Develop Reference

How to add a search filter in RecyclerView to filter through parsed JSON data? edited

I am developing an android app which shows a list of countries affected by Coronavirus , the total number of confirmed cases and total Deaths. I am using a JSON API to get the data and displaying it using a RecyclerView . The app works fine , and i get a list of all the countries with their respective case counts. I want to add a search option so that the users can filter the list and find a specific country. How do i do that? I am new to programming , if someone could help with this that would be awesome.
Here is the code snippet
MainActivity.java
private RecyclerView mRecyclerView;
private Corona_Stats_Adapter mCorona_Stats_Adapter;
private TextView mErrorDisplay;
private ProgressBar mProgressBar;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.corona_stats);
mRecyclerView = (RecyclerView)findViewById(R.id.Corona_stats_recycler);
mErrorDisplay = (TextView) findViewById(R.id.tv_error_message_display);
LinearLayoutManager layoutManager = new LinearLayoutManager(this, LinearLayoutManager.VERTICAL, false);
mRecyclerView.setLayoutManager(layoutManager);
mRecyclerView.setHasFixedSize(true);
mCorona_Stats_Adapter = new Corona_Stats_Adapter();
mRecyclerView.setAdapter(mCorona_Stats_Adapter);
mProgressBar = (ProgressBar)findViewById(R.id.pb_loading_indicator) ;
loadCoronaData();
}
private void loadCoronaData(){
showCoronaDataView();
//String Country = String.valueOf(mSearchQuery.getText());
new Fetch_data().execute();
}
private void showCoronaDataView(){
mErrorDisplay.setVisibility(View.INVISIBLE);
mRecyclerView.setVisibility(View.VISIBLE);
}
private void showErrorMessage(){
mRecyclerView.setVisibility(View.INVISIBLE);
mErrorDisplay.setVisibility(View.VISIBLE);
}
public class Fetch_data extends AsyncTask<Void,Void,String[]> {
#Override
protected void onPreExecute() {
super.onPreExecute();
mProgressBar.setVisibility(View.VISIBLE);
}
#Override
protected String[] doInBackground(Void... voids) {
URL covidRequestURL = NetworkUtils.buildUrl();
try {
String JSONCovidResponse = NetworkUtils.getResponseFromHttpUrl(covidRequestURL);
String[] simpleJsonCovidData = CovidJSON_Utils.getSimpleStringFromJson(MainActivity.this, JSONCovidResponse);
return simpleJsonCovidData;
} catch (IOException | JSONException e) {
e.printStackTrace();
return null;
}
}
#Override
protected void onPostExecute(String[] coronaData) {
mProgressBar.setVisibility(View.INVISIBLE);
if(coronaData !=null){
showCoronaDataView();
mCorona_Stats_Adapter.setCoronaData(coronaData);
} else{
showErrorMessage();
}
}
}
}
RecyclerView Adapter class Corona_stats_Adapter.java
public class Corona_Stats_Adapter extends RecyclerView.Adapter<Corona_Stats_Adapter.Corona_Stats_AdapterViewHolder>
{
private Context context;
// private List<Country> countryList;
// private List<Country> countryListFiltered;
private String[] mCoronaData;
public Corona_Stats_Adapter(){
}
#NonNull
#Override
public Corona_Stats_AdapterViewHolder onCreateViewHolder(#NonNull ViewGroup viewGroup, int viewType) {
Context context = viewGroup.getContext();
int LayoutIdForListItem =R.layout.corona_stats_list_item;
LayoutInflater inflater =LayoutInflater.from(context);
boolean ShouldAttachToParentImmediately = false;
View view = inflater.inflate(LayoutIdForListItem,viewGroup,ShouldAttachToParentImmediately);
return new Corona_Stats_AdapterViewHolder(view);
}
#Override
public void onBindViewHolder(#NonNull Corona_Stats_AdapterViewHolder corona_stats_adapterViewHolder, int position) {
String coronaStats = mCoronaData[position];
corona_stats_adapterViewHolder.mCoronaTextView.setText(coronaStats);
}
#Override
public int getItemCount() {
if(null == mCoronaData) return 0;
return mCoronaData.length;
// return countryListFiltered.size();
}
public class Corona_Stats_AdapterViewHolder extends RecyclerView.ViewHolder {
public final TextView mCoronaTextView;
public Corona_Stats_AdapterViewHolder(#NonNull View view) {
super(view);
mCoronaTextView = (TextView) view.findViewById(R.id.tv_corona_data);
}
}
public void setCoronaData(String[] coronaData){
mCoronaData = coronaData;
notifyDataSetChanged();
}
}
Parsing the JSON data in CovidJSON_Utils.java
public final class CovidJSON_Utils {
public static String[] getSimpleStringFromJson(Context context, String codivJsonString)
throws JSONException {
final String COV_COUNTRY = "Countries";
final String COV_CONFIRMED = "confirmed";
final String COV_DEATHS = "deaths";
final String COV_MESSAGE_CODE = "code";
String[] parsedCovidData = null;
JSONObject covidJsonObject = new JSONObject(codivJsonString);
if (covidJsonObject.has(COV_MESSAGE_CODE)) {
int errorCode = covidJsonObject.getInt(COV_MESSAGE_CODE);
switch (errorCode) {
case HttpURLConnection.HTTP_OK:
break;
case HttpURLConnection.HTTP_NOT_FOUND:
return null;
default:
return null;
}
}
JSONArray countryCovidArray = covidJsonObject.getJSONArray(COV_COUNTRY);
parsedCovidData = new String[countryCovidArray.length()];
for (int i = 0; i < countryCovidArray.length(); i++) {
JSONObject countryJSONObject = countryCovidArray.getJSONObject(i);
String Country = countryJSONObject.getString("Country");
String Confirmed = String.valueOf(countryJSONObject.getInt("TotalConfirmed"));
String Deaths = String.valueOf(countryJSONObject.getInt("TotalDeaths"));
parsedCovidData[i] = Country + "- Cases " + Confirmed + "- Deaths " + Deaths;
}
return parsedCovidData;
}
}

