append more items to listfragment on scroll end

append more items to listfragment on scroll end - android

i know there are a lot of examples for this question on stackoverflow , but i don't know how to implement any of them on my code .
what i want to do is to load data from json url (first 15 element) , and append them to listfragment and when the user scroll down to the end of the list another 15 elements appended (total 30 elements on the list) and so on..
now i can fetch the first 15 elements correctly , but when i try to add more items when the user reach end of scroll i don't know what to do ... here is my code:
in MainActivity i have the following class which extend listfragment :
public static class NewsFragment extends ListFragment implements ILoadDataListener, OnScrollListener {
private ListView listView;
private NewsAdapter newsAdapter;
private int currentPage=1;
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,Bundle savedInstanceStatee){
View rootView = inflater.inflate(R.layout.fragment_news, container, false);
listView = (ListView) rootView.findViewById(android.R.id.list);
return rootView;
}
#Override
public void onActivityCreated(Bundle savedInstanceState) {
super.onActivityCreated(savedInstanceState);
getListView().setOnScrollListener( this);
// URL to the JSON data
String strUrl = "http://opetmar.hostzi.com/test.php";
// Creating a new non-ui thread task to download json data
ProgressDialog progress = new ProgressDialog(getActivity());
progress.setMessage("loading ...");
GetJSON downloadTask = new GetJSON(this , progress , "news");
// Starting the download process
downloadTask.execute(strUrl);
}
#Override
public void onComplete(String[] titles , String[] images , String[] ids , String[] snippets , String[] data) {
if ( currentPage == 1 ){
newsAdapter = new NewsAdapter( getActivity() , titles , images , ids , snippets , data );
listView.setAdapter(newsAdapter);
}else {
}
}
#Override
public void onListItemClick(ListView l, View v, int position, long id) {
super.onListItemClick(l, v, position, id);
DataHolder holder;
holder = (DataHolder) v.getTag();
Intent myIntent = new Intent(getActivity(), NewsOpen.class);
myIntent.putExtra("image", holder.image);
myIntent.putExtra("data", holder.data);
startActivity(myIntent);
}
#Override
public void onScroll(AbsListView view, int firstVisibleItem,
int visibleItemCount, int totalItemCount) {
}
#Override
public void onScrollStateChanged(AbsListView listView, int scrollState) {
if (scrollState == SCROLL_STATE_IDLE) {
if (listView.getLastVisiblePosition() >= listView.getCount() - 1 ) {
currentPage++;
String strUrl = "http://opetmar.hostzi.com/test.php?page="+currentPage;
ProgressDialog progress = new ProgressDialog(getActivity());
progress.setMessage("loading ...");
GetJSON downloadTask = new GetJSON(this , progress , "news");
// Starting the download process
downloadTask.execute(strUrl);
}
}
}
}
NewsAdapter.java
public class NewsAdapter extends ArrayAdapter<String> {
private final Context context;
private final String[] titles;
private final String[] images;
private final String[] ids;
private final String[] snippets;
private final String[] data;
public NewsAdapter(Context context, String[] titles, String[] images , String[] ids , String[] snippets , String[] data) {
super(context, R.layout.drawer_list_item, titles);
this.context = context;
this.titles = titles;
this.images = images;
this.ids = ids;
this.snippets = snippets;
this.data = data;
}
#Override
public View getView(int position, View convertView, ViewGroup parent) {
LayoutInflater inflater = (LayoutInflater) context.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
View rowView = inflater.inflate(R.layout.news_list_item, parent, false);
TextView title = (TextView) rowView.findViewById(R.id.news_title);
TextView snippet = (TextView) rowView.findViewById(R.id.news_snippet);
ImageView imageView = (ImageView) rowView.findViewById(R.id.news_thumble);
title.setText(titles[position]);
snippet.setText(snippets[position]);
DataHolder holder = new DataHolder();
holder.data=data[position];
holder.image=images[position];
rowView.setTag(holder);
new DownloadImageTask(imageView).execute(images[position]);
return rowView;
}
public class DataHolder {
String image;
String data;
}
}
GetJSON.java
/** AsyncTask to download json data */
public class GetJSON extends AsyncTask<String, Integer, String>{
String data = null;
private ListView listView;
private NewsAdapter newsAdapter;
private ILoadDataListener mListener;
private ProgressDialog progress;
private String type;
public GetJSON(ILoadDataListener listener , ProgressDialog progress , String type) {
this.mListener = listener;
this.progress = progress;
this.type = type;
}
public void onPreExecute() {
progress.show();
}
#Override
protected String doInBackground(String... url) {
try{
data = downloadUrl(url[0]);
}catch(Exception e){
Log.d("Background Task",e.toString());
}
return data;
}
#Override
protected void onPostExecute(String result) {
if (result != null){
if (this.type == "news") {
try {
JSONObject jObject;
jObject = new JSONObject(result);
JSONArray jCountries = jObject.optJSONArray("news");
ArrayList<String> stringArrayList = new ArrayList<String>();
ArrayList<String> stringArrayList2 = new ArrayList<String>();
ArrayList<String> stringArrayList3 = new ArrayList<String>();
ArrayList<String> stringArrayList4 = new ArrayList<String>();
ArrayList<String> stringArrayList5 = new ArrayList<String>();
for (int i=0; i < jCountries.length(); i++)
{
try {
JSONObject oneObject = jCountries.getJSONObject(i);
// Pulling items from the array
stringArrayList.add(oneObject.getString("title"));
stringArrayList2.add( oneObject.getString("image"));
stringArrayList3.add( oneObject.getString("id"));
stringArrayList4.add( oneObject.getString("snippet"));
stringArrayList5.add( oneObject.getString("data"));
} catch (JSONException e) {
// Oops
}
}
String [] stringArray = stringArrayList.toArray(new String[stringArrayList.size()]);
String [] stringArray2 = stringArrayList2.toArray(new String[stringArrayList2.size()]);
String [] stringArray3 = stringArrayList3.toArray(new String[stringArrayList3.size()]);
String [] stringArray4 = stringArrayList4.toArray(new String[stringArrayList4.size()]);
String [] stringArray5 = stringArrayList5.toArray(new String[stringArrayList5.size()]);
progress.dismiss();
if (mListener != null) {
mListener.onComplete(stringArray , stringArray2 , stringArray3 , stringArray4 , stringArray5);
}
} catch (JSONException e) {
e.printStackTrace();
}
}
}else{
Log.e("ServiceHandler", "Couldn't get any data from the url");
}
}
/** A method to download json data from url */
private String downloadUrl(String strUrl) throws IOException{
String data = "";
InputStream iStream = null;
try{
URL url = new URL(strUrl);
// Creating an http connection to communicate with url
HttpURLConnection urlConnection = (HttpURLConnection) url.openConnection();
// Connecting to url
urlConnection.connect();
// Reading data from url
iStream = urlConnection.getInputStream();
BufferedReader br = new BufferedReader(new InputStreamReader(iStream));
StringBuffer sb = new StringBuffer();
String line = "";
while( ( line = br.readLine()) != null){
sb.append(line);
}
data = sb.toString();
br.close();
}catch(Exception e){
Log.d("Exception while downloading url", e.toString());
}finally{
iStream.close();
}
return data;
}
}
to be more specific , when the user reach the end of the scroll the following code will triggered which load more data from json url:
#Override
public void onScrollStateChanged(AbsListView listView, int scrollState) {
if (scrollState == SCROLL_STATE_IDLE) {
if (listView.getLastVisiblePosition() >= listView.getCount() - 1 ) {
currentPage++;
String strUrl = "http://opetmar.hostzi.com/test.php?page="+currentPage;
ProgressDialog progress = new ProgressDialog(getActivity());
progress.setMessage("loading ...");
GetJSON downloadTask = new GetJSON(this , progress , "news");
// Starting the download process
downloadTask.execute(strUrl);
}
}
then the GetJSON will call the following method after finish fetching and parsing data :
#Override
public void onComplete(String[] titles , String[] images , String[] ids , String[] snippets , String[] data) {
if ( currentPage == 1 ){
newsAdapter = new NewsAdapter( getActivity() , titles , images , ids , snippets , data );
listView.setAdapter(newsAdapter);
}else {
}
}
so if currentpage is not equal one , i want to append more data . how to achieve that ?

