I am using AsyncTask to get data from RSS feed and DOM parser and ArrayAdapter.
I noticed that the RSS feed is taking too long to load and show data on screen, at first I thought because the number of articles is big but when I limited the for loop to read only 3 articles it remained taking too long to show the articles!!
below is the full code I am using to parse the data and the main activity
Main activity code:
public class NewsMainActivity extends Activity implements OnItemClickListener {
/** Called when the activity is first created. */
ListView listview;
List<NewsBean> arrayList;
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
//Remove title bar
this.requestWindowFeature(Window.FEATURE_NO_TITLE);
setContentView(R.layout.main);
initComponents();
if (Utils.isNetworkAvailable(this)) {
new MyRssReadTask()
.execute("feed_URL");
} else {
Toast.makeText(this, "Please check your internet connection", Toast.LENGTH_SHORT)
.show();
}
}
private void initComponents() {
listview = (ListView) findViewById(android.R.id.list);
listview.setOnItemClickListener(this);
}
class MyRssReadTask extends AsyncTask<String, Void, Void> {
ProgressDialog waitingDialog;
#Override
protected void onPreExecute() {
waitingDialog = new ProgressDialog(NewsMainActivity.this);
waitingDialog.setMessage("Loading articles, Please wait...");
waitingDialog.show();
super.onPreExecute();
}
#Override
protected Void doInBackground(String... urls) {
arrayList = new NewsParser().getData(urls[0]);
return null;
}
#Override
protected void onPostExecute(Void result) {
waitingDialog.dismiss();
setDataToListView();
super.onPostExecute(result);
}
}
protected void setDataToListView() {
if (null != arrayList && arrayList.size() != 0) {
NewsRowAdapter objNewsRowAdapter = new NewsRowAdapter(
NewsMainActivity.this, R.layout.row, arrayList);
listview.setAdapter(objNewsRowAdapter);
} else {
showToast("There was an error to get data, please try again later.");
}
}
void showToast(String msg) {
Toast.makeText(NewsMainActivity.this, msg, Toast.LENGTH_SHORT).show();
}
public void onItemClick(AdapterView<?> parent, View view, int position,
long id) {
final NewsBean objBean = (NewsBean) arrayList.get(position);
Intent intent = new Intent(NewsMainActivity.this,
NewsDetail.class);
intent.putExtra("title", objBean.getTitle());
intent.putExtra("description", objBean.getDescription());
//intent.putExtra("pubdate", objBean.getPubDate());
//intent.putExtra("creator", objBean.getCreator());
intent.putExtra("link", objBean.getLink());
startActivity(intent);
}
News Parser
public class NewsParser {
private List<NewsBean> arrayListPasre;
public List<NewsBean> getData(String _url) {
try {
arrayListPasre = new ArrayList<NewsBean>();
URL url = new URL(_url);
URLConnection con = url.openConnection();
System.out.println("Connection is : " + con);
System.out.println("Connection InputStream is : "
+ con.getInputStream());
BufferedReader reader = new BufferedReader(new InputStreamReader(
con.getInputStream()));
System.out.println("Reader us now : " + reader);
String inputLine;
String fullStr = "";
while ((inputLine = reader.readLine()) != null)
fullStr = fullStr.concat(inputLine + "\n");
InputStream istream = url.openStream();
DocumentBuilder builder = DocumentBuilderFactory.newInstance()
.newDocumentBuilder();
System.out.println("Builder : " + builder);
Document doc = builder.parse(istream);
doc.getDocumentElement().normalize();
NodeList nList = doc.getElementsByTagName("item");
System.out.println("nlist " + nList);
for (int temp = 0; temp < 3; temp++) {
Node nNode = nList.item(temp);
if (nNode.getNodeType() == Node.ELEMENT_NODE) {
Element eElement = (Element) nNode;
NewsBean objBean = new NewsBean();
objBean.setTitle(getTagValue("title", eElement));
objBean.setDescription(getTagValue("description", eElement));
objBean.setLink(getTagValue("link", eElement));
arrayListPasre.add(objBean);
}
}
} catch (Exception e) {
e.printStackTrace();
}
return arrayListPasre;
}
private String getTagValue(String sTag, Element eElement) {
NodeList nlList = eElement.getElementsByTagName(sTag).item(0)
.getChildNodes();
Node nValue = (Node) nlList.item(0);
return nValue.getNodeValue();
}
}
any suggestions i would be thankful!! :)
You do no need to parse whole rss at once time. You can do this partially. For example parse document and get rss items count and then call you async task for 3 or 5 or 10 items only. In onPostExecute() add results to your adapter and call notifydatasetchanged().
Related
im trying to parse data from SQL Database into Listview.
My PHP script is working because if i run it in the browser i get the content.
