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Loading JSON from String to JSONArray on Android

I had some problems for some time trying to load a JSON string into a JSONArray. I was hoping the post here would help me solve the problem.

The file is located in the assets folder and contains objects of the Kabelskap class. The JSON string is formatted as follows:

[{"driftsmerking":"1420 10 04","objektnummer":"56569.0","adresse":"KANEBOGÅSEN 4","fabrikat":"NEBB","typebetegnelse":"KO500","spenning":"0.23","posisjon":"OK","kompNr":"1420","kommune":"1901 HARSTAD","latitude":"68.7786964342854","longitude":"16.5598512563035"},{"driftsmerking":"4416 01 04","objektnummer":"246349.0","adresse":"NONSÅSEN","fabrikat":"ABB","typebetegnelse":"KO300","spenning":"0.23","posisjon":"OK","kompNr":"4416","kommune":"1911 KVÆFJORD","latitude":"68.7367985627796","longitude":"16.2694481350258"},{"driftsmerking":"4080 05 02","objektnummer":"275933.0","adresse":"KVÆFJORD PLANTESKOLE VEKSTHUS","fabrikat":"ABB","typebetegnelse":"KO700","spenning":"0.23","posisjon":"OK","kompNr":"4080","kommune":"1911 KVÆFJORD","latitude":"68.7712454761326","longitude":"16.1901046355049"},{"driftsmerking":"1383 01 02","objektnummer":"150951.0","adresse":"SKILLEVN. 13","fabrikat":"ABB","typebetegnelse":"","spenning":"0.4","posisjon":"OK","kompNr":"1383","kommune":"1901 HARSTAD","latitude":"68.7781436806564","longitude":"16.5643438120601"},{"driftsmerking":"4085 07 02","objektnummer":"275122.0","adresse":"MATHUSET","fabrikat":"NEBB","typebetegnelse":"70","spenning":"0.23","posisjon":"OK","kompNr":"4085","kommune":"1911 KVÆFJORD","latitude":"68.7721426826508","longitude":"16.1785193494225"}]

This string is read into the String variable, which is then passed to this code segment:

 try { JSONObject jsonObj = new JSONObject(finalString); for(int i = 0; i < json.length(); i++){ Kabelskap ks = (Kabelskap) json.get(i); skap.put(ks.objektnummer, ks); } } catch (JSONException e) { e.printStackTrace(); }

This should, in accordance with what I expected, return a JSON array, which I could then execute and pass to the objects of my class.

 11-30 00:31:33.568: INFO/System.out(389): {"driftsmerking":"1420 10 04","objektnummer":"56569.0","adresse":"KANEBOG SEN 4","fabrikat":"NEBB","typebetegnelse":"KO500","spenning":"0.23","posisjon":"OK","kompNr":"1420","kommune":"1901 HARSTAD","latitude":"68.7786964342854","longitude":"16.5598512563035"}{"driftsmerking":"4416 01 04","objektnummer":"246349.0","adresse":"NONS SEN","fabrikat":"ABB","typebetegnelse":"KO300","spenning":"0.23","posisjon":"OK","kompNr":"4416","kommune":"1911 KV FJORD","latitude":"68.7367985627796","longitude":"16.2694481350258"}{"driftsmerking":"4080 05 02","objektnummer":"275933.0","adresse":"KV FJORD PLANTESKOLE VEKSTHUS","fabrikat":"ABB","typebetegnelse":"KO700","spenning":"0.23","posisjon":"OK","kompNr":"4080","kommune":"1911 KV FJORD","latitude":"68.7712454761326","longitude":"16.1901046355049"}{"driftsmerking":"1383 01 02","objektnummer":"150951.0","adresse":"SKILLEVN. 13" of type org.json.JSONObject cannot be converted to JSONArray 11-30 00:31:33.588: WARN/System.err(389): at org.json.JSON.typeMismatch(JSON.java:107) 11-30 00:31:33.588: WARN/System.err(389): at org.json.JSONArray.<init>(JSONArray.java:91) 11-30 00:31:33.588: WARN/System.err(389): at org.json.JSONArray.<init>(JSONArray.java:103) 11-30 00:31:33.588: WARN/System.err(389): at net.lovholm.kraftwerk.Kraftwerk.onCreate(Kraftwerk.java:68)

This error message indicates a formatting problem, but to test this, I tested the JSON framework against some online validators and seemed to be right.

