My current objective is to parse the Google Map API to return information about certain coordinates.
The main issue I am having is that I cannot get anything to display when I run the program. The code given below will run without any errors stopping the program, but will simply come up with a blank TextView. I am not very familiar with JSON parsing (this being the first program I've ever worked on with it) and I was wondering what was missing that was preventing the returned information to display on a TextView.
Is there a specific way to get the text to appear when parsing through JSON? I appreciate all the help.
My MainActivity.java class:
import org.json.JSONArray;
import org.json.JSONException;
import org.json.JSONObject;
import android.app.Activity;
import android.os.Bundle;
import android.os.StrictMode;
import android.os.StrictMode.ThreadPolicy;
import android.widget.TextView;
public class MainActivity extends Activity {
// URL to make the request to
private static String url = "http://maps.googleapis.com/maps/api/geocode/json?latlng=40.1031,-75.1522&sensor=true";
// JSON Node names
private static final String TAG_LOCATION = "results";
private static final String TAG_CITY = "long_name";
// The JSON Array
JSONArray location = null;
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
ThreadPolicy tp = ThreadPolicy.LAX;
StrictMode.setThreadPolicy(tp);
// Creating JSON Parser instance
JSONParser jParser = new JSONParser();
// getting JSON string from URL
JSONObject json = jParser.getJSONFromUrl(url);
try {
// Getting Array of Location
location = json.getJSONArray(TAG_LOCATION);
// looping through each part of location
for(int i = 0; i < location.length(); i++){
JSONObject c = location.getJSONObject(i);
// Storing each JSON item in a variable
String city = c.getString(TAG_CITY);
// For whichever one works
System.out.println(city);
TextView textView = (TextView) findViewById(R.id.textView1);
textView.setText("City: " + city);
}
} catch (JSONException e) {
e.printStackTrace();
}
}
}
My JSONParser.java class:
package com.example.finalproject;
import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.io.UnsupportedEncodingException;
import org.apache.http.HttpEntity;
import org.apache.http.HttpResponse;
import org.apache.http.client.ClientProtocolException;
import org.apache.http.client.methods.HttpGet;
import org.apache.http.impl.client.DefaultHttpClient;
import org.json.JSONException;
import org.json.JSONObject;
import android.util.Log;
public class JSONParser {
static InputStream is = null;
static JSONObject jObj = null;
static String json = "";
// constructor
public JSONParser() {
}
public JSONObject getJSONFromUrl(String url) {
// Making HTTP request
try {
// defaultHttpClient
DefaultHttpClient httpClient = new DefaultHttpClient();
HttpGet httpGet = new HttpGet(url);
HttpResponse httpResponse = httpClient.execute(httpGet);
HttpEntity httpEntity = httpResponse.getEntity();
is = httpEntity.getContent();
} catch (UnsupportedEncodingException e) {
e.printStackTrace();
} catch (ClientProtocolException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
}
try {
BufferedReader reader = new BufferedReader(new InputStreamReader(
is, "iso-8859-1"), 8);
StringBuilder sb = new StringBuilder();
String line = null;
while ((line = reader.readLine()) != null) {
sb.append(line + "\n");
}
is.close();
json = sb.toString();
} catch (Exception e) {
Log.e("Buffer Error", "Error converting result " + e.toString());
}
// try parse the string to a JSON object
try {
jObj = new JSONObject(json);
} catch (JSONException e) {
Log.e("JSON Parser", "Error parsing data " + e.toString());
}
// return JSON String
return jObj;
}
}
long_name key is in JSONObject which is in address_components JSONArray instead of JSONObject which is in results JSONArray so you should need to first get JSONArray from c JSONObject as:
for(int i = 0; i < location.length(); i++){
JSONObject c = location.getJSONObject(i);
// get address_components JSONArray from c
JSONArray add_array=c.getJSONArray("address_components");
for(int j = 0; j < add_array.length(); j++){
JSONObject obj_add = add_array.getJSONObject(i);
// Storing each JSON item in a variable
String city = c.getString(TAG_CITY);
//your code here....
}
}
and also use AsyncTask for getting data from weservice instead of doing network operations on Main UI Thread.
