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 file in Gdx.files.localStorage if it doesnt exist and if it does, append new data to it.
I have checked code given at :
1>Using Json.Serializable to parse Json files
2>Parsing Json in libGDX
But I failed to locate how to actually create a Json file and write multiple unique object values (name and score of each player) to it. Did I miss something from their codes?
This link mentions how to load an existing json but nothing else.
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.
Related
I'm trying to make a simple dictionary program based on server-client socket communication. I'm trying to save user word and meaning input as a JSON file (which is dictionary data to search later on) but when I do add query it ends up with having duplicated JSON objects
for example, if I add happy and then weather and hello, the result written in JSON file is
like below
{"hello":"greeting"}{"happy":"joy","hello":"greeting"}
{"happy":"joy","weather":"cold","hello":"greeting"}`
instead of getting
{"hello":"greeting"}{"happy":"joy"}{"weather":"cold"} like I wanted
how can I fix this problem?
my code for that function is
case "add":{
FileWriter dictionaryWriter = new FileWriter("dictionary.json",true);
//split command again into 2 part now using delimiter ","
String break2[] = msgBreak[1].split(",");
String word = break2[0];
String meaning = break2[1];
dictionary.put(word, meaning);
System.out.println("Writing... " + word+":"+meaning);
dictionaryWriter.write(dictionary.toString());
//flush remain byte
dictionaryWriter.flush();
//close writer
dictionaryWriter.close();
break;}
this function is in while(true) loop with other dictionary functions
I tried to remove the appending file part, but when I remove the (,true) part the duplication error stopped but whenever I get a new connection, new dictionary file is created instead of having all data saved.
If anyone can help me solve this problem, I would appreciate it a lot!
Thanks you in advance.
You can try to create a new dictionary every time instead of using the existing one
Map<String, String> dictionary = new HashMap<>();
dictionary.put(word, meaning);
...
I am writing an application/class that will take in a template text file and a JSON value and return interpolated text back to the caller.
The format of the input template text file needs to be determined. For example: my name is ${fullName}
Example of the JSON:
{"fullName": "Elon Musk"}
Expected output:
"my name is Elon Musk"
I am looking for a widely used library/formats that can accomplish this.
What format should the template text file be?
What library would support the template text file format defined above and accept JSON values?
Its easy to build my own parser but there are many edge cases that needs to be taken care of and I do not want to reinvent the wheel.
For example, if we have a slightly complex JSON object with lists, nested values etc. then I will have to think about those as well and implement it.
I have always used org.json library. Found at http://www.json.org/.
It makes it really easy to go through JSON Objects.
For example if you want to make a new object:
JSONObject person = new JSONObject();
person.put("fullName", "Elon Musk");
person.put("phoneNumber", 3811111111);
The JSON Object would look like:
{
"fullName": "Elon Musk",
"phoneNumber": 3811111111
}
It's similar to retrieving from the Object
String name = person.getString("fullName");
You can read out the file with BufferedReader and parse it as you wish.
Hopefully I helped out. :)
This is how we do it.
Map inputMap = ["fullName": "Elon Musk"]
String finalText = StrSubstitutor.replace("my name is \${fullName}", inputMap)
You can try this：
https://github.com/alibaba/fastjson
Fastjson is a Java library that can be used to convert Java Objects into their JSON representation. It can also be used to convert a JSON string to an equivalent Java object. Fastjson can work with arbitrary Java objects including pre-existing objects that you do not have source-code of.
To start off, I'm pretty new in programming. I have to create an Android Weather App for a school project and I'm stuck with this big ass JSON:
JSON Data
Out of this, how would I read the temperature out of every 3 hour interval(example: 9.00-12.00 temperature: 5°C, 12.00-15.00 temperature: 7°C etc.).
So I have an Activity that displays the temperature of the entire day by three hour intervals. Since I have no experience with JSON I have no idea what the certain indexes mean, when does it increment(there are like 8 main: thingies).
DISCLAIMER: I have to use JSON, no GSON or other shortcuts, I have to parse and read certain data from this JSON. I get this JSON from open weather map API so it changes every day.