I'm not sure whether it's possible for ListView, but using Gallery you can override
public boolean onFling(MotionEvent e1, MotionEvent e2, float velocityX, float velocityY);
and use it to define the events when the items scrolled to the end. I did so to organize infinite list of calendar ietms in the gallery.
Regards,
Alex.

Related

How to show only list view items which value is equal to a value in the Json

iam creating an App which should show the Sights in a Listview.
The datas are parsed from a json.
At this json there is a column which declares in which City the sight is.
Now i would like to create a kind of a filter which should check the current Cityname with the City values in my Json.
For example there is a Sight in Berlin and my current city is Berlin, the Listview should show it. If the user is in Munich and the sight is in Berlin, the listview shouldnt show this item.
I get the current cityname value from a different Activity in a TextView.
Here is my Listview Activity:
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 = "http://partypeople.bplaced.net/maptest.json";
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;
}
}

Get current city name from intent.
String currentCityName;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.content_main);
Intent i = getIntent();
currentCityName = i.getExtras().getString("cityname");
...........
.................
}
Add condition to match cityName with currentCityName before adding productforloc object to ArrayList:
try {
JSONObject jo = new JSONObject(content);
JSONArray ja = jo.getJSONArray("contacts");
for(int i=0;i<ja.length();i++){
JSONObject po = ja.getJSONObject(i);
String cityName = po.getString("city");
if(!cityName.equals(currentCityName)) {
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();
}

