How do I save files with libgdx so that users can't read them?

Question

Writing my game in libgdx, I arrived at the point when I need to save the player stats and the info of the levels. However, in libgdx it's not allowed to write the file inside folder of the application, only external (on the SD) is allowed. The point is that I don't want the file to be seen by anyone, or if they can see it, how can I convert it to a binary file so it's not human readable? I just want to hide the file.

Answer 1

Libgdx has built in decoding and encoding functionality. Gustavo Steigert has written a nice article about this on his blog: http://steigert.blogspot.be/2012/03/5-libgdx-tutorial-files.html. Scroll down a bit to the section "2. Persist Profile operation".

In this blogpost, he explains that by using the class com.badlogic.gdx.utils.Base64Coder you can encode and decode files in the Base64-format. Leaving the unreadable and unmodifiable for end users.

Answer 2

It sounds like using a "preference" is what you need to do. It allows you to save small bits of data (like a high score, or other settings) which persist when the game is shut down.

And it's a lot easier than trying to write to a file; you don't really have to concern yourself where the file is.

See: http://code.google.com/p/libgdx/wiki/Preferences

On Windows it gets put in the user's home directory. Android uses a SharedPreference system.

If you don't want users being able to read what's in there, you can always save your values in an encoded way. Ex:

prefs.putInteger("HighLevel", 15);

or

prefs.putString("SecretInfo", myEncodeFunction("here's the secret text to save."));

Answer 3

The following code will create a text file where you can store basic data

FileHandle file= Gdx.files.local("files/myfile.txt");
file.writeString("my_first_file", false);

to read from it

FileHandle file= Gdx.files.local("files/myfile.txt");
String text = file.readString();

now

    if (text.equals("my_first_file")) {
           //your code
    }

if you'd like to check first whether not the file exits,

first, initialize :

boolean my_file_exits = Gdx.files.local("files/myfile.txt").exists();

then

  if (exists) {
        FileHandle file= Gdx.files.local("files/myfile.txt");
        String text = file.readString();

        if (text.equals("my_first_file")) {
               //your code
        }
} else {
 //create a textfile and store default value
}

Answer 4

Again, try asking here..

http://www.badlogicgames.com/forum/

Basically, you may want to read up on how Android handles directories in your app. There is a file handle class in libgdx that should work for you. If you just want it saved in a protected place, use the internal process and it should be local to your app directory and not visible. It doesn't have to be on an sd card. Read the android docs and ask on the badlogic forum if you still need help and don't get any answers here

Answer 5

I resolved it with callbacks, with that I can use Android methods, that way I can write to the internal memory.