Here's some example code for using the Android/Google location API
http://developer.android.com/google/play-services/location.html
import android.location.Address;
import android.location.Criteria;
import android.location.Geocoder;
import android.location.Location;
import android.location.LocationManager;
private void reverseGeocode()
{
AsyncTask< LatLng, Integer, List< Address > > task
= new AsyncTask< LatLng, Integer, List< Address > >()
{
#Override
protected List< Address > doInBackground( LatLng... params )
{
LatLng latLng = params[0];
Geocoder geoCoder = new Geocoder(getActivity().getApplicationContext() );
List< Address > matches = null;
try
{
matches = geoCoder.getFromLocation(latLng.latitude, latLng.longitude, 1);
}
catch ( IOException e )
{
e.printStackTrace();
}
return matches;
}
#Override
protected void onPostExecute( List< Address > result )
{
if ( result != null && result.size() > 0 )
{
if ( D ) Log.v( TAG, "onPostExecute result size=" + result.size() );
Address bestMatch = (result.isEmpty() ? null : result.get(0));
//showGeocodedAddress( bestMatch );
}
}
};
task.execute( latLng );
}
Related
I'm New to android development and I don't understand clearly how to create a appwidget for application that parse JSON Data and display in list.
I solved my problem using this link (https://laaptu.wordpress.com/2013/07/19/android-app-widget-with-listview/).
It has Series of Tutorials
(1.app widget with listview
2.populate app widget listview with data from web
3.download images and show on imageview of appwidget with listview
4.setting update interval on appwidget with listview
5.how to make appwidget update work after phone reboot)
To Use Simple JSON URL to fetch images and texts, i made the following changes in RemoteFetchService.java from third tutorial,
import java.util.ArrayList;
import org.json.JSONArray;
import org.json.JSONException;
import org.json.JSONObject;
import android.app.Service;
import android.appwidget.AppWidgetManager;
import android.content.Intent;
import android.graphics.Bitmap;
import android.os.AsyncTask;
import android.os.IBinder;
import android.util.Log;
import com.androidquery.AQuery;
import com.androidquery.callback.AjaxCallback;
import com.androidquery.callback.AjaxStatus;
import com.example.mk.widgets.data.DatabaseManager;
import com.example.mk.widgets.data.FileManager;
public class RemoteFetchService extends Service {
private int appWidgetId = AppWidgetManager.INVALID_APPWIDGET_ID;
JSONObject jsonobject;
JSONArray jsonarray;
AQuery aquery;
private String remoteJsonUrl = "http://microblogging.wingnity.com/JSONParsingTutorial/jsonActors";
public static ArrayList<ListItem> listItemList;
private int count = 0;
#Override
public IBinder onBind(Intent arg0) {
return null;
}
/*
* Retrieve appwidget id from intent it is needed to update widget later
* initialize our AQuery class
*/
#Override
public int onStartCommand(Intent intent, int flags, int startId) {
if (intent.hasExtra(AppWidgetManager.EXTRA_APPWIDGET_ID))
appWidgetId = intent.getIntExtra(
AppWidgetManager.EXTRA_APPWIDGET_ID,
AppWidgetManager.INVALID_APPWIDGET_ID);
aquery = new AQuery(getBaseContext());
new DownloadJSON().execute();
return super.onStartCommand(intent, flags, startId);
}
// DownloadJSON AsyncTask
private class DownloadJSON extends AsyncTask<Void, Void, Void> {
#Override
protected Void doInBackground(Void... params) {
// Create an array
listItemList = new ArrayList<ListItem>();
// Retrieve JSON Objects from the given URL address
jsonobject = JSONfunctions.getJSONfromURL(remoteJsonUrl);
try {
// Locate the array name in JSON
jsonarray = jsonobject.getJSONArray("actors");
for (int i = 0; i < jsonarray.length(); i++) {
jsonobject = jsonarray.getJSONObject(i);
// Retrive JSON Objects
ListItem listItem = new ListItem();
listItem.heading = jsonobject.getString("name");
listItem.content = jsonobject.getString("country");
listItem.imageUrl = jsonobject.getString("image");
listItemList.add(listItem);
}
storeListItem();
} catch (JSONException e) {
Log.e("Error", e.getMessage());
e.printStackTrace();
}
return null;
}
}
/**
* Instead of using static ArrayList as we have used before,no we rely upon
* data stored on database so saving the fetched json file content into
* database and at same time downloading the image from web as well
*/
private void storeListItem() {
DatabaseManager dbManager = DatabaseManager.INSTANCE;
dbManager.init(getBaseContext());
dbManager.storeListItems(appWidgetId, listItemList);