How do I pass a JSON value to another class [duplicate]

This question already has answers here:
Passing JSONObject into another activity
(7 answers)
How to pass JSON Object to new activity [duplicate]
(3 answers)
Closed 5 years ago.
I have this class (TodosOsPaises) where I get the data from json and I want to show images from the JSON in the listView for that I'm using a custom adapter (MyAdapter) and on it picasso. The problem is I can't access the "URL_IMAGEM" in the MyAdapter class
TodosOsPaises class:
public class TodosOsPaises extends AppCompatActivity{
private String TAG = TodosOsPaises.class.getSimpleName();
private ProgressDialog pDialog;
private ListView lv;
private static String url = "http://**********/api/continent/any/country/all?id=siF1uXXEsltXOi5CWlSIzy7EABlnE5iF33bnNmfAHJiYXYNmjY";
ArrayList<HashMap<String, String>> listaPaises;
public String URL_IMAGEM;
String Designacao;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_todos_os_paises);
getSupportActionBar().setDisplayHomeAsUpEnabled(true);
getSupportActionBar().setTitle("Países");
listaPaises = new ArrayList<>();
lv = (ListView) findViewById(R.id.list);
new GetPaises().execute();
}
#Override
public boolean onOptionsItemSelected(MenuItem item) {
switch (item.getItemId()) {
case android.R.id.home:
finish();
return true;
default:
return super.onOptionsItemSelected(item);
}
}
#Override
public boolean onCreateOptionsMenu(Menu menu) {
MenuInflater inflater = getMenuInflater();
inflater.inflate(R.menu.main, menu);
menu.findItem(R.id.spinner_cat).setVisible(false);
menu.findItem(R.id.spinner_pais).setVisible(false);
return true;
}
private class GetPaises extends AsyncTask<Void, Void, Void> implements Serializable {
#Override
protected void onPreExecute() {
super.onPreExecute();
pDialog = new ProgressDialog(TodosOsPaises.this);
pDialog.setMessage("Aguarde...");
pDialog.setCancelable(false);
pDialog.show();
}
#Override
protected Void doInBackground(Void... params) {
HttpHandler sh = new HttpHandler();
final String jsonStr = sh.makeServiceCall(url);
Log.e(TAG, "Response from URL: " + jsonStr);
if (jsonStr != null) {
try {
JSONArray array = new JSONArray(jsonStr);
for (int i = 0; i < array.length(); i++) {
JSONObject jsonObject = array.getJSONObject(i);
JSONArray paises = jsonObject.optJSONArray("paises");
if (paises != null) {
for (int j = 0; j < paises.length(); j++) {
JSONObject jsonObject1 = paises.getJSONObject(j);
String K_PAIS = jsonObject1.getString("K_PAIS");
Designacao = jsonObject1.getString("Designacao");
//String URL_IMAGE_SMALL = jsonObject1.getString("URL_IMAGE_SMALL");
URL_IMAGEM = ("http://**********t" + jsonObject1.getString("URL_IMAGE_SMALL")).toString();
String Coord_LAT = jsonObject1.getString("Coord_LAT");
String Coord_LONG = jsonObject1.getString("Coord_LONG");
String Coord_Zoom = jsonObject1.getString("Coord_Zoom");
HashMap<String, String> pais = new HashMap<>();
pais.put("K_PAIS", K_PAIS);
pais.put("Designacao", Designacao);
//pais.put("URL_IMAGE_SMALL", URL_IMAGE_SMALL);
pais.put("URL_IMAGEM", URL_IMAGEM);
pais.put("Coord_LAT", Coord_LAT);
pais.put("Coord_LONG", Coord_LONG);
pais.put("Coord_Zoom", Coord_Zoom);
listaPaises.add(pais);
}
}
}
} catch (final JSONException e) {
Log.e(TAG, "Json parsing error: " + e.getMessage());
runOnUiThread(new Runnable() {
#Override
public void run() {
Toast.makeText(getApplicationContext(), "Json parsin 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 errpr!", Toast.LENGTH_LONG).show();
}
});
}
return null;
}
#Override
protected void onPostExecute(Void result) {
super.onPostExecute(result);
if (pDialog.isShowing()) {
pDialog.dismiss();
}
ListView list= (ListView) (TodosOsPaises.this).findViewById(R.id.list);
ListAdapter adapter =
new MyAdapter(
(TodosOsPaises.this),
listaPaises,
R.layout.list_item,
new String[]{Designacao},
new int[]{R.id.Designacao});
list.setAdapter(adapter);
/*ListAdapter adapter = new SimpleAdapter(
TodosOsPaises.this,
listaPaises,
R.layout.list_item,
new String[]{"Designacao", },
new int[]{R.id.Designacao, });
lv.setAdapter(adapter);
lv.setOnItemClickListener(new AdapterView.OnItemClickListener() {
#Override
public void onItemClick(AdapterView<?> pare, View view, int position, long id) {
Intent intent = new Intent(TodosOsPaises.this, MapsActivity.class);
intent.putExtra("data", listaPaises.get(position));
startActivity(intent);
}
});*/
Collections.sort(listaPaises, new Comparator<HashMap<String, String>>() {
#Override
public int compare(HashMap<String, String> first, HashMap<String, String> second) {
String firstValue = first.get("Designacao");
String secondValue = second.get("Designacao");
return firstValue.compareTo(secondValue);
}
});
}
}
}
MyAdapter class:
public class MyAdapter extends SimpleAdapter {
public MyAdapter(Context context, List<? extends Map<String, ?>> data, int resource, String[] from, int[] to) {
super(context, data, resource, from, to);
}
public View getView(int position, View convertView, ViewGroup parent){
View v = super.getView(position, convertView, parent);
ImageView img = (ImageView) v.getTag();
if (img == null){
img = (ImageView) v.findViewById(R.id.imageView7);
v.setTag(img);
}
String imageFlag = (String) ((Map)getItem(position)).get(URL_IMAGEM); <<-- here it says "Cannot resolve symbol 'URL_IMAGEM'"
Picasso.with(v.getContext()).load(imageFlag).into(img);
return v;
}
}
That happens, because I don't have URL_IMAGEM defined, I think I need to get it from the TodosOsPaises.
I'm a beginner in android so I'm sorry if I made something wrong