The problem is with below initialization in the MainActivity.Oncreate method
mCorona_Stats_Adapter = new Corona_Stats_Adapter(this,countries);
Initialize the adapter in onPostExecute method with updated countries data.
Hope this will help you.

You have to set arraylist to update country data in adapter after getting data from the server.
Public void setCoronaData (Arraylist coronaData) {
countryList = coronaData;
notifyDataSetChanged ();
}

Cannot display images in Html.fromHtml() in text view for images coming dynamically

I am developing an app in android studio in which contents are coming form an Api in a recyclerview. In the api there is an element "content" that sends all html tags with images like a full page. I have to display that page in textview. I have tried Htm.fromHtml method but it is not displaying the images. I have searched all answers and got the solution of ImageGetter method, but I am not able to display dynamic content in the recycleradapter from ImageGetter. I have to keep the images in the drawable of my app and match the source URL that is being parsed. Please help. Below is my code.
PageActivity.java
public class PageActivity extends AppCompatActivity {
RequestQueue queue;
String menuidpage;
RecyclerView recyclerView;
List<MenuFeeds> feedsList = new ArrayList<MenuFeeds>();
String newimage = "http://www.groveus.com/micro/assets/uploads/page/";
PageRecyclerAdapter adapter;
private ProgressDialog pDialog;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_page);
getSupportActionBar().setDisplayHomeAsUpEnabled(true);
getSupportActionBar().setDisplayShowHomeEnabled(true);
Bundle bundle=getIntent().getExtras();
menuidpage=bundle.getString("page_id");
recyclerView = (RecyclerView) findViewById(R.id.recyclerviewpage);
pDialog = new ProgressDialog(this);
adapter = new PageRecyclerAdapter(this, feedsList);
recyclerView.setLayoutManager(new LinearLayoutManager(this));
recyclerView.setAdapter(adapter);
//Getting Instance of Volley Request Queue
queue = NetworkController.getInstance(this).getRequestQueue();
//Volley's inbuilt class to make Json array request
pDialog.setMessage("Loding...");
pDialog.show();
String url = "http://www.groveus.com/micro/api/index.php/pages/view?
id="+menuidpage;
JsonArrayRequest menuReq = new JsonArrayRequest(url, new
Response.Listener<JSONArray>() {
#Override
public void onResponse(JSONArray response) {
pDialog.dismiss();
for (int i = 0; i < response.length(); i++) {
try {
JSONObject obj = response.getJSONObject(i);
MenuFeeds feeds = new MenuFeeds(obj.getInt("page_id"),
obj.getString("status"), obj.getString("title"),
newimage+obj.getString("image"),obj.getString("content"));
// adding movie to movies array
feedsList.add(feeds);
} catch (Exception e) {
System.out.println(e.getMessage());
} finally {
//Notify adapter about data changes
adapter.notifyItemChanged(i);
}
}
}
}, new Response.ErrorListener() {
#Override
public void onErrorResponse(VolleyError error) {
System.out.println(error.getMessage());
pDialog.dismiss();
}
});
//Adding JsonArrayRequest to Request Queue
queue.add(menuReq);
}
#Override
public boolean onSupportNavigateUp() {
onBackPressed();
return true;
}
}
PageRecyclerAdapter.java
public class PageRecyclerAdapter extends
RecyclerView.Adapter<PageRecyclerAdapter.MyViewHolder> implements
View.OnTouchListener
{
private List<MenuFeeds> feedsList;
private Context context;
private LayoutInflater inflater;
public PageRecyclerAdapter(Context context, List<MenuFeeds> feedsList) {
this.context = context;
this.feedsList = feedsList;
inflater = (LayoutInflater)
context.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
}
#Override
public MyViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
View rootView = inflater.inflate(R.layout.list_layout5, parent, false);
return new MyViewHolder(rootView);
}
#RequiresApi(api = Build.VERSION_CODES.N)
#Override
public void onBindViewHolder(MyViewHolder holder, int position) {
final MenuFeeds feeds = feedsList.get(position);
//Pass the values of feeds object to Views
//holder.idmenu.setText(feeds.getMenuId());
//holder.title.setText(feeds.getFeedName());
/* holder.description.setText(Html.fromHtml(feeds.getDescription(), 0,
new Html.ImageGetter() {
#Override
public Drawable getDrawable(String s) {
int id;
if
(s.equals("http://www.groveus.com/micro/assets/images/URINARY TRACT
INFECTION 1.png")) {
id = R.drawable.urin1;
}
else if
(s.equals("http://www.groveus.com/micro/assets/images/URINARY TRACT
INFECTION 2.png")) {
id = R.drawable.urin2;
}
else if
(s.equals("http://www.groveus.com/micro/assets/images/SKIN AND SOFT TISSUE
INFECTION 1.png")) {
id = R.drawable.skinsoft1;
}
else if
(s.equals("http://www.groveus.com/micro/assets/images/SKIN AND SOFT TISSUE
INFECTION 2.png")) {
id = R.drawable.skinsoft2;
}
else if
(s.equals("http://groveus.com/micro/assets/images/RESPIRATORY TRACT
INFECTION.png")) {
id = R.drawable.respo;
}
else if (s.equals("http://groveus.com/micro/assets/images/LOCAL
BACTERIAL INFECTIONS.png")) {
id = R.drawable.local;
}
else if
(s.equals("http://groveus.com/micro/assets/images/URINARY TRACT INFECTION
2nd 1.png")) {
id = R.drawable.urine2nd1;
}
else if
(s.equals("http://groveus.com/micro/assets/images/URINARY TRACT INFECTION
2nd 2.png")) {
id = R.drawable.urine2nd2;
}
else if
(s.equals("http://groveus.com/micro/assets/images/table.png")) {
id = R.drawable.table;
}
else if
(s.equals("http://www.groveus.com/micro/assets/images/table 2.png")) {
id = R.drawable.table2;
}
else {
return null;
}
Drawable d = context.getResources().getDrawable(id);
d.setBounds(0,0,1020,600);
return d;
}
}, null));*/
holder.description.setText(Html.fromHtml(feeds.getDescription()));
holder.description.setOnTouchListener(this);
holder.description.setMovementMethod(new ScrollingMovementMethod());
holder.imageview.setImageUrl(feeds.getImgURL(),
NetworkController.getInstance(context).getImageLoader());
// holder.ratingbar.setProgress(feeds.getRating());
}
#Override
public int getItemCount() {
return feedsList.size();
}
#Override
public boolean onTouch(View view, MotionEvent motionEvent) {
view.getParent().requestDisallowInterceptTouchEvent(true);
return false;
}
public class MyViewHolder extends RecyclerView.ViewHolder {
private TextView title,description;
private NetworkImageView imageview;
//private ProgressBar ratingbar;
public MyViewHolder(View itemView) {
super(itemView);
title = (TextView) itemView.findViewById(R.id.ImageNameTextView);
description = (TextView) itemView.findViewById(R.id.desc);
//idmenu = (TextView) itemView.findViewById(R.id.ImageNameTextView2);
UrlImageParser p=new UrlImageParser(description,context);
// Volley's NetworkImageView which will load Image from URL
imageview = (NetworkImageView) itemView.findViewById(R.id.thumbnail);
}
}
}
MenuFeeds.java
public class MenuFeeds
{
private String imgURL, feedName, description,page;
//private String id;
private int id;
public MenuFeeds(int menuid, String page, String name, String imgurl,String
desc) {
this.id=menuid;
this.page=page;
this.feedName = name;
this.imgURL = imgurl;
this.description = desc;
//this.rating = rating;
}
public int getMenuId() {
return id;
}
public String getPageID()
{
return page;
}
public String getDescription() {
return description;
}
public String getImgURL() {
return imgURL;
}
public String getFeedName() {
return feedName;
}
}

