Ion是一个Android异步网络和图像加载库，优雅得API大大简化了网络操作。
地址：https://github.com/koush/ion

特点：

异步下载：

• Images into ImageViews or Bitmaps (animated GIFs supported too)
• JSON (via Gson)
• Strings
• Files
• Java types using Gson

易于使用地流式API

• 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
示例：https://github.com/koush/ion/tree/master/ion-sample

安装：

jar方式：

• 本身jar:ion.jar
• Gson:gson.jar
• AndroidAsync：https://github.com/koush/AndroidAsync

Maven：

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

Gradle：

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

使用：

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("filename.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(int downloaded, int 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");

Ion图像加载API特点

• Disk and memory caching
• Bitmaps are held via weak references so memory is managed very effeciently
• 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.

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

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（利用Gson无缝使用POJO）:

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();

Request Groups请求组合

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 [email protected] void onStop() {
    super.onStop();
    Ion.getDefault(activity).cancelAll(activity);}

Ion also lets you tag your requests into groups to allow for easy cancellation of requests in that group later:
自定义Group便于管理：

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 all requestsIon.getDefault(context).configure().proxy("mycomputer", 8888); // or... to proxy specific requestsIon.with(context).load("http://example.com/proxied.html").proxy("mycomputer", 8888).getString();

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:ResponseFuture同时包含头部和请求结果

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());
    }});