String imageFlag = (String) ((Map)getItem(position)).get("URL_IMAGEM");
thats because their is no string varible of that name in your adapter.You have to supply the string name itseld

Android - Display data from Adapter in Listview

I've currently got an application that pulls data from a mysql database and displays it in raw JSON format. I'm currently working on pushing this data into a String variable and displaying it on a Listview on a specific activity.
Problem is, when trying to display this data, my Listview is not populating; I'm sure the variable is not empty as the if statement would have captured this.
Here is snippet of MainActivity code:
//Methods to grab information from abhandym_DB database
public void getJSON(View view){
new BackgroundTask().execute();
}
public void parseJSON(View view){
if(JSON_String==null){
Toast.makeText(getApplicationContext(), "First Get Json", Toast.LENGTH_LONG).show();
}else{
Intent intent = new Intent(this,Test.class);
intent.putExtra("JSON_Data",JSON_String);
startActivity(intent);
}
}
class BackgroundTask extends AsyncTask<Void,Void,String>{
String json_url;
#Override
protected void onPreExecute() {
json_url = "http://abhandyman.x10host.com/json_get_data.php";
}
#Override
protected String doInBackground(Void... params) {
try {
URL url = new URL(json_url);
HttpURLConnection httpURLConnection = (HttpURLConnection)url.openConnection();
InputStream inputSteam = httpURLConnection.getInputStream();
BufferedReader buffereredReader = new BufferedReader(new InputStreamReader(inputSteam));
StringBuilder stringBuilder = new StringBuilder();
while((JSON_String = buffereredReader.readLine())!=null){
stringBuilder.append(JSON_String+"\n");
}
buffereredReader.close();
inputSteam.close();
httpURLConnection.disconnect();
return stringBuilder.toString().trim();
} catch (MalformedURLException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
}
return null;
}
#Override
protected void onProgressUpdate(Void... values) {
super.onProgressUpdate(values);
}
#Override
protected void onPostExecute(String result) {
TextView textView = (TextView)findViewById(R.id.fragment1_textview_JSONAPPEAR);
textView.setText(result);
JSON_String = result;
}
}
Here is the code for my Test.java
public class Test extends AppCompatActivity {
String JSON_String;
JSONObject jsonObject;
JSONArray jsonArray;
DataAdapter dataAdapter;
ListView listView;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.test_layout);
listView = (ListView)findViewById(R.id.test_listView);
dataAdapter = new DataAdapter(this, R.layout.row_layout);
listView.setAdapter(dataAdapter);
JSON_String = getIntent().getExtras().getString("JSON_Data");
try {
jsonObject = new JSONObject(JSON_String);
jsonArray = jsonObject.getJSONArray("server_response");
int count = 0;
String jobid,problem,resolution;
while(count<jsonObject.length()){
JSONObject JO = jsonArray.getJSONObject(count);
jobid = JO.getString("jobid");
problem = JO.getString("problem");
resolution = JO.getString("resolution");
Data data = new Data(jobid,problem,resolution);
dataAdapter.add(data);
count++;
}
} catch (JSONException e) {
e.printStackTrace();
}
}
}
Here is the code for my DataAdapter:
public class DataAdapter extends ArrayAdapter{
List list = new ArrayList();
public DataAdapter(Context context, int resource) {
super(context, resource);
}
public void add(Data object) {
super.add(object);
list.add(object);
}
#Override
public int getCount() {
return list.size();
}
#Override
public Object getItem(int position) {
return list.get(position);
}
#Override
public View getView(int position, View convertView, ViewGroup parent) {
View row;
row = convertView;
DataHolder dataHolder;
if(row == null){
LayoutInflater layoutInflater = (LayoutInflater)this.getContext().getSystemService(Context.LAYOUT_INFLATER_SERVICE);
row = layoutInflater.inflate(R.layout.row_layout,parent,false);
dataHolder = new DataHolder();
dataHolder.tx_jobid = (TextView) row.findViewById(R.id.tx_jobid);
dataHolder.tx_problem = (TextView) row.findViewById(R.id.tx_problem);
dataHolder.tx_resolution = (TextView) row.findViewById(R.id.tx_resolution);
row.setTag(dataHolder);
}else{
dataHolder = (DataHolder)row.getTag();
}
Data data = (Data)this.getItem(position);
dataHolder.tx_jobid.setText(data.getJobid());
dataHolder.tx_problem.setText(data.getProblem());
dataHolder.tx_resolution.setText(data.getResolution());
return row;
}
static class DataHolder{
TextView tx_jobid,tx_problem,tx_resolution;
}
}
and here is what it displays when clicking on "Parse JSON" button.
listView empty after population
Any help or advise on why its not displaying would be much appreciated!
Thanks in advance!