int length = listItemList.size();
for (int i = 0; i < length; i++) {
ListItem listItem = listItemList.get(i);
final int index = i;
aquery.ajax(listItem.imageUrl, Bitmap.class,new AjaxCallback<Bitmap>() {
#Override
public void callback(String url, Bitmap bitmap, AjaxStatus status) {
super.callback(url, bitmap, status);
storeBitmap(index, bitmap);
};
});
}
}
/**
* Saving the downloaded images into file and after all the download of
* images be complete begin to populate widget as done previously
*/
private void storeBitmap(int index, Bitmap bitmap) {
FileManager.INSTANCE.storeBitmap(appWidgetId, bitmap,
listItemList.get(index).heading, getBaseContext());
count++;
Log.i("count",String.valueOf(count) + "::"+ Integer.toString(listItemList.size()));
if (count == listItemList.size()) {
count = 0;
populateWidget();
}
}
/**
* Method which sends broadcast to WidgetProvider so that widget is notified
* to do necessary action and here action == WidgetProvider.DATA_FETCHED
*/
private void populateWidget() {
Intent widgetUpdateIntent = new Intent();
widgetUpdateIntent.setAction(WidgetProvider.DATA_FETCHED);
widgetUpdateIntent.putExtra(AppWidgetManager.EXTRA_APPWIDGET_ID,
appWidgetId);
sendBroadcast(widgetUpdateIntent);
this.stopSelf();
}
}
JSONfunctions.java
import java.io.BufferedReader;
import java.io.InputStream;
import java.io.InputStreamReader;
import org.apache.http.HttpEntity;
import org.apache.http.HttpResponse;
import org.apache.http.client.HttpClient;
import org.apache.http.client.methods.HttpPost;
import org.apache.http.impl.client.DefaultHttpClient;
import org.json.JSONException;
import org.json.JSONObject;
import android.util.Log;
public class JSONfunctions {
public static JSONObject getJSONfromURL(String url) {
InputStream is = null;
String result = "";
JSONObject jArray = null;
// Download JSON data from URL
try {
HttpClient httpclient = new DefaultHttpClient();
HttpPost httppost = new HttpPost(url);
HttpResponse response = httpclient.execute(httppost);
HttpEntity entity = response.getEntity();
is = entity.getContent();
} catch (Exception e) {
Log.e("log_tag", "Error in http connection " + e.toString());
}
// Convert response to string
try {
BufferedReader reader = new BufferedReader(new InputStreamReader(
is, "iso-8859-1"), 8);
StringBuilder sb = new StringBuilder();
String line = null;
while ((line = reader.readLine()) != null) {
sb.append(line + "\n");
}
is.close();
result = sb.toString();
} catch (Exception e) {
Log.e("log_tag", "Error converting result " + e.toString());
}
try {
jArray = new JSONObject(result);
} catch (JSONException e) {
Log.e("log_tag", "Error parsing data " + e.toString());
}
return jArray;
}
}
Hope this helps someone and Great thanks to ( https://stackoverflow.com/users/739306/laaptu ) for the tutorials.
i am working on an app using json parsing...in this parsing is done by json of the given url.
As i run my project on emulator having target = "Google APIs (Google Inc.) - API level 10"
then it runs properly and shows needed results from the target url.
but when run my project on emulator having target = "Google APIs (Google Inc.) - API level 16"
then it shows error and it never parse the given url data and get force close.
i want to make app which run on every API level.
please help...
here's my code:
json parser class:
import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.io.UnsupportedEncodingException;
import org.apache.http.HttpEntity;
import org.apache.http.HttpResponse;
import org.apache.http.client.ClientProtocolException;
import org.apache.http.client.methods.HttpGet;
import org.apache.http.client.methods.HttpPost;
import org.apache.http.impl.client.DefaultHttpClient;
import org.json.JSONArray;
import org.json.JSONException;
import org.json.JSONObject;
import android.util.Log;
public class JSONParser {
static InputStream is = null;
static JSONArray jObj = null;
static String json = "";
static String req = "POST";
// constructor
public JSONParser() {
}
public JSONArray getJSONFromUrl(String url, String method) {
// Making HTTP request
try {
// defaultHttpClient
DefaultHttpClient httpClient = new DefaultHttpClient();
HttpResponse httpResponse = null;
if(method == req) {
HttpPost httpC = new HttpPost(url);
httpResponse = httpClient.execute(httpC);
}else {
HttpGet httpC = new HttpGet(url);
httpResponse = httpClient.execute(httpC);
}
HttpEntity httpEntity = httpResponse.getEntity();
is = httpEntity.getContent();
