AsyncTask取消和多次运行

Question

I´m facing a problem running my AsyncTask multiple time after its cancelation. Check this:

Calling AsyncTask:

Log.d("Pre Cancel: ", uploadDB.isCancelled()+"");
uploadDB.executeOnExecutor(AsyncTask.THREAD_POOL_EXECUTOR, filenameTxt+".db");

AsyncTask code:

package com.example.rtls;

import java.io.File;
import java.io.FileInputStream;

import org.apache.commons.net.ftp.FTP;
import org.apache.commons.net.ftp.FTPClient;
import org.apache.commons.net.ftp.FTPReply;

import android.content.ContextWrapper;
import android.os.AsyncTask;
import android.util.Log;

public class UploadDB extends AsyncTask<String,Integer,String>{
public FTPClient client = null; 
public boolean status=false;

int i=0;
@Override
protected String doInBackground(String... filenameTxt) 
{
    while(i==0){
    client = new FTPClient();

    try {

        client.connect(Global.IP,Integer.parseInt(Global.port));

        client.login(Global.user,Global.pass);
        if (FTPReply.isPositiveCompletion(client.getReplyCode())) {  
            /* Set File Transfer Mode  
             *  
             * To avoid corruption issue you must specified a correct  
             * transfer mode, such as ASCII_FILE_TYPE, BINARY_FILE_TYPE,  
             * EBCDIC_FILE_TYPE .etc. Here, I use BINARY_FILE_TYPE  
             * for transferring text, image, and compressed files.  
             */  
            client.setFileType(FTP.BINARY_FILE_TYPE);  
            client.enterLocalPassiveMode();  
       }  
        Log.d("Filename: ", filenameTxt[0]);
        client.changeWorkingDirectory("/RTLS/databases/");  
        FileInputStream fis = new FileInputStream (new     File("/sdcard/rtls/Databases/"+filenameTxt[0]));  
        status=client.storeFile(filenameTxt[0], fis);  
        fis.close(); 
        if (this.isCancelled()) 
        {
//              Thread.currentThread().interrupt();
            Global.progressDialog.dismiss();
            break;
        }
        i=1;


    } catch (Exception e) {
        e.printStackTrace();
        try {
            client.logout();  
            client.disconnect();     
        } catch (Exception e2) {
            e2.printStackTrace();
        }
    }


    }

    return null;
}
@Override
protected void onPreExecute() {
  super.onPreExecute();
        Global.progressDialog.show();
    }

/**
 * update průběhu progressDialog
 */
@Override
protected void onProgressUpdate(Integer... progress) {
  super.onProgressUpdate(progress);
        Global.progressDialog.setIndeterminate(false);
        Global.progressDialog.setMax(100);
        Global.progressDialog.setProgress(progress[0]);
    }
@Override
protected void onPostExecute(String result) 
    {

        Global.progressDialog.dismiss();
        this.cancel(true);
        Log.d("Cancel: ", this.isCancelled()+"");

    }
@Override
protected void onCancelled(String result)
{
    Global.progressDialog.dismiss();
    //super.cancel(true);

}
}

After first run, Log Pre Cancel before AsyncTask wrotes false and then Log Cancel inside it is true, because its canceled in OnPostExecute(). When I want to run it for second, first Pre Cancel log is true (AsyncTask seems canceled). However, I cant start it again even it shouldnt be running. Any idea how to run it or cancel properly? Remember I need to run it as many times as needed! And also forgive me other mistakes. Just focus on canceling AsyncTask or idea how to run in many times. Thanks in advance!

EDIT: I´ve already checked all possible solutions here and on other places. Nothing helped :(

Answer 1

From the docs

The task can be executed only once (an exception will be thrown if a second execution is attempted.)

You need to create a new instance of the AsyncTask class to run it again.