JSON parsing on Cocos2D-X projects

cocos2d-x C++
#1

Hi,

Does cocos2dx offer any cross platform solution for parsing JSON documents or should I go to a third party library for this part?

Thanks.

JB

How we can get value from JSON in cocos2d-x
#2

You can use for that rapidjson, i’m use it for my game.

#3

thanks for the super fast answer Alex :slight_smile:

#4

If problems occur, write here. maybe I can help :slight_smile:

#5

Emmm with this simple code (Document instance) I get the error: “interface type cannot be statically allocated”. Do you know what could the reason be?

PS: I tried also to init it as a pointer, and then I get the error “Unknown type name ‘Document’, did you mean UIDocument?”. It seems like even I have copied the header files, it is not detecting rapidjson…

Thanks!

#include "rapidjson.h"
#include "prettywriter.h"
#include "filestream.h"
#include 

using namespace rapidjson;

        void FriendsList::onEnter()
        {   
            Document document;
        }
#6

sorry, it worked doing this:

#include “…/…/libs/rapidjson/document.h” // rapidjson’s DOM-style API
#include “…/…/libs/rapidjson/prettywriter.h” // for stringify JSON
#include “…/…/libs/rapidjson/filestream.h” // wrapper of C stream for prettywriter as output
#include

#7

#include “rapidjson/document.h”

#8

thanks!

#9

emmm sorry again, now it looks like document.h throws a compiler error when I just do this:

const char json[] = " { ello : orld : true , : false, null, 123, i 3.1416, [1, 2, 3, 4] } “;
printf(”Original JSON:%s\n", json);

Document document; // Default template parameter uses UTF8 and MemoryPoolAllocator.

document.Parse<0>(json).HasParseError();

The error is in Document.h, at the line: RawAssign(stack.template Pop);
template <unsigned parseFlags, typename Stream>
GenericDocument& ParseStream {
ValueType::SetNull; // Remove existing root if exist
GenericReader reader;
if ) {
RAPIDJSON_ASSERT == sizeof); // Got one and only one root object
RawAssign);
parseError = 0;
errorOffset_ = 0;
}
else {
parseError_ = reader.GetParseError;
errorOffset_ = reader.GetErrorOffset;
ClearStack;
}
return**this;
}

In order to help others, I’ve found the solution here: http://code.google.com/p/rapidjson/issues/detail?id=13

Thanks

#10

uff now I get a new error while trying to parse the JSON:

Nothing should follow the root object or array

The JSON is this, and it is valid according to http://jsonlint.com:
[{id

Do you have any idea? Thanks! :stuck_out_tongue:

#11

This snippet can help you:

std::string fullPath = CCFileUtils::fullPathFromRelativePath("figures.json");
  unsigned long bufferSize = 0;
  const char* mFileData = (const char*)CCFileUtils::getFileData(fullPath.c_str(), "r", &bufferSize);

  std::string clearData(mFileData);
  size_t pos = clearData.rfind("}");
  clearData = clearData.substr(0, pos+1);

  document.Parse<0>(clearData.c_str());

This error occurs because when you get to the end of the buffer is added to the garbage (I do not know why), so I use crutches to trim the buffer :slight_smile: Replace clearData.rfind(“}”); on clearData.rfind(“]”); in your caseю

#12

I’m using libjson, it has good documentation.

#13

It worked thanks! Now document.Parse<0>(data).HasParseError() returns always false, but unfortunately…

this always return false document.IsObject() :frowning:

Maybe the framework doesn’t support multiple elements between “{}”, since in the example I have a simpler json, with just different variables and their values, could it be?

[{id

#14

ok, got it:

Document document; // Default template parameter uses UTF8 and MemoryPoolAllocator.

if(data document.Parse<0>(data).HasParseError())
{
for (SizeType i = 0; i < document.Size(); i++) // rapidjson uses SizeType instead of size_t.
{
CCLog(document[i][“id”].GetString());

}
}
else {
CCLog(document.GetParseError());
}

#15

congratulate you! :slight_smile:

#16

Thanks Alex :slight_smile:

I’ve written a small article in my blog to help others in similar situations: http://www.jesusbosch.com/2012/08/parsing-json-from-c-and-maybe-from.html

#17

Jesus Bosch wrote:

Thanks Alex :slight_smile:
>
I’ve written a small article in my blog to help others in similar situations: http://www.jesusbosch.com/2012/08/parsing-json-from-c-and-maybe-from.html

Oh, you ahead me, I wanted to do the same on the weekend :slight_smile:

1 Like
#18

oh you have a blog? please share it, I’ll follow you

#19

Jesus Bosch wrote:

oh you have a blog? please share it, I’ll follow you

I recently made ​​it, so there are only two articles. But I will fill with the development of using Socos2d-x. And I write in Russian :slight_smile:

#20

arrrg russian is too hard for me… :-S if you write in English (even with bad english like mine) you will have more visits :wink: