Android Asynchronous Http Client

原文：http://loopj.com/android-async-http/

Overview

An asynchronous callback-based Http client for Android built on top of Apache’s HttpClient libraries.
All requests are made outside of your app’s main UI thread, but any callback logic will be executed on the same thread as the callback was created using Android’s Handler message passing.

Features

Make asynchronous HTTP
requests, handle responses in anonymous
callbacks

HTTP requests happen outside
the UI thread

Requests use a threadpool to
cap concurrent resource usage

GET/POST params
builder (RequestParams)

Multipart
file uploads with no additional third party libraries

Tiny size overhead to your application, only 25kb for
everything

Automatic smart request
retries optimized for spotty mobile connections

Automatic gzip response
decoding support for super-fast requests

Binary file (images etc) downloading with

BinaryHttpResponseHandler

Built-in response parsing into JSON with

JsonHttpResponseHandler

Persistent
cookie store, saves cookies into your app’s SharedPreferences

Who is Using It?

Heyzap
Social game discovery app with millions of users
DoubanFM
Popular personal online music radio service
Pose
Pose is the #1 fashion app for sharing and discovering new styles
Pocket
Salsa
Pocket Salsa is the easiest way to learn how to dance salsa.

Send me a message on
github to let me know if you are using this library in a released android application!

Installation & Basic Usage

Download the latest .jar file from github and place it in your Android app’s

libs/

folder.

Import the http package.

import com.loopj.android.http.*;

Create a new

AsyncHttpClient

instance
and make a request:

AsyncHttpClient client = new AsyncHttpClient();
client.get("http://www.google.com", new AsyncHttpResponseHandler() {
@Override
public void onSuccess(String response) {
System.out.println(response);
}
});

Recommended Usage: Make a Static Http Client

In this example, we’ll make a http client class with static accessors to make it easy to communicate with Twitter’s API.

import com.loopj.android.http.*;
public class TwitterRestClient {
private static final String BASE_URL = "http://api.twitter.com/1/";

private static AsyncHttpClient client = new AsyncHttpClient();

public static void get(String url, RequestParams params, AsyncHttpResponseHandler responseHandler) {
client.get(getAbsoluteUrl(url), params, responseHandler);
}

public static void post(String url, RequestParams params, AsyncHttpResponseHandler responseHandler) {
client.post(getAbsoluteUrl(url), params, responseHandler);
}

private static String getAbsoluteUrl(String relativeUrl) {
return BASE_URL + relativeUrl;
}
}

This then makes it very easy to work with the Twitter API in your code:

import org.json.*;
import com.loopj.android.http.*;
class TwitterRestClientUsage {
public void getPublicTimeline() throws JSONException {
TwitterRestClient.get("statuses/public_timeline.json", null, new JsonHttpResponseHandler() {
@Override
public void onSuccess(JSONArray response) {
// Pull out the first event on the public timeline
JSONObject firstEvent = timeline.get(0);
String tweetText = firstEvent.getString("text");

// Do something with the response
System.out.println(tweetText);
}
});
}
}

Check out the AsyncHttpClient, RequestParams and AsyncHttpResponseHandlerJavadocs
for more details.

Persistent Cookie Storage with

PersistentCookieStore

This library also includes a

PersistentCookieStore

which
is an implementation of the Apache HttpClient

CookieStore

interface
that automatically saves cookies to

SharedPreferences

storage
on the Android device.

This is extremely useful if you want to use cookies to manage authentication sessions, since the user will remain logged in even after closing and re-opening your app.

First, create an instance of

AsyncHttpClient

:

AsyncHttpClient myClient = new AsyncHttpClient();

Now set this client’s cookie store to be a new instance of

PersistentCookieStore

,
constructed with an activity or application context (usually

this

will
suffice):

PersistentCookieStore myCookieStore = new PersistentCookieStore(this);
myClient.setCookieStore(myCookieStore);

Any cookies received from servers will now be stored in the persistent cookie store.

To add your own cookies to the store, simply construct a new cookie and call

addCookie

:

BasicClientCookie newCookie = new BasicClientCookie("cookiesare", "awesome");
newCookie.setVersion(1);
newCookie.setDomain("mydomain.com");
newCookie.setPath("/");
myCookieStore.addCookie(newCookie);

See the PersistentCookieStore
Javadoc for more information.