your problem seems to be here :
while(count<jsonObject.length()){
you're not looping using the number of array elements but using the number of mapped key:value object which is one (the "server_response") , you have to change this line to :
while(count<jsonArray.length()){
,
you have just the first element showing because jsonObject.length() will return 1 since it have just one element.
from the doc, JSONObject, length() method:
Returns the number of name/value mappings in this object.
and in your case you have just one name/value mapped ("server_response":[array items...])

Check in Test.java. I think You are setting the adapter to the listview before adding data to it
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.test_layout);
listView = (ListView)findViewById(R.id.test_listView);
dataAdapter = new DataAdapter(this, R.layout.row_layout);
JSON_String = getIntent().getExtras().getString("JSON_Data");
try {
jsonObject = new JSONObject(JSON_String);
jsonArray = jsonObject.getJSONArray("server_response");
int count = 0;
String jobid,problem,resolution;
while(count<jsonObject.length()){
JSONObject JO = jsonArray.getJSONObject(count);
jobid = JO.getString("jobid");
problem = JO.getString("problem");
resolution = JO.getString("resolution");
Data data = new Data(jobid,problem,resolution);
dataAdapter.add(data);
count++;
}
} catch (JSONException e) {
e.printStackTrace();
}
listView.setAdapter(dataAdapter); //change effected
}

How to refresh GridView for Custom Image Adapter?

