Android AsyncTask使用openFileOutputStream

Question

i have a error in my AsyncTask. I tried to save Data with FileOutputStream to a File, cause i need this Data permanent.

So iam reading this tutorial: Tutorial

But if iam adding the Code to my AsyncTask i get this error:

"The method openFileOutputStream(String, int) is undefined for the type MainActivity.DownloadSpielplan"

DownloadSpielplan is my AsyncTask

private class DownloadSpielplan extends AsyncTask <Void, Void, String>
    {
        @Override
        protected void onPreExecute() {
            // TODO Auto-generated method stub
            super.onPreExecute();
        }
        @Override
        protected String doInBackground(Void... params) {
            // TODO Auto-generated method stub


            //dont wonder reverseString is created and filled i delete this part from the code for more readability


            FILENAME = "SpielTag";
            JOUR = reverseString;

            FileOutputStream fos = openFileOutputStream(FILENAME, Context.MODE_PRIVATE);
            fos.write(JOUR.getBytes());
            fos.close();


            return reverseString;
        }

        @Override
        protected void onPostExecute(String reverseString) {
            // TODO Auto-generated method stub
            Toast.makeText(getApplicationContext(), "Download abgeschlossen!", Toast.LENGTH_LONG).show();
            super.onPostExecute(reverseString);
        }
    }   

I guess the Problem is, iam calling openFileOutputStream from the AsyncTask, but i cant find a solution how to fix it. (cause iam realy new in Android)

Answer 1

Method name is openFileOutput, not openFileOutputStream

Call

MainActivity.this.openFileOutput(FILENAME, Context.MODE_PRIVATE)

instead of

openFileOutputStream(FILENAME, Context.MODE_PRIVATE)

in your doInBackground method.

Answer 2

Because you are trying to access the method openFileOutputStream from a class which is not an Activity . Instead, write your code as-

FileOutputStream fos = MainActivity.this.openFileOutputStream(FILENAME, Context.MODE_PRIVATE);

or an other option would be pass the context from the activity calling the DownloadSpielplan in its constructor and use the context to open file output-

FileOutputStream fos = context.openFileOutputStream(FILENAME, Context.MODE_PRIVATE);