If im trying to get the data from my SQL Databse into the listview my app shows nothing.
Here is my MainActivity:
public class Locations extends AppCompatActivity implements AdapterView.OnItemClickListener {
ArrayList<productforloc> arrayList;
ListView lv;
private String TAG = Locations.class.getSimpleName();
private TextView addressField; //Add a new TextView to your activity_main to display the address
private LocationManager locationManager;
private String provider;
int i = 1;
private ProgressDialog pDialog;
String name;
// URL to get contacts JSON
private static String url = "Mylink";
ArrayList<HashMap<String, String>> contactList;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.content_main);
Intent i = getIntent();
String cityname = i.getExtras().getString("cityname");
TextView city = (TextView) findViewById(R.id.ort);
city.setText(cityname);
pDialog = new ProgressDialog(Locations.this);
pDialog.setMessage("Please wait...");
pDialog.setCancelable(true);
pDialog.show();
arrayList = new ArrayList<>();
lv = (ListView) findViewById(R.id.lv);
lv.setOnItemClickListener((AdapterView.OnItemClickListener) this);
runOnUiThread(new Runnable() {
#Override
public void run() {
new ReadJSON().execute(url);
}
});
final ImageButton filteropen = (ImageButton) findViewById(R.id.aufklaupen);
filteropen.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
RelativeLayout filter = (RelativeLayout) findViewById(R.id.filterloc);
filter.setVisibility(View.VISIBLE);
ImageButton filterclose = (ImageButton) findViewById(R.id.zuklappen);
filterclose.setVisibility(View.VISIBLE);
filteropen.setVisibility(View.INVISIBLE);
}
});
final ImageButton filterclose = (ImageButton) findViewById(R.id.zuklappen);
filterclose.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
RelativeLayout filter = (RelativeLayout) findViewById(R.id.filterloc);
filter.setVisibility(View.INVISIBLE);
ImageButton filteropen = (ImageButton) findViewById(R.id.aufklaupen);
filteropen.setVisibility(View.VISIBLE);
filterclose.setVisibility(View.INVISIBLE);
}
});
}
class ReadJSON extends AsyncTask<String,Integer,String> {
#Override
protected String doInBackground(String... params) {
return readURL(params[0]);
}
#Override
protected void onPostExecute(String content) {
try{
JSONObject jo = new JSONObject(content);
JSONArray ja = jo.getJSONArray("contacts");
for(int i=0;i<ja.length();i++){
JSONObject po = ja.getJSONObject(i);
arrayList.add(new productforloc(
po.getString("imageurl"),
po.getString("name"),
po.getString("street"),
po.getString("postalcode"),
po.getString("musicstyle"),
po.getString("musicsecond"),
po.getString("entry"),
po.getString("opening"),
po.getString("agegroup"),
po.getString("urlbtn"),
po.getString("Fsk"),
po.getString("city"),
po.getString("bg")
));
}
} catch (JSONException e) {
e.printStackTrace();
}
final CustomListAdapterforloc adapter = new CustomListAdapterforloc(getApplicationContext(),R.layout.model,arrayList);
lv.setAdapter(adapter);
if(pDialog.isShowing()){
pDialog.dismiss();
}
}
}
private String readURL(String url){
StringBuilder content = new StringBuilder();
try{
URL uri = new URL(url);
URLConnection urlConnection = uri.openConnection();
BufferedReader bufferedReader= new BufferedReader(new InputStreamReader(urlConnection.getInputStream()));
String line;
while((line = bufferedReader.readLine()) !=null){
content.append(line+"\n");
}
bufferedReader.close();
} catch (MalformedURLException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
}
return content.toString();
}
#Override
public void onItemClick(AdapterView<?> parent, View view, int position, long id) {
productforloc pForloc = arrayList.get(position);
Intent intent = new Intent();
intent.setClass(this,DetailActivity.class);
intent.putExtra("name",pForloc.getName());
intent.putExtra("imageurl",pForloc.getImage());
intent.putExtra("street",pForloc.getStreet());
intent.putExtra("postalcode",pForloc.getPostalcode());
intent.putExtra("entry",pForloc.getEntry());
intent.putExtra("agegroup",pForloc.getAgegroup());
intent.putExtra("opening",pForloc.getOpening());
intent.putExtra("urlbtn",pForloc.getUrlbtn());
intent.putExtra("Fsk",pForloc.getFsk());
intent.putExtra("city",pForloc.getCity());
intent.putExtra("musicstyle",pForloc.getMusicstyle());
intent.putExtra("musicsecond",pForloc.getMusicsecond());
intent.putExtra("bg",pForloc.getBg());
startActivity(intent);
}
/**
* Async task class to get json by making HTTP call
}
*/
}
and here is my Customlistadapter Activity:
public class CustomListAdapterforloc extends ArrayAdapter<productforloc>{
ArrayList<productforloc> products;
Context context;
int resource;
public CustomListAdapterforloc(Context context, int resource, List<productforloc> products) {
super(context, resource, products);