} catch (UnsupportedEncodingException e) {
e.printStackTrace();
} catch (ClientProtocolException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
}
try {
BufferedReader reader = new BufferedReader(new InputStreamReader(
is, "iso-8859-1"), 8);
StringBuilder sb = new StringBuilder();
String line = null;
while ((line = reader.readLine()) != null) {
sb.append(line + "\n");
}
is.close();
json = sb.toString();
} catch (Exception e) {
Log.e("Buffer Error", "Error converting result " + e.toString());
}
// try parse the string to a JSON object
try {
jObj = new JSONArray(json);
} catch (JSONException e) {
Log.e("JSON Parser", "Error parsing data " + e.toString());
}
// return JSON String
return jObj;
}
}
Another class using json parser class snd fetch data:
import java.util.ArrayList;
import java.util.HashMap;
import org.json.JSONArray;
import org.json.JSONException;
import org.json.JSONObject;
import android.app.ListActivity;
import android.content.Intent;
import android.os.Bundle;
import android.util.Log;
import android.widget.ListAdapter;
import android.widget.SimpleAdapter;
public class showData extends ListActivity{
public static String url = "http://something/something/";
public static final String TAG_A = "a";
public static final String TAG_B = "b";
public static final String TAG_C = "c";
public static final String TAG_D = "d";
public static final String TAG_E = "e";
public static final String TAG_F = "f";
public static final String GET = "get";
JSONArray Data1 = null;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
ArrayList<HashMap<String, String>> contactList = new ArrayList<HashMap<String, String>>();
EditText editext_text = (EditText) findViewById(R.id.et);
String urlnew = url + editext_text.getText().toString();
Log.d("url", urlnew);
JSONParser jParser = new JSONParser();
// getting JSON string from URL
area1 = jParser.getJSONFromUrl(urlnew, GET);
Log.d("Json String", area1.toString());
try {
for(int i = 0; i < area1.length(); i++){
JSONObject c = area1.getJSONObject(i);
// Storing each json item in variable
String a = c.getString(TAG_A);
String b = c.getString(TAG_B);
String c = c.getString(TAG_C);
String d = c.getString(TAG_D);
String e = c.getString(TAG_E);
HashMap<String,String> map = new HashMap<String, String>();
// adding each child node to HashMap key => value
map.put(TAG_A, a);
map.put(TAG_B, b);
map.put(TAG_C, c);
map.put(TAG_D, d);
map.put(TAG_E, e);
// adding HashList to ArrayList
contactList.add(map);
}
} catch (JSONException e) {
e.printStackTrace();
}
ListAdapter adapter = new SimpleAdapter(this, contactList,
R.layout.list_item_area,
new String[] { TAG_B, TAG_A, TAG_C, TAG_D, TAG_E }, new int[] {
R.id.b, R.id.a, R.id.c, R.id.d, R.id.e });
setListAdapter(adapter);
}
}
You are getting a NetworkOnMainThreadException because as the name is self-explaining, you are doing network request on UI Thread that will make your application laggy and create an horrible experience.
The exception that is thrown when an application attempts to perform a
networking operation on its main thread.
This is only thrown for applications targeting the Honeycomb SDK or
higher. Applications targeting earlier SDK versions are allowed to do
networking on their main event loop threads, but it's heavily
discouraged. See the document Designing for Responsiveness.
You should use Threads or AsyncTask, do you need some explanations on how to use them?
private class NetworkTask extends AsyncTask<String, Void, String> {
#Override
protected String doInBackground(String... params) {
//DO YOUR STUFF
}
#Override
protected void onPostExecute(String result) {
//Update UI
}
#Override
protected void onPreExecute() {
}
#Override
protected void onProgressUpdate(Void... values) {
}
}
This is Network On Main Thread Exception, You have to use Thread for network connection, because the main thread is UI thread will not give any response for Network connection. Use separate thread for network connection
I'm having trouble with my application. I'm trying to pass json data from my database in a custom class in android, and then display this in a list. When i run my app nothing happens, no errors, no list displayed. if anyone can help i would be very grateful!! :)
All the network stuff is done in async, and im trying to return the an array of objects so i suspect that this could be the problem is here or else when i am converting the string from the httphandler class into a JSONArray.
