C

Get the Index of a JSON Member

See more JSON Examples

This example demonstrates how to get the index of a given member by name.

{
  "name": "donut",
  "image":
    {
    "fname": "donut.jpg",
    "w": 200,
    "h": 200
    },
  "thumbnail":
    {
    "fname": "donutThumb.jpg",
    "w": 32,
    "h": 32
    }
}

C

#include <C_CkJsonObject.h>

void ChilkatSample(void)
    {
    BOOL success;
    HCkJsonObject json;
    const char *jsonStr;
    int nameIndex;
    int thumbIndex;
    int fnameIndex;
    HCkJsonObject imageObj;

    success = FALSE;

    json = CkJsonObject_Create();

    // This is the above JSON with whitespace chars removed (SPACE, TAB, CR, and LF chars).
    // The presence of whitespace chars for pretty-printing makes no difference to the Load
    // method. 
    jsonStr = "{\"name\": \"donut\",\"image\":{\"fname\": \"donut.jpg\",\"w\": 200,\"h\": 200},\"thumbnail\":{\"fname\": \"donutThumb.jpg\",\"w\": 32,\"h\": 32}}";

    success = CkJsonObject_Load(json,jsonStr);
    if (success == FALSE) {
        printf("%s\n",CkJsonObject_lastErrorText(json));
        CkJsonObject_Dispose(json);
        return;
    }

    // The top-level JSON object has three members: name, image, and thumbnail.
    nameIndex = CkJsonObject_IndexOf(json,"name");
    // The index of the "name" member is 0.
    printf("nameIndex = %d\n",nameIndex);

    thumbIndex = CkJsonObject_IndexOf(json,"thumbnail");
    // The index of the "thumbnail" member is 2.
    printf("thumbIndex = %d\n",thumbIndex);

    // The "fname" member is NOT a direct member of the top-level JSON object.
    // It is a member of a nested object.  If we try to get the index of this
    // member using the top-level JSON object, it is not found (and returns -1).
    fnameIndex = CkJsonObject_IndexOf(json,"fname");
    // The fnameIndex is -1 (not found).  This is correct.
    printf("fnameIndex = %d\n",fnameIndex);

    // Get the "image" object.
    imageObj = CkJsonObject_Create();
    CkJsonObject_ObjectOf2(json,"image",imageObj);

    // Now we can get the index of the "fname" object, because it is a direct
    // member of the "image" object:
    fnameIndex = CkJsonObject_IndexOf(imageObj,"fname");
    printf("fnameIndex = %d\n",fnameIndex);


    CkJsonObject_Dispose(json);
    CkJsonObject_Dispose(imageObj);

    }