache) Error :" + error.getLocalizedMessage());
hidePb();
}
});
// Add the request to the RequestQueue.
mRequestQueue.add(stringRequest);
}
void downloadImage() {
showPb();
mNetworkImageView.setVisibility(View.GONE);
mImageView.setVisibility(View.VISIBLE);
// Retrieves an image specified by the URL, displays it in the UI.
ImageRequest request = new ImageRequest(IMAGE_URL,
new Response.Listener<Bitmap>() {
@Override
public void onResponse(Bitmap bitmap) {
mImageView.setImageBitmap(bitmap);
hidePb();
}
}, 0, 0, null,
new Response.ErrorListener() {
public void onErrorResponse(VolleyError error) {
mImageView.setImageResource(R.drawable.no_image);
hidePb();
}
});
// Access the RequestQueue through your singleton class.
MySingleton.getInstance(this).addToRequestQueue(request);
}
// You can use ImageLoader by itself to display an Image.
void loadLocalImageWithoutListener() {
showPb();
mNetworkImageView.setVisibility(View.GONE);
mImageView.setVisibility(View.VISIBLE);
// Get the ImageLoader through your singleton class.
mImageLoader = MySingleton.getInstance(this).getImageLoader();
mImgCont = mImageLoader.get(IMAGE_URL, ImageLoader.getImageListener(mImageView,
R.drawable.android, R.drawable.no_image));
mImageView.setImageBitmap(mImgCont.getBitmap());
hidePb();
}
// You can use ImageLoader by itself to display an Image.
void loadLocalImageWithListener() {
showPb();
mNetworkImageView.setVisibility(View.GONE);
mImageView.setVisibility(View.VISIBLE);
// Get the ImageLoader through your singleton class.
mImageLoader = MySingleton.getInstance(this).getImageLoader();
mImgCont = mImageLoader.get(IMAGE_URL, ImageLoader.getImageListener(mImageView,
R.drawable.android, R.drawable.no_image));
mImageLoader.get(IMAGE_URL, new ImageLoader.ImageListener() {
@Override
public void onResponse(ImageLoader.ImageContainer response, boolean isImmediate) {
mImageView.setImageBitmap(response.getBitmap());
hidePb();
}
@Override
public void onErrorResponse(VolleyError error) {
mImageView.setImageResource(R.drawable.no_image);
hidePb();
}
});
}
void downloadImage2() {
showPb();
mImageView.setVisibility(View.GONE);
mNetworkImageView.setVisibility(View.VISIBLE);
// Get the ImageLoader through your singleton class.
mImageLoader = MySingleton.getInstance(this).getImageLoader();
// Set the URL of the image that should be loaded into this view, and
// specify the ImageLoader that will be used to make the request.
mNetworkImageView.setImageUrl(IMAGE_URL, mImageLoader);
hidePb();
}
void loadImageWithDiskCache() {
showPb();
mNetworkImageView.setVisibility(View.GONE);
mImageView.setVisibility(View.VISIBLE);
ImageLoader mImageLoader = new ImageLoader(mRequestQueue, new LruBitmapCache(
LruBitmapCache.getCacheSize(getApplicationContext())));
mImgCont = mImageLoader.get(IMAGE_URL, ImageLoader.getImageListener(mImageView,
R.drawable.android, R.drawable.no_image));
mImageView.setImageBitmap(mImgCont.getBitmap());
hidePb();
}
void requestJSON() {
showPb();
JsonObjectRequest jsObjRequest = new JsonObjectRequest
(Request.Method.GET, jsonUrl, null, new Response.Listener<JSONObject>() {
@Override
public void onResponse(JSONObject response) {
mTextView.setVisibility(View.VISIBLE);
try {
Log.i(TAG, "Site : " + response.getString("Site"));
mTextView.setText("Site : " + response.getString("Site") +
"\n" + "Demo : " + response.getString("demo"));
} catch (JSONException e) {
}
hidePb();
}
}, new Response.ErrorListener() {
@Override
public void onErrorResponse(VolleyError error) {
mTextView.setVisibility(View.VISIBLE);
Log.i(TAG, "requestJSON :" + error.getLocalizedMessage());
mTextView.setText("RequestJSON :JSON Error");
hidePb();
}
});
// Access the RequestQueue through your singleton class.
