Im trying to parse some items in a listview and when I scroll down I want to get more products and add them to the list.
But my code doesnt do that it either refreshes it or crashes.
Any help?
Also adding a footer doesnt work either i get an classcastexception
JSONParser:
package com.lars.json;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import org.json.JSONArray;
import org.json.JSONException;
import org.json.JSONObject;
import com.lars.R.drawable;
import android.R;
import android.util.Log;
/** A class to parse json data */
public class JSONParser {
// Receives a JSONObject and returns a list
public List<HashMap<String,Object>> parse(JSONObject jObject){
JSONArray jProducts = null;
try {
// Retrieves all the elements in the 'countries' array
jProducts = jObject.getJSONArray("products");
} catch (JSONException e) {
e.printStackTrace();
}
// Invoking getCountries with the array of json object
// where each json object represent a country
return getProducts(jProducts);
}
private List<HashMap<String, Object>> getProducts(JSONArray jProducts){
int productsCount = jProducts.length();
List<HashMap<String, Object>> productList = new ArrayList<HashMap<String,Object>>();
HashMap<String, Object> product = null;
// Taking each country, parses and adds to list object
for(int i=0; i<productsCount;i++){
try {
// Call getCountry with country JSON object to parse the country
product = getJSON((JSONObject)jProducts.get(i));
productList.add(product);
} catch (JSONException e) {
e.printStackTrace();
}
}
return productList;
}
// Parsing the Country JSON object
private HashMap<String, Object> getJSON(JSONObject f){
HashMap<String, Object> country = new HashMap<String, Object>();
String id = "";
String naam = "";
String status = "";
String prijs = "";
String productnum = "";
try {
String priceone = f.getString("prijsex");
id = f.getString("id");
naam = f.getString("naam");
status = f.getString("status");
prijs = "€" + priceone;
productnum = f.getString("productnum");
country.put("id", id);
country.put("naam", naam);
country.put("img", com.lars.R.drawable.tlogotrans);
country.put("prijs", prijs);
country.put("img_path", "http://www.lars.com/images/" + productnum + ".jpg");
if(Integer.parseInt(status) > 0){
country.put("status", com.lars.R.drawable.stock);
}else{
country.put("status", com.lars.R.drawable.nostock);
}
} catch (JSONException e) {
e.printStackTrace();
}
return country;
}
}
Download tasks and Listview loaders:
/** 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;
}
/** AsyncTask to download json data */
private class DownloadTask extends AsyncTask<String, Integer, String>{
String data = null;
#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) {
// The parsing of the xml data is done in a non-ui thread
ListViewLoaderTask listViewLoaderTask = new ListViewLoaderTask();
Log.i("Result", result);
if(result.equals(" ")){
Log.i("No img", "No Img");
}else{
listViewLoaderTask.execute(result);
}
// Start parsing xml data
}
}
/** AsyncTask to parse json data and load ListView */
private class ListViewLoaderTask extends AsyncTask<String, Void, SimpleAdapter>{
JSONObject jObject;
private List<HashMap<String, Object>> products;
// Doing the parsing of xml data in a non-ui thread
#Override
protected SimpleAdapter doInBackground(String... strJson) {
try{
jObject = new JSONObject(strJson[0]);
JSONParser jsonpars = new JSONParser();
jsonpars.parse(jObject);
}catch(Exception e){
Log.d("JSON Exception1",e.toString());
}
// Instantiating json parser class
JSONParser jsonpars = new JSONParser();
// A list object to store the parsed countries list
try{
// Getting the parsed data as a List construct
if(set == 0){
products = jsonpars.parse(jObject);
}else{
products.addAll(jsonpars.parse(jObject));
}
}catch(Exception e){
Log.d("Exception",e.toString());
}
// Keys used in Hashmap
String[] from = { "img","naam","status","prijs"};
// Ids of views in listview_layout
int[] to = { R.id.imPThumb,R.id.tvPRName,R.id.imstock,R.id.tvPRPrijs};
// Instantiating an adapter to store each items
// R.layout.listview_layout defines the layout of each item
SimpleAdapter adapter = new SimpleAdapter(getBaseContext(), products, R.layout.productlijstrow, from, to);
return adapter;
}
#Override
protected void onProgressUpdate(Void... values) {
// TODO Auto-generated method stub
publishProgress();
Log.i("ListView Loader Task", "Update");
super.onProgressUpdate(values);
}
/** Invoked by the Android on "doInBackground" is executed */
#SuppressWarnings("unchecked")
#Override
protected void onPostExecute(SimpleAdapter adapter) {
// View v = getLayoutInflater().inflate(R.layout.footerview, null);