The line, since it is being returned from the log, seems to use a different encoding than the UTF-8 file. I'm not sure if this could be part of the problem or is it just a character encoding in the log console.

Any suggestions on this issue are very welcome.

---- UPDATE ---- ---- UPDATE ---- ---- UPDATE ---- ---- UPDATE ----

Now I have updated the code with the suggestions from aj.esler, which fixes some errors that I made in the code excerpt above. Here is a long excerpt from my code, and I'm still experiencing the problem with the error message above. This line seems to be JSONArray json = new JSONArray (finalString); causes something evil in the JSONArray constructor. The carry string must comply with API requirements with valid JSON syntax and open square brackets.

 try { AssetManager assetManager = getAssets(); fis = assetManager.open(sourcePath); BufferedReader bw = new BufferedReader(new InputStreamReader(fis, "utf8")); while ((str = bw.readLine()) != null){ finalString += str; } } catch (FileNotFoundException e) { e.printStackTrace(); } catch (IOException e) { e.printStackTrace(); } System.out.println(finalString); try { JSONArray json = new JSONArray(finalString); for(int i = 0; i < json.length(); i++){ JSONObject jsonObj = json.getJSONObject(i); try { Kabelskap ks = getKabelskapFromJSON(jsonObj); skap.put(ks.objektnummer, ks); } catch (JSONException e) { e.printStackTrace(); } } } catch (JSONException e) { e.printStackTrace(); }

----- UPDATE 2.0 --------

System.out.println (finalString)> Not sure if the reader or System.out.println () skips the long parts of the text. I would suggest that DDMS LogCat uses an encoding that does not support Norwegian special letters.

