Android Asynchronous Networking and Image Loading

Download

• Maven
• Git

Features

• Asynchronously download:
  • Images into ImageViews or Bitmaps (animated GIFs supported too)
  • JSON (via Gson)
  • Strings
  • Files
  • Java types using Gson
• Easy to use Fluent API designed for Android
  • Automatically cancels operations when the calling Activity finishes
  • Manages invocation back onto the UI thread
  • All operations return a Future and can be cancelled
• HTTP POST/PUT:
  • text/plain
  • application/json - both JsonObject and POJO
  • application/x-www-form-urlencoded
  • multipart/form-data
• Transparent usage of HTTP features and optimizations:
  • SPDY and HTTP/2
  • Caching
  • Gzip/Deflate Compression
  • Connection pooling/reuse via HTTP Connection: keep-alive
  • Uses the best/stablest connection from a server if it has multiple IP addresses
  • Cookies
• View received headers
• Grouping and cancellation of requests
• Download progress callbacks
• Supports file:/, http(s):/, and content:/ URIs
• Request level logging and profiling
• Support for proxy servers like Charles Proxy to do request analysis
• Based on NIO and AndroidAsync
• Ability to use self signed SSL certificates

Samples

The included documented ion-sample project includes some samples that demo common Android network operations:

• Twitter Client Sample
  • Download JSON from a server (twitter feed)
  • Populate a ListView Adapter and fetch more data as you scroll to the end
  • Put images from a URLs into ImageViews (twitter profile pictures)
• File Download with Progress Bar Sample
• Get JSON and show images with the Image Search Sample

More Examples

Looking for more? Check out the examples below that demonstrate some other common scenarios. You can also take a look at 30+ ion unit tests in the ion-test.

Get JSON

Ion.with(context)
.load("http://example.com/thing.json")
.asJsonObject()
.setCallback(new FutureCallback<JsonObject>() {
   @Override
    public void onCompleted(Exception e, JsonObject result) {
        // do stuff with the result or error
    }
});

Post JSON and read JSON

JsonObject json = new JsonObject();
json.addProperty("foo", "bar");

Ion.with(context)
.load("http://example.com/post")
.setJsonObjectBody(json)
.asJsonObject()
.setCallback(new FutureCallback<JsonObject>() {
   @Override
    public void onCompleted(Exception e, JsonObject result) {
        // do stuff with the result or error
    }
});

Post application/x-www-form-urlencoded and read a String

Ion.with(getContext())
.load("https://koush.clockworkmod.com/test/echo")
.setBodyParameter("goop", "noop")
.setBodyParameter("foo", "bar")
.asString()
.setCallback(...)

Post multipart/form-data and read JSON with an upload progress bar

Ion.with(getContext())
.load("https://koush.clockworkmod.com/test/echo")
.uploadProgressBar(uploadProgressBar)
.setMultipartParameter("goop", "noop")
.setMultipartFile("archive", "application/zip", new File("/sdcard/filename.zip"))
.asJsonObject()
.setCallback(...)

Download a File with a progress bar

Ion.with(context)
.load("http://example.com/really-big-file.zip")
// have a ProgressBar get updated automatically with the percent
.progressBar(progressBar)
// and a ProgressDialog
.progressDialog(progressDialog)
// can also use a custom callback
.progress(new ProgressCallback() {@Override
   public void onProgress(long downloaded, long total) {
       System.out.println("" + downloaded + " / " + total);
   }
})
.write(new File("/sdcard/really-big-file.zip"))
.setCallback(new FutureCallback<File>() {
   @Override
    public void onCompleted(Exception e, File file) {
        // download done...
        // do stuff with the File or error
    }
});

Setting Headers

Ion.with(context)
.load("http://example.com/test.txt")
// set the header
.setHeader("foo", "bar")
.asString()
.setCallback(...)

Load an image into an ImageView

// This is the "long" way to do build an ImageView request... it allows you to set headers, etc.
Ion.with(context)
.load("http://example.com/image.png")
.withBitmap()
.placeholder(R.drawable.placeholder_image)
.error(R.drawable.error_image)
.animateLoad(spinAnimation)
.animateIn(fadeInAnimation)
.intoImageView(imageView);

// but for brevity, use the ImageView specific builder...
Ion.with(imageView)
.placeholder(R.drawable.placeholder_image)
.error(R.drawable.error_image)
.animateLoad(spinAnimation)
.animateIn(fadeInAnimation)
.load("http://example.com/image.png");

The Ion Image load API has the following features:

• Disk and memory caching
• Bitmaps are held via weak references so memory is managed very efficiently
• ListView Adapter recycling support
• Bitmap transformations via the .transform(Transform)
• Animate loading and loaded ImageView states
• DeepZoom for extremely large images

Futures

All operations return a custom Future that allows you to specify a callback that runs on completion.

public interface Future<T> extends Cancellable, java.util.concurrent.Future<T> {
    /**
     * Set a callback to be invoked when this Future completes.
     * @param callback
     * @return
     */
    public Future<T> setCallback(FutureCallback<T> callback);
}

Future<String> string = Ion.with(context)
.load("http://example.com/string.txt")
.asString();

Future<JsonObject> json = Ion.with(context)
.load("http://example.com/json.json")
.asJsonObject();

Future<File> file = Ion.with(context)
.load("http://example.com/file.zip")
.write(new File("/sdcard/file.zip"));

Future<Bitmap> bitmap = Ion.with(context)
.load("http://example.com/image.png")
.intoImageView(imageView);

Cancelling Requests

Futures can be cancelled by calling .cancel():

bitmap.cancel();
json.cancel();

Blocking on Requests

Though you should try to use callbacks for handling requests whenever possible, blocking on requests is possible too. All Futures have a Future.get() method that waits for the result of the request, by blocking if necessary.