I am currently working on an online android learning project and am facing issue with refreshing my grid view.
My app displays a grid with several images initially. On click of the Refresh Button from the Menu, the GridView should be populated with the new images.Also,on click of any image, app goes to Detail Activity which shows the current image URL.
Currently I first populate the GridView with sample images, using my custom adapter & Picasso. Then an AsyncTask executes which gets the new image URLs from a JSON. This new imageURL List has to be fed to my adapter so that the grid displays the new images.
However, I am not able to accomplish this. My initial grid shows images and on click of these, I get their URL on detail activity screen as expected. However, when I click on the Refresh in the menu, I don't see the new images. I am trying to set the adapter with the updated URL array in the onPostExecute().
On click of the old image I see the new URL in the detail activity, however once I click back the image is still not updated and URL changes back to the old one. Sometimes when I scroll the new image shows up and then app crashes.
So the basic issue is that even after getting the new URLs, I am unable to populate the GridView with new images. Any help on this will be appreciated. Thanks,
Code Snippet:
public class MovieListFragment extends Fragment {
public CustomAdapter customAdapter;
public GridView gv;
public List<String> allImages=new ArrayList<String>();
public List<String> newImages=new ArrayList<String>();
public String LOG_TAG=MovieListFragment.class.getSimpleName();
public int abc=0;
public MovieListFragment() {
}
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
View rootview= inflater.inflate(R.layout.movie_list_fragment, container, false);
//Fake Data Creation for 1st time GridView load.
allImages.add("http://www.pnas.org/site/misc/images/15-01065.500.jpg");
allImages.add("http://41.media.tumblr.com/78335e84b3b353ad60c335b24a5f267e/tumblr_nz2bke3fJ51rldeoho1_500.jpg");
allImages.add("http://41.media.tumblr.com/78335e84b3b353ad60c335b24a5f267e/tumblr_nz2bke3fJ51rldeoho1_500.jpg");
allImages.add("http://41.media.tumblr.com/78335e84b3b353ad60c335b24a5f267e/tumblr_nz2bke3fJ51rldeoho1_500.jpg");
allImages.add("http://41.media.tumblr.com/78335e84b3b353ad60c335b24a5f267e/tumblr_nz2bke3fJ51rldeoho1_500.jpg");
allImages.add("http://www.pnas.org/site/misc/images/15-01065.500.jpg");
allImages.add("http://www.pnas.org/site/misc/images/15-01065.500.jpg");
allImages.add("http://www.pnas.org/site/misc/images/15-01065.500.jpg");
allImages.add("http://www.pnas.org/site/misc/images/15-01065.500.jpg");
//Set Adapter
gv = (GridView) rootview.findViewById(R.id.gridview);
customAdapter=new CustomAdapter(getActivity(),allImages);
gv.setAdapter(customAdapter);
//On Click Listener
gv.setOnItemClickListener(new AdapterView.OnItemClickListener() {
#Override
public void onItemClick(AdapterView<?> parent, View view, int position, long id) {
Intent intent = new Intent(getActivity(), DetailActivity.class);
intent.putExtra("imageURL", allImages.get(position).toString());
startActivity(intent);
}
});
return rootview;
}
//My Custom Adapter
public class CustomAdapter extends BaseAdapter{
private Context mContext;
private List<String> myImageList;
public CustomAdapter(Context c, List<String> finalImageList) {
mContext = c;
myImageList=finalImageList;
notifyDataSetChanged();
}
#Override
public int getCount() {
return myImageList.size();
}
#Override
public Object getItem(int position) {
return myImageList.get(position);
}
#Override
public long getItemId(int position) {
return 0;
}
#Override
public View getView(int position, View convertView, ViewGroup parent) {
ImageView imageView;
if (convertView == null) {
// if it's not recycled, initialize some attributes
imageView = new ImageView(mContext);
imageView.setLayoutParams(new GridView.LayoutParams(500, 500));
imageView.setScaleType(ImageView.ScaleType.CENTER_CROP);
// imageView.setPadding(2, 2, 2, 2);
} else {
imageView = (ImageView) convertView;
}
Picasso.with(getActivity())
.load(myImageList.get(position))
.into(imageView);
return imageView;
}
}
#Override
public void onCreateOptionsMenu(Menu menu, MenuInflater inflater) {
inflater.inflate(R.menu.movie_list_fragment_menu, menu);
}
#Override
public boolean onOptionsItemSelected(MenuItem item) {
int id=item.getItemId();
if(id==R.id.action_refresh){
updateMovieList();
return true;
}
return super.onOptionsItemSelected(item);
}
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setHasOptionsMenu(true);
}
private void updateMovieList() {
FetchMovieDetailsTask fetchMovieDetailsTask=new FetchMovieDetailsTask();
fetchMovieDetailsTask.execute("Popularity");
}
public class FetchMovieDetailsTask extends AsyncTask<String, Void, String[]>{
public String LOG_TAG_SECOND=FetchMovieDetailsTask.class.getSimpleName();
#Override
protected String[] doInBackground(String... params) {
HttpURLConnection urlConnection = null;
BufferedReader reader = null;
// Will contain the raw JSON response as a string.
String movieDetailJsonStr = "";
String filterType = "";
String api_key = "e77c4d231a4c24ffe0357b694751910c";
if (params[0].equals("Popularity")) {
filterType = "vote_average.desc";
} else if (params[0].equals("Rating")) {
filterType = "popularity.desc";
}
try {
final String MOVIEDETAIL_BASE_URL = "https://api.themoviedb.org/3/discover/movie?";
final String FILTER_PARAM = "sort_by";
final String APP_KEY_PARAM = "api_key";
Uri builtUri = Uri.parse(MOVIEDETAIL_BASE_URL).buildUpon()
.appendQueryParameter(FILTER_PARAM, filterType)
.appendQueryParameter(APP_KEY_PARAM, api_key).build();
URL url = new URL(builtUri.toString());
Log.v(LOG_TAG_SECOND, builtUri.toString());
urlConnection = (HttpURLConnection) url.openConnection();
urlConnection.setRequestMethod("GET");
urlConnection.connect();
// Read the input stream into a String
InputStream inputStream = urlConnection.getInputStream();
StringBuffer buffer = new StringBuffer();
if (inputStream == null) {
// Nothing to do.
return null;
}
reader = new BufferedReader(new InputStreamReader(inputStream));
String line;
while ((line = reader.readLine()) != null) {
buffer.append(line + "\n");
}
if (buffer.length() == 0) {
// Stream was empty. No point in parsing.
return null;
}
movieDetailJsonStr = buffer.toString();
Log.v(LOG_TAG_SECOND, " Movie Details JSON " + movieDetailJsonStr);
try {
getMovieDetailsFromJSON(movieDetailJsonStr);
} catch (JSONException e) {
e.printStackTrace();
}
} catch (IOException e) {
Log.e(LOG_TAG, "Error ", e);
return null;
} finally {
if (urlConnection != null) {
urlConnection.disconnect();
}
if (reader != null) {
try {
reader.close();
} catch (final IOException e) {
Log.e(LOG_TAG, "Error closing stream", e);
}
}
}
return null;
}
private String[] getMovieDetailsFromJSON(String movieDetailsJSON) throws JSONException{
final String MOV_TITLE = "title";
final String MOV_OVERVIEW = "overview";
final String MOV_RATING = "vote_average";
final String MOV_POSTER_PATH = "poster_path";
final String MOV_LIST = "results";
JSONObject movieListJSON = new JSONObject(movieDetailsJSON);
JSONArray movieListArray = movieListJSON.getJSONArray(MOV_LIST);
int numOfMovies=8;
allImages.clear();
String[] resultStrs = new String[numOfMovies];
String[] resultPosters= new String[numOfMovies];
for(int i=0; i<numOfMovies; i++){
String title;
String overview;
String rating;
String poster_path;
JSONObject movieDetails=movieListArray.getJSONObject(i);
overview=movieDetails.getString(MOV_OVERVIEW);
title=movieDetails.getString(MOV_TITLE);
rating=movieDetails.getString(MOV_RATING);
poster_path=movieDetails.getString(MOV_POSTER_PATH);
resultStrs[i]=title + "\n" + overview + "\n" + rating + "\n" + poster_path;
resultPosters[i]=poster_path;
makePosterURL(resultPosters[i]);
}
for (String s : resultStrs) {
Log.v(LOG_TAG_SECOND, "MOVIE DETAILS: " + s);
}
return resultStrs;
}
private void makePosterURL(String resultPoster) {
String baseURL="http://image.tmdb.org/t/p/w500";
//resultPoster=resultPoster.replace("\\", "");
String finalURL="";
finalURL=baseURL+resultPoster;
Log.v(LOG_TAG_SECOND, "Final Poster URL " + finalURL);
allImages.add(finalURL);
}
#Override
protected void onPostExecute(String[] strings) {
if(strings!=null){
customAdapter=new CustomAdapter(getActivity(), allImages);
gv.invalidateViews();
gv.setAdapter(customAdapter);
}
// super.onPostExecute(strings);
}
}