this.products = (ArrayList<productforloc>) products;
this.context = context;
this.resource = resource;
}
#NonNull
#Override
public View getView(int position, View convertView, ViewGroup parent) {
if(convertView== null){
LayoutInflater layoutInflater = (LayoutInflater) getContext().getSystemService(Activity.LAYOUT_INFLATER_SERVICE);
convertView = layoutInflater.inflate(R.layout.model,null,true);
}
productforloc product = getItem(position);
ImageView imageView = (ImageView) convertView.findViewById(R.id.imagelist);
Picasso.with(context).load(product.getImage()).into(imageView);
TextView txtName= (TextView) convertView.findViewById(R.id.namelist);
txtName.setText(product.getName());
return convertView;
}
}
i solved it using this code in my MAinActivity:
public class Locations extends AppCompatActivity {
private String TAG = Locations.class.getSimpleName();
private ProgressDialog pDialog;
private ListView lv;
// URL to get contacts JSON
private static String url = "http://partypeople.bplaced.net/loli.php";
ArrayList<HashMap<String, String>> contactList;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
contactList = new ArrayList<>();
lv = (ListView) findViewById(R.id.lv);
new GetContacts().execute();
}
/**
* Async task class to get json by making HTTP call
*/
private class GetContacts extends AsyncTask<Void, Void, Void> {
#Override
protected void onPreExecute() {
super.onPreExecute();
// Showing progress dialog
pDialog = new ProgressDialog(Locations.this);
pDialog.setMessage("Please wait...");
pDialog.setCancelable(false);
pDialog.show();
}
#Override
protected Void doInBackground(Void... arg0) {
HttpHandler sh = new HttpHandler();
// Making a request to url and getting response
String jsonStr = sh.makeServiceCall(url);
Log.e(TAG, "Response from url: " + jsonStr);
if (jsonStr != null) {
try {
JSONArray contacts = new JSONArray(jsonStr);
// Getting JSON Array node
// looping through All Contacts
for (int i = 0; i < contacts.length(); i++) {
JSONObject c = contacts.getJSONObject(i);
String id = c.getString("id");
String name = c.getString("name");
String email = c.getString("email");
String address = c.getString("address");
String gender = c.getString("gender");
// tmp hash map for single contact
HashMap<String, String> contact = new HashMap<>();
// adding each child node to HashMap key => value
contact.put("id", id);
contact.put("name", name);
contact.put("email", email);
// adding contact to contact list
contactList.add(contact);
}
} catch (final JSONException e) {
Log.e(TAG, "Json parsing error: " + e.getMessage());
runOnUiThread(new Runnable() {
#Override
public void run() {
Toast.makeText(getApplicationContext(),
"Json parsing error: " + e.getMessage(),
Toast.LENGTH_LONG)
.show();
}
});
}
} else {
Log.e(TAG, "Couldn't get json from server.");
runOnUiThread(new Runnable() {
#Override
public void run() {
Toast.makeText(getApplicationContext(),
"Couldn't get json from server. Check LogCat for possible errors!",
Toast.LENGTH_LONG)
.show();
}
});
}
return null;
}
#Override
protected void onPostExecute(Void result) {
super.onPostExecute(result);
// Dismiss the progress dialog
if (pDialog.isShowing())
pDialog.dismiss();
/**3
* Updating parsed JSON data into ListView
* */
ListAdapter adapter = new SimpleAdapter(
Locations.this, contactList,
R.layout.model, new String[]{"name", "email",
"mobile"}, new int[]{R.id.namelist,
});
lv.setAdapter(adapter);
}
}
and used in my CustomlistadapterActivity:
public class HttpHandler {
private static final String TAG = HttpHandler.class.getSimpleName();
public HttpHandler() {
}
public String makeServiceCall(String reqUrl) {
String response = null;
try {
URL url = new URL(reqUrl);
HttpURLConnection conn = (HttpURLConnection) url.openConnection();
conn.setRequestMethod("GET");
// read the response
InputStream in = new BufferedInputStream(conn.getInputStream());
response = convertStreamToString(in);
} catch (MalformedURLException e) {
Log.e(TAG, "MalformedURLException: " + e.getMessage());
} catch (ProtocolException e) {
Log.e(TAG, "ProtocolException: " + e.getMessage());
} catch (IOException e) {
Log.e(TAG, "IOException: " + e.getMessage());
} catch (Exception e) {
Log.e(TAG, "Exception: " + e.getMessage());
}
return response;
}
private String convertStreamToString(InputStream is) {
BufferedReader reader = new BufferedReader(new InputStreamReader(is));
StringBuilder sb = new StringBuilder();
String line;
try {
while ((line = reader.readLine()) != null) {
sb.append(line).append('\n');
}
} catch (IOException e) {
e.printStackTrace();
} finally {
try {
is.close();
} catch (IOException e) {
e.printStackTrace();
}
}
return sb.toString();
}
}
Thanks for your input
Override getCount method into adapter class.
