我正面临着一个我不知道如何解决的问题
GetDataTask工作正常。但是当我上传文件时，会发送请求，但只有在文件上传完成后才会响应！ GetDataTask和UploadTask使用AsyncTask异步运行
知道为什么它不起作用以及为什么文件上传时响应不会回来
还有另一种方法可以实现这一点吗？
问题是，它应该并行运行但不幸的是它们同步运行
我在下面发布了我的实际来源
提前谢谢。
GetData任务：
private class GetDataTask extends AsyncTask<String, Void, String>{
@Override
protected void onPreExecute() {
}
@Override
protected String doInBackground(String... params) {
return NetConnection.getRecordData(mUserId, mUserPassword);
}
@Override
protected void onPostExecute(String result) {
parseJson(result);
}
}
上传任务：
private class HttpMultipartPost extends AsyncTask<String, Integer, String>
{
TextProgressBar pb;
long totalSize;
String filePath;
@Override
protected void onPreExecute()
{
pb = (TextProgressBar) findViewById(R.id.idPBUploadProgress);
pb.setMax(100);
}
@Override
protected String doInBackground(String... arg)
{
HttpClient httpClient = new DefaultHttpClient();
HttpContext httpContext = new BasicHttpContext();
HttpPost httpPost = new HttpPost( Utils.UPLOAD_URL );
try
{
CustomMultiPartEntity multipartContent = new CustomMultiPartEntity(new ProgressListener()
{
@Override
public void transferred(long num)
{
publishProgress((int) ((num / (float) totalSize) * 100));
//Log.v(TAG, "Progress =" + num);
}
});
// We use FileBody to transfer an file
filePath = arg[0];
multipartContent.addPart("upfile", new FileBody(new File( filePath )));
totalSize = multipartContent.getContentLength();
Log.e(TAG, "Upload file size = " + totalSize/1048576 + "MB") ;
// Send it
httpPost.setEntity(multipartContent);
HttpResponse response = httpClient.execute(httpPost, httpContext);
String serverResponse = EntityUtils.toString(response.getEntity());
return serverResponse;
}
catch (Exception e)
{
System.out.println(e);
}
return null;
}
@Override
protected void onProgressUpdate(Integer... progress)
{
pb.setProgress((int) (progress[0]));
pb.setText(progress[0] + "%");
}
@Override
protected void onPostExecute(String result)
{
Log.e(TAG, "Response =" + result);
parseResult( result, filePath );
}
}
答案 0 :(得分：3)
以下是official java doc ...
的说明执行顺序
首次引入时，AsyncTasks在单个上串行执行 背景线程。从DONUT开始，这已更改为a 允许多个任务并行运行的线程池。 从HONEYCOMB开始，任务在单个线程上执行 避免因并行执行而导致的常见应用程序错误。
如果您真的想要并行执行，可以调用 executeOnExecutor(java.util.concurrent.Executor, Object[]) THREAD_POOL_EXECUTOR
所以如果你一起调用两个AsyncTask ......它们不会并行执行（例外是甜甜圈，ECLAIR和姜饼）......你可以使用executeOnExecutor并行执行它们......
