The document provides an overview of popular Android HTTP libraries and image loading libraries. It discusses Apache HTTP Client, HttpURLConnection, OkHttp, and Volley for making HTTP requests. It also covers Picasso and Glide for loading images from URLs. For each library, it describes features like caching, asynchronous requests, error handling. It compares the libraries based on size, speed, ease of use and other factors. Benchmark results are shown for the different HTTP clients. The relationships between the libraries are illustrated in a diagram.

1. Android HTTP Library
Allan Shih

2. 2
Agenda

Introduction

HTTP library
- Apache Http Client
- HttpUrlConnection
- OkHttp
- Volley

Image library
- Picasso
- Glide

Reference

3. 3
Introduction
Most apps use HTTP to send and receive data

4. 4
Introduction
Every thing you need

JSON, images, raw text

Memory and disk caching

Powerful customization
abilities

Simple async interface

Easy to use

5. 5
Available official HTTP Client

Apache HttpClient
－ Provides a huge set of APIs/methods
－ Full implementation of all HTTP methods
－ Support for HTTP/1.1 response caching

HttpURLConnection
－ Lightweight HTTP client suitable for most apps
－ Transparent compression (Android 2.3)
－ Response caching (Android 4.0)

6. 6
Apache HTTP Client
Get server time

7. 7
Apache HTTP Client
Make a default HttpClient
HttpClient client = new DefaultHttpClient();
class HttpGetTask extends AsyncTask<String, Void, String> {
protected String doInBackground(String... params) {
HttpGet httpGet = new HttpGet(params[0]);
httpGet.addHeader("Accept", "application/json");
HttpResponse response = client.execute(httpGet);
return getJsonString(httpResponse);
}
...
}

8. 8
Apache HTTP Client
Add Headers to the request
HttpClient client = new DefaultHttpClient();
class HttpGetTask extends AsyncTask<String, Void, String> {
protected String doInBackground(String... params) {
HttpGet httpGet = new HttpGet(params[0]);
httpGet.addHeader("Accept", "application/json");
HttpResponse response = client.execute(httpGet);
return getJsonString(httpResponse);
}
...
}

9. 9
Apache HTTP Client
Make http request call
HttpClient client = new DefaultHttpClient();
class HttpGetTask extends AsyncTask<String, Void, String> {
protected String doInBackground(String... params) {
HttpGet httpGet = new HttpGet(params[0]);
httpGet.addHeader("Accept", "application/json");
HttpResponse response = client.execute(httpGet);
return getJsonString(httpResponse);
}
...
}

10. 10
HTTPUrlConnection
Getting a connection from a URL
class HttpGetTask extends AsyncTask<String, Void, String> {
protected String doInBackground(String... params) {
URL mURL = new URL(params[0]);
HttpURLConnection conn = (HttpURLConnection)
mURL.openConnection();
conn.setRequestMethod("GET");
conn.setRequestProperty("Accept", "application/json");
result = getJsonString(conn.getInputStream());
conn.disconnect();
}

11. 11
HTTPUrlConnection
Add Headers to the request
class HttpGetTask extends AsyncTask<String, Void, String> {
protected String doInBackground(String... params) {
URL mURL = new URL(params[0]);
HttpURLConnection conn = (HttpURLConnection)
mURL.openConnection();
conn.setRequestMethod("GET");
conn.setRequestProperty("Accept", "application/json");
result = getJsonString(conn.getInputStream());
conn.disconnect();
}

12. 12
HTTPUrlConnection
Read the response
class HttpGetTask extends AsyncTask<String, Void, String> {
protected String doInBackground(String... params) {
URL mURL = new URL(params[0]);
HttpURLConnection conn = (HttpURLConnection)
mURL.openConnection();
conn.setRequestMethod("GET");
conn.setRequestProperty("Accept", "application/json");
result = getJsonString(conn.getInputStream());
conn.disconnect();
}

13. 13
Problems

Apache HttpClient
－ Huge size of library
－ Difficult to improve it without breaking compatibility
－ Android 6.0 removes support for the Apache HTTP client

HttpURLConnection
－ Has some issues on Froyo (Android 2.2)
－ Fully-synchronous API
－ Not easy to use