Outline:
I have to get some operators list from server.
Below is my JSON data
{"PrepaidServiceList":[{"operator_id":"2","operator_name":"Reliance GSM"},{"operator_id":"9","operator_name":"TATA CDMA\/Walky"},{"operator_id":"10","operator_name":"Virgin GSM - TATA"},{"operator_id":"17","operator_name":"Docomo Mobile"},{"operator_id":"18","operator_name":"Idea Mobile"},{"operator_id":"35","operator_name":"T24 (DOCOMO)"},{"operator_id":"22","operator_name":"VodaFone Mobile"},{"operator_id":"28","operator_name":"MTS DataCard"},{"operator_id":"29","operator_name":"Reliance CDMA\/NetConnect\/Land Line"},{"operator_id":"30","operator_name":"TATA Photon"},{"operator_id":"32","operator_name":"Idea Netsetter"},{"operator_id":"33","operator_name":"MTS Prepaid"},{"operator_id":"38","operator_name":"Bsnl - Data\/Validity"},{"operator_id":"39","operator_name":"Bsnl Topup"},{"operator_id":"41","operator_name":"Bsnl Data Card"},{"operator_id":"45","operator_name":"Aircel"},{"operator_id":"46","operator_name":"Aircel Pocket Internet"},{"operator_id":"52","operator_name":"Virgin CDMA - TATA"},{"operator_id":"53","operator_name":"Docomo Special"},{"operator_id":"55","operator_name":"Videocon"},{"operator_id":"56","operator_name":"MTNL Mumbai"},{"operator_id":"57","operator_name":"MTNL Mumbai Special"},{"operator_id":"58","operator_name":"Uninor"},{"operator_id":"59","operator_name":"MTNL Delhi"},{"operator_id":"60","operator_name":"MTNL Delhi Special"},{"operator_id":"61","operator_name":"Uninor Special"},{"operator_id":"62","operator_name":"Videocon Special"},{"operator_id":"63","operator_name":"MTNL Delhi"},{"operator_id":"64","operator_name":"MTNL Mumbai"}]}
JSON data has "operator_id" and "operator_name".
I have to get both from url and display only "operator_name" in a spinner.
I Have already implemented the above. Please find the main_activity for reference
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
spinner = (Spinner) findViewById(R.id.spinner);
plans = (TextView)findViewById(R.id.browseplans);
plans.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
Intent in = new Intent(getApplicationContext(), BrowsePlans.class);
in.putExtra("operator_id", id_click);
startActivity(in);
}
});
SimpleDateFormat sdf = new SimpleDateFormat("ddMMyyyyHHmmss");
sdf.setTimeZone(TimeZone.getTimeZone("GMT+5:30"));
currentDateandTime = sdf.format(new Date());
apikey = API_KEY.toString();
currentDateandTime.toString();
codetohash = currentDateandTime + apikey;
SHA1Hash = computeSha1OfString(codetohash);
uri = new Uri.Builder()
.scheme("http")
.authority("xxx.in")
.path("atm")
.appendQueryParameter("op", "GetPrepaidServiceList")
.appendQueryParameter("responseType", "json")
.appendQueryParameter("time", currentDateandTime)
.appendQueryParameter("clientId", ClientId)
.appendQueryParameter("hash", SHA1Hash)
.build();
stringUri = uri.toString();
new DataFromServer().execute();
} //end onCreate()
private class DataFromServer extends AsyncTask<String, Void, Void> {
#Override
protected void onPreExecute() {
}
#Override
protected Void doInBackground(String... params) {
try {
url = new URL(stringUri);
HttpURLConnection conn = (HttpURLConnection) url.openConnection();
conn.setDoInput(true);
conn.setDoOutput(true);
conn.setUseCaches(false);
conn.setRequestMethod("POST");
conn.setRequestProperty("Content-Type", "application/x-www-form-urlencoded");
conn.setRequestProperty("Host", "xxx.in");
/* Uri.Builder builder = new Uri.Builder()
.appendQueryParameter("val1", from)
.appendQueryParameter("val2", to);
String query = builder.build().getEncodedQuery();
OutputStream os = conn.getOutputStream();
BufferedWriter writer = new BufferedWriter(new OutputStreamWriter(os, "UTF-8"));
writer.write(query);
writer.flush();
writer.close();
os.close();*/
conn.connect();
reader = new BufferedReader(new InputStreamReader(conn.getInputStream()));
StringBuilder sb = new StringBuilder();
String line = null;
while ((line = reader.readLine()) != null) {
sb.append(line + "\n");
}
text = sb.toString();
} catch (Exception ex) {