 11-30 11:02:27.888: INFO/System.out(4304): {"driftsmerking":"1420 10 04","objektnummer":"56569.0","adresse":"KANEBOG SEN 4","fabrikat":"NEBB","typebetegnelse":"KO500","spenning":"0.23","posisjon":"OK","kompNr":"1420","kommune":"1901 HARSTAD","latitude":"68.7786964342854","longitude":"16.5598512563035"}{"driftsmerking":"4416 01 04","objektnummer":"246349.0","adresse":"NONS SEN","fabrikat":"ABB","typebetegnelse":"KO300","spenning":"0.23","posisjon":"OK","kompNr":"4416","kommune":"1911 KV FJORD","latitude":"68.7367985627796","longitude":"16.2694481350258"}{"driftsmerking":"4080 05 02","objektnummer":"275933.0","adresse":"KV FJORD PLANTESKOLE VEKSTHUS","fabrikat":"ABB","typebetegnelse":"KO700","spenning":"0.23","posisjon":"OK","kompNr":"4080","kommune":"1911 KV FJORD","latitude":"68.7712454761326","longitude":"16.1901046355049"}{"driftsmerking":"1383 01 02","objektnummer":"150951.0","adresse":"SKILLEVN. 13","fabrikat":"ABB","typebetegnelse":"","spenning":"0.4","posisjon":"OK","kompNr":"1383","kommune":"1901 HARSTAD","latitude":"68.7781436806564","longitude":"16.5643438120601"}{"driftsmerking":"4085 07 02","objektnummer":"275122.0","adresse":"MATHUSET","fabrikat":"NEBB","typebetegnelse":"70","spenning":"0.23","posisjon":"OK","kompNr":"4085","kommune":"1911 KV FJORD","latitude":"68.7721426826508","longitude":"16.1785193494225"}{"driftsmerking":"3410 05 12","objektnummer":"35184.0","adresse":"HANS EGEDESGT. 20 (ERIKSGATE)","fabrikat":"NEBB","typebetegnelse":"","spenning":"0.23","posisjon":"OK","kompNr":"3410","kommune":"1901 HARSTAD","latitude":"68.7980203542316","longitude":"16.538182961594"}{"driftsmerking":"0800 06 10","objektnummer":"266928.0","adresse":"GAMNES V/MAGNE HARALD OLSEN","fabrikat":"ABB","typebetegnelse":"KO35","spenning":"0.23","posisjon":"OK","kompNr":"","kommune":"1901 HARSTAD","latitude":"68.8206299498345","longitude":"16.4915959572276"}{"driftsmerking":"2580 02 02","objektnummer":"186379.0","adresse":"RESSAN","fabrikat":"ELMEK","typebetegnelse":"50 CM","spenning":"0.23","posisjon":"OK","kompNr":"2580","kommune":"1913 SK NLAND","latitude":"68.6729130202412","longitude":"17.127746958547"}{"driftsmerking":"1500 10 06","objektnummer":"193875.0","adresse":"TUVSLETTVN. 9","fabrikat":"ABB","typebetegnelse":"KO500","spenning":"0.23","posisjon":"OK","kompNr":"1500","kommune":"1901 HARSTAD","latitude":"68.74741783798","longitude":"16.5517037722856"}{"driftsmerking":"3282 02 02","objektnummer":"35547.0","adresse":"TEGEB RVN. 12B","fabrikat":"NEBB","typebetegnelse":"","spenning":"0.23","posisjon":"OK","kompNr":"3282","kommune":"1901 HARSTAD","latitude":"68.7991934883357","longitude":"16.5033927383319"}{"driftsmerking":"1430 05 02","objektnummer":"116375.0","adresse":" VERLAND 2","fabrikat":"ABB","typebetegnelse":"KO700","spenning":"0.23","posisjon":"OK","kompNr":"1430","kommune":"1901 HARSTAD","latitude":"68.7759663213591","longitude":"16.5611455110691"}{"driftsmerking":"4150 05 06","objektnummer":"275496.0","adresse":" NYVN. 21","fabrikat":"ABB","typebetegnelse":"KO500","spenning":"0.4","posisjon":"OK","kompNr":"4150","kommune":"1911 KV FJORD","latitude":"68.7741925557284","longitude":"16.1726621696438"}{"driftsmerking":"1486 07 02","objektnummer":"162192.0","adresse":"ROHOLTVN. 7","fabrikat":"ABB","typebetegnelse":"KO 700","spenning":"0.23","posisjon":"OK","kompNr":"1486","kommune":"1901 HARSTAD","latitude":"68.7550368601091","longitude":"16.5679658964195"}{"driftsmerking":"3025 02 06 / 3060 /","objektnummer":"35174.0","adresse":"HANS EGEDESGT. 6 (HVEDINGSGATE)","fabrikat":"NEBB","typebetegnelse":"","spenning":"0.23","posisjon":"OK","kompNr":"3025","kommune":"1901 HARSTAD","latitude":"68.7994885383443","longitude":"16.5414817371666"}{"driftsmerking":"7045 03 06","objektnummer":"251410.0","adresse":"KONGSVIKDALEN","fabrikat":"","typebetegnelse":"","spenning":"0.23","posisjon":"OK","kompNr":"7045","kommune":"1852 TJELDSUND","latitude":"68.5682671357777","longitude":"16.2428412985428"}{"driftsmerking":"3010 03 02","objektnummer":"35143.0","adresse":"6.DIVISJONSGT. 10","fabrikat":"ABB","typebetegnelse":"KO500",

- New update -

Full error tracing from the JSONArray (String json) constructor:

 12-03 15:14:44.290: WARN/System.err(412): org.json.JSONException: Value {"posisjon":"OK","spenning":"0.23","driftsmerking":"1420 10 04","adresse":"KANEBOG SEN 4","kompNr":"1420","objektnummer":"56569.0","typebetegnelse":"KO500","longitude":"16.5598512563035","latitude":"68.7786964342854","kommune":"1901 HARSTAD","fabrikat":"NEBB"} of type org.json.JSONObject cannot be converted to JSONArray 12-03 15:14:44.290: WARN/System.err(412): at org.json.JSON.typeMismatch(JSON.java:107) 12-03 15:14:44.290: WARN/System.err(412): at org.json.JSONArray.<init>(JSONArray.java:91) 12-03 15:14:44.290: WARN/System.err(412): at org.json.JSONArray.<init>(JSONArray.java:103) 12-03 15:14:44.290: WARN/System.err(412): at net.lovholm.kraftwerk.Kraftwerk.onCreate(Kraftwerk.java:66) 12-03 15:14:44.290: WARN/System.err(412): at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1047) 12-03 15:14:44.290: WARN/System.err(412): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:1611) 12-03 15:14:44.290: WARN/System.err(412): at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:1663) 12-03 15:14:44.290: WARN/System.err(412): at android.app.ActivityThread.access$1500(ActivityThread.java:117) 12-03 15:14:44.290: WARN/System.err(412): at android.app.ActivityThread$H.handleMessage(ActivityThread.java:931) 12-03 15:14:44.290: WARN/System.err(412): at android.os.Handler.dispatchMessage(Handler.java:99) 12-03 15:14:44.290: WARN/System.err(412): at android.os.Looper.loop(Looper.java:130) 12-03 15:14:44.290: WARN/System.err(412): at android.app.ActivityThread.main(ActivityThread.java:3683) 12-03 15:14:44.290: WARN/System.err(412): at java.lang.reflect.Method.invokeNative(Native Method) 12-03 15:14:44.290: WARN/System.err(412): at java.lang.reflect.Method.invoke(Method.java:507) 12-03 15:14:44.290: WARN/System.err(412): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:839) 12-03 15:14:44.290: WARN/System.err(412): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:597) 12-03 15:14:44.290: WARN/System.err(412): at dalvik.system.NativeStart.main(Native Method)

