Objective-C

Get the Root of a JSON Document

See more JSON Examples

Demonstrates how to get back to the JSON root object from anywhere in the JSON document. This example uses the following JSON document:

{
  "flower": "tulip",
  "abc":
    {
    "x": [
       { "a" : 1 },
       { "b1" : 100, "b2" : 200 },
       { "c" : 3 }
    ],
    "y": 200,
    "z": 200
    }
}

Objective-C

#import <CkoJsonObject.h>
#import <NSString.h>
#import <CkoJsonArray.h>

BOOL success = NO;

CkoJsonObject *json = [[CkoJsonObject alloc] init];

NSString *jsonStr = @"{\"flower\": \"tulip\",\"abc\":{\"x\": [{ \"a\" : 1 },{ \"b1\" : 100, \"b2\" : 200 },{ \"c\" : 3 }],\"y\": 200,\"z\": 200}}";

success = [json Load: jsonStr];
if (success == NO) {
    NSLog(@"%@",json.LastErrorText);
    return;
}

// Get the "abc" object.
CkoJsonObject *abcObj = [[CkoJsonObject alloc] init];
success = [json ObjectOf2: @"abc" jsonObj: abcObj];
if (success == NO) {
    NSLog(@"%@",json.LastErrorText);
    return;
}

// Side note: The JSON of a sub-part of the document can be emitted from any JSON object:
abcObj.EmitCompact = NO;
NSLog(@"%@",[abcObj Emit]);

// Navigate to the "x" array
CkoJsonArray *xArray = [[CkoJsonArray alloc] init];
[abcObj ArrayOf2: @"x" jarr: xArray];

// Navigate to the 2nd object contained within the array.  This contains members b1 and b2
CkoJsonObject *bObj = [[CkoJsonObject alloc] init];
[xArray ObjectAt2: [NSNumber numberWithInt: 1] jsonObj: bObj];

// Show that we're at "b1/b2".
// The value of "b1" should be "200"
NSLog(@"%@%d",@"b2 = ",[[bObj IntOf: @"b2"] intValue]);

// Now go back to the JSON doc root:
CkoJsonObject *docRoot = [[CkoJsonObject alloc] init];
[bObj GetDocRoot2: docRoot];

// We'll skip the null check and assume it's non-null...

// Pretty-print the JSON doc from the root to show that this is indeed the root.
docRoot.EmitCompact = NO;
NSLog(@"%@",[docRoot Emit]);