I also faced a similar problem month ago and used this and it works fine :
String htmlData = listData.get(position).getValue();
String showData = htmlData.replace("\n", "");
URLImageParser p = new URLImageParser(holder.textt, context);
Spanned htmlAsSpanned = Html.fromHtml(showData,p,null);
holder.yourTextView.setText(htmlAsSpanned);
Now copy and paste these 2 methods :
First method :
public class URLDrawable extends BitmapDrawable {
protected Drawable drawable;
#Override
public void draw(Canvas canvas) {
if(drawable != null) {
drawable.draw(canvas);
}
}
}
///Second Method :
public class URLImageParser implements Html.ImageGetter {
Context c;
TextView container;
/***
* Construct the URLImageParser which will execute AsyncTask and refresh the container
* #param t
* #param c
*/
public URLImageParser(TextView t, Context c) {
this.c = c;
this.container = t;
}
public Drawable getDrawable(String source) {
URLDrawable urlDrawable = new URLDrawable();
// get the actual source
ImageGetterAsyncTask asyncTask =
new ImageGetterAsyncTask( urlDrawable);
asyncTask.execute(source);
// return reference to URLDrawable where I will change with actual image from
// the src tag
return urlDrawable;
}
public class ImageGetterAsyncTask extends AsyncTask<String, Void, Drawable> {
URLDrawable urlDrawable;
public ImageGetterAsyncTask(URLDrawable d) {
this.urlDrawable = d;
}
#Override
protected Drawable doInBackground(String... params) {
String source = params[0];
return fetchDrawable(source);
}
#Override
protected void onPostExecute(Drawable result) {
// set the correct bound according to the result from HTTP call
urlDrawable.setBounds(0, 0, 0 + result.getIntrinsicWidth(), 0
+ result.getIntrinsicHeight());
// change the reference of the current drawable to the result
// from the HTTP call
urlDrawable.drawable = result;
// redraw the image by invalidating the container
URLImageParser.this.container.invalidate();
URLImageParser.this.container.setHeight((URLImageParser.this.container.getHeight()
+ result.getIntrinsicHeight()));
}
/***
* Get the Drawable from URL
* #param urlString
* #return
*/
public Drawable fetchDrawable(String urlString) {
try {
InputStream is = fetch(urlString);
Drawable drawable = Drawable.createFromStream(is, "src");
drawable.setBounds(0, 0, 0 + drawable.getIntrinsicWidth(), 0
+ drawable.getIntrinsicHeight());
return drawable;
} `enter code here`catch (Exception e) {
return null;
}
}
private InputStream fetch(String urlString) throws MalformedURLException, IOException {
DefaultHttpClient httpClient = new DefaultHttpClient();
HttpGet request = new HttpGet(urlString);
HttpResponse response = httpClient.execute(request);
return response.getEntity().getContent();
}
}
}