this is my main activity
package com.example.test1;
import java.util.ArrayList;
import org.json.JSONArray;
import org.json.JSONException;
import org.json.JSONObject;
import android.app.Activity;
import android.net.ParseException;
import android.os.AsyncTask;
import android.os.Bundle;
import android.widget.ArrayAdapter;
import android.widget.ListView;
public class clubpage extends Activity {
class Programme {
public String name;
public String event;
public String price;
}
String clubphp = "http://10.0.2.2/corkgaa/Nemo.php";
String progString;
ArrayList<Programme> Programmedata = new ArrayList<Programme>();
ListView clublistview = (ListView)findViewById(R.id.listview1);
#Override
protected void onCreate(Bundle savedInstanceState) {
// TODO Auto-generated method stub
super.onCreate(savedInstanceState);
setContentView(R.layout.clubpage);
new Dbhandler().execute(clubphp);
ArrayAdapter<Programme> adapter = new ArrayAdapter<Programme>(this,
android.R.layout.simple_list_item_1, Programmedata);
clublistview.setAdapter(adapter);
}
public class Dbhandler extends AsyncTask<String, Void, ArrayList<Programme>> {
protected ArrayList<Programme> doInBackground(String... arg0) {
ArrayList<Programme> arraydata = new ArrayList<Programme>();
progString = httphandler.HttpGetExec(clubphp);
try{
JSONArray jArray = new JSONArray(progString);
JSONObject json_data=null;
for(int i=0;i<jArray.length();i++){
json_data = jArray.getJSONObject(i);
Programme Progresult = new Programme();
Progresult.name = json_data.getString("Name");
Progresult.event = json_data.getString("Event");
Progresult.price = json_data.getString("Price");
arraydata.add(Progresult);
}
}
catch(JSONException e1){
}
catch (ParseException e1) {
e1.printStackTrace();
}
return arraydata;
}
#Override
protected void onPostExecute(ArrayList<Programme> result) {
Programmedata = result;
}
}
#Override
protected void onPause() {
// TODO Auto-generated method stub
super.onPause();
}
}
httphandler class here:
package com.example.test1;
import java.io.BufferedReader;
import java.io.InputStream;
import java.io.InputStreamReader;
import org.apache.http.HttpEntity;
import org.apache.http.HttpResponse;
import org.apache.http.client.HttpClient;
import org.apache.http.client.methods.HttpPost;
import org.apache.http.impl.client.DefaultHttpClient;
import android.util.Log;
public class httphandler {
//Main Dev setup
public static String HttpGetExec (String URI) {
// TODO Auto-generated method stub
String result = "no response";
InputStream is = null;
StringBuilder sb = null;
//http post
try{
HttpClient httpclient = new DefaultHttpClient();
HttpPost httppost = new HttpPost("http://10.0.2.2/corkgaa/Nemo.php");
HttpResponse response = httpclient.execute(httppost);
HttpEntity entity = response.getEntity();
is = entity.getContent();
}
catch(Exception e){
Log.e("log_tag", "Error in http connection"+e.toString());
}
//convert response to string
try{
BufferedReader reader = new BufferedReader(new InputStreamReader(is,"iso-8859-1"),8);
sb = new StringBuilder();
sb.append(reader.readLine() + "\n");
String line="0";
while ((line = reader.readLine()) != null) {
sb.append(line + "\n");
}
is.close();
result=sb.toString();
}
catch(Exception e){
Log.e("log_tag", "Error converting result "+e.toString());
}
return result;
//aa=new ArrayAdapter<String>(clubpage.this, R.layout.listrow, R.id.title, result);
//ArrayAdapter<String> adapter = new ArrayAdapter<String>(this,R.layout.listrow, R.id.title, result);
//listview.setAdapter(aa);
}
}
Move this line to your onCreate after setContentView
clublistview = (ListView)findViewById(R.id.listview1);
And move the following lines to onPostExecute in your async task:
ArrayAdapter<Programme> adapter = new ArrayAdapter<Programme>(this,
android.R.layout.simple_list_item_1, Programmedata);
clublistview.setAdapter(adapter);
While your async task is executing, consider showing some kind of progress indicator.
