Write to Json using libGDX

Question

I am new to Json and libGDX but I have created a simple game and I want to store player names and their scores in a Json file. Is there a way to do this? I want to create a Json

Answer 1

First of all i have to say that i never used the Libgdx Json API myself. But i try to help you out a bit. I think this Tutorial on github should help you out a bit.
Basicly the Json API allows you to write a whole object to a Json object and then parse that to a String. To do that use:

PlayerScore score = new PlayerScore("Player1", 1537443);      // The Highscore of the Player1 
Json json = new Json();
String score = json.toJson(score);

This should then be something like:

{name: Player1, score: 1537443}

Instead of toJson() you can use prettyPrint(), which includes linebreaks and tabs.

To write this to a File use:

FileHandle file = Gdx.files.local("scores.json");
file.writeString(score, true);         // True means append, false means overwrite.

You can also customize your Json by implementing Json.Serializable or by adding the values by hand, using writeValue.

Reading is similar:

FileHandle file = Gdx.files.local("scores.json");
String scores = file.readString();
Json json = new Json();
PlayerScore score = json.fromJson(PlayerScore.class, scores);

If you have been using a customized version by implementing Json.Serializable you have implemented the read (Json json, JsonValue jsonMap) method. If you implemented it correctly you the deserialization should work. If you have been adding the values by hand you need to create a JsonValuejsonFile = new JsonValue(scores). scores is the String of the File. Now you can cycle throught the childs of this JsonValue or get its childs by name.

One last thing: For highscores or things like that maybe the Libgdx Preferences are the better choice. Here you can read how to use them.

Hope i could help.