try this
load your image using piccaso
add below library in your build.gradle
implementation 'com.squareup.picasso:picasso:2.71828'
when you need to set image use piccaso this way
Picasso.get()
.load(your_image)
.placeholder(R.drawable.user_placeholder)
.error(R.drawable.your_error_image_or_blank)
.into(your_imageView);

OkHTTP AndroidBaseAdapter to ListView from data

I've set up okhttp to download data from my server and display it in normal text view.
But I would love to get it to ListView.
I know I need to have base adapter, some item layout and I need help with how to get it working with OKHTTP.
This is code that I use to download it, if you need anything else, please comment.
public class TaskAktualnosci extends AsyncTask<String, Void, String> {
protected String doInBackground(String... params) {
try {
//*OKHTTP ponoć parametry dodaje do buildera*
// RequestBody parametry = new FormBody.Builder()
// .add("offset", "0")
// .add("limit", "50")
// .build();
OkHttpClient klient = new OkHttpClient();
final Gson gson = new Gson();
Request request = new Request.Builder()
.url("http://www.apirest.poligon.webimpuls.pl/v1/restapi/aktualnosci?offset=0?limit=50")
// .post(parametry)
.build();
Response response = klient.newCall(request).execute();
return response.body().string();
}catch (Exception e){
return null;
}
}
#Override
protected void onPostExecute(String s){
super.onPostExecute(s);
TextView textView = (TextView) findViewById(R.id.ciastko);
textView.setText(s);
}
}
}
I'm kinda new to android as whole and using Android Studio.
Can anyone explain it to me in normal way or show code snippet?

You need to make your own adapter. I prefer to extend from BaseAdapter and create a own list item class:
class ListItem {
private long mId;
private String mContent;
public ListItem(final long mId, final String mContent) {
this.mId = mId;
this.mContent = mContent;
}
public long getId() {
return mId;
}
public String getContent() {
return mContent;
}
}
public class adapter_akt extends BaseAdapter {
private List<ListItem> mData = new ArrayList<>();
public void setData(List<ListItem> data){
mData = data;
notifyDataSetChanged();
}
public ListItem getItem(int position){
return mData.get(position);
}
#Override
public long getItemId(final int position) {
return getItem(position).getId();
}
#Override
public View getView(final int position, View convertView, final ViewGroup parent) {
if (convertView == null){
convertView = LayoutInflater.from(parent.getContext()).inflate(android.R.layout.simple_list_item_1, parent);
ViewHolder h = new ViewHolder();
h.textView1 = (TextView) convertView.findViewById(android.R.id.text1);
convertView.setTag(h);
}
ViewHolder holder = (ViewHolder)convertView.getTag();
ListItem item = getItem(position);
holder.textView1.setText(item.getContent());
return convertView;
}
public int getCount(){
return mData.size();
}
private class ViewHolder{
TextView textView1;
}
}
then all u need is something to set your adapter to your ListView.
Your AsyncTask would look like:
public class Test1 extends AsyncTask<String, Void, String> {
protected String doInBackground(String... params) {
try {
//*OKHTTP ponoć parametry dodaje do buildera*
// RequestBody parametry = new FormBody.Builder()
// .add("offset", "0")
// .add("limit", "50")
// .build();
OkHttpClient klient = new OkHttpClient();
final Gson gson = new Gson();
Request request = new Request.Builder()
.url("http://www.apirest.poligon.webimpuls.pl/v1/restapi/aktualnosci?offset=0?limit=50")
// .post(parametry)
.build();
Response response = klient.newCall(request).execute();
return response.body().string();
}catch (Exception e){
return null;
}
}
#Override
protected void onPostExecute(String s){
super.onPostExecute(s);
List<ListItem> contentList = new ArrayList<>();
/*
her u need to read data from s to the list;
*/
MyListAdapter adapter = find();//here u need to get your Adapter, maybe its member of your fragment class
adapter.setData(contentList);
}
}

how to display details of single item of list in another activity from url (json data)?

