Using Toast in another class file without Activity extends Android

Question

I've 2 files: Core (extends Activity) and DwCore. I'm using AsyncTask in a Core subclass and I want to use Toast in DwCore subclass but I can't get properly the Core Context.

Core

class DwFiles extends AsyncTask<Void, Void, Long> {
    protected Long doInBackground(Void... parms) {
        long totalSize = 0;
        dwCore.mainCounter(Core.this);
        return totalSize;
    }
}

DwCore subclass

public void mainCounter(Context c){
    Integer count = 0;
    for(int i=0;i<count;i++){
        Toast.makeText(c, count.toString(), Toast.LENGTH_SHORT).show();
    }
}

Answer 1

You can't do anything that affects the UI from worker threads - that includes showing toasts.

class DwFiles extends AsyncTask<Void, Void, Long> {
protected Long doInBackground(Void... parms) {
    long totalSize = 0;
     publishProgress(check_point);
    return totalSize;
}
}

protected void onProgressUpdate(Integer integers) {
   dwCore.mainCounter(Core.this);
}