Android app writes to file and seems to be deleted when activity is finished

I have an android app that is writing a values to a file that the app also creates. I am able to write to the file and then again read from the file. However, as soon as that activity is finished, it seems that the file is now gone, or loses it's values.

I know you can't browse the files through explorer unless you root your phone and/or run the adb server as a specific user.

Here is my code for writing to the file: public void savePrices(View view) { FileOutputStream outputStream;

        File getFilesDir = this.getFilesDir();
        File filePathOne = new File(getFilesDir, filename);
        try {
            outputStream = openFileOutput(filename, Context.MODE_PRIVATE);
            for (int i = 0; i < priceArray.length; i++) {
                outputStream.write(String.format("%.2f\n", priceArray[i]).getBytes());
            }

            Toast.makeText(this, "Prices saved successfully!", Toast.LENGTH_SHORT).show();
            outputStream.close();
            } catch (Exception e) {
            e.printStackTrace();
        }

Here is my code that reads the file:

public void loadPrices(View view) {
        int i = 0;
        final InputStream file;
        BufferedReader reader;
        try{
            file = getAssets().open(filename);
            reader = new BufferedReader(new InputStreamReader(file));
            String line = reader.readLine();
            while(line != null){
                line = reader.readLine();
                priceArray[i] = Double.parseDouble(line);
                i++;
            }
        } catch(IOException ioe){
        ioe.printStackTrace();

        hamburgerPriceText.setText(String.format("%.2f", priceArray[0]));
        hotDogPriceText.setText(String.format("%.2f", priceArray[1]));
        chipsPriceText.setText(String.format("%.2f", priceArray[2]));
        beerPriceText.setText(String.format("%.2f", priceArray[3]));
        popPriceText.setText(String.format("%.2f", priceArray[4]));

        Toast.makeText(this, "Prices loaded successfully!", Toast.LENGTH_SHORT).show();

        }catch (NumberFormatException e) {
            Log.e("Load File", "Could not parse file data: " + e.toString());
        }
    }

After I call the save method which sets the values in the array and saves the values to the file, I run a clear method that removes all the values on the activity fields and in the array. So when I run the read method and it populates the fields on the activity, I know the values are coming from reading the file. This is the only way that I know that I'm saving and reading from the file successfully.

My question is how do I make it permanent? If I close the activity that saves the values and then immediately run the read method, all the values are 0.

Is there something that I am missing? How can I write to a file so if the activity is closed, or the app is completely closed, I can still retain the values?

Solution

Here is my code that reads the file:

There is nothing in that code that reads a file. It is reading some stuff out of the your app's assets. Also, for some reason, it is only updating the UI if you have an exception.

So when I run the read method and it populates the fields on the activity, I know the values are coming from reading the file.

No, they are coming from your app's assets, and you are only populating the fields if you have an IOException.

My question is how do I make it permanent?

Step #1: Actually read from the file. Since you are using openFileOutput() to write to the file, use openFileInput() to read from the file.

Step #2: Update the UI when you successfully read in the data, not in the catch block for the IOException.