I have written a program to display the list of json data from a url which has an image and 5 textviews which is displaying perfectly.
Url : https://itunes.apple.com/search?term=jack+johnson&limit=50.
When i click on an item from the list i want to display the details of that item in another activity based on the track-id
Url : https://itunes.apple.com/lookup?id=659234741
So when i click on the item the details are getting displayed in the textview , but by default it is displaying the details of id = 659234741 for some items or in short the details does not match.
Need some help to figure out the problem
My Code :
MainActivity.java
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
resultsList = new ArrayList<HashMap<String, String>>();
lv = getListView();
// Calling async task to get json
new GetTunesDetails().execute();
}
/**
* Async task class to get json by making HTTP call
* */
private class GetTunesDetails 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... params) {
// 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
tunes = jsonObj.getJSONArray(TAG_RESULT);
// looping through All Products
for (int i = 0; i < tunes.length(); i++) {
JSONObject c = tunes.getJSONObject(i);
artworkImage = c.getString("artworkUrl100");
wrapperType = c.getString("wrapperType");
artistName = c.getString("artistName");
collectionName = c.getString("collectionName");
trackName = c.getString("trackName");
collectionPrice = c.getString("collectionPrice");
trackId = c.getString("trackId");
// tmp hashmap for single contact
HashMap<String, String> tunesMap = new HashMap<String,
String>();
// adding each child node to HashMap key => value
// contact.put(TAG_ID, firstname);
tunesMap.put(TAG_ARTWORK_IMAGE, artworkImage);
tunesMap.put(TAG_WRAPPER_TYPE, wrapperType);
tunesMap.put(TAG_ARTIST_NAME, artistName);
tunesMap.put(TAG_COLLECTION_NAME, collectionName);
tunesMap.put(TAG_TRACK_NAME, trackName);
tunesMap.put(TAG_COLLECTION_PRICE, collectionPrice);
tunesMap.put(TAG_TRACK_ID, trackId);
// adding contact to contact list
resultsList.add(tunesMap);
}
} 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);
if (pDialog.isShowing())
pDialog.dismiss();
// Pass the results into ListViewAdapter.java
adapter = new ListViewAdapter(MainActivity.this, resultsList);
// Set the adapter to the ListView
lv.setAdapter(adapter);
}
}
ListViewAdapter.java
public class ListViewAdapter extends BaseAdapter {
// Declare Variables
Context context;
LayoutInflater inflater;
ArrayList<HashMap<String, String>> data;
ImageLoader imageLoader;
HashMap<String, String> resultp = new HashMap<String, String>();
int position;
TextView wrapperType, artistName, collectionName, trackName,
collectionPrice;
ImageView artworkImage;
public ListViewAdapter(Context context, ArrayList<HashMap<String, String>>
arraylist) {
this.context = context;
data = arraylist;
imageLoader = new ImageLoader(context);
}
#Override
public int getCount() {
return data.size();
}
#Override
public Object getItem(int position) {
return null;
}
#Override
public long getItemId(int position) {
return 0;
}
public View getView(final int position, View convertView, ViewGroup parent) {
// Declare Variables
// this.position = position;
inflater = (LayoutInflater)
context.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
View itemView = inflater.inflate(R.layout.custom_row, parent, false);
// Get the position
resultp = data.get(position);
// Locate the TextViews in listview_item.xml
wrapperType = (TextView) itemView.findViewById(R.id.wrapperType);
artistName = (TextView) itemView.findViewById(R.id.artistName);
collectionName = (TextView) itemView.findViewById(R.id.collectionName);
trackName = (TextView) itemView.findViewById(R.id.trackName);
collectionPrice = (TextView)
itemView.findViewById(R.id.collectionPrice);
// Locate the ImageView in listview_item.xml
artworkImage = (ImageView) itemView.findViewById(R.id.artworkImage);
// Capture position and set results to the TextViews
wrapperType.setText(resultp.get(MainActivity.TAG_WRAPPER_TYPE));
artistName.setText(resultp.get(MainActivity.TAG_ARTIST_NAME));
collectionName.setText(resultp.get(MainActivity.TAG_COLLECTION_NAME));
trackName.setText(resultp.get(MainActivity.TAG_TRACK_NAME));
collectionPrice.setText(resultp.get(MainActivity.TAG_COLLECTION_PRICE));
// Capture position and set results to the ImageView
// Passes flag images URL into ImageLoader.class
imageLoader.DisplayImage(resultp.get(MainActivity.TAG_ARTWORK_IMAGE),
artworkImage);
// Capture ListView item click
itemView.setOnClickListener(new OnClickListener() {
#Override
public void onClick(View v) { // TODO Auto-generated method
Toast.makeText(context, "Clicked at position " + position,
Toast.LENGTH_LONG).show();
Intent intent = new Intent(context, SingleTrack.class);
intent.putExtra("track_image",