14. OkHttp
An efficient HTTP client developed by Square

15. 15
OkHttp Client

GZIP

HTTP/2

Response caching

Async calls with callbacks

Recover from common connection problems

16. 16
OkHttp Client
Make a default client
private OkHttpClient client = new OkHttpClient();
Request request = new Request.Builder()
.url(requestURL)
.addHeader("Accept", "application/json")
.build();
Response response =
client.newCall(request).execute();
result = getJsonString(response);

17. 17
OkHttp Client
Synchronous Get
private OkHttpClient client = new OkHttpClient();
Request request = new Request.Builder()
.url(params[0])
.addHeader("Accept", "application/json")
.build();
Response response = client.newCall(request).execute();
result = getJsonString(response.body().byteStream());

18. 18
OkHttp Client
Asynchronous Get
Request request = new Request.Builder().url(url).build();
client.newCall(request).enqueue(new Callback() {
public void onFailure(Request request, Throwable t) {
...
}
public void onResponse(Response response) {
result = getJsonString(response.body().byteStream());
...
}
});

19. Volley
Easy, Fast Networking for Android

20. 20
What is Volley
A burst or
emission of many
things or a large
amount at once

21. 21
Volley

Automatic scheduling

Response caching

Support prioritization

Cancellation request API

Ease of customization

Debugging and tracing tools

22. 22
Volley architecture

23. 23
Volley
Setting Up a RequestQueue
RequestQueue mRequestQueue =
Volley.newRequestQueue(context);
StringRequest stringRequest =
new StringRequest(Request.Method.GET,
url,
listener,
errorListener);
mRequestQueue.add(getRequest);

24. 24
Volley
Make a GET Request
RequestQueue mRequestQueue =
Volley.newRequestQueue(context);
StringRequest stringRequest =
new StringRequest(Request.Method.GET,
url,
listener,
errorListener);
mRequestQueue.add(getRequest);

25. 25
Volley
Set Response Listener
StringRequest getRequest = new StringRequest(url,
new Response.Listener<String>() {
@Override
public void onResponse(String s) {
result = getJsonString(s);
}
},
new Response.ErrorListener() {
@Override
public void onErrorResponse(VolleyError volleyError) {
}
});

26. 26
Volley
Set Error Listener
StringRequest getRequest = new StringRequest(url,
new Response.Listener<String>() {
@Override
public void onResponse(String s) {
result = getJsonString(s);
}
},
new Response.ErrorListener() {
@Override
public void onErrorResponse(VolleyError volleyError) {
}
});

27. 27
Volley
Send POST request with JSON data
...
JsonObjectRequest jsonObjectRequest
= new JsonObjectRequest(Request.Method.POST,
url,
jsonDataObject,
listener,
errorListener);
mRequestQueue.add(jsonObjectRequest);

28. Benchmark
Using the Google Places Service

29. 29
Google place service
Get current places

30. 30
Google place service
Json data
"results" : [
{
"geometry" : {
"location" : {
"lat" : 25.0352548,
"lng" : 121.5625101
}
},
"id" : "137348ad7b2fc06d1ed646ca215062ccbf",
"name" : "Grand Hyatt Taipei",
"place_id" : "ChIJty1ap7erQjQRWmO-mTv1zkQ",
"rating" : 4,
"scope" : "GOOGLE",
"types" : ["restaurant", "food"],
"vicinity" : "No. 2, Songshou Road, Xinyi District"
},

31. 31
How did I test?
1. 清除 APP 資料
2. 發送 Request 到 Google Place Server
3. 連續送 25 個非同步 Request
4. 使用 Android Studio Monitor 記錄結果

32. 32
Response time (milliseconds)
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25
0
500
1000
1500
2000
2500
HttpClient HttpUrlConnection OkHttp Volley
Request
ResponseTime(ms)

33. 33
Memory
HttpUrl
Connection
HttpClient OkHttp Volley
108~124.47MB 108~122MB 108~124MB 108~120MB

34. 34
CPU
User mode and Kernel mode
HttpUrl
Connection
HttpClient OkHttp Volley
MAX 30% 38% 27% 33%

35. 35
Network
HttpUrl
Connection
HttpClient OkHttp Volley
MAX 208 KB/s 240 KB/s 260.49 KB/s 24 KB/s