Adding GET/POST Parameters with

RequestParams

The

RequestParams

class
is used to add optional GET or POST parameters to your requests.

RequestParams

can
be built and constructed in various ways:

Create empty

RequestParams

and
immediately add some parameters:

RequestParams params = new RequestParams();
params.put("key", "value");
params.put("more", "data");

Create

RequestParams

for
a single parameter:

RequestParams params = new RequestParams("single", "value");

Create

RequestParams

from
an existing

Map

of
key/value strings:

HashMap<String, String> paramMap = new HashMap<String, String>();
paramMap.put("key", "value");
RequestParams params = new RequestParams(paramMap);

See the RequestParams
Javadoc for more information.

Uploading Files with

RequestParams

The

RequestParams

class
additionally supports multipart file uploads as follows:

Add an

InputStream

to
the

RequestParams

to
upload:

InputStream myInputStream = blah;
RequestParams params = new RequestParams();
params.put("secret_passwords", myInputStream, "passwords.txt");

Add a

File

object
to the

RequestParams

to
upload:

File myFile = new File("/path/to/file.png");
RequestParams params = new RequestParams();
try {
params.put("profile_picture", myFile);
} catch(FileNotFoundException e) {}

Add a byte array to the

RequestParams

to
upload:

byte[] myByteArray = blah;
RequestParams params = new RequestParams();
params.put("soundtrack", new ByteArrayInputStream(myByteArray), "she-wolf.mp3");

See the RequestParams
Javadoc for more information.

Downloading Binary Data with

BinaryHttpResponseHandler

The

BinaryHttpResponseHandler

class
can be used to fetch binary data such as images and other files. For example:

AsyncHttpClient client = new AsyncHttpClient();
String[] allowedContentTypes = new String[] { "image/png", "image/jpeg" };
client.get("http://example.com/file.png", new BinaryHttpResponseHandler(allowedContentTypes) {
@Override
public void onSuccess(byte[] fileData) {
// Do something with the file
}
});

See the BinaryHttpResponseHandler
Javadoc for more information.

Adding HTTP Basic Auth credentials

Some requests may need username/password credentials when dealing with API services that use HTTP Basic Access Authentication requests. You can use the method

setBasicAuth()

to
provide your credentials.

Set username/password for any host and realm for a particular request. By default the Authentication Scope is for any host, port and realm.

AsyncHttpClient client = new AsyncHttpClient();
client.setBasicAuth("username","password/token");
client.get("http://example.com");

You can also provide a more specific Authentication Scope (recommended)

AsyncHttpClient client = new AsyncHttpClient();
client.setBasicAuth("username","password", new AuthScope("example.com", 80, AuthScope.ANY_REALM));
client.get("http://example.com");

See the RequestParams
Javadoc for more information.

Building from Source

To build a

.jar

file
from source, first make a clone of the android-async-http github repository. You’ll then need to copy the

local.properties.dist

file
to

local.properties

and
edit the

sdk.dir

setting
to point to where you have the android sdk installed. You can then run:

ant package

This will generate a file named

android-async-http-version.jar

.

Reporting Bugs or Feature Requests

Please report any bugs or feature requests on the github issues page for this project here:

https://github.com/loopj/android-async-http/issues

Credits & Contributors

James Smith (http://github.com/loopj)
Creator and Maintainer
Micah Fivecoate (http://github.com/m5)
Major Contributor, including the original

RequestParams

The Droid Fu Project (https://github.com/kaeppler/droid-fu)
Inspiration and code for better http retries
Rafael Sanches (http://blog.rafaelsanches.com)
Original

SimpleMultipartEntity

code
Anthony Persaud (http://github.com/apersaud)
Added support for HTTP Basic Authentication requests.
Linden Darling (http://github.com/coreform)
Added support for binary/image responses

License

The Android Asynchronous Http Client is released under the Android-friendly Apache License, Version 2.0. Read the full license here:

http://www.apache.org/licenses/LICENSE-2.0

About the Author

I'm James Smith, CTO of heyzap.com.
Originally from London, UK I now live in San Francisco.