Write in existing .txt file

Question

How can I write in existing .txt file? I've tried multiple approaches, I've stopped on this one:

 private void writeToFile(String data) {
    try {

        File file = new File(infoDirectory, txtName);
        FileOutputStream fOut = new FileOutputStream(file);
        OutputStreamWriter myOutWriter = new OutputStreamWriter(fOut);
        myOutWriter.append(data);
        myOutWriter.close();
        fOut.close();

    }
    catch (IOException e) {
        Log.i("Debug", "File write failed: " + e.toString());
    }
}

But instead of adding string to the file, it re-writes insides.

[UPDATE]

private void writeToFile(String data) {
    try {
        File file = new File(infoDirectory, txtName);
        FileWriter append = new FileWriter(file, true);
        BufferedWriter output = new BufferedWriter(append);

        output.write(data);

    }
    catch (IOException e) {
        Log.i("Debug", "File write failed: " + e.toString());
    }
}

[WORKING CODE]

private void writeToFile(String data) {
        try {

            File file = new File(infoDirectory, txtName);
            FileOutputStream fOut = new FileOutputStream(file,true);
            OutputStreamWriter myOutWriter = new OutputStreamWriter(fOut);
            myOutWriter.append(data);
            myOutWriter.close();
            fOut.close();
        }
        catch (IOException e) {
            Log.i("Debug", "File write failed: " + e.toString());
        }
    }

http://stackoverflow.com/questions/1625234/how-to-append-text-to-an-existing-file-in-java — pvllnspk, Jan 09 '16 at 21:52
in your code, try this constructor for FileOutputStream https://docs.oracle.com/javase/7/docs/api/java/io/FileOutputStream.html#FileOutputStream%28java.io.File,%20boolean%29, with an additional parameter to append — A_Di-Matteo, Jan 09 '16 at 21:53

Kristo · Accepted Answer · 2016-01-09T22:27:04.613

1

You have to open the file in append mode, which can be achieved by using the

FileWriter(String fileName, boolean append) constructor.

Replace this line

FileOutputStream fOut = new FileOutputStream(file);

To

FileOutputStream fOut = openFileOutput("yourfile.txt", MODE_APPEND);

Hope it helps.

edited Jan 09 '16 at 22:27

answered Jan 09 '16 at 21:58

Kristo

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22

It doesn't write anything. Check my Update section. – Oleksandr Firsov Jan 09 '16 at 22:06
you are still not using append mode... – Kristo Jan 09 '16 at 22:13
try this it seems to work with java 7 `try { Files.write(Paths.get("myfile.txt"), "the text".getBytes(), StandardOpenOption.APPEND); }catch (IOException e) { //exception handling left as an exercise for the reader }` – Kristo Jan 09 '16 at 22:17
this piece of code won't work in android if I copy paste it. `Files` require `MediaStore` import, but `MediaStore.Files` does not have `write` method. – Oleksandr Firsov Jan 09 '16 at 22:21
Checkout my edited answer and let me know if anything changed. – Kristo Jan 09 '16 at 22:27
`FileOutputStream fOut = new FileOutputStream(file,true);` – Kristo Jan 09 '16 at 22:38
Yes, it did the trick. Thanks. – Oleksandr Firsov Jan 09 '16 at 23:12
You are welcome mate :) – Kristo Jan 09 '16 at 23:50

Write in existing .txt file

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