Android Activity MainThread 中不能执行http通信解决办法

Android Activity MainThread 中不能执行http通信解决办法

今天在做离线文件传输时。用HTTP上传文件。程序一运行　报如下的错误

android.os.NetworkOnMainThreadException

原因是Google从3开始，强制默认禁止UI主线程发起通信请求　

解决办法：  

把通信的代码转移到子线程里去做， 比较靠谱的是new一个AyncTask，在里面做通信

                          有几个细节性的问题是，

                                第一， 一般原有通信的代码都是共通的API， 被许多个Activity调用， 一个良好的修改方法是在共通API里面new AyncTask

                               第二， 通信的API一般来说都是同步的， 你通信，然后画面主线程需要堵塞住，等待API的通信结果，再决定下面的业务逻辑的走向。

所以，这块可以采取 AyncTask.get()， 让主线程堵塞，直到通信结束。 当然，如果你需要将通信异步的话， 可以用Handler机制来解决


具体调用代码如下：HTTP异

步请求

package com.qqtech.ucstar.utils;

import java.io.File;
import java.io.IOException;
import java.nio.charset.Charset;

import org.apache.http.HttpResponse;
import org.apache.http.client.HttpClient;
import org.apache.http.client.methods.HttpPost;
import org.apache.http.entity.mime.HttpMultipartMode;
import org.apache.http.entity.mime.MultipartEntity;
import org.apache.http.entity.mime.content.FileBody;
import org.apache.http.impl.client.DefaultHttpClient;

import android.os.AsyncTask;

public class HttpReqTask extends AsyncTask < Object, Object, HttpResponse > {

@Override
protected HttpResponse doInBackground(Object arg0) {
String fileUploadUrl = (String) arg0[0];
String streamid = (String) arg0[1];
File file = (File) arg0[2];
//boolean paramBoolean = Boolean.parseBoolean((String) arg0[3]);
//String paramString3 = (String) arg0[4];
HttpClient localHttpClient = new DefaultHttpClient();
//String str1 = "fileName";
File localFile = file;
try {
if ((localFile == null) || (!localFile.exists()))
throw new IOException("文件不存在:" + localFile);
} catch (IOException e1) {
e1.printStackTrace();
}
HttpPost localPostMethod = new HttpPost(fileUploadUrl+"?streamid="+streamid+"&fileencode=UTF-8");
//MultipartEntity reqEntity = new MultipartEntity(HttpMultipartMode.BROWSER_COMPATIBLE);
MultipartEntity reqEntity = new MultipartEntity(HttpMultipartMode.BROWSER_COMPATIBLE,null, Charset.forName("UTF-8"));
try {
FileBody bin = new FileBody(file);
reqEntity.addPart("file", bin);
localPostMethod.setEntity(reqEntity);
HttpResponse response = localHttpClient.execute(localPostMethod);
return response;
} catch (Exception e) {
e.printStackTrace();
}
return null;
}

}

调用代码如下：


Object[] param = new Object[5];
     param[0] = answer.getUploadURL();
     param[1] = answer.getStreamid();
     param[2] = new File(answer.getFileURL());
     param[3] = "false";
     param[4] = "";
     AsyncTask res = new HttpReqTask().execute(param);
     HttpResponse rep = null;
     rep = (HttpResponse) res.get();
     if (rep.getStatusLine().getStatusCode() == 200) {
      System.out.println("文件上传成功");
     }else{
      System.out.println("文件上传失败");
     }
    }