ex.toString();
} finally {
try {
reader.close();
} catch (Exception ex) {
ex.toString();
}
}
/*//only for json object not array
JSONObject parentObject = new JSONObject(text);
name = parentObject.getString("Hello");*/
try {
JSONObject jsonObj = new JSONObject(text);
// Getting JSON Array node
JSONArray jsonArray = jsonObj.getJSONArray("PrepaidServiceList");
// looping through All Contacts
for (int i = 0; i < jsonArray.length(); i++) {
c = jsonArray.getJSONObject(i);
id = c.getString("operator_id");
name = c.getString("operator_name");
list.add(name);
}
} catch (Exception e) {
e.toString();
}
return null;
}
#Override
protected void onPostExecute(Void unused) {
ArrayAdapter adapter =
new ArrayAdapter(getApplication(), R.layout.list_item, R.id.text1, list);
spinner.setAdapter(adapter);
spinner.setOnItemSelectedListener(new AdapterView.OnItemSelectedListener() {
public void onItemSelected(AdapterView<?> arg0, View view, int position, long id) {
int item = spinner.getSelectedItemPosition();
id_click = spinner.getSelectedItem().toString();
}
public void onNothingSelected(AdapterView<?> arg0) {
}
});
}
}
Problem:
I am able to get user selected "operator_name" from spinner using "onItemSelectedListener".
But i need the "operator_id" of user selected "operator_name"
I have to pass the exact user selected "operator_id" to another class.
If i directly pass the operator_id, it has only the last id which is not the user selected one.
I am confused and don't know how to implement this.
Any Help would be greatly appreciated.
Thanks.
Try this way it worked for me
class LoadAlbums extends AsyncTask<String, String, ArrayList<HashMap<String,String>>> {
ArrayAdapter<String> adaptercountry ;
#Override
protected void onPreExecute() {
super.onPreExecute();
}
protected ArrayList<HashMap<String,String>> doInBackground(String... args) {
ServiceHandler sh = new ServiceHandler();
// Making a request to url and getting response
data = new ArrayList<HashMap<String, String>>();
String jsonStr = sh.makeServiceCall(COUNTRY_URL, ServiceHandler.GET);
Log.d("Response: ", "> " + jsonStr);
if (jsonStr != null) {
try {
JSONObject jsonObj = new JSONObject(jsonStr);
// Getting JSON Array node your array
country_list = jsonObj.getJSONArray(COUNTRY_LIST);
// looping through All Contacts
for (int i = 0; i < country_list.length(); i++) {
JSONObject c = country_list.getJSONObject(i);
// creating new HashMap
HashMap<String, String> map = new HashMap<String, String>();
// adding each child node to HashMap key => value
map.put(OP_ID, c.getString(OP_ID));
map.put(OP_NAME,c.getString(OP_NAME));
data.add(map);
}
} catch (JSONException e) {
e.printStackTrace();
}
} else {
Log.e("ServiceHandler", "Couldn't get any data from the url");
}
return data;
}
protected void onPostExecute(ArrayList<HashMap<String,String>> result) {
super.onPostExecute(result);
String[] arrConuntry=new String[data.size()];
for(int index=0;index<data.size();index++){
HashMap<String, String> map=data.get(index);
arrConuntry[index]=map.get(OP_NAME);
}
// pass arrConuntry array to ArrayAdapter<String> constroctor :
adaptercountry = new ArrayAdapter<String>(getActivity(),
android.R.layout.simple_spinner_dropdown_item,
arrConuntry);
spcountry.setOnClickListener(new OnClickListener() {
#Override
public void onClick(View w) {
new AlertDialog.Builder(getActivity())
.setTitle("Select")
.setAdapter(adaptercountry, new DialogInterface.OnClickListener() {
#Override
public void onClick(DialogInterface dialog, int which) {
spcountry.setText(adaptercountry.getItem(which).toString());
try {
cname=country_list.getJSONObject(which).getString("operator_id");
Log.d("Response: ", "> " + cname);
} catch (JSONException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
dialog.dismiss();
}
}).create().show();
}
});
}
In this case you can modify the AsyncTask to return in the doInBackground() method a List<HashMap<Integer, String>>. So you can store both operator_id and operator_name in the list and display each wanted item in the spinner.
Hope it helps!!!