//list.addFooterView(v);
// Setting adapter for the listview
list.setAdapter(adapter);
if(set == 0){
list.setOnScrollListener(onAnswersScrolled);
set++;
}
list.setOnItemClickListener(onAnswerClicked);
list.setTextFilterEnabled(true);
/* list.setOnItemClickListener(new OnItemClickListener() {
public void onItemClick(AdapterView<?> parent, View view, int position, long id) {
#SuppressWarnings("unchecked")
HashMap<String, String> o = (HashMap<String, String>) lv.getItemAtPosition(position);
Bundle extra = new Bundle();
Intent i = new Intent("com.lars.productdescription");
extra.putString("id", o.get("id"));
i.putExtras(extra);
startActivity(i);
}
});*/
for(int i=0;i<adapter.getCount();i++){
HashMap<String, Object> hm = (HashMap<String, Object>) adapter.getItem(i);
String imgUrl = (String) hm.get("img_path");
Log.i("imgurlonPost", imgUrl);
ImageLoaderTask imageLoaderTask = new ImageLoaderTask();
HashMap<String, Object> hmDownload = new HashMap<String, Object>();
hmDownload.put("img_path",imgUrl);
hmDownload.put("position", i);
// Starting ImageLoaderTask to download and populate image in the listview
imageLoaderTask.execute(hmDownload);
adapter.notifyDataSetChanged();
}
/* list.setOnScrollListener(new OnScrollListener(){
});*/
}
}
/** AsyncTask to download and load an image in ListView */
private class ImageLoaderTask extends AsyncTask<HashMap<String, Object>, Void, HashMap<String, Object>>{
#Override
protected HashMap<String, Object> doInBackground(HashMap<String, Object>... hm) {
InputStream iStream=null;
String imgUrl = (String) hm[0].get("img_path");
int position = (Integer) hm[0].get("position");
HashMap<String, Object> hmBitmap = new HashMap<String, Object>();
URL url;
try {
url = new URL(imgUrl);
// Creating an http connection to communicate with url
HttpURLConnection urlConnection = (HttpURLConnection) url.openConnection();
Log.i("imgUrl", imgUrl);
// Connecting to url
urlConnection.connect();
// Log.i("Response", urlConnection.getResponseMessage());
// Reading data from url
if(urlConnection.getResponseMessage().contains("OK")){
iStream = urlConnection.getInputStream();
// Getting Caching directory
File cacheDirectory = getBaseContext().getCacheDir();
cacheDirectory.delete();
// Temporary file to store the downloaded image
File tmpFile = new File(cacheDirectory.getPath() + "/wpta_"+position+".png");
// The FileOutputStream to the temporary file
FileOutputStream fOutStream = new FileOutputStream(tmpFile);
// Creating a bitmap from the downloaded inputstream
Bitmap b = BitmapFactory.decodeStream(iStream);
// Writing the bitmap to the temporary file as png file
b.compress(Bitmap.CompressFormat.PNG,100, fOutStream);
// Flush the FileOutputStream
fOutStream.flush();
//Close the FileOutputStream
fOutStream.close();
// Create a hashmap object to store image path and its position in the listview
// Storing the path to the temporary image file
hmBitmap.put("img",tmpFile.getPath());
// Storing the position of the image in the listview
hmBitmap.put("position",position);
// Returning the HashMap object containing the image path and position
return hmBitmap;
}else{
Log.i("nope", "nb");
String uriStr = "android.resource://" + "com.lars" + "/" + R.drawable.ic_launcher;
hmBitmap.put("img", uriStr);
hmBitmap.put("position",position);
return hmBitmap;
}
}catch (Exception e) {
e.printStackTrace();
}
return null;
}
#SuppressWarnings("unchecked")
#Override
protected void onPostExecute(HashMap<String, Object> result) {
// Getting the path to the downloaded image
String path = (String) result.get("img");
// Getting the position of the downloaded image
int position = (Integer) result.get("position");
// Getting adapter of the listview
adapter = (SimpleAdapter ) list.getAdapter();
// Getting the hashmap object at the specified position of the listview
HashMap<String, Object> hm = (HashMap<String, Object>) adapter.getItem(position);
// Overwriting the existing path in the adapter
hm.put("img",path);
// Noticing listview about the dataset changes
adapter.notifyDataSetChanged();
}
#Override
protected void onProgressUpdate(Void... values) {
// TODO Auto-generated method stub
publishProgress();
adapter.notifyDataSetChanged();
Log.i("Image Task", "Update");
super.onProgressUpdate(values);
}
}
private OnItemClickListener onAnswerClicked = new OnItemClickListener() {
public void onItemClick(AdapterView<?> parent, View view, int position,
long id) {
#SuppressWarnings("unchecked")
HashMap<String, String> o = (HashMap<String, String>) parent.getItemAtPosition(position);
Bundle extra = new Bundle();
