Dart Requires Chilkat v11.0.0+

JSON: Miscellaneous Operations

See more JSON Examples

Demonstrates a variety of JSON API methods. This example uses the following JSON document:

{
   "alphabet": "abcdefghijklmnopqrstuvwxyz",
   "sampleData" : {
           "pi": 3.14,
	   "apple": "juicy",
	   "hungry": true,
	   "withoutValue": null,
           "answer": 42
          
	}
}

Dart

import 'package:chilkat/chilkat.dart';

void main() {
  final json = CkJsonObject();
  json.emitCompact = false;

  // Assume the file contains the data as shown above..
  try {
    json.loadFile('qa_data/json/sample2.json');
  } on ChilkatException catch (e) {
    print(e.lastErrorText);
    return;
  }

  // Get the "sampleData" object:
  final sampleData = CkJsonObject();
  json.objectOf2('sampleData', sampleData);

  // Demonstrate BoolAt and BoolOf
  print('hungry: ${sampleData.boolOf('hungry')}');
  print('hungry: ${sampleData.boolAt(2)}');

  // StringOf returns the value as a string regardless of it's actual type:
  print('pi: ${sampleData.stringOf('pi')}');
  print('answer: ${sampleData.stringOf('answer')}');
  print('withoutValue: ${sampleData.stringOf('withoutValue')}');
  print('hungry: ${sampleData.stringOf('hungry')}');

  // Demonstrate IsNullOf / IsNullAt
  print('withoutValue is null? ${sampleData.isNullOf('withoutValue')}');
  print('withoutValue is null? ${sampleData.isNullAt(3)}');
  print('apple is null? ${sampleData.isNullOf('apple')}');
  print('apple is null? ${sampleData.isNullAt(1)}');

  // IntOf
  print('answer: ${sampleData.intOf('answer')}');

  // SetNullAt, SetNullOf
  // Set "pi" to null
  sampleData.setNullAt(0);
  // Set "answer" to null
  sampleData.setNullOf('answer');

  // Show the changes:
  print(json.emit());

  // Restore pi and apple:
  sampleData.setNumberAt(0, '3.14');
  sampleData.setNumberOf('answer', '42');

  // Show the changes:
  print(json.emit());

  // Add a null value named "afterApple" just after "apple"
  sampleData.addNullAt(2, 'afterApple');

  // Add a boolean value just after "pi"
  sampleData.addBoolAt(1, 'afterPi', false);

  // Examine the changes..
  print(json.emit());
}