JSON Parsing in android

JSON


JSON (JavaScript Object Notation) is a lightweight data-interchange format. It is easy for humans to read and write. It is easy for machines to parse and generate. It is based on a subset of the JavaScript Programming Language, Standard ECMA-262 3rd Edition - December 1999. JSON is a text format that is completely language independent but uses conventions that are familiar to programmers of the C-family of languages, including C, C++, C#, Java, JavaScript, Perl, Python, and many others. These properties make JSON an ideal data-interchange language.



JSON is built on two structures:

• A collection of name/value pairs. In various languages, this is realized as an object, record, struct, dictionary, hash table, keyed list, or associative array.
• An ordered list of values. In most languages, this is realized as an array, vector, list, or sequence.

These are universal data structures. Virtually all modern programming languages support them in one form or another. It makes sense that a data format that is interchangable with programming languages also be based on these structures.


JSON with android


org.json package available in android SDK which suports JSON parsing 


JSONObject
JSONArray

String json = "{"
         + "  \"query\": \"Pizza\", "
         + "  \"locations\": [ 94043, 90210 ] "
         + "}";

 JSONObject object = (JSONObject) new JSONTokener(json).nextValue();
 String query = object.getString("query");
 JSONArray locations = object.getJSONArray("locations");

This is a very simple JSON String

{"key1":"value1","key2":"value2"}

In order to get values for it use JSONObject like this :

JSONObject json_obj=new JSONObject(your json string);<br>
String value1=json_obj.getString("key1");<br>
String value2=json_obj.getString("key2");

This is a slightly complex json string

[{"key1":"value1","key2":"value2"},{"key1":"value1","key2":"value2"}]

In order to extract values from this use JSONArray

JSONArray jArray=new JSONArray(your json string);<br>
for(int i=0;i<(jArray.length());i++)<br>
{

  JSONObject json_obj=jArray.getJSONObject(i);

   String value1=json_obj.getString("key1");
   String value2=json_obj.getString("key2");
}