Because you always return null in your doInBackground() so the code never resets your adapter with the updated lits. To update your updater you just need to call
adapter.notifyDataSetChanged();
in your onPostExecuted()
btw, your getMovieDetailsFromJSON() return type String[] is useless the same as doInBackgound() and you should make it void as you don't use the value.

Adding a image from url to a ListView

I am using a modified version of the contacts project from AndroidHive.
It basically just pulls n list of articles and their contact from a Joomla Site.
I am using a Image Plugin that gets a image from a url. i can successfully use it on the article detail activity view but i don't know how to add it to each List Item on the MainAcitivity file. I am new to Android development so please excuse the confusion.
The script to add the image is:
ImageView thumb = (ImageView) findViewById(R.id.thumb);
UrlImageViewHelper.setUrlDrawable(thumb, "https://www.site.co.za/test.png");
and my MainActivity which generated the ListView:
public class MainActivity extends ListActivity {
private ProgressDialog pDialog;
// URL to get articles JSON
private static String url = "http://192.168.12.21/sebastian/broadcast/index.php/blog?format=json";
// JSON Node names
private static final String TAG_ARTICLES = "articles";
// Get the fields
private static final String TAG_ID = "id";
private static final String TAG_TITLE = "title";
private static final String TAG_SHORTTEXT = "shorttext";
private static final String TAG_FULLTEXT = "fulltext";
private static final String TAG_IMAGE = "image";
private static final String TAG_DATE = "date";
// articles JSONArray
JSONArray articles = null;
// Hashmap for ListView
ArrayList<HashMap<String, String>> articleList;
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
articleList = new ArrayList<HashMap<String, String>>();
ListView lv = getListView();
// Listview on item click listener
lv.setOnItemClickListener(new OnItemClickListener() {
#Override
public void onItemClick(AdapterView<?> parent, View view,
int position, long id) {
// getting values from selected ListItem
String title = ((TextView) view.findViewById(R.id.title)).getText().toString();
String shorttext = ((TextView) view.findViewById(R.id.shorttext)).getText().toString();
String fulltext = ((TextView) view.findViewById(R.id.fulltext)).getText().toString();
String image = ((TextView) view.findViewById(R.id.image)).getText().toString();
String date = ((TextView) view.findViewById(R.id.date)).getText().toString();
// Starting single article activity
Intent in = new Intent(getApplicationContext(),
SingleArticleActivity.class);
in.putExtra(TAG_TITLE, title);
in.putExtra(TAG_SHORTTEXT, shorttext);
in.putExtra(TAG_FULLTEXT, fulltext);
in.putExtra(TAG_IMAGE, image);
in.putExtra(TAG_DATE, date);
startActivity(in);
}
});
// Calling async task to get json
new GetArticles().execute();
}
/**
* Async task class to get json by making HTTP call
* */
private class GetArticles extends AsyncTask<Void, Void, Void> {
#Override
protected void onPreExecute() {
super.onPreExecute();
// Showing progress dialog
pDialog = new ProgressDialog(MainActivity.this);
pDialog.setMessage("Please wait...");
pDialog.setCancelable(false);
pDialog.show();
}
#Override
protected Void doInBackground(Void... arg0) {
// Creating service handler class instance
ServiceHandler sh = new ServiceHandler();
// Making a request to url and getting response
String jsonStr = sh.makeServiceCall(url, ServiceHandler.GET);
Log.d("Response: ", "> " + jsonStr);
if (jsonStr != null) {
try {
JSONObject jsonObj = new JSONObject(jsonStr);
// Getting JSON Array node
articles = jsonObj.getJSONArray(TAG_ARTICLES);
// looping through All articles
for (int i = 0; i < articles.length(); i++) {
JSONObject c = articles.getJSONObject(i);
String id = c.getString(TAG_ID);
String title = c.getString(TAG_TITLE);
String shorttext = c.getString(TAG_SHORTTEXT);
String fulltext = c.getString(TAG_FULLTEXT);
String image = c.getString(TAG_IMAGE);
String date = c.getString(TAG_DATE);
// tmp hashmap for single article
HashMap<String, String> article = new HashMap<String, String>();
// adding each child node to HashMap key => value
article.put(TAG_ID, id);
article.put(TAG_TITLE, title);
article.put(TAG_SHORTTEXT, shorttext);
article.put(TAG_FULLTEXT, fulltext);
article.put(TAG_IMAGE, image);
article.put(TAG_DATE, date);
// adding article to article list
articleList.add(article);
}
} catch (JSONException e) {
e.printStackTrace();
}
} else {
Log.e("ServiceHandler", "Couldn't get any data from the url");
}
return null;
}
#Override
protected void onPostExecute(Void result) {
super.onPostExecute(result);
// Dismiss the progress dialog
if (pDialog.isShowing())
pDialog.dismiss();
/**
* Updating parsed JSON data into ListView
* */
ListAdapter adapter = new SimpleAdapter(
MainActivity.this, articleList,
R.layout.list_item, new String[] {
TAG_TITLE,
TAG_SHORTTEXT,
TAG_FULLTEXT,
TAG_IMAGE,
TAG_DATE
},
new int[] {
R.id.title,
R.id.shorttext,
R.id.fulltext,
R.id.image,
R.id.date
});
setListAdapter(adapter);
}
}
}
**I don't know where in the MainActivity file do i add the script to add an image to each List Item.
I already got it working on the SingleArticleActivity but cannot get it to work on the List of Items**
Thanks for the help
UPDATE
What im trying to do:
foreach(ListItem in the List) {
ImageView thumb = (ImageView) findViewById(R.id.thumb);
UrlImageViewHelper.setUrlDrawable(thumb, "https://www.site.co.za/test.png");
}