JsonObject json = Ion.with(context)
.load("http://example.com/thing.json").asJsonObject().get();

Seamlessly use your own Java classes with Gson

public static class Tweet {
    public String id;
    public String text;
    public String photo;
}

public void getTweets() throws Exception {
    Ion.with(context)
    .load("http://example.com/api/tweets")
    .as(new TypeToken<List<Tweet>>(){})
    .setCallback(new FutureCallback<List<Tweet>>() {
       @Override
        public void onCompleted(Exception e, List<Tweet> tweets) {
          // chirp chirp
        }
    });
}

Logging

Wondering why your app is slow? Ion lets you do both global and request level logging.

To enable it globally:

Ion.getDefault(getContext()).configure().setLogging("MyLogs", Log.DEBUG);

Or to enable it on just a single request:

Ion.with(context)
.load("http://example.com/thing.json")
.setLogging("MyLogs", Log.DEBUG)
.asJsonObject();

Log entries will look like this:

D/MyLogs(23153): (0 ms) http://example.com/thing.json: Executing request.
D/MyLogs(23153): (106 ms) http://example.com/thing.json: Connecting socket
D/MyLogs(23153): (2985 ms) http://example.com/thing.json: Response is not cacheable
D/MyLogs(23153): (3003 ms) http://example.com/thing.json: Connection successful

Request Groups

By default, Ion automatically places all requests into a group with all the other requests created by that Activity or Service. Using the cancelAll(Activity) call, all requests still pending can be easily cancelled:

Future<JsonObject> json1 = Ion.with(activity, "http://example.com/test.json").asJsonObject();
Future<JsonObject> json2 = Ion.with(activity, "http://example.com/test2.json").asJsonObject();

// later... in activity.onStop
@Override
protected void onStop() {
    Ion.getDefault(activity).cancelAll(activity);
    super.onStop();
}

Ion also lets you tag your requests into groups to allow for easy cancellation of requests in that group later:

Object jsonGroup = new Object();
Object imageGroup = new Object();

Future<JsonObject> json1 = Ion.with(activity)
.load("http://example.com/test.json")
// tag in a custom group
.group(jsonGroup)
.asJsonObject();

Future<JsonObject> json2 = Ion.with(activity)
.load("http://example.com/test2.json")
// use the same custom group as the other json request
.group(jsonGroup)
.asJsonObject();

Future<Bitmap> image1 = Ion.with(activity)
.load("http://example.com/test.png")
// for this image request, use a different group for images
.group(imageGroup)
.intoImageView(imageView1);

Future<Bitmap> image2 = Ion.with(activity)
.load("http://example.com/test2.png")
// same imageGroup as before
.group(imageGroup)
.intoImageView(imageView2);

// later... to cancel only image downloads:
Ion.getDefault(activity).cancelAll(imageGroup);

Proxy Servers (like Charles Proxy)

Proxy server settings can be enabled all Ion requests, or on a per request basis:

// proxy all requests
Ion.getDefault(context).configure().proxy("mycomputer", 8888);

// or... to proxy specific requests
Ion.with(context)
.load("http://example.com/proxied.html")
.proxy("mycomputer", 8888)
.getString();

Using Charles Proxy on your desktop computer in conjunction with request proxying will prove invaluable for debugging!

Viewing Received Headers

Ion operations return a ResponseFuture, which grant access to response properties via the Response object. The Response object contains the headers, as well as the result:

Ion.with(getContext())
.load("http://example.com/test.txt")
.asString()
.withResponse()
.setCallback(new FutureCallback<Response<String>>() {
    @Override
    public void onCompleted(Exception e, Response<String> result) {
        // print the response code, ie, 200
        System.out.println(result.getHeaders().code());
        // print the String that was downloaded
        System.out.println(result.getResult());
    }
});

Get Ion

Maven

<dependency>
   <groupId>com.koushikdutta.ion</groupId>
   <artifactId>ion</artifactId>
   <version>2,</version>
</dependency>

Gradle

dependencies {
    compile 'com.koushikdutta.ion:ion:2.+'
}

Local Checkout (with AndroidAsync dependency)

git clone git://github.com/koush/AndroidAsync.git
git clone git://github.com/koush/ion.git
cd ion/ion
ant -Dsdk.dir=$ANDROID_HOME release install

Jars are at

• ion/ion/bin/classes.jar
• AndroidAsync/AndroidAsync/bin/classes.jar

Hack in Eclipse

git clone git://github.com/koush/AndroidAsync.git
git clone git://github.com/koush/ion.git

• Import the project from AndroidAsync/AndroidAsync into your workspace
• Import all the ion projects (ion/ion, ion/ion-sample) into your workspace.

Projects using ion

There's hundreds of apps using ion. Feel free to contact me or submit a pull request to add yours to this list.

• AllCast
• Helium
• Repost
• Cloupload
• Binge
• PictureCast
• Eventius
• Plume
• GameRaven
• See You There
• Doogles