AS3, PHP & JSON - Decoding one object is fine, an array returns null

Question

I've been hunting around for a few hours and I still have no idea what's going on. I'm new to PHP, but fairly comfortable with simple Flash stuff.

I'm passing a JSON object from PHP into Flash AS3 using URLLoaders, etc. This is my PHP-created test JSON array:

$objJSON = array('sample' => null);
    $objJSON['sample'] = "TESTING";
    $objJSON['sample2'] = "TESTING2";
    $objJSON = json_encode($objJSON);

I return it to flash with

echo "arrayData=$jsonArray";

When I parse that as a SINGLE object in flash, using

var tempJSON = JSON.decode(event.target.data.arrayData);

I get 'TESTING' as my output (textBox.text = tempJSON.sample; using localhost via WAMP), which is correct. Everything looks good, there's communication, the JSON library is being used right, the object is there and accessible...

BUT! When I treat it as an Array (because that's what it is) by changing the code directly above (and touching NOTHING else) to:

var tempJSON:Array = JSON.decode(event.target.data.arrayData, true);

I throw a compiler error of:

TypeError: Error #1009: Cannot access a property or method of a null object reference. at com.adobe.serialization.json::JSONTokenizer/nextChar()[....\json\JSONTokenizer.as:545]

Running the swf in localhost gets me no return where I used to get string. Am I making some newbie mistake that the data suddenly becomes null when I treat it like an array?

I've checked the validity of my JSON via the output in PHP and it checks out. I've made sure I have no extra echos in the PHP class being called. I'm just stumped.

FIX'D!

Guided by the comments, I basically wasn't forming my JSON to be an array, just objects with multiple properties. The correct way to do it was:

$objArray = array(
   array(
   "sample1" => "Testing!",
   "sample2" => "Testing2!",
),
   array (
   "sample1" => "Testing!",
   "sample2" => "Testing2!",
  )
);


$objArray = json_encode($objArray);

Please also add examples of your JSON.

Lee Taylor
– Lee Taylor

2012-12-03 22:50:02 +00:00
Commented Dec 3, 2012 at 22:50 — Lee Taylor
– Lee Taylor, Commented Dec 3, 2012 at 22:50

Selosindis · Accepted Answer · 2012-12-03 22:43:22Z

2

I believe it is because your JSON is decoding into an object and not an array. This will happen if you are using non-integer values as your array keys (ie. 'sample', 'sample2').

I'm not overly familiar with AS3, but you will likely need to cast it into an Object-like instance instead of an Array.

$objJSON = array('sample' => "TESTING", 'sample2' => "TESTING2");
echo json_encode($objJSON);

// Will output
{ "sample": "TESTING", "sample2": "TESTING2" }

This is not array notation using JSON. It is object notation.

I hope this helps!

edited Dec 3, 2012 at 22:43

answered Dec 3, 2012 at 22:37

Selosindis

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2 Comments

Sven Over a year ago

Yes, Javascript (and also ActionScript, which should be the same) does not treat Arrays and Objects the same like PHP. If you have numeric indices starting at 0, with no gaps, you get an Array. Anything else, including text strings as key: Object.

Kate Over a year ago

Thank you, this was exactly it. I wasn't forming my JSON objects correctly as an array to be parsed right.

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