Create a new ArrayList like
operator_List = new ArrayList<String>();
Add value in ArrayList like
opt_code.setName(jsonobject.optString("operator_name"));
opt_code.setId(jsonobject.optString("operator_id"));
list.add(opt_code);
datalist.add(jsonobject.optString("operator_name"));
operator_List .add(jsonobject.getString("operator_id")
and get operator_id
protected void onPostExecute(Void unused) {
ArrayAdapter adapter =
new ArrayAdapter(getApplication(), R.layout.list_item, R.id.text1, list);
spinner.setAdapter(adapter);
spinner.setOnItemSelectedListener(new AdapterView.OnItemSelectedListener() {
public void onItemSelected(AdapterView<?> arg0, View view, int position, long id) {
id_click = spinner.getSelectedItemPosition();
String opt_code = operator_List.get(position);
String selectedItem = arg0.getItemAtPosition(position).toString();
}
public void onNothingSelected(AdapterView<?> arg0) {
}
});
}
May be help you
Your can get Whole object of selected Spinner item use below code:
Object item = arg0.getItemAtPosition(position);
I'm trying to retrieve data from MySql database and put it on a ListView, everything works fine, I even put that data into textviews(dynamically) and it works fine. But when I used a ListView, only the last element was displayed, I think that means every new element is overwritten the old one, right?
What can I do to solve this? here's my code tell what's wrong??
public class MakeAppointementActivity extends AppCompatActivity {
public List<AvailabilityList> customList;
public ListView lv;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_make_appointement);
lv=(ListView)findViewById(R.id.listView);
Intent intent=getIntent();
new RetrieveTask().execute();
}
private class RetrieveTask extends AsyncTask<Void, Void, String> {
#Override
protected String doInBackground(Void... params) {
String strUrl = "availableAppointments1.php";
URL url;
StringBuffer sb = new StringBuffer();
try {
url = new URL(strUrl);
HttpURLConnection connection = (HttpURLConnection) url.openConnection();
connection.connect();
InputStream iStream = connection.getInputStream();
BufferedReader reader = new BufferedReader(new InputStreamReader(iStream));
String line;
while( (line = reader.readLine()) != null){
sb.append(line);
}
reader.close();
iStream.close();
} catch (IOException e) {
e.printStackTrace();
}
return sb.toString();
}
#Override
protected void onPostExecute(String result) {
super.onPostExecute(result);
new ParserTask().execute(result);
}
}
// Background thread to parse the JSON data retrieved from MySQL server
private class ParserTask extends AsyncTask<String, Void, List<HashMap<String, String>>> {
#Override
protected List<HashMap<String, String>> doInBackground(String... params) {
AppointementJSONParser appointementParser = new AppointementJSONParser();
JSONObject json = null;
try {
json = new JSONObject(params[0]);
} catch (JSONException e) {
e.printStackTrace();
}
return appointementParser.parse(json);
}
#Override
protected void onPostExecute(List<HashMap<String, String>> result) {
customList=new ArrayList<>(); / move it to here
for (int i = 0; i < result.size(); i++) {
HashMap<String, String> appointement = result.get(i);
String fromT = appointement.get("fromT");
String toT = appointement.get("toT");
String date = appointement.get("date");
addAvailableAppoint(fromT,toT,date);
}
updateListView(); // update listview when you add all data to arraylist
}
}
private void addAvailableAppoint(final String fromT, final String toT, final String date) {
customList.add(new AvailabilityList(fromT));
}
// split new function for update listview
private updateListView(){
ArrayAdapter adapter=new DoctorAvailabilityAdapter(MakeAppointementActivity.this,R.layout.list_items,customList);
adapter.notifyDataSetChanged();
lv.setAdapter(adapter);
lv.setOnItemClickListener(new AdapterView.OnItemClickListener() {
#Override
public void onItemClick(AdapterView<?> parent, View view, int position, long id) {
Intent intent = new Intent(MakeAppointementActivity.this, AppointementActivity.class);
intent.putExtra("fromT", fromT);
intent.putExtra("toT", toT);
intent.putExtra("date", date);
startActivity(intent);
}
});
}
}
Try this code
.....// your above code
#Override
protected void onPostExecute(List<HashMap<String, String>> result) {
customList=new ArrayList<>(); / move it to here
for (int i = 0; i < result.size(); i++) {
HashMap<String, String> appointement = result.get(i);
String fromT = appointement.get("fromT");
String toT = appointement.get("toT");
String date = appointement.get("date");
addAvailableAppoint(fromT,toT,date);
}
updateListView(); // update listview when you add all data to arraylist
}
}
private void addAvailableAppoint(final String fromT, final String toT, final String date) {
customList.add(new AvailabilityList(fromT));
}
// split new function for update listview
private updateListView(){
ArrayAdapter adapter=new DoctorAvailabilityAdapter(MakeAppointementActivity.this,R.layout.list_items,customList);
adapter.notifyDataSetChanged();
lv.setAdapter(adapter);
lv.setOnItemClickListener(new AdapterView.OnItemClickListener() {
#Override
public void onItemClick(AdapterView<?> parent, View view, int position, long id) {
Intent intent = new Intent(MakeAppointementActivity.this, AppointementActivity.class);
// intent.putExtra("fromT", fromT); // change it to
intent.putExtra("fromT", customList.get(position).getFromT());
intent.putExtra("toT", toT);
intent.putExtra("date", date);
startActivity(intent);
}
});
}
}
Hope this help
You create new ArrayList for every item customList=new ArrayList<>();
Create list only once in OnCreate for example.