Hello # All out there :)
I am having a little problem. I want to show a ProgressDialog when I click on Login but nothing is shown it just does the Task without the ProgressDialog. I am using a AsyncTask and opening the ProgressDialog in that thread but nothing comes up. Here is my Source Code:
It is called like this:
ProgressDialog progress = new ProgressDialog(mainActivity);
progress.setMessage("Sie werden registriert...");
jsonParser = new JSONParser(progress, url_create_user, "POST", params);
And this is the JSONParser Class:
import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.io.UnsupportedEncodingException;
import java.util.List;
import org.apache.http.HttpEntity;
import org.apache.http.HttpResponse;
import org.apache.http.NameValuePair;
import org.apache.http.client.ClientProtocolException;
import org.apache.http.client.entity.UrlEncodedFormEntity;
import org.apache.http.client.methods.HttpGet;
import org.apache.http.client.methods.HttpPost;
import org.apache.http.client.params.ClientPNames;
import org.apache.http.client.params.CookiePolicy;
import org.apache.http.client.utils.URLEncodedUtils;
import org.apache.http.impl.client.DefaultHttpClient;
import org.json.JSONException;
import org.json.JSONObject;
import android.app.ProgressDialog;
import android.content.Context;
import android.os.AsyncTask;
import android.os.Handler;
import android.os.Looper;
import android.os.Message;
import android.util.Log;
public class JSONParser extends AsyncTask<Context, Void, JSONObject>{
static InputStream is = null;
static JSONObject jObj = null;
static String json = "";
String url = "";
String method = "";
List<NameValuePair> parameters;
ProgressDialog prog;
// constructor
public JSONParser(ProgressDialog prog, String url, String method, List<NameValuePair> param) {
this.url = url;
this.method = method;
this.parameters = param;
this.prog = prog;
}
private Handler handler = new Handler() {
#Override
public void handleMessage(Message msg) {
if (msg.what == 0)
{
prog.show();
}
else
{
prog.dismiss();
}
}
};
#Override
protected JSONObject doInBackground(Context... params) {
try {
handler.sendEmptyMessage(0);
// Überprüfen welche Request Methode benutzt werden soll
if(method == "POST"){
DefaultHttpClient httpClient = new DefaultHttpClient();
httpClient.getParams().setParameter(ClientPNames.COOKIE_POLICY,
CookiePolicy.BROWSER_COMPATIBILITY);
HttpPost httpPost = new HttpPost(url);
httpPost.setEntity(new UrlEncodedFormEntity(this.parameters));
HttpResponse httpResponse = httpClient.execute(httpPost);
HttpEntity httpEntity = httpResponse.getEntity();
is = httpEntity.getContent();
}else if(method == "GET"){
DefaultHttpClient httpClient = new DefaultHttpClient();
String paramString = URLEncodedUtils.format(this.parameters, "utf-8");
url += "?" + paramString;
HttpGet httpGet = new HttpGet(url);
HttpResponse httpResponse = httpClient.execute(httpGet);
HttpEntity httpEntity = httpResponse.getEntity();
is = httpEntity.getContent();
}
} catch (UnsupportedEncodingException e) {
e.printStackTrace();
} catch (ClientProtocolException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
}
//Stream in ein String umwandeln
try {
BufferedReader reader = new BufferedReader(new InputStreamReader(
is, "iso-8859-1"), 8);
StringBuilder sb = new StringBuilder();
String line = null;
while ((line = reader.readLine()) != null) {
sb.append(line + "\n");
}
is.close();
json = sb.toString();
} catch (Exception e) {
Log.e("Fehler!", "Fehler mein umwandeln von Stream in String: " + e.toString());
}
// JSON Object parsen
try {
jObj = new JSONObject(json);
} catch (JSONException e) {
Log.e("JSON Parser", "Error beim parsen " + e.toString());
}
handler.sendEmptyMessage(1);
// Das JSONObject zurückgeben
return jObj;
}
}
see the following example code of JSON parser with async task
package com.androidhive.jsonparsing;
import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.io.UnsupportedEncodingException;
import java.util.ArrayList;
import java.util.HashMap;
import org.apache.http.HttpEntity;
import org.apache.http.HttpResponse;
import org.apache.http.client.ClientProtocolException;
import org.apache.http.client.methods.HttpPost;
import org.apache.http.impl.client.DefaultHttpClient;
import org.json.JSONArray;
import org.json.JSONException;
import org.json.JSONObject;
import android.app.ListActivity;
import android.app.ProgressDialog;
import android.content.Intent;
import android.os.AsyncTask;
import android.os.Bundle;
import android.util.Log;
import android.view.View;
import android.widget.AdapterView;
import android.widget.AdapterView.OnItemClickListener;
import android.widget.ListAdapter;
import android.widget.ListView;
import android.widget.SimpleAdapter;
import android.widget.TextView;
public class AndroidJSONParsingActivity extends ListActivity {
// url to make request
private static String url = "http://api.androidhive.info/contacts/";
// JSON Node names