36. 36
HTTP Client Comparison
HttpUrl
Connection
HttpClient OkHttp Volley
Creator Java.net Apache Square inc Google inc
Last version Android 6.0 4.3.5 2.6 1.0.19
Size - 591KB 327KB 91KB
Support HTTP/2 NO NO YES NO
Easy to use NO YES YES YES
Async call NO NO YES YES
Response Cache >= Android 4.0 >= 4.1 YES Enable

37. Image Loading
Load image from remote URL in ImageView

38. 38
Typical implementation
ImageAsyncTask
public class ImageAsyncTask extends AsyncTask<String, Void, Bitmap> {
protected Bitmap doInBackground(String... strings) {
HttpURLConnection connection = null;
URL imageUrl = new URL(strings[0]);
connection = (HttpURLConnection) imageUrl.openConnection();
if(connection.getResponseCode() == HttpURLConnection.HTTP_OK){
return BitmapFactory.decodeStream(connection.getInputStream());
}
connection.disconnect();
return null;
}
public void onPostExecute(Bitmap bitmap){
if (bitmap != null) mImageView.setImageBitmap(bitmap);
}

39. 39
Volley
Image Loading

ImgaeRequest
- Specify a URL and receive an image in response
- Image caching is enabled by default

ImageLoader
- A helper class that handles loading and caching images from URLs

NetworkImageView
- Builds on ImageLoader and effectively replaces ImageView

40. 40
Volley
Download image using ImageRequest
...
ImageRequest imageRequest = new ImageRequest(url,
new Response.Listener<Bitmap>() {
@Override
public void onResponse(Bitmap bitmap) {
imageView.setImageBitmap(bitmap);
}
},
width, height,
ImageView.ScaleType.FIT_XY,
Bitmap.Config.RGB_565,
errorListener);

41. 41
Volley
Download image using ImageRequest
...
ImageRequest imageRequest = new ImageRequest(url,
new Response.Listener<Bitmap>() {
@Override
public void onResponse(Bitmap bitmap) {
imageView.setImageBitmap(bitmap);
}
},
width, height,
ImageView.ScaleType.FIT_XY,
Bitmap.Config.RGB_565,
errorListener);

42. 42
Volley
Retrieving images with ImageLoader
ImageLoader imageLoader
= new ImageLoader(mRequestQueue, new BitmapLruCache());
ImageListener listener
= ImageLoader.getImageListener(imageView,
R.drawable.default_image,
R.drawable.failed_image);
imageLoader.get(imageURL, listener, 400, 400);

43. 43
Volley
Download image using NetworkImageView
- <ImageView
+ <com.android.volley.NetworkImageView
XML
mImageView = (NetworkImageView) findViewById(R.id.image);
mImageView.setImageUrl(IMAGE_URL, mImageLoader);
JAVA

44. 44
Picasso and Glide

Picasso
- Complex image transformations
- Automatic memory and disk caching
- ImageView recycling and download cancelation

Glide
- Fast loading big images from internet
- GIF (animated image) support
- Recommended by Google

45. 45
Load image from url to ImageView
Picasso.with(context).load(url).into(view);
Picasso
Glide.with(context).load(url).into(view);
Glide

46. 46
Re-size the image
Picasso.with(context).load(url)
.resize(200, 200).into(view);
Picasso
Glide.with(context).load(url)
.override(200, 200).into(view);
Glide

47. 47
GIF (animated image) support

48. 48
Image Loading
1920x1080 image is loaded into 768x432 ImageView

49. 49
Image Loader Comparison
Volley Picasso Glide
Creator Google inc Square inc BumpTech
Last version 1.0.19 2.5.2 3.6.1
Size 91KB 120KB 464KB
Speed
GIF support NO NO YES
Easy to use
Image Caching YES YES YES

50. 50
Relationships between the libraries

51. 51
Reference
1. HttpUrlConnection
2. Apache HTTP Client https://hc.apache.org/httpcomponents-client-ga/
3. Square OkHttp http://square.github.io/okhttp/
4. Volley documentation https://developer.android.com/training/volley
5. Picasso http://square.github.io/picasso/
6. Glide https://github.com/bumptech/glide
7. Which Android HTTP library to use?
8. HTTP 2.0