Optimize JSonArray for Loop

Question

Today, I'm trying to optimize my JSONArray regarding android developer documentation. I was supposed to optimize it but there is error message coming out.

JSONArray infojson = json.getJSONArray("getInfo");          
for(int i=0;i < infojson.length();i++){                                     
    JSONObject e = infojson.getJSONObject(i);
    hm = new HashMap<String, Object>();
    hm.put(MYNAME, e.getString("uname"));
    hm.put(MYAGE, e.getString("uage"));
}

And I've optimized above coding as follow

JSONArray infojson = jsonObject.getJSONArray("getInfo");
for (Object o : infojson ) {
    JSONObject jsonLineItem = (JSONObject) o;
    String myname = jsonLineItem.getString("uname");
    String myage = jsonLineItem.getString("uage");
}

Unfortunately, I got the following error message occuring on "infojson ) {"

Can only iterate over an array or an instance of java.lang.Iterable

momo · Accepted Answer · 2011-09-08 00:14:41Z

8

You can't use JSONArray with the that syntax as it doesn't implement Iterable interface. As a side note, the micro performance improvement you get probably won't affect your application performance as JSON results that are returned from the WebService are typically not large in size.

answered Sep 8, 2011 at 0:14

momo

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1 Comment

choz Over a year ago

My JSON is about 650.000 bytes. Does it also count as not large?

bumbumpaw · Accepted Answer · 2014-07-30 17:32:28Z

2

You're getting that error because JSONArray doesn't implement the Iterable interface.

In short, there's no clean way to solve this; you'd have to serialize the JSONObjects into your custom class.

To save you time though, using (Object one: all) over (i=0; i < all.getLength(); i++) won't give you any runtime improvements.

Just stick to the normal for loop.

edited Jul 30, 2014 at 17:32

bumbumpaw

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answered Sep 8, 2011 at 0:17

soBinary

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Comments

Mirza Hadzic · Accepted Answer · 2024-06-04 11:17:36Z

-1

If you have very long arrays, don't iterate it that way. You can use gson to convert JSONArray to java array, like this:

static class Elem {    
   public String uname;
   public double uage;
}

...
JSONArray infojson = json.getJSONArray("getInfo");
String arrAsStr = infojson.toString();
Elem[] naviPoints = new Gson().fromJson(arrAsStr, Elem[].class);

answered Jun 4, 2024 at 11:17

Mirza Hadzic

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