Intent i = new Intent("com.lars.productdescription");
extra.putString("id", o.get("id"));
i.putExtras(extra);
startActivity(i);
}
};
private OnScrollListener onAnswersScrolled = new OnScrollListener() {
public void onScroll(AbsListView view, int first, int visibleitems, int totalitemcount) {
// TODO Auto-generated method stub
int lastInScreen = first + visibleitems;
if(lastInScreen == totalitemcount){
if(kf == 0){
Log.i("onScroll", "" + c);
Log.i("kf", "0");
String filfinal = keuze.replace(" ", "thisisaspace");
String strUrl = "http://www.lars.nl/getName.php?name=" + filfinal + "&page=" + c ;
DownloadTask downloadTask = new DownloadTask();
downloadTask.execute(strUrl);
c = c + o;
Log.i("After Scroll", "" + c);
}else{
Log.i("onScroll", "" + c);
Log.i("kf", "1");
String strUrl = "http://www.lars.nl/get.php?id=" + filter + "&page=" + c ;
DownloadTask downloadTask = new DownloadTask();
downloadTask.execute(strUrl);
c = c + o;
Log.i("After Scroll", "" + c);
}
}
}
public void onScrollStateChanged(AbsListView view, int scrollstate) {
// TODO Auto-generated method stub
}
};
}
I'd like to introduce you to CWAC-ENDLESS by non other than the brilliant mark murphy (commonsware). Not only is it a fine example of the power of putting an adapter inside another adapter, it handles all the background tasks for you as well as scrolling so that your data list may be added to very easily by following the demo
I sincerely hope this helps you as much as its helped me.
Related
I am using listview in android with JSON Parser the listview sucessful working, here is my problem, onitemclicklistner is not working in listview?
Here this my code
Main Activity code
public class MainActivity extends Activity {
private static final String TAG_NAME = "name";
private static final String TAG_EMAIL = "email";
private static final String TAG_PHONE_MOBILE = "mobile";
ListView mListView;
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
// URL to the JSON data
String strUrl = "http://192.168.0.200/android/count.php";
// Creating a new non-ui thread task to download json data
DownloadTask downloadTask = new DownloadTask();
// Starting the download process
downloadTask.execute(strUrl);
// Getting a reference to ListView of activity_main
mListView = (ListView) findViewById(R.id.lv_countries);
}
/** 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;
}
/** AsyncTask to download json data */
private class DownloadTask extends AsyncTask<String, Integer, String>{
String data = null;
#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) {
// The parsing of the xml data is done in a non-ui thread
ListViewLoaderTask listViewLoaderTask = new ListViewLoaderTask();
// Start parsing xml data
listViewLoaderTask.execute(result);
}
}
/** AsyncTask to parse json data and load ListView */
private class ListViewLoaderTask extends AsyncTask<String, Void, SimpleAdapter>{
JSONObject jObject;
// Doing the parsing of xml data in a non-ui thread
#Override
protected SimpleAdapter doInBackground(String... strJson) {
try{
jObject = new JSONObject(strJson[0]);
CountryJSONParser countryJsonParser = new CountryJSONParser();
countryJsonParser.parse(jObject);
}catch(Exception e){
Log.d("JSON Exception1",e.toString());
}
// Instantiating json parser class
CountryJSONParser countryJsonParser = new CountryJSONParser();
// A list object to store the parsed countries list
List<HashMap<String, Object>> countries = null;
try{
// Getting the parsed data as a List construct
countries = countryJsonParser.parse(jObject);
}catch(Exception e){
Log.d("Exception",e.toString());
}
// Keys used in Hashmap
String[] from = { "flag","details"};
// Ids of views in listview_layout
int[] to = { R.id.iv_flag,R.id.tv_country_details};
// Instantiating an adapter to store each items
// R.layout.listview_layout defines the layout of each item
SimpleAdapter adapter = new SimpleAdapter(getBaseContext(), countries, R.layout.lv_layout, from, to);
return adapter;
}
/** Invoked by the Android on "doInBackground" is executed */
#Override
protected void onPostExecute(SimpleAdapter adapter) {
// Setting adapter for the listview
mListView.setAdapter(adapter);
for(int i=0;i<adapter.getCount();i++){
HashMap<String, Object> hm = (HashMap<String, Object>) adapter.getItem(i);
String imgUrl = (String) hm.get("flag_path");
ImageLoaderTask imageLoaderTask = new ImageLoaderTask();
HashMap<String, Object> hmDownload = new HashMap<String, Object>();
hm.put("flag_path",imgUrl);
hm.put("position", i);
// Starting ImageLoaderTask to download and populate image in the listview
imageLoaderTask.execute(hm);
}
}
}
/** AsyncTask to download and load an image in ListView */