resultp.get(MainActivity.TAG_ARTWORK_IMAGE));
intent.putExtra("wrapper_type",
resultp.get(MainActivity.TAG_WRAPPER_TYPE));
intent.putExtra("artistName",
resultp.get(MainActivity.TAG_ARTIST_NAME));
intent.putExtra("collectionName",
resultp.get(MainActivity.TAG_COLLECTION_NAME));
intent.putExtra("trackName",
resultp.get(MainActivity.TAG_TRACK_NAME));
intent.putExtra("collectionPrice",
resultp.get(MainActivity.TAG_COLLECTION_PRICE));
intent.putExtra("trackId",
resultp.get(MainActivity.TAG_TRACK_ID));
context.startActivity(intent);
}
});
return itemView;
}
SingleTrack.java : This is the class where i displaying the details on single item click
public class SingleTrack extends Activity {
// URL to get contacts JSON
private static String url = "";
// JSON Node names
static final String TAG_RESULT = "results";
static final String TAG_ARTWORK_IMAGE = "artworkUrl100";
static final String TAG_WRAPPER_TYPE = "wrapperType";
static final String TAG_ARTIST_NAME = "artistName";
static final String TAG_COLLECTION_NAME = "collectionName";
static final String TAG_TRACK_NAME = "trackName";
static final String TAG_COLLECTION_PRICE = "collectionPrice";
static final String TAG_TRACK_ID = "trackId";
// contacts JSONArray
JSONArray tracks = null;
// Hashmap for ListView
ArrayList<HashMap<String, String>> singleTrackDetails;
ProgressDialog pDialog;
String passedData1, passedData2, passedData3, passedData4, passedData5,
passedData6, passedData7;
TextView wrapperTypeText, artistNameText, collectionNameText, trackNameText,
collectionPriceText;
ImageView trackImage;
String artworkImage, wrapperType, artistName, collectionName, trackName,
collectionPrice, trackId;
#Override
protected void onCreate(Bundle savedInstanceState) {
// TODO Auto-generated method stub
super.onCreate(savedInstanceState);
setContentView(R.layout.single_track);
wrapperTypeText = (TextView) findViewById(R.id.wrapperType1);
artistNameText = (TextView) findViewById(R.id.artistName1);
collectionNameText = (TextView) findViewById(R.id.collectionName1);
trackNameText = (TextView) findViewById(R.id.trackName1);
collectionPriceText = (TextView) findViewById(R.id.collectionPrice);
trackImage = (ImageView) findViewById(R.id.artworkImage1);
passedData1 = getIntent().getStringExtra("track_image");
passedData2 = getIntent().getStringExtra("wrapper_type");
passedData3 = getIntent().getStringExtra("artistName");
passedData4 = getIntent().getStringExtra("collectionName");
passedData5 = getIntent().getStringExtra("trackName");
passedData6 = getIntent().getStringExtra("collectionPrice");
passedData7 = getIntent().getStringExtra("trackId");
singleTrackDetails = new ArrayList<HashMap<String, String>>();
// url
url = "https://itunes.apple.com/lookup?id=" + passedData7;
// Calling async task to get json
new GetSingleTrackDetails().execute();
}
class GetSingleTrackDetails extends AsyncTask<String, Void, String> {
private JSONObject jsonObj;
#Override
protected void onPreExecute() {
super.onPreExecute();
// Showing progress dialog
pDialog = new ProgressDialog(SingleTrack.this);
pDialog.setMessage("Loading Track Details...");
pDialog.setCancelable(false);
pDialog.show();
}
#Override
protected String doInBackground(String... params) {
// 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
tracks = jsonObj.getJSONArray(TAG_RESULT);
// looping through All Products
for (int i = 0; i < tracks.length(); i++) {
JSONObject c = tracks.getJSONObject(i);
artworkImage = c.getString("artworkUrl100");
wrapperType = c.getString("wrapperType");
artistName = c.getString("artistName");
collectionName = c.getString("collectionName");
trackName = c.getString("trackName");
collectionPrice = c.getString("collectionPrice");
trackId = c.getString("trackId");
// tmp hashmap for single contact
HashMap<String, String> tunesMap = new HashMap<String,
String>();
// adding each child node to HashMap key => value
// contact.put(TAG_ID, firstname);
tunesMap.put(TAG_ARTWORK_IMAGE, artworkImage);
tunesMap.put(TAG_WRAPPER_TYPE, wrapperType);
tunesMap.put(TAG_ARTIST_NAME, artistName);
tunesMap.put(TAG_COLLECTION_NAME, collectionName);
tunesMap.put(TAG_TRACK_NAME, trackName);
tunesMap.put(TAG_COLLECTION_PRICE, collectionPrice);
tunesMap.put(TAG_TRACK_ID, trackId);
// adding contact to contact list
singleTrackDetails.add(tunesMap);
}
} catch (JSONException e) {
e.printStackTrace();
}
} else {
Log.e("ServiceHandler", "Couldn't get any data from the url");
}
return null;
}
#Override
protected void onPostExecute(String result) {
super.onPostExecute(result);
if (pDialog != null) {
pDialog.dismiss();
pDialog = null;
}
wrapperTypeText.setText(wrapperType);
artistNameText.setText(artistName);
collectionNameText.setText(collectionName);
trackNameText.setText(trackName);
collectionPriceText.setText(collectionPrice);
}
}
Thank you

