AsyncHttpClient是异步的,但是有时候我们需要得到请求的结果集来返回给某个函数,由于是异步的,所以不能够直接return会去,所以可以定义一个interface来给调用AsyncHttpClient方法的一个回调来获取结果集。
1 public void click(View view) { 2 AsyncHttpClient client = new AsyncHttpClient(); 3 try { 4 String url = "http://url?name=" 5 + URLEncoder.encode("aaa", "utf-8") + "&pass=" 6 + URLEncoder.encode("bbb", "utf-8"); 7 client.get(url, new AsyncHttpResponseHandler() { 8 @Override 9 public void onSuccess(int statusCode, Header[] headers, 10 byte[] responseBody) { 11 super.onSuccess(statusCode, headers, responseBody); 12 13 Toast.makeText(Main.this, 14 "请求成功" + new String(responseBody), 0).show(); 15 } 16 17 @Override 18 public void onFailure(int statusCode, Header[] headers, 19 byte[] responseBody, Throwable error) { 20 // TODO Auto-generated method stub 21 super.onFailure(statusCode, headers, responseBody, error); 22 } 23 }); 24 } catch (Exception e) { 25 } 26 27 } 28 29 public void postclick(View view) { 30 try { 31 AsyncHttpClient client = new AsyncHttpClient(); 32 String url = "http://url"; 33 RequestParams params = new RequestParams(); 34 params.put("name", "张三"); 35 params.put("pass", "123456"); 36 client.post(url, params, new AsyncHttpResponseHandler() { 37 38 @Override 39 public void onSuccess(int statusCode, Header[] headers, 40 byte[] responseBody) { 41 super.onSuccess(statusCode, headers, responseBody); 42 Toast.makeText(Main.this, 43 "请求成功" + new String(responseBody), 0).show(); 44 } 45 46 }); 47 48 } catch (Exception e) { 49 // TODO: handle exception 50 } 51 52 } 53 54 public void btnupfile(View view) { 55 56 AsyncHttpClient client = new AsyncHttpClient(); 57 58 RequestParams params = new RequestParams(); 59 60 try { 61 File file = new File("/sdcard/1.jpg"); 62 System.out.println(file); 63 params.put("pic", file); 64 65 client.post("http://url", params, 66 new AsyncHttpResponseHandler() { 67 @Override 68 public void onSuccess(int statusCode, Header[] headers, 69 byte[] responseBody) { 70 super.onSuccess(statusCode, headers, responseBody); 71 Toast.makeText(Main.this, 72 "上传文件成功!", 0).show(); 73 } 74 }); 75 76 } catch (Exception e) { 77 // TODO Auto-generated catch block 78 e.printStackTrace(); 79 } 80 81 }
android-async-http 开源框架可以使我们轻松地获取网络数据或者向服务器发送数据,最关键的是,它是异步框架,在底层使用线程池处理并发请求,效率很高,使用又特别简单。
以往我们在安卓上做项目,比如要下载很多图片、网页或者其他的资源,多数开发者会选择一个线程一个下载任务这种模型,因为安卓自带的 AndroidHttpClient 或者 java 带的 java.net.URL ,默认都是阻塞式操作。这种模型效率不高,对并发要求高的 APP 来讲,并不适用。有的人会选择使用 nio 自己实现,代码复杂度又很高。
AsyncHttpClient 作为 android-async-http 框架的一个核心应用类,使用简单,可以处理文本、二进制等各种格式的 web 资源。下面提供一些代码来看如何使用:
1 public class Downloader { 2 public static AsyncHttpClient mHttpc = new AsyncHttpClient(); 3 public static String TAG = "Downloader"; 4 5 public void downloadText(String uri){ 6 mHttpc.get(uri, null, new AsyncHttpResponseHandler(){ 7 @Override 8 public void onSuccess(String data){ 9 Log.i(TAG, "downloaded, thread id " + Thread.currentThread().getId()); 10 // TODO: do something on 11 } 12 @Override 13 public void onFailure(Throwable e, String data){ 14 Log.i(TAG, "download failed."); 15 // TODO: error proceed 16 } 17 }); 18 } 19 20 public void downloadImage(String uri, String savePath){ 21 mHttpc.get(uri, new ImageResponseHandler(savePath)); 22 } 23 24 public class ImageResponseHandler extends BinaryHttpResponseHandler{ 25 private String mSavePath; 26 27 public ImageResponseHandler(String savePath){ 28 super(); 29 mSavePath = savePath; 30 } 31 @Override 32 public void onSuccess(byte[] data){ 33 Log.i(TAG, "download image, file length " + data.length); 34 // TODO: save image , do something on image 35 } 36 @Override 37 public void onFailure(Throwable e, String data){ 38 Log.i(TAG, "download failed"); 39 // TODO : error proceed 40 } 41 } 42 };