API
Use volly library for it. You can easily fetch data from json. No async task is needed, if you are using volly library.
First validate the json by going to http://jsonlint.com/. This will help you see the formatted Json string.
Next read up on Json array and Object .
Use AsynTask to get the Json into forecastJsonStr string.
Then you need to convert this forecastJsonStr into JSon object forecastJsonObj
To get weather data in "list" do something similar to
JSONArray weatherArray = forecastJson.getJSONArray("list");
Hope this helps
JSONObject receivedData = new JSONObject("The string that you get as response from the API");
JSONArray weatherList = receivedData.getJSONArray("list");
for(int i=0;i<weatherList.length();i++){
JSONObject data = weatherList.getJSONObjectAt(i);
String date_text - data.getString("dt_txt");
JSONArray weatherData = weatherList.getJSONArray("main");
for(int j=0;j<weatherData.length();j++){
// Here is where you will get all the weather stuff that you need
int temp = weatherData.getInt("temp");
// Similarly other values like temp_min, temp_max
}
}
So basically you need to parse the entire thing. In order to understand the whole structure more clearly use something like http://jsonviewer.stack.hu/ in order to view the JSON in a more clear way so that you know what you need from the JSON data better. Simple copy paste your data into there and click "Format".
JSON is just a name-value pair kind of storage if you see stored like "name":"value". Integer values don't have the "".
Remember all the JSON is stored in { } and a JSON can be nested in a JSON. So in your example if you see, the entire thing is a JSON. Within that you have a "city" key which has a value within { }. So "city" is a JSONObject.
Similarly "coord" is a JSONObject while "cod" is a String and "cnt" is an integer.
There can also be some instances where a name points to an array of JSON objects like "list" over here. JSON Arrays are signified using a [ ]. Enclosed within are JSON objects separated by comma.
Above is a very simple sample to get you started so that you get a jist of what is going on. So play around and try to extract more data from in there.
All the best and Happy Coding :)
So I'm in the process of developing a Java IRC bot as a bit of a side project for a friend of mine, and while development is going well, I'm a little unsure as how to save the current state of certain variables in between sessions. It doesn't have a GUI, so I didn't think that it would be too complex, but my searching efforts have been futile thus far.
Thanks.
It will depend on the sort of variables you want to keep, but all methods will require you to write some sort data to a file.
If you only need to keep a handful of variables, you could consider implementing a .config file that could be a simple delimited text file.
If it's an entire object that you want to keep track of, say, a player in an irc game, one option you have is to parse the object into JSON, and save it to a textfile, for reading later. You can use Gson for this
example for a 'player' object:
public String savePlayer(String playerName){
Gson gsonPretty = new GsonBuilder().setPrettyPrinting().create();
String playerFile = System.getProperty("user.dir")+"\\players\\"+playerName;
String jsonplayers = gsonPretty.toJson(players.get(playerName));
try{
FileWriter writer = new FileWriter(playerFile+".json");
writer.write(jsonplayers);
writer.close();
return "Player file saved successfully!";
}catch(Exception e){
e.printStackTrace();
}
return "Something went wrong";
}
you can then create a load method that either has the file name hard coded, or a string input to determine which file to load, and use something like:
playerFromJson = gson.fromJson(jsonString, Player.class);
to use that object in the code
I'm relatively new to using JSON and all I really need to do read in a few key value pairs from a JSON file on the file system.
What I figured I would do is read in the file as a string and then parse it that way but it seems kind of redundant that way.
Here's what my file will be like:
{
"username" : "myname"
"domain" : "mydomain"
}
So essentially I need some help making an easy and efficient block of code to read in the key/value pairs. I've been trying to use GSON for the most part and haven't had much luck with examples I've found.
Thanks everyone
One other alternative is JSON.org, in which creating a JSON object from a JSON string requires only one line:
JSONObject jsonObject = new JSONObject(someJSONString);
When you need to access its value, use the functions that the JSONObject provides. For example,
String userName = jsonObject.getString("username");
String domainName = jsonObject.getString("mydomain");