You have to just use this one..
ImageView thumb = (ImageView) findViewById(R.id.thumb);
UrlImageViewHelper.setUrlDrawable(thumb, articleList.get(position).get(TAG_IMAGE));
CustomAdapter cdp = new CustomAdapter(YourActivityName.this , articleList);
setListAdapter(adapter);
Now make class of CustomAdapter extends with BaseAdapter
public class CustomAdapter extends BaseAdapter {
ArrayList<HashMap<String, String>> list;
Context ctx;
public CustomAdapter(Context c , ArrayList<HashMap<String, String>> articleList){
this.ctx = c;
this.list = articleList;
}
#Override
public int getCount() {
return list.size();
}
#Override
public Object getItem(int position) {
return null;
}
#Override
public long getItemId(int position) {
return position;
}
#Override
public View getView(int position, View convertView, ViewGroup parent) {
final ViewHolder holder;
View view = convertView;
if (view == null) {
view = getLayoutInflater().inflate(R.layout.list_item,
parent, false);
holder = new ViewHolder();
assert view != null;
holder.imageView = (ImageView) view.findViewById(R.id.image);
view.setTag(holder);
} else {
holder = (ViewHolder) view.getTag();
}
UrlImageViewHelper.setUrlDrawable(thumb, articleList.get(position).get(TAG_IMAGE));
return view;
}
class ViewHolder {
ImageView imageView;
}
}

I am using this method in the getView method of my ListView adapter which returns a drawable which I later set it to my ImageView.
public Drawable LoadImageFromWebOperations(String url) {
try {
InputStream is = (InputStream) new URL(url).getContent();
Drawable d = Drawable.createFromStream(is, "src name");
return d;
} catch (Exception e) {
return default_image;
}
}
Hope this helps.

Try this A powerful image downloading and caching library for Android Picasso
Images add much-needed context and visual flair to Android applications. Picasso allows for hassle-free image loading in your application-often in one line of code!
Picasso.with(context).load("http://i.imgur.com/DvpvklR.png").into(imageView);

Develop Reference

The Android operating system is a mobile operating system that was developed by Google (GOOGL?) to be primarily used for touchscreen devices, cell phones, and tablets.

append more items to listfragment on scroll end - android

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