答案 1 :(得分：0)
尝试这样，
package com.file.upload;
import java.io.FilterOutputStream;
import java.io.IOException;
import java.io.OutputStream;
import java.nio.charset.Charset;
import org.apache.http.entity.mime.HttpMultipartMode;
import org.apache.http.entity.mime.MultipartEntity;
public class CustomMultiPartEntity extends MultipartEntity{
private final ProgressListener listener;
public CustomMultiPartEntity (final ProgressListener listener)
{
super();
this.listener = listener;
}
public CustomMultiPartEntity (final HttpMultipartMode mode, final ProgressListener listener)
{
super(mode);
this.listener = listener;
}
public CustomMultiPartEntity (HttpMultipartMode mode, final String boundary, final Charset charset, final ProgressListener listener)
{
super(mode, boundary, charset);
this.listener = listener;
}
@Override
public void writeTo(final OutputStream outstream) throws IOException
{
super.writeTo(new CountingOutputStream(outstream, this.listener));
}
public static interface ProgressListener
{
void transferred(long num);
}
public static class CountingOutputStream extends FilterOutputStream
{
private final ProgressListener listener;
private long transferred;
public CountingOutputStream(final OutputStream out, final ProgressListener listener)
{
super(out);
this.listener = listener;
this.transferred = 0;
}
public void write(byte[] b, int off, int len) throws IOException
{
out.write(b, off, len);
this.transferred += len;
this.listener.transferred(this.transferred);
}
public void write(int b) throws IOException
{
out.write(b);
this.transferred++;
this.listener.transferred(this.transferred);
}
}
}
这是HttpMultipartPost .java上传文件
import java.io.File;
import java.io.IOException;
import org.apache.http.HttpResponse;
import org.apache.http.HttpStatus;
import org.apache.http.client.ClientProtocolException;
import org.apache.http.client.HttpClient;
import org.apache.http.client.methods.HttpPost;
import org.apache.http.entity.mime.MultipartEntity;
import org.apache.http.entity.mime.content.ContentBody;
import org.apache.http.entity.mime.content.FileBody;
import org.apache.http.impl.client.DefaultHttpClient;
import org.apache.http.params.BasicHttpParams;
import org.apache.http.params.HttpConnectionParams;
import org.apache.http.params.HttpParams;
import org.apache.http.util.EntityUtils;
import com.file.upload.MyMultipartEntity.ProgressListener;
import android.app.ProgressDialog;
import android.content.Context;
import android.os.AsyncTask;
import android.util.Log;
public class HttpMultipartPost extends AsyncTask<Void, Integer, Void> {
private Context context;
private String filepath;
private HttpClient client;
private ProgressDialog pd;
private long totalSize;
private static final String url = "Your URL";
public HttpMultipartPost (Context context, String filepath) {
super();
this.context = context;
this.filepath= filepath;
}
@Override
protected void onPreExecute() {
//Set timeout parameters
int timeout = 10000;
HttpParams httpParameters = new BasicHttpParams();
HttpConnectionParams.setConnectionTimeout(httpParameters, timeout);
HttpConnectionParams.setSoTimeout(httpParameters, timeout);
//We'll use the DefaultHttpClient
client = new DefaultHttpClient(httpParameters);
pd = new ProgressDialog(context);
pd.setProgressStyle(ProgressDialog.STYLE_HORIZONTAL);
pd.setMessage("Uploading File...");
pd.setCancelable(false);
pd.show();
}
@Override
protected Void doInBackground(Void... params) {
try {
File file = new File(filepath);
//Create the POST object
HttpPost post = new HttpPost(url);
//Create the multipart entity object and add a progress listener
//this is a our extended class so we can know the bytes that have been transfered
MultipartEntity entity = new CustomMultiPartEntity (new ProgressListener()
{
@Override
public void transferred(long num)
{
//Call the onProgressUpdate method with the percent completed
publishProgress((int) ((num / (float) totalSize) * 100));
Log.d("DEBUG", num + " - " + totalSize);
}
});
//Add the file to the content's body
ContentBody cbFile = new FileBody( file, "image/jpeg" );// change according
entity.addPart("source", cbFile);
//After adding everything we get the content's lenght
totalSize = entity.getContentLength();
//We add the entity to the post request
post.setEntity(entity);
//Execute post request
HttpResponse response = client.execute( post );
int statusCode = response.getStatusLine().getStatusCode();
if(statusCode == HttpStatus.SC_OK){
//If everything goes ok, we can get the response
String fullRes = EntityUtils.toString(response.getEntity());
Log.d("DEBUG", fullRes);
} else {
Log.d("DEBUG", "HTTP Fail, Response Code: " + statusCode);
}
} catch (ClientProtocolException e) {
// Any error related to the Http Protocol (e.g. malformed url)
e.printStackTrace();
} catch (IOException e) {
// Any IO error (e.g. File not found)
e.printStackTrace();
}
return null;
}
@Override
protected void onProgressUpdate(Integer... progress) {
//Set the pertange done in the progress dialog
pd.setProgress((int) (progress[0]));
}
@Override
protected void onPostExecute(Void result) {
//Dismiss progress dialog
pd.dismiss();
}
}
Hope this will helpful to you.
答案 2 :(得分：0)
当我用一个简单的线程替换 GetData Task 时，工作正常。
new Thread( new Runnable() {
@Override
public void run() {
String res = NetConnection. getRecordData(mUserId, mUserPassword);
Log.e(TAG, res);
parseJson(res);
}
}).start();
AsyncTask有些可疑，我不知道为什么。