I want to save the state of the game in a file, so I can read it at the next start. The Problem is, that I get a exception, if I try to save something internal. If I try to save it local all work fine. I save the file as a Json.

Bird bird = new Bird();
bird.setSkin(new Texture("data/foo.png"));

The save mthod:

Json json = new Json();
file.writeString(json.prettyPrint(this), false);

Exception in thread "LWJGL Application" com.badlogic.gdx.utils.GdxRuntimeException: Error writing file: bird.json (Internal) at com.badlogic.gdx.files.FileHandle.writeString(FileHandle.java:349) at com.badlogic.gdx.files.FileHandle.writeString(FileHandle.java:335) at com.buschmannmichael.fattybird.core.Bird.save(Bird.java:31) at com.buschmannmichael.fattybird.game.FattyBirdGame.create(FattyBirdGame.java:16) at com.badlogic.gdx.backends.lwjgl.LwjglApplication.mainLoop(LwjglApplication.java:137) at com.badlogic.gdx.backends.lwjgl.LwjglApplication$1.run(LwjglApplication.java:115) Caused by: com.badlogic.gdx.utils.GdxRuntimeException: Cannot write to an internal file: bird.json at com.badlogic.gdx.files.FileHandle.writer(FileHandle.java:315) at com.badlogic.gdx.files.FileHandle.writeString(FileHandle.java:346) ... 5 more

Whats the problem of LibGDX, where I should save the files, so I can run the game on android, desktop and html ? (I tested this method I showed above only on desktop, maybe it works on android but I want a solution for all platforms)

Maybe someone can help me :)


Gdx.file.internal is read-only. You can use local file or preferences (creates an internal .xml file where you can store small amount of data). It is perfect for game saving.

Take a look at : https://github.com/libgdx/libgdx/wiki/Preferences

You can also use an external file (stored on sdcard), but you can optionally encrypt it, as it can be edited by the user.

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    \$\begingroup\$ Sometimes allowing something to be edited by the user isn't such a bad thing. \$\endgroup\$ – Vaughan Hilts Mar 28 '14 at 13:08
  • \$\begingroup\$ Yes, but I think you should create in-game features for the editable parts, because if you give him full privileges, he could completely manipulate the game process :) \$\endgroup\$ – Ion Farima Mar 28 '14 at 13:20
  • \$\begingroup\$ If this is a single player game, that's not an issue. They are only cheating themselves. If this is a multiplayer game and a local file can affect the state of the game for all other player, you have failed to design a secure game. \$\endgroup\$ – Vaughan Hilts Mar 28 '14 at 13:36
  • \$\begingroup\$ It's true ! In online multiplayer games I think you should store important files on a server, if the framework has this feature. Is it a good idea ? \$\endgroup\$ – Ion Farima Mar 28 '14 at 13:44
  • \$\begingroup\$ Yes is it, the local way is to unsafe. :D \$\endgroup\$ – user2933016 Mar 31 '14 at 16:10

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