The problem is that you are initializing the resultp each element in your getView method, so therefore the last id/element of the listview adapter's data will be considered as the resultp.
Im sure that the id 659234741 is the last element, which will always be the id for each onclick that would happen.
A solution for this is to create a final resultp within your getView method instead of having just one global resultp.
final HashMap<String, String> resultp = data.get(position);

Loading images from JSON as you scroll in Android

I am creating an app with many products being loaded from a JSON file. Everything is working fine, but I have a small problem and I am having difficulty finding an answer to it. On a click of a button, I get all data from JSON file located on a server (it contains a URL value to get the picture of the product). When the button is clicked I would like to move to a list of products straight away and only load visible images. Instead it takes about 8 seconds to load and it loads all images before hand. Could somebody please tell me what am I doing wrong? I read online I should use something like so: imageLoader.DisplayImage(data[position], image);, but I am using a Hashmap, not just a string.
Here is my code, any help would be greatly appreciated:
LazyAdapter
public class LazyAdapter extends BaseAdapter {
private Activity activity;
private ArrayList<HashMap<String, String>> data;
private static LayoutInflater inflater=null;
public ImageLoader imageLoader;
public LazyAdapter(Activity a, ArrayList<HashMap<String, String>> d) {
activity = a;
data=d;
inflater = (LayoutInflater)activity.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
imageLoader=new ImageLoader(activity.getApplicationContext());
}
public int getCount() {
return data.size();
}
public Object getItem(int position) {
return position;
}
public long getItemId(int position) {
return position;
}
public View getView(int position, View convertView, ViewGroup parent) {
View vi=convertView;
if(convertView==null)
vi = inflater.inflate(R.layout.list_row, null);
TextView brand = (TextView)vi.findViewById(R.id.brand); // title
TextView name = (TextView)vi.findViewById(R.id.name); // artist name
TextView price = (TextView)vi.findViewById(R.id.price); // duration
TextView imgValue = (TextView)vi.findViewById(R.id.imgValue);
//TextView rating = (TextView)vi.findViewById(R.id.rating); // rating
ImageView thumb_image=(ImageView)vi.findViewById(R.id.list_image); // thumb image
HashMap<String, String> products = new HashMap<String, String>();
products = data.get(position);
// Setting all values in listview
brand.setText(products.get(CustomizedListView.TAG_BRAND));
name.setText(products.get(CustomizedListView.TAG_NAME));
price.setText("£" + products.get(CustomizedListView.TAG_MIN_GBP));
imgValue.setText(products.get(CustomizedListView.TAG_IMG));
imgValue.setVisibility(View.GONE);
//rating.setText("Rating: " + song.get(CustomizedListView.TAG_RATING_NO) + "/5");
imageLoader.DisplayImage("http://debenhams.scene7.com/is/image/Debenhams/" + imgValue.getText() + "?hei=440&op_usm=1.1,0.5,0,0", thumb_image);
return vi;
}
}
ListView
public class CustomizedListView extends Activity {
// All static variables
static final String link = "https://dl.dropboxusercontent.com/u/142838353/productlist.json";
// XML node keys
static final String TAG_PRODUCTS = "Products";
static final String TAG_PRODNUM = "prodnum";
static final String TAG_BRAND = "brand";
static final String TAG_NAME = "name"; // parent node
static final String TAG_MIN_GBP = "minGBP";
static final String TAG_IMG = "img";
static final String TAG_RATING_NO = "rating_number";
JSONArray products = null;
ListView list;
LazyAdapter adapter;
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.shop);
// Hashmap for ListView
ArrayList<HashMap<String, String>> productList = new ArrayList<HashMap<String, String>>();
// Creating JSON Parser instance
JSONParser jParser = new JSONParser();
// getting JSON string from URL
JSONObject json = jParser.getJSONFromUrl(link);
try {
// Getting Array of Contacts
products = json.getJSONArray(TAG_PRODUCTS);
// looping through All Contacts
for(int i = 0; i < products.length(); i++){
JSONObject c = products.getJSONObject(i);
// Storing each json item in variable
// String prodnum = c.getString(TAG_PRODNUM);
String brand = c.getString(TAG_BRAND);
String name = c.getString(TAG_NAME);
String img = c.getString(TAG_IMG);
String price = c.getString(TAG_MIN_GBP);
//String ratingNo = c.getString(TAG_RATING_NO);
// creating new HashMap
HashMap<String, String> map = new HashMap<String, String>();
// adding each child node to HashMap key => value
map.put(TAG_MIN_GBP, price);
map.put(TAG_BRAND, brand);
map.put(TAG_NAME, name);
map.put(TAG_IMG, img);
//map.put(TAG_RATING_NO, ratingNo);
// adding HashList to ArrayList
productList.add(map);
}
} catch (JSONException e) {
e.printStackTrace();
}
list=(ListView)findViewById(R.id.list);
// Getting adapter by passing xml data ArrayList
adapter=new LazyAdapter(this, productList);
list.setAdapter(adapter);
// Click event for single list row
