Android网络请求库——android-async-http

使用android-async-http也非常简单，到官网http://loopj.com/android-async-http/下载依赖jar包，导入工程中libs文件夹下并添加到工程路径即可。通过下面的代码来创建一个异步请求：

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

 通过Get请求指定的URL并通过回调函数处理请求结果，同时，请求方式还支持POST和PUT，请求的同时还支持参数传递，下面看看如何通过JSON字符串作为参数访问服务器：

try {
					JSONObject jsonObject = new JSONObject();
					jsonObject.put("username", "ryantang");
					StringEntity stringEntity = new StringEntity(jsonObject.toString());
					client.post(MainActivity.this, "http://api.com/login", stringEntity, "application/json", new JsonHttpResponseHandler(){

						@Override
						public void onSuccess(JSONObject jsonObject) {
							super.onSuccess(jsonObject);
							
						}
						
					});
				} catch (JSONException e) {
					e.printStackTrace();
				} catch (UnsupportedEncodingException e) {
					e.printStackTrace();
				}

 官方推荐的使用方法，使用一个静态的请求对象，我们来看看官方例举的一个访问Twitter的API的例子：

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;
  }
}

 
 使用方法：

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 timeline) {
                // 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);
            }
        });
    }
}

 
 由于涉及网络请求，最后别忘了添加权限：

<uses-permission android:name="android.permission.INTERNET" />

 其他功能例如上传、下载文件等大家可以去官网查看

post

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

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