JSON Parsing in android
Let’s look at how to parse JSON objects in android
1> First we’ll need an example :
Lets look at a standard example from the json site http://json.org/example.html
{"menu": {
"id": "file",
"value": "File",
"popup": {
"menuitem": [
{"value": "New", "onclick": "CreateNewDoc()"},
{"value": "Open", "onclick": "OpenDoc()"},
{"value": "Close", "onclick": "CloseDoc()"}
]
}
}}
you could either save this in a file or save it in a string…..like I’ve done
2> Android already contains the required JSON libraries
Lets create a JSON Object;
private JSONObject jObject;
and lets our example be a String ,
private String jString = "{\"menu\": {\"id\": \"file\", \"value\": \"File\", \"popup\": { \"menuitem\": [ {\"value\": \"New\", \"onclick\": \"CreateNewDoc()\"}, {\"value\": \"Open\", \"onclick\": \"OpenDoc()\"}, {\"value\": \"Close\", \"onclick\": \"CloseDoc()\"}]}}}";
now we have to convert jString to the jObject ,
jObject = new JSONObject(jString);
Now we have to start extracting the content from jObject ,
Lets extract the menu object by creating a new menu object,
JSONObject menuObject = jObject.getJSONObject("menu");
Now lets extract its atrtibutes ,
String attributeId = menuObject.getString("id");
String attributeValue = menuObject.getString("value");
JSONObject popupObject = menuObject.getJSONObject("popup");
since “popup” is not plainly a String lets extract it to an object ,
3> Now popup contains an array of “menuitem”
So, we’ll have to extract it to a JSONArray,
JSONArray menuitemArray = popupObject.getJSONArray("menuitem");
Since it contains 3 items lets put it in a for loop.
for (int i = 0; i < 3; i++) {
System.out.println(menuitemArray.getJSONObject(i)
.getString("value").toString());
System.out.println(menuitemArray.getJSONObject(i).getString(
"onclick").toString());
}
Basically thats it , u should see the output in the DDMS
4> The full code is as below,
import org.json.JSONArray;
import org.json.JSONObject;
import android.app.Activity;
import android.os.Bundle;
public class JsonParser extends Activity {
private JSONObject jObject;
private String jString = "{\"menu\": {\"id\": \"file\", \"value\": \"File\", \"popup\": { \"menuitem\": [ {\"value\": \"New\", \"onclick\": \"CreateNewDoc()\"}, {\"value\": \"Open\", \"onclick\": \"OpenDoc()\"}, {\"value\": \"Close\", \"onclick\": \"CloseDoc()\"}]}}}";
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
try {
parse();
} catch (Exception e) {
e.printStackTrace();
}
}
private void parse() throws Exception {
jObject = new JSONObject(jString);
JSONObject menuObject = jObject.getJSONObject("menu");
String attributeId = menuObject.getString("id");
System.out.println(attributeId);
String attributeValue = menuObject.getString("value");
System.out.println(attributeValue);
JSONObject popupObject = menuObject.getJSONObject("popup");
JSONArray menuitemArray = popupObject.getJSONArray("menuitem");
for (int i = 0; i < 3; i++) {
System.out.println(menuitemArray.getJSONObject(i)
.getString("value").toString());
System.out.println(menuitemArray.getJSONObject(i).getString(
"onclick").toString());
}
}
}