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| /*
*Steps to be followed for JSON parsing with Gson Library :-
* Download Gson library from above link & add jar to eclipse project.
* Create AsyncTask class to handle background operations.
* Use the DefaultHttpClient to retrieve the data if this is a web resource.
* Create respective model classes to handle response data.
* Create instance of Gson class.
* Use the fromJson() in order to parse the JSON input and return the model object.
* Update the UI elements by using model objetcs.
/*
* parse json
*/
package com.sample;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.io.Reader;
import org.apache.http.HttpEntity;
import org.apache.http.HttpResponse;
import org.apache.http.HttpStatus;
import org.apache.http.client.methods.HttpGet;
import org.apache.http.impl.client.DefaultHttpClient;
import android.app.Activity;
import android.app.ProgressDialog;
import android.content.DialogInterface;
import android.content.DialogInterface.OnCancelListener;
import android.os.AsyncTask;
import android.os.Bundle;
import android.text.Html;
import android.util.Log;
import android.widget.TextView;
import com.google.gson.Gson;
public class MyClass extends Activity {
TextView capitalTextView;
ProgressDialog progressDialog;
/** Called when the activity is first created. */
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
capitalTextView = (TextView) findViewById(R.id.capital_textview);
this.retrieveCapitals();
}
void retrieveCapitals() {
progressDialog = ProgressDialog.show(this, "Please wait...", "Retrieving data...", true, true);
CapitalsRetrieverAsyncTask task = new CapitalsRetrieverAsyncTask();
task.execute();
progressDialog.setOnCancelListener(new CancelListener(task));
}
private class CapitalsRetrieverAsyncTask extends AsyncTask<Void, Void, Response> {
@Override
protected Response doInBackground(Void... params) {
String url = "http://api.androidsmith.com/capitals.php";
Reader inputStreamReader = getInputStreamReader(url);
return parseResponse(inputStreamReader);
}
@Override
protected void onPostExecute(Response myresponse) {
super.onPostExecute(myresponse);
StringBuilder builder = new StringBuilder();
for (Country country : myresponse.data) {
builder.append(String.format("<br>Country: <b>%s</b><br>Capital: <b>%s</b><br><br>", country.getCountry(), country.getCapital()));
}
capitalTextView.setText(Html.fromHtml(builder.toString()));
progressDialog.cancel();
}
}
private class CancelListener implements OnCancelListener {
AsyncTask<?, ?, ?> cancellableTask;
public CancelListener(AsyncTask<?, ?, ?> task) {
cancellableTask = task;
}
@Override
public void onCancel(DialogInterface dialog) {
cancellableTask.cancel(true);
}
}
private Reader getInputStreamReader(String url) {
Reader inputStreamReader = null;
HttpGet getRequest = new HttpGet(url);
try {
DefaultHttpClient httpClient = new DefaultHttpClient();
HttpResponse getResponse = httpClient.execute(getRequest);
final int statusCode = getResponse.getStatusLine().getStatusCode();
if (statusCode != HttpStatus.SC_OK) {
Log.w(getClass().getSimpleName(), "Error " + statusCode + " for URL " + url);
return null;
}
HttpEntity getResponseEntity = getResponse.getEntity();
InputStream httpResponseStream = getResponseEntity.getContent();
inputStreamReader = new InputStreamReader(httpResponseStream);
}
catch (IOException e) {
getRequest.abort();
Log.w(getClass().getSimpleName(), "Error for URL " + url, e);
}
return inputStreamReader;
}
private Response parseResponse(Reader inputStreamReader){
Gson gson = new Gson();
Response response = gson.fromJson(inputStreamReader, Response.class);
return response;
}
}
Country.Java:-
package com.sample;
public class Country {
String country;
String capital;
public Country() {
this.country = "";
this.capital = "";
}
public String getCountry() {
return this.country;
}
public String getCapital() {
return this.capital;
}
}
Response.Java:-
package com.sample;
import java.util.ArrayList;
import com.androidsmith.sacc.model.Country;
public class Response {
ArrayList<Country> data;
public Response() {
data = new ArrayList<Country>();
}
}
|
