Android Asynchronous Http Client

转自: loopj.com/android-async-http/

github上的地址: https://github.com/loopj/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 19kb for everything
• Automatic smart request retries optimized for spotty mobile connections
• Automatic gzip response decoding support for super-fast requests
• Optional built-in response parsing into JSON (JsonHttpResponseHandler)
• Optional persistent cookie store , saves cookies into your app’s SharedPreferences

Who is Using It?

Heyzap for Android

Social game discovery app with 800,000+ installs

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 AsyncHttpResponseHandler Javadocs 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.

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

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.