JSON - how to convert variables it into text and vice versa (with Unity3D & PlayerPrefs)

Recently I used JSON a lot and I'd like to share some knowledge about it.

Here I'm using MiniJSON (link) because I prefer C# rather than JS (this one make me sick!).

So at beginning what JSON is?
JSON is a... string :) And it can have our arrays, dictionaries, variables and other crazy things. And this is all about it, but if you like reading you should go to Wikipedia and read all about it :P


Okey, you know what JSON is (or not) so now I can tell you how to use it.

First we have to add some usings at the beginnig.

using System.Collections.Generic;
using MiniJSON;

Now we need to create Dictionary. This will be our storage.

Dictionary<string, object> dictionary = new Dictionary<string, object>();

Great! Next we need some variables.

int intNum = 6;
float floNum = 3.14f;
string word = "Some random text"; 

int[] decArr = new int[2] {6, 3};
float[] floArr = new float[2] {3.14f, 1.23f};
string[] words = new string[3] {"Yey", "Nope", "Wow"};

 And we need to add them to our dictionary.

dictionary.Add("intNum", intNum);
dictionary.Add("floNum", floNum);
dictionary.Add("word", word);  

dictionary.Add("intArr", intArr);
dictionary.Add("floArr", floArr);
dictionary.Add("words", words);

So we have dictionary with some variables within it. So let's turn it into JSON! ];->

string ourJSON = Json.Serialize(dictionary);

Now it's easy to save it into register. I hope you know about PlayerPrefs in Unity :)

PlayerPrefs.SetString("ourJSON", ourJSON );

That was easy part. And now how to turn it back to our variables?!

First we need our JSON back and turn it into Dictionary.

string ourJson = PlayerPrefs.GetString("ourJSON");
Dictionary<string, object> dict = new Dictionary<string, object>();
dict = Json.Deserialize(ourJson) as Dictionary<string, object>;

And it's almost good :) Let's get our non-array variables. Because we casting from object variables we have to use 64-bit types.

object obj = dict["intNum"];
long lonNum = (long)obj; 

obj = dict["floNum"];
double douNum = (double)obj; 

obj = dict["word"];
string word = (string)obj;

But you can easily turn it into 32-bit. For example:

int intNum = (int)lonNum;

It's time for arrays.. As we can't do it easily we have to do little trick ;)

obj = dict["intArr"];
long[] lonArr = new long[(obj as ICollection).Count];
(obj as ICollection).CopyTo(lonArr, 0); 

obj = dict["floArr"];
double[] douArr = new double[(obj as ICollection).Count];
(obj as ICollection).CopyTo(douArr, 0);

obj = dict["words"];
string[] words = new string[(obj as ICollection).Count];
(obj as ICollection).CopyTo(words, 0);

 And if you need just 32-bit arrays you have to do this.

int[] intArr = new int[lonArr.Length];
for (int i = 0; i < lonArr.Length; i++) {
intArr[i] = (int)lonArr[i];
}

Bravo! Now you know how to use JSON with PlayerPrefs in Unity3D!

Have fun and make a good use of it :)

If you need my script here you can download it. :)