Also you create new Adapter every time you add an item, adapter should also be created only once in OnCreate then you should update data with adapter.NotifyDataSetChanged()
my app needs to download a rss file in xml. i parse the data but i don't able to insert them into listview.
my code is.
public class MainActivity extends Activity {
ProgressDialog progress =null;
private final static String ADDRESS ="http://www.repubblica.it/rss/sport/rss2.0.xml";
private ListView lista =null ;
private List<ArticleInfo> list = null;
private ArrayAdapter<ArticleInfo> adapter = null ;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
lista= (ListView)findViewById(R.id.listView);
//adapter =new ArrayAdapter<ArticleInfo>(this,android.R.layout.simple_list_item_1,list);
//lista.setAdapter(adapter);
progress = new ProgressDialog(this);
progress.setMax(100);
progress.setMessage("Attendi qualche istante");
}
public void start(View v){
new BackgroundTask().execute();
}
private class BackgroundTask extends AsyncTask<String,Integer,String> {
#Override
protected String doInBackground(String... params) {
URL url = null;
try {
url = new URL(ADDRESS);
} catch (MalformedURLException e) {
return null;
}
StringBuffer buffer=null;
try {
BufferedReader reader = new BufferedReader(new InputStreamReader(url.openStream()));
String tmp = null;
buffer = new StringBuffer();
while((tmp=reader.readLine())!= null){
buffer.append(tmp);
}
} catch (IOException e) {
return null;
}
list = RssParser.parseXML(buffer.toString());
return buffer.toString();
}
#Override
protected void onPreExecute(){
progress.setProgress(0);
progress.show();
}
#Override
protected void onProgressUpdate(Integer ... values){
super.onProgressUpdate(values);
progress.setProgress(values[0]);
}
#Override
protected void onPostExecute(String res){
super.onPostExecute(res);
progress.dismiss();
if (res!=null){
// TextView text = (TextView)findViewById(R.id.text);
//text.setText(res);
adapter =new ArrayAdapter<ArticleInfo>(this,android.R.layout.simple_list_item_1,res);
lista.setAdapter(adapter); **THIS IS MY ERROR**
}
}
}
}
this is my parser class
public class RssParser {
public static List<ArticleInfo> parseXML(String rss){
List<ArticleInfo> res =new ArrayList<>();
DocumentBuilderFactory factory =DocumentBuilderFactory.newInstance();
DocumentBuilder builder =null;
try {
builder=factory.newDocumentBuilder();
} catch (ParserConfigurationException e) { }
try {
Document doc = builder.parse(new InputSource(new StringReader(rss)));
doc.getDocumentElement().normalize();// aggiungo getDocumentElement()
NodeList list = doc.getElementsByTagName("item");
for(int i=0;i<list.getLength();i++){
Node n=list.item(i);
if(n.getNodeType()==Node.ELEMENT_NODE){
Element e= (Element) n;
String title = e.getElementsByTagName("title").item(0).getTextContent();
String url = e.getElementsByTagName("link").item(0).getTextContent();
res.add(new ArticleInfo(title,url));
}
}
} catch (SAXException e) {
} catch (IOException e) {
}
return res;
}
the framework gives me an error in the last row of main activity where i try to crate the adapter
Could you give me an hand ?
Thanks in advance
The issue is due of this line
adapter =new ArrayAdapter<ArticleInfo>(this,android.R.layout.simple_list_item_1,res);
your ArrayAdapter is expecting a Collection of ArticleInfo, but you are passing res which is one single String. Change your AsyncTask in order to make it return list instead of buffer.toString(), E.g.
private class BackgroundTask extends AsyncTask<String,Integer,List<ArticleInfo>>
and doInBackground returns list instead of buffer.toString()
ok i used the context and the error desappear . when i launch the emulator , when the asynctask works, the app goes in crash. the logcat is j
ava.lang.NullPointerException
at android.widget.ArrayAdapter.init(ArrayAdapter.java:310)
at android.widget.ArrayAdapter.<init>(ArrayAdapter.java:153)
at artetecapp.ilfattounofficial.MainActivity$BackgroundTask.onPostExecute(MainActivity.java:123)
at artetecapp.ilfattounofficial.MainActivity$BackgroundTask.onPostExecute(MainActivity.java:73)
at android.os.AsyncTask.finish(AsyncTask.java:632)
at android.os.AsyncTask.access$600(AsyncTask.java:177)
I have made a normal class and an AsyncTask and I want to make this code:
private void addNewQuake (Quake _quake) {
//Add the new quake to our list of earthquakes
earthquakes.add(_quake);
//Notify the array adapter of a change
aa.notifyDataSetChanged();
}
So I can add it to AsyncTask?
