Delete file if AsyncTask Fail

Question

Currently

I am downloading a file from a URL, I'm doing this within AsyncTask inside a Adapter. The problem I have is that when I press back onBackPressed the download stops but the file remains in the folder FileOutputStream(Environment.getExternalStorageDirectory().toString()+"/file.mp4");

My Question

Is it possible to delete the file if AsyncTask does not complete?

I have tried to do file.delete(); in the catch of doinbackground but I get error file.delete(); is ignored

Here is a summary of my adapter----

When Item in holder is clicked I call AsyncTask:

holder.setItemClickListener(new ItemClickListener() {
    if (pos == 1) {
                if(manager.fetchVideoPath(pos)==null) {

                    DownloadFileFromURL p = new DownloadFileFromURL();                  
                    p.execute(pos + "", "https://www.dropbox.com/s/xnzw753f13k68z4/Piper%20First%20Look%20%282016%29%20-%20Pixar%20Animated%20Short%20HD.mp4?dl=1");
                    a = "one";
                    bars.set(pos,new ProgressModel(pos,1));
                    //This is what is causing the issue
                    RecyclerVideoAdapter.this.notifyItemChanged(pos);
}

My AsyncTask:

private class DownloadFileFromURL extends AsyncTask<String, String, String> {

@Override
protected void onPreExecute() {
    super.onPreExecute();
    ((CircularProgressBar)vview.findViewById(R.id.circularProgressBar)).setProgress(1);
}

@Override
    protected String doInBackground(String... f_url) {
        int count;
        String pathreference = f_url[0]+",";
        positionnumber = Integer.parseInt(f_url[0]);
        try {
            URL url = new URL(f_url[1]);
            URLConnection conection = url.openConnection();
            conection.connect();

            int lenghtOfFile = conection.getContentLength();

            InputStream input = new BufferedInputStream(url.openStream(),
                    8192);

            if (a.equals("one")) {
                OutputStream output = new FileOutputStream(Environment
                        .getExternalStorageDirectory().toString()
                        + "/file.mp4");


                byte data[] = new byte[1024];

                long total = 0;

                while ((count = input.read(data)) != -1) {
                    total += count;
                    publishProgress("" + (int) ((total * 100) / lenghtOfFile));

                    output.write(data, 0, count);
                }

                output.flush();
                pathreference = pathreference+Environment.getExternalStorageDirectory().toString()+"/file.mp4";
                output.close();
                input.close();




            }
        } catch (Exception e) {
            Log.e("Error: ", e.getMessage());
        }

        return pathreference;
    }

protected void onProgressUpdate(String... progress) {           
        bars.get(positionnumber).setProgress_(Float.parseFloat(progress[0]));
        ((CircularProgressBar)vview.findViewById(R.id.circularProgressBar)).setProgress(bars.get(positionnumber).getProgress_());
    }

@Override
    protected void onPostExecute(String file_url) {
        String []split = file_url.split(",");
        int index1 = Integer.parseInt(split[0]);
        videoHolderClass.set(index1,new VideoHolderClass(index1,imgres[0]));
        bars.get(index1).setProgress_(0);
        manager.insertVideoPath(index1+"",split[1]);
        RecyclerVideoAdapter.this.notifyItemChanged(index1);

    }

}

possible duplicate of [this](https://stackoverflow.com/questions/6039158/android-cancel-async-task) post — AhmedAbdelaal, Jul 18 '17 at 16:47
@AhmedAbdelaal that post only cancel the `AsyncTask` but the file remain. — ClassA, Jul 18 '17 at 16:50
@MarcosVasconcelos what if it did not finish properly in `onPostExecute`? — ClassA, Jul 18 '17 at 16:51
If the error should occcur in the onPostExecute your must try/catch on it instead of the doInBackground. — Marcos Vasconcelos, Jul 18 '17 at 16:53
@MarcosVasconcelos can you please answer showing what you mean? — ClassA, Jul 18 '17 at 16:55
What kind of errors or interruptions you expect in your code? — Marcos Vasconcelos, Jul 18 '17 at 17:03
@MarcosVasconcelos everything works fine, the only problem I have is that when user exit the app the `AsyncTask` stops, but the file that was download remain(corrupted). So I want to detect when user exits or when `AsyncTask` stops and then delete the uncompleted file. — ClassA, Jul 18 '17 at 17:05
I have tried to do `file.delete();` in the catch Exception in doinbackground, but I get error, `file.delete(); is ignored` — ClassA, Jul 18 '17 at 17:11
But any Exception is caught there? Post the stacktraces of the exception and the complete error message about the "file.delete" is ignored — Marcos Vasconcelos, Jul 18 '17 at 17:17
This does mean that the task is finished correctly. Or if the URLConnection is interrupted without Exception you are receiving the endoffile and should check with the input-lenght if available — Marcos Vasconcelos, Jul 18 '17 at 18:00
@MarcosVasconcelos I found the reason why this is happening `RecyclerVideoAdapter.this.notifyItemChanged(pos);` please look at `holder-clicklistner` above. Now I need some way to update the progress without causing the download to stop when home/back button is pressed.. — ClassA, Jul 19 '17 at 04:27
Why do you are notifying the item changed? You can update it from the holder directly — Marcos Vasconcelos, Jul 19 '17 at 12:27

AhmedAbdelaal · Answer 1 · 2017-07-18T17:01:04.680

0

Building on the answer on this post, try to put the logic of deleting the file inside isCancelled() like this:

if (isCancelled() && file.exists()) 
    file.delete();
else
{
   // do your work here
}

Then you can call p.cancel(true) inside onBackPressed

edited Jul 18 '17 at 17:01

answered Jul 18 '17 at 16:58

AhmedAbdelaal

286
2
6

But the `AsyncTask` is called within a `Adapter` so I can't call `onBackPressed` – ClassA Jul 18 '17 at 17:00

Delete file if AsyncTask Fail

1 Answers1