MySingleton.getInstance(this).addToRequestQueue(jsObjRequest);
}
private Response.Listener<MyGson> createSuccessListener() {
return new Response.Listener<MyGson>() {
@Override
public void onResponse(MyGson response) {
Log.i(TAG, "Response : " + response.getSite());
mTextView.setVisibility(View.VISIBLE);
mTextView.setText("Site : " + response.getSite());
hidePb();
}
};
}
private Response.ErrorListener createErrorListener() {
return new Response.ErrorListener() {
@Override
public void onErrorResponse(VolleyError error) {
Log.i(TAG, "Error : " + error.getLocalizedMessage());
mTextView.setVisibility(View.VISIBLE);
mTextView.setText("Error : " + error.getLocalizedMessage());
hidePb();
}
};
}
public void customGSONRequest() {
showPb();
GsonRequest<MyGson> myReq = new GsonRequest<MyGson>(jsonUrl,
MyGson.class, null,
createSuccessListener(),
createErrorListener());
mRequestQueue.add(myReq);
}
@Override
public void onItemClick(AdapterView<?> parent, View view, int position, long id) {
switch (position) {
case 0:
simpleRequest();
break;
case 1:
simpleRequestWithNetworkCache();
break;
case 2:
downloadImage();
break;
case 3:
loadLocalImageWithoutListener();
break;
case 4:
downloadImage2();
break;
case 5:
loadImageWithDiskCache();
break;
case 6:
requestJSON();
break;
default:
customGSONRequest();
break;
}
}
@Override
protected void onStop() {
super.onStop();
if (mRequestQueue != null) {
mRequestQueue.cancelAll(queueTAG);
Log.i(TAG, "Cancelled : " + queueTAG);
}
}
@Override
public void onClick(View v) {
v.setVisibility(View.GONE);
}
}
Layouts
Layout – activity_main.xml
<?xml version="1.0" encoding="utf-8"?>
<android.support.design.widget.CoordinatorLayout 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:fitsSystemWindows="true"
tools:context="com.coderzheaven.volleydemo.MainActivity">
<android.support.design.widget.AppBarLayout
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:theme="@style/AppTheme.AppBarOverlay">
<android.support.v7.widget.Toolbar
android:id="@+id/toolbar"
android:layout_width="match_parent"
android:layout_height="?attr/actionBarSize"
android:background="?attr/colorPrimary"
app:popupTheme="@style/AppTheme.PopupOverlay">
<ProgressBar
android:id="@+id/toolbar_progress_bar"
android:layout_width="30dp"
android:layout_height="30dp"
android:layout_gravity="right"
android:layout_marginRight="10dp"
android:indeterminateTint="#FFFFFF"
android:indeterminateTintMode="src_in" />
</android.support.v7.widget.Toolbar>
</android.support.design.widget.AppBarLayout>
<include layout="@layout/content_main" />
</android.support.design.widget.CoordinatorLayout>
The Layout – content_main.xml
<?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"
android:paddingBottom="@dimen/activity_vertical_margin"
android:paddingLeft="@dimen/activity_horizontal_margin"
android:paddingRight="@dimen/activity_horizontal_margin"
android:paddingTop="@dimen/activity_vertical_margin"
app:layout_behavior="@string/appbar_scrolling_view_behavior"
tools:context="com.coderzheaven.volleydemo.MainActivity"
tools:showIn="@layout/activity_main">
<android.support.v7.widget.ListViewCompat
android:id="@+id/list1"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_alignParentTop="true"
android:layout_marginBottom="10dp"
android:scrollIndicators="right"
android:scrollbars="vertical" />
<TextView
android:id="@+id/tv"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_alignParentBottom="true"
android:layout_marginTop="5dp"
android:visibility="gone"
android:background="@android:color/holo_green_light"
android:padding="5dp"
android:textColor="@android:color/white" />
<android.support.v7.widget.AppCompatImageView
android:id="@+id/image1"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_centerInParent="true" />
<com.android.volley.toolbox.NetworkImageView
android:id="@+id/networkImageView"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_centerInParent="true" />
</RelativeLayout>
All Done.
You can download the complete Android Studio Source Code from here.
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