Or do I need to do in a other way?
#Override
protected void onCreate(Bundle savedInstanceState) {
// your other code
new DataLoadAsync().execute(); //start to get data
}
public class DataLoadAsync extends AsyncTask{
private Quake quake;
#Override
protected void doInBackground(){
// handle network data in here and put the result to quake in here.
refreshEarthquakes();
}
#Override
protected void onPostExecute(){
// use the result
addNewQuake(quake);
}
}
syntax is not complete, I just wanted to show you, you need to put your network data load method in doInBackground to get data, then you can use it in onPostExecute()
Here is my new code:
public class Earthquake extends Activity {
ListView earthquakeListView;
ArrayAdapter<Quake> aa;
ArrayList<Quake> earthquakes = new ArrayList<Quake>();
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
earthquakeListView = (ListView) this
.findViewById(R.id.earthquakeListView);
int layoutID = android.R.layout.simple_list_item_1;
aa = new ArrayAdapter<Quake>(this, layoutID, earthquakes);
earthquakeListView.setAdapter(aa);
new DataLoadAsync().execute();
}
public class DataLoadAsync extends AsyncTask<Object, Object, Object>{
private Quake quake;
protected void doInBackground(){
// handle network data in here and put the result to quake in here.
refreshEarthquakes();
}
protected void onPostExecute(){
// use the result
addNewQuake(quake);
}
#Override
protected Object doInBackground(Object... arg0) {
// TODO Auto-generated method stub
return null;
}
}
void refreshEarthquakes() {
//get the XML
URL url;
try {
String quakeFeed = getString(R.string.quake_feed);
url = new URL(quakeFeed);
URLConnection connection;
connection = url.openConnection();
HttpURLConnection httpConnection = (HttpURLConnection)connection;
int responseCode = httpConnection.getResponseCode();
if (responseCode == HttpURLConnection.HTTP_OK) {
InputStream in = httpConnection.getInputStream();
DocumentBuilderFactory dbf = DocumentBuilderFactory.newInstance();
DocumentBuilder db = dbf.newDocumentBuilder();
//Parse the earthquake feed
Document dom = db.parse(in);
Element docEle = dom.getDocumentElement();
//Clear the old earthquakes
earthquakes.clear();
//Get a list of each earthquake entry
NodeList nl = docEle.getElementsByTagName("entry");
if (nl != null && nl.getLength() > 0) {
for (int i = 0 ; i < nl.getLength(); i++) {
Element entry = (Element)nl.item(i);
Element title = (Element)entry.getElementsByTagName("title").item(0);
Element g = (Element)entry.getElementsByTagName("georss:point").item(0);
Element when = (Element)entry.getElementsByTagName("updated").item(0);
Element link = (Element)entry.getElementsByTagName("link").item(0);
String details = title.getFirstChild().getNodeValue();
String hostname = "http://earthquake.usgs.gov";
String linkString = hostname + link.getAttribute("href");
String point = g.getFirstChild().getNodeValue();
String dt = when.getFirstChild().getNodeValue();
SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd'T'hh:mm:ss'Z'");
Date qdate = new GregorianCalendar(0,0,0).getTime();
try {
qdate = sdf.parse(dt);
} catch (ParseException e) {
e.printStackTrace();
}
String[] location = point.split(" ");
Location l = new Location("dummyGPS");
l.setLatitude(Double.parseDouble(location[0]));
l.setLongitude(Double.parseDouble(location[1]));
String magnitudeString = details.split(" ")[1];
int end = magnitudeString.length()-1;
double magnitude = Double.parseDouble(magnitudeString.substring(0, end));
details = details.split(",")[1].trim();
Quake quake = new Quake(qdate, details, l, magnitude, linkString);
}
}
}
} catch (MalformedURLException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
} catch (ParserConfigurationException e) {
e.printStackTrace();
} catch (SAXException e) {
e.printStackTrace();
}
finally {
}
}
private void addNewQuake (Quake _quake) {
//Add the new quake to our list of earthquakes
earthquakes.add(_quake);
//Notify the array adapter of a change
aa.notifyDataSetChanged();
}
}