Implementation of JSONArray initialization and getKabelskapfromJSON method:

  • JSON array initialization output

    try {JSONArray json = new JSONArray (finalString);

     for(int i = 0; i < json.length(); i++){ JSONObject jsonObj = json.getJSONObject(i); try { Kabelskap ks = getKabelskapFromJSON(jsonObj); skap.put(ks.objektnummer, ks); } catch (JSONException e) { e.printStackTrace(); } }

    } catch (JSONException e) {e.printStackTrace (); }

  • getKabelselskapFromJSON method:

    private Kabelskap getKabelskapFromJSON (JSONObject jsonObj) throws JSONException {

     String driftsmerking = jsonObj.getString("driftsmerking"); String adresse = jsonObj.getString("addresse"); String objektnummer = jsonObj.getString("objektnummer"); String spenning = jsonObj.getString("spenning"); String fabrikat = jsonObj.getString("fabrikat"); String typebetegnelse = jsonObj.getString("typebetegnelse"); String posisjon = jsonObj.getString("posisjon"); String kompNr = jsonObj.getString("kompNr"); String kommune = jsonObj.getString("kommune"); String latitude = jsonObj.getString("latitude"); String longitude = jsonObj.getString("longitude"); Kabelskap k = new Kabelskap(driftsmerking, objektnummer, adresse, fabrikat, typebetegnelse, spenning, posisjon, kompNr, kommune, latitude, longitude); return k;

}

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2 answers

A few problems that I see:

  • You are using jsonObj in the first line, which is a JSONObject. Then in a for loop you use another object named json. I am going to assume that these two are the same object. Otherwise, your example is missing information.
  • JSONObject does not have a get method that accepts an integer. There is one that takes a string, so I assume you meant this.
  • JSONObject.get returns data corresponding to the key that you give it. It returns an object.

The error you are getting is that you are trying to pass a JSONObject to Kabelskap.

What I would do is create a helper method as shown below. In addition, you can create a special constructor for the Kabelstap object.

 public Kabelskap getKabelskapFromJSON(JSONObject jsonObj) { Kabelskap k = new Kabelskap(); String driftsmerking = jsonObj.getString("driftsmerking"); k.setDriftsmerking(driftsmerking); String addresse = jsonObj.getString("addresse"); k.setAddresse(addresse); String objektnummer = jsonObj.getString("objektnummer"); k.setObjektNummer(objektnummer); double spenning = jsonObj.getDouble("spenning"); k.setSpenning(spenning); // ... and so on for each property. return k; }

which can then be used as follows:

 try { JSONArray jsonArray = new JSONArray(yourJSONString); for(int i = 0; i < jsonArray.length(); i++) { JSONObject jsonObj = jsonArray.getJSONObject(i); Kabelskap k = getKabelskapFromJSON(jsonObj); // do something with k. eg System.out.println(" Kabelskap@ "+i+": "+k); } } catch (JSONException e) { e.printStackTrace(); }

The documentation for JSONObject is here , and JSONArray is here .

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Two things,

  • When analyzing data, you should use JSONArray .
  • You need to parse json and create Kabelskap objects yourself. json.get (i) will return an Object , which in this case will be a JSONObject . With this JSONObject you use getters to get fields and create your Kabelskap object.
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