private static final String TAG_CONTACTS = "contacts";
private static final String TAG_ID = "id";
private static final String TAG_NAME = "name";
private static final String TAG_EMAIL = "email";
private static final String TAG_ADDRESS = "address";
private static final String TAG_GENDER = "gender";
private static final String TAG_PHONE = "phone";
private static final String TAG_PHONE_MOBILE = "mobile";
private static final String TAG_PHONE_HOME = "home";
private static final String TAG_PHONE_OFFICE = "office";
static InputStream is = null;
static JSONObject jObj = null;
static String json = "";
// contacts JSONArray
JSONArray contacts = null;
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
new GetEventsTask().execute("");
}
protected class GetEventsTask extends
AsyncTask<String, Integer, ArrayList<HashMap<String, String>>> {
protected ArrayList<HashMap<String, String>> contactList;
private final ProgressDialog dialog = new ProgressDialog(
AndroidJSONParsingActivity.this);
//PreExecute Method
protected void onPreExecute() {
this.dialog.setMessage("Loading, Please Wait..");
this.dialog.setCancelable(false);
this.dialog.show();
}
//doInBackground Method
#Override
protected ArrayList<HashMap<String, String>> doInBackground(
String... params) {
contactList = new ArrayList<HashMap<String, String>>();
// Making HTTP request
try {
// defaultHttpClient
DefaultHttpClient httpClient = new DefaultHttpClient();
HttpPost httpPost = new HttpPost(url);
HttpResponse httpResponse = httpClient.execute(httpPost);
HttpEntity httpEntity = httpResponse.getEntity();
is = httpEntity.getContent();
BufferedReader reader = new BufferedReader(
new InputStreamReader(is, "iso-8859-1"), 8);
StringBuilder sb = new StringBuilder();
String line = null;
while ((line = reader.readLine()) != null) {
sb.append(line + "\n");
}
is.close();
json = sb.toString();
} catch (UnsupportedEncodingException e) {
e.printStackTrace();
} catch (ClientProtocolException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
}
// try parse the string to a JSON object
try {
jObj = new JSONObject(json);
Log.i("json objects",""+json);
} catch (JSONException e) {
Log.e("JSON Parser", "Error parsing data " + e.toString());
}
try {
// Getting Array of Contacts
contacts = jObj.getJSONArray(TAG_CONTACTS);
// looping through All Contacts
for (int i = 0; i < contacts.length(); i++) {
JSONObject c = contacts.getJSONObject(i);
// Storing each json item in variable
String id = c.getString(TAG_ID);
String name = c.getString(TAG_NAME);
String email = c.getString(TAG_EMAIL);
String address = c.getString(TAG_ADDRESS);
String gender = c.getString(TAG_GENDER);
// Phone number is agin JSON Object
JSONObject phone = c.getJSONObject(TAG_PHONE);
String mobile = phone.getString(TAG_PHONE_MOBILE);
String home = phone.getString(TAG_PHONE_HOME);
String office = phone.getString(TAG_PHONE_OFFICE);
// creating new HashMap
HashMap<String, String> map = new HashMap<String, String>();
// adding each child node to HashMap key => value
map.put(TAG_ID, id);
map.put(TAG_NAME, name);
map.put(TAG_EMAIL, email);
map.put(TAG_PHONE_MOBILE, mobile);
// adding HashList to ArrayList
contactList.add(map);
}
} catch (JSONException e) {
e.printStackTrace();
}
return contactList;
}
//onPostExecute Method
protected void onPostExecute(ArrayList<HashMap<String, String>> result) {
ListAdapter adapter = new SimpleAdapter(getApplicationContext(),
contactList, R.layout.list_item, new String[] { TAG_NAME,
TAG_EMAIL, TAG_PHONE_MOBILE }, new int[] {
R.id.name, R.id.email, R.id.mobile });
// selecting single ListView item
ListView lv = getListView();
lv.setAdapter(adapter);
// Launching new screen on Selecting Single ListItem
lv.setOnItemClickListener(new OnItemClickListener() {
#Override
public void onItemClick(AdapterView<?> parent, View view,
int position, long id) {
// getting values from selected ListItem
String name = ((TextView) view.findViewById(R.id.name)).getText().toString();
String cost = ((TextView) view.findViewById(R.id.email)).getText().toString();
String description = ((TextView) view.findViewById(R.id.mobile)).getText().toString();
// Starting new intent
Intent in = new Intent(getApplicationContext(),SingleMenuItemActivity.class);
in.putExtra(TAG_NAME, name);
in.putExtra(TAG_EMAIL, cost);
in.putExtra(TAG_PHONE_MOBILE, description);
startActivity(in);
}
});
if (this.dialog.isShowing()) {
this.dialog.dismiss();
}
}
}
}
Let me know your problem is resolved or not?
you can't compare == between 2 string
Use:
method.equals("POST");
I am developing a final year project and I am stuck at a point. I have to retrieve names of doctors from my database (MySQL database) and show it in a list view. I was able to establish a connection with the server and retrieve values, but when I tried to show the values in a list view, the application crashed!
I tried the same example given in [Hello, Views, List View][4].
