CODEWITHSUNDEEP
javaandroidjsongson
Bankzilla
Bankzilla

Reputation: 2096

Iterate JSON array object

I'm querying out and getting a json string returned, for the sake of this example I'll post an example. I'm trying to figure out how I would go about digging through the array of values and find which is marked as default.

Example JSON

{
    "id": "333706819617",
    "guid": "4aCdriCG0WvfYEUkFf8_xqQEFxgwgNU8",
    "title": "Test entry",
    "author": "",
    "description": "Desc",
    "added": 1411702963000,
    "content": [
        {
            "audioChannels": 2,
            "audioSampleRate": 44100,
            "bitrate": 281656,
            "checksums": {
                "md5": "70DF3E21131F9F02C3F0A74F3664AB73"
            },
            "contentType": "audio",
            "duration": 43.258,
            "expression": "full",
            "fileSize": 1522986,
            "frameRate": 0.0,
            "format": "AAC",
            "height": 288,
            "isDefault": false,
            "language": "en",
            "sourceTime": 0.0,
            "url": "http://example.com/dZiASoxchRyS",
            "width": 352
        },
        {
            "audioChannels": 2,
            "audioSampleRate": 44100,
            "bitrate": 160000,
            "checksums": {
                "md5": "3AC622D31B9DED37792CC7FF2F086BE6"
            },
            "contentType": "audio",
            "duration": 43.206,
            "expression": "full",
            "fileSize": 866504,
            "frameRate": 0.0,
            "format": "MP3",
            "height": 0,
            "isDefault": false,
            "language": "",
            "sourceTime": 0.0,
            "url": "http://example.com/59M_PSFgGGXE",
            "width": 0
        }
    ],
    "thumbnails": [
        {
            "audioChannels": 0,
            "audioSampleRate": 0,
            "bitrate": 0,
            "checksums": {
                "md5": "BE8C98A07B3FE9020BFA464C42112999"
            },
            "contentType": "image",
            "duration": 0.0,
            "expression": "full",
            "fileSize": 20379,
            "frameRate": 0.0,
            "format": "JPEG",
            "height": 256,
            "isDefault": true,
            "language": "",
            "sourceTime": 0.0,
            "url": "http://img.example.com/waveform.jpg",
            "width": 256
        }
    ]
}

I take the JSON string and convert it back into a JSONObject

JSONObject mediaObject = new Gson().fromJson(mediaString, JSONObject.class);
String content = mediaObject.optString("content");

When I output content it returns the following.

{values=[{nameValuePairs={audioChannels=2.0, audioSampleRate=44100.0, bitrate=281656.0, checksums={nameValuePairs={md5=70DF3E21131F9F02C3F0A74F3664AB73}}......

How do I correctly step through the values of content and find the value of isDefault? In the example JSON there is no content where isDefault = true so it would default to the first object.

Seems I can only target the values as string, do I have to cast content as a JSONArray?

Edit: I can't seem to convert mediaObject.content into a JSONArray. mediaObject.optJSONArray("content") returns null. I've also tried getting it as a string then converting into a JSONArray with no prevail.

Edit 2: Found what the issue with the data was, when I was parsing the json with gson, it was messing with the final outputted data.

So I changed from new Gson().toJson(jsonObject); to jsonObject.toString()) and I could now target the arrays using optJSONArray. To get them data back into a JSONObject, I used JSONObject mediaObject = new JSONObject(mediaString);

GSON was altering the data

Upvotes: 4

Views: 3460

Answers (2)

Tyler Sebastian
Tyler Sebastian

Reputation: 9448

Can you not just 

JSONObject mJson = new JSONObject(inputString);

why are you using Gson?

Upvotes: 2

Enrico
Enrico

Reputation: 10665

Instead of pulling the string value of content out of your JSONObject, you can get a JSONArray instead

JSONArray content = mediaObject.getJSONArray("content");

Now you can loop through the objects in your array with a pretty conventional for loop

for(int i = 0; i < content.length(); i++) {
    JSONObject mediaItem = content.getJSONObject(i);
    boolean itemIsDefault = mediaItem.getBoolean("isDefault");
}

Here are the links to all the JSONObject methods and JSONArray methods

Upvotes: 3

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