How do I overwrite a .txt file on android?

in my APP I receive a socket periodically through String . I need to save only the last received String but with the functions that I have obtained I am adding rows and Strings to the file. How can I overwrite the file every time I receive the coordinates to have only the last ones? destroy the file and recreate it does not seem a very clean solution, is there any way to simply write on it? I leave you the ones I have currently created:

Create file if it does not exist:

protected boolean crearSiNoExiste(String nombreFichero, String contenido){
        file = new File(getFilesDir(), nombreFichero);
        Log.d("log1", nombreFichero);
//Si el Fichero no existe se crea con una entrada inicial
        if (!file.exists()) {
            try{
                FileOutputStream out = new FileOutputStream(file);
                out.write(contenido.getBytes());
                out.close();
                Toast.makeText(this, "Creada categoría " + nombreFichero, Toast.LENGTH_SHORT).show();a
            }catch (IOException e){
                Toast.makeText(this, "Error creando categoría", Toast.LENGTH_SHORT).show();
                return false;
            }
        }
        return true;
    }

Which checks if the file exists and if it does not create it.

The following is to add a line to the file, it is the one that I want to modify so that it overwrites everything:

protected boolean Entrada(){
//Comprobar que no hay ningún EditText vacío
        if (categoria.getText().toString().isEmpty()) {
            Toast.makeText(this, "No hay nombre de categoría", Toast.LENGTH_SHORT).show();
            return true;
        }
        try {
            OutputStreamWriter fout = new OutputStreamWriter(
                    openFileOutput(nomFichero, Context.MODE_APPEND));
            fout.write(System.getProperty("line.separator"));
            fout.write(categoria.getText().toString()); //Escribir término en inglés
            fout.close();
        }
        catch (Exception ex) {
            Toast.makeText(this, "Error añadiendo categoría", Toast.LENGTH_SHORT).show();
            return false;
        }
        return true;
    }