java - How avoid a File created inside an app gets deleted when it get closed

Question

I'm making an simple login app in Android Studio, and I dont want to use any data base to store the credentials of the users. I tried to make an Object File inside the app, and in this storage a HashMap with all the users. I made that with the following code:

File archivo_users = new File("Users.bixa");
    if (!archivo_users.exists()){ 
        try {
            ObjectOutputStream admin = new ObjectOutputStream( openFileOutput(archivo_users.toString(), Activity.MODE_PRIVATE));
            
            HashMap<String, Usuario> admin_user = new HashMap<>();
            // Make an Hash Map with a 'admin' default user
            admin_user.put("admin",new Usuario("admin","admin","admin","admin",'h'));
            admin.writeObject(admin_user);
            admin.close();
        } catch (IOException e) {
            Toast.makeText(this,"An error ocurred creating Users.bixa",Toast.LENGTH_LONG).show();
        }

After that, I read the file and make an static variable for enter to the data in all the app:

try {
            ObjectInputStream baseDatos_usuarios = new ObjectInputStream(openFileInput(archivo_users.toString()));

            UsuariosRegistrados = (HashMap<String,Usuario>) baseDatos_usuarios.readObject();
            baseDatos_usuarios.close();
        } catch (IOException | ClassNotFoundException e) {
            // Muestra ventana emergente en la app con el mensaje de la excepcion
            Toast.makeText(this,"Error al intentar leer la base de Usuarios",Toast.LENGTH_LONG).show();
        }

Then, in my register activity, when the user introduce correctly all the data, I update the file this way:

BienvenidaActivity.UsuariosRegistrados.put(username,new Usuario(username, contrasenia, nombre, apellido, genero));
                    
                    try {
                        ObjectOutputStream archivo = new ObjectOutputStream( openFileOutput("Usuarios.bixa", Activity.MODE_PRIVATE));
                        
                        archivo.writeObject(BienvenidaActivity.UsuariosRegistrados);
                        archivo.close();
                    } catch (IOException e) {
                        Toast.makeText(this,"ERROR: No se logro actualizar la base de datos",Toast.LENGTH_LONG).show();
                    }

All of this works perfectly, but the problem is that when I close the app, the File dosen't conteins the new users, I dont now if the File is deleted when the app is closed or if my conditional of the firts code is wrong and always creates a new file.

Hope someone can help me, and thanks for the time if you read this. Note: Sorry if I wrote something wrong, my native language is spanish.

question from:https://stackoverflow.com/questions/65874754/how-avoid-a-file-created-inside-an-app-gets-deleted-when-it-get-closed

Answer 1

Save that file in files directory app-specific storage

File file = new File(context.filesDir(),"file.txt");

Other apps cannot access to this file