It works for a predefined array like
private String lv_arr[]={"Android","iPhone","BlackBerry","AndroidPeople"};
but for a string array retrieved from the database it shows a run time exception. Is there any way I can achieve this?
package com.proj;
import java.io.BufferedReader;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.util.ArrayList;
import org.apache.http.HttpEntity;
import org.apache.http.HttpResponse;
import org.apache.http.NameValuePair;
import org.apache.http.client.HttpClient;
import org.apache.http.client.entity.UrlEncodedFormEntity;
import org.apache.http.client.methods.HttpPost;
import org.apache.http.impl.client.DefaultHttpClient;
import org.apache.http.message.BasicNameValuePair;
import org.json.JSONArray;
import org.json.JSONException;
import org.json.JSONObject;
import android.widget.*;
import android.app.ListActivity;
import android.app.Activity;
import android.content.Intent;
import android.os.Bundle;
import android.util.Log;
import android.widget.LinearLayout;
import android.widget.TextView;
public class proj extends ListActivity {
/** Called when the activity is first created. */
public int n=0;
public int t=0;
public int i=0;
public String name[]=new String[30];
#Override
public void onCreate(Bundle savedInstanceState)
{
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
// Create a crude view - this should really be set via the layout resources
// but since its an example saves declaring them in the XML.
TextView txt=(TextView)findViewById(R.id.tv);;
//Call the method to run the data retrieval
getServerData(KEY_121);
setListAdapter(new ArrayAdapter(this,
android.R.layout.simple_list_item_1, name));
}
public static final String KEY_121 = "http://10.0.2.2/doc.php"; //I use my real IP address here.
private String getServerData(String returnString) {
InputStream is = null;
String result = "";
//The year data to send.
ArrayList<NameValuePair> nameValuePairs = new ArrayList<NameValuePair>();
nameValuePairs.add(new BasicNameValuePair("year","1970"));
//HTTP post
try{
HttpClient httpclient = new DefaultHttpClient();
HttpPost httppost = new HttpPost(KEY_121);
httppost.setEntity(new UrlEncodedFormEntity(nameValuePairs));
HttpResponse response = httpclient.execute(httppost);
HttpEntity entity = response.getEntity();
is = entity.getContent();
}
catch(Exception e){
Log.e("log_tag", "Error in http connection "+e.toString());
}
//Convert response to string
try{
BufferedReader reader = new BufferedReader(new InputStreamReader(is,"iso-8859-1"),8);
StringBuilder sb = new StringBuilder();
String line = null;
while ((line = reader.readLine()) != null) {
sb.append(line + "\n");
}
is.close();
result=sb.toString();
}
catch(Exception e){
Log.e("log_tag", "Error converting result "+e.toString());
}
//Parse JSON data
try {
JSONArray jArray = new JSONArray(result);
for(i=0;i<jArray.length();i++)
{
JSONObject json_data = jArray.getJSONObject(i);
n=jArray.length();
name[i]=json_data.getString("name");
//Get an output to the screen
returnString += "\n\t" + jArray.getJSONObject(i);
}
}
catch(JSONException e)
{
Log.e("log_tag", "Error parsing data "+e.toString());
e.printStackTrace();
}
return returnString;
}
}
You are using
1.)
android:id="#+id/list"
inside the ListView, but if your extend an activity by ListActivity you have to use
android:id = "#android:id/list"
2.)
You return a String[] here, not String
private String[] getServerData(String returnString) {
.......
JSONArray jArray = new JSONArray(result);
name = new String[jArray.length()];
for(i=0;i<jArray.length();i++)
{
JSONObject json_data = jArray.getJSONObject(i);
name[i]=json_data.getString("name");
}
return name;
}
And in ArrayAdapter, do it like this:
ArrayAdapter<String> adapter = new ArrayAdapter<String>(this, android.R.layout.simple_list_item_1, getServerData(KEY_121));
setListAdapter(adapter);
public String name[];
#Override
public void onCreate(Bundle savedInstanceState)
{
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
// Create a crude view - this should really be set via the layout resources
// but since its an example saves declaring them in the XML.
TextView txt=(TextView)findViewById(R.id.tv);;
...
...
try {
JSONArray jArray = new JSONArray(result);
name[]=new String[jArray.length()];
for(i=0;i<jArray.length();i++)
{
JSONObject json_data = jArray.getJSONObject(i);
n=jArray.length();
name[i]=json_data.getString("name");
//Get an output to the screen
returnString += "\n\t" + jArray.getJSONObject(i);
}
}
catch(JSONException e)
{
Log.e("log_tag", "Error parsing data "+e.toString());
e.printStackTrace();
}
It seems that initializing name[] with a size of 30 may be too small.