How do I stop my AsyncTask?

Question

My asynctask downloads a file in background when the app is opened, once the file gets downloaded, it starts an activity. Which is working fine. The problem is, I want to STOP my asynctask from downloading and opening activity if I close the app. I have tried this, It stops the service, but the AsyncTask doesn't stop.

class DownloadFileAsync extends AsyncTask<String, String, String> {
    @Override
    protected void onPreExecute() {
        super.onPreExecute();
    }

    @Override
    protected String doInBackground(String... aurl) {
        int count;
        try {
            URL url = new URL(aurl[0]);
            URLConnection conexion = url.openConnection();
            conexion.connect();
            int lenghtOfFile = conexion.getContentLength();
            Log.d("ANDRO_ASYNC", "Lenght of file: " + lenghtOfFile);
            InputStream input = new BufferedInputStream(url.openStream());
            // OutputStream output = new
            // FileOutputStream("/sdcard/.temp");//.temp is the image file
            // name

            OutputStream output = new FileOutputStream(VersionFile);
            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();
            output.close();
            input.close();
        } catch (Exception e) {
        }
        return null;
    }

    protected void onProgressUpdate(String... progress) {
        Log.d("ANDRO_ASYNC", progress[0]);
    }

    @Override
    protected void onPostExecute(String unused) {
        //start activity
        Intent dialogIntent = new Intent(context,
                NSOMUHBroadcastDisplay.class);
        dialogIntent.addFlags(Intent.FLAG_ACTIVITY_NEW_TASK);
        startActivity(dialogIntent);
        // now stop the service
        context.stopService(new Intent(context,
                NSOMUHBroadcastService.class));
    }
}

@Override
public void onDestroy() {
    Log.v("SERVICE", "Service killed");
    stopService(new Intent(this, NSOMUHBroadcastService.class));
    super.onDestroy();
}

score 0 · Answer 1 · edited May 23 '17 at 11:46

0

use yourtask.cancel() in onDestroy().

Use this link for more clarification: Android - Cancel AsyncTask Forcefully

edited May 23 '17 at 11:46

Community

1
1

answered Mar 03 '17 at 00:01

Asif Patel

1,744
1
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score 0 · Answer 2 · answered Mar 03 '17 at 00:03

0

First of all you need a reference to your AsyncTask instance. Let's say

DownloadFileAsync mTask;

You need to call:

mTask.cancel(true);

This is still not enough. Inside your doInBackground() method, you have to check if the AsyncTask has been cancelled.

if(isCancelled) {
    // exit
}

In your case probably you can use this check inside your while, so that if the Task is cancelled you close the stream and finish.

NOTE: In case you don't care about stopping the work in the doInBackground(), calling mTask.cancel(true) is enough, because the isCancelled() method is automatically called in the onPostExecute().

answered Mar 03 '17 at 00:03

GVillani82

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30
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172

The first one is a global variable. When you need to start your `AsyncTask` do `mTask = new DownloadFileAsync();` and start it `mTask.execute(your_input);` Then when you want to stop your AsyncTask just call `mTask.cancel(true)`. The isCancelled() is used inside the `doInBackground` [example](https://developer.android.com/reference/android/os/AsyncTask.html) – GVillani82 Mar 03 '17 at 00:17
I not understand) could you post a snippet, ? – user352621 Mar 03 '17 at 00:29

How do I stop my AsyncTask?

2 Answers2