list.setOnItemClickListener(new OnItemClickListener() {
#Override
public void onItemClick(AdapterView<?> parent, View view,
int position, long id) {
String brand = ((TextView) view.findViewById(R.id.brand)).getText().toString();
String name = ((TextView) view.findViewById(R.id.name)).getText().toString();
String imgValue = ((TextView) view.findViewById(R.id.imgValue)).getText().toString();
String price = ((TextView) view.findViewById(R.id.price)).getText().toString();
//String imgVal = ((ImageView) view.findViewById(R.id.list_image)).;
//String imgVal = ((ImageView) view.findViewById(R.id.img)).getResources().toString();
// Starting new intent
Intent in = new Intent(getApplicationContext(), ProductActivity.class);
in.putExtra(TAG_BRAND, brand);
in.putExtra(TAG_NAME, name);
in.putExtra(TAG_IMG, imgValue);
in.putExtra(TAG_MIN_GBP, price);
startActivity(in);
}
});
}
#Override
public void onDestroy()
{
list.setAdapter(null);
super.onDestroy();
}
}
ImageLoader
public class ImageLoader {
MemoryCache memoryCache=new MemoryCache();
FileCache fileCache;
private Map<ImageView, String> imageViews=Collections.synchronizedMap(new WeakHashMap<ImageView, String>());
ExecutorService executorService;
Handler handler=new Handler();//handler to display images in UI thread
public ImageLoader(Context context){
fileCache=new FileCache(context);
executorService=Executors.newFixedThreadPool(5);
}
final int stub_id=R.drawable.default_image;
public void DisplayImage(String url, ImageView imageView)
{
imageViews.put(imageView, url);
Bitmap bitmap=memoryCache.get(url);
if(bitmap!=null)
imageView.setImageBitmap(bitmap);
else
{
queuePhoto(url, imageView);
imageView.setImageResource(stub_id);
}
}
private void queuePhoto(String url, ImageView imageView)
{
PhotoToLoad p=new PhotoToLoad(url, imageView);
executorService.submit(new PhotosLoader(p));
}
private Bitmap getBitmap(String url)
{
File f=fileCache.getFile(url);
//from SD cache
Bitmap b = decodeFile(f);
if(b!=null)
return b;
//from web
try {
Bitmap bitmap=null;
URL imageUrl = new URL(url);
HttpURLConnection conn = (HttpURLConnection)imageUrl.openConnection();
conn.setConnectTimeout(30000);
conn.setReadTimeout(30000);
conn.setInstanceFollowRedirects(true);
InputStream is=conn.getInputStream();
OutputStream os = new FileOutputStream(f);
Utils.CopyStream(is, os);
os.close();
conn.disconnect();
bitmap = decodeFile(f);
return bitmap;
} catch (Throwable ex){
ex.printStackTrace();
if(ex instanceof OutOfMemoryError)
memoryCache.clear();
return null;
}
}
//decodes image and scales it to reduce memory consumption
private Bitmap decodeFile(File f){
try {
//decode image size
BitmapFactory.Options o = new BitmapFactory.Options();
o.inJustDecodeBounds = true;
FileInputStream stream1=new FileInputStream(f);
BitmapFactory.decodeStream(stream1,null,o);
stream1.close();
//Find the correct scale value. It should be the power of 2.
final int REQUIRED_SIZE=256;
int width_tmp=o.outWidth, height_tmp=o.outHeight;
int scale=1;
while(true){
if(width_tmp/2<REQUIRED_SIZE || height_tmp/2<REQUIRED_SIZE)
break;
width_tmp/=2;
height_tmp/=2;
scale*=2;
}
//decode with inSampleSize
BitmapFactory.Options o2 = new BitmapFactory.Options();
o2.inSampleSize=scale;
FileInputStream stream2=new FileInputStream(f);
Bitmap bitmap=BitmapFactory.decodeStream(stream2, null, o2);
stream2.close();
return bitmap;
} catch (FileNotFoundException e) {
}
catch (IOException e) {
e.printStackTrace();
}
return null;
}
//Task for the queue
private class PhotoToLoad
{
public String url;
public ImageView imageView;
public PhotoToLoad(String u, ImageView i){
url=u;
imageView=i;
}
}
class PhotosLoader implements Runnable {
PhotoToLoad photoToLoad;
PhotosLoader(PhotoToLoad photoToLoad){
this.photoToLoad=photoToLoad;
}
#Override
public void run() {
try{
if(imageViewReused(photoToLoad))
return;
Bitmap bmp=getBitmap(photoToLoad.url);
memoryCache.put(photoToLoad.url, bmp);
if(imageViewReused(photoToLoad))
return;
BitmapDisplayer bd=new BitmapDisplayer(bmp, photoToLoad);
handler.post(bd);
}catch(Throwable th){
th.printStackTrace();
}
}
}
boolean imageViewReused(PhotoToLoad photoToLoad){
String tag=imageViews.get(photoToLoad.imageView);
if(tag==null || !tag.equals(photoToLoad.url))
return true;
return false;
}
//Used to display bitmap in the UI thread
class BitmapDisplayer implements Runnable
{
Bitmap bitmap;
PhotoToLoad photoToLoad;
public BitmapDisplayer(Bitmap b, PhotoToLoad p){bitmap=b;photoToLoad=p;}
public void run()
{
if(imageViewReused(photoToLoad))
return;
if(bitmap!=null)
photoToLoad.imageView.setImageBitmap(bitmap);
else
photoToLoad.imageView.setImageResource(stub_id);
}
}
public void clearCache() {
memoryCache.clear();
fileCache.clear();
}
}

If you're not averse to using a library to do it, I had a lot of success with Universal Image Loader. It takes a lot of the complexity of the problem away and is pretty easy to get set up. There's some discussion of the problem from a while back with a few other implementations (I'm not sure if any of them are maintained though). Even if you don't use the library, their design patterns might be a useful starting point.