private class ImageLoaderTask extends AsyncTask<HashMap<String, Object>, Void, HashMap<String, Object>>{
#Override
protected HashMap<String, Object> doInBackground(HashMap<String, Object>... hm) {
InputStream iStream=null;
String im,gUrl;
gUrl = (String) hm[0].get("flag_path");
int position = (Integer) hm[0].get("position");
URL url;
try {
url = new URL(gUrl);
// 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();
// Getting Caching directory
File cacheDirectory = getBaseContext().getCacheDir();
// Temporary file to store the downloaded image
File tmpFile = new File(cacheDirectory.getPath() + "/wpta_"+position+".png");
// The FileOutputStream to the temporary file
FileOutputStream fOutStream = new FileOutputStream(tmpFile);
// Creating a bitmap from the downloaded inputstream
Bitmap b = BitmapFactory.decodeStream(iStream);
// Writing the bitmap to the temporary file as png file
b.compress(Bitmap.CompressFormat.PNG,100, fOutStream);
// Flush the FileOutputStream
fOutStream.flush();
//Close the FileOutputStream
fOutStream.close();
// Create a hashmap object to store image path and its position in the listview
HashMap<String, Object> hmBitmap = new HashMap<String, Object>();
// Storing the path to the temporary image file
hmBitmap.put("flag",tmpFile.getPath());
// Storing the position of the image in the listview
hmBitmap.put("position",position);
// Returning the HashMap object containing the image path and position
return hmBitmap;
}catch (Exception e) {
e.printStackTrace();
}
return null;
}
#Override
protected void onPostExecute(HashMap<String, Object> result) {
// Getting the path to the downloaded image
String path = (String) result.get("flag");
// Getting the position of the downloaded image
int position = (Integer) result.get("position");
// Getting adapter of the listview
SimpleAdapter adapter = (SimpleAdapter ) mListView.getAdapter();
// Getting the hashmap object at the specified position of the listview
HashMap<String, Object> hm = (HashMap<String, Object>) adapter.getItem(position);
// Overwriting the existing path in the adapter
hm.put("flag",path);
// Noticing listview about the dataset changes
adapter.notifyDataSetChanged();
mListView.setOnItemClickListener(new OnItemClickListener() {
#Override
public void onItemClick(AdapterView<?> arg0, View arg1,
int arg2, long arg3) {
Activity view = null;
// TODO Auto-generated method stub
// getting values from selected ListItem
String type = ((TextView) view.findViewById(R.id.tv_country_details)).getText().toString();
// Starting new intent
Intent in = new Intent(getApplicationContext(), SingleMenuItemActivity.class);
in.putExtra(type, type);
startActivity(in);
}
});
}
}
#Override
public boolean onCreateOptionsMenu(Menu menu) {
getMenuInflater().inflate(R.menu.main, menu);
return true;
}
}
SingleMenuItemActivity code
public class SingleMenuItemActivity extends Activity {
// JSON node keys
private static final String TAG_details = "details";
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.single_list_item);
// getting intent data
Intent in = getIntent();
// Get JSON values from previous intent
String cost = in.getStringExtra(TAG_details);
// Displaying all values on the screen
TextView lblCost = (TextView) findViewById(R.id.tv_country_details);
lblCost.setText(cost);
}
}
Json Parser Code
public class CountryJSONParser {
// Receives a JSONObject and returns a list
public List<HashMap<String,Object>> parse(JSONObject jObject){
JSONArray jCountries = null;
try {
// Retrieves all the elements in the 'countries' array
jCountries = jObject.getJSONArray("countries");
} catch (JSONException e) {
e.printStackTrace();
}
// Invoking getCountries with the array of json object
// where each json object represent a country
return getCountries(jCountries);
}
private List<HashMap<String, Object>> getCountries(JSONArray jCountries){
int countryCount = jCountries.length();
List<HashMap<String, Object>> countryList = new ArrayList<HashMap<String,Object>>();
HashMap<String, Object> country = null;
// Taking each country, parses and adds to list object
for(int i=0; i<countryCount;i++){
try {
// Call getCountry with country JSON object to parse the country
country = getCountry((JSONObject)jCountries.get(i));
countryList.add(country);
} catch (JSONException e) {
e.printStackTrace();
}
}
return countryList;
}
// Parsing the Country JSON object
private HashMap<String, Object> getCountry(JSONObject jCountry){
HashMap<String, Object> country = new HashMap<String, Object>();
String flag="";
String currencyName = "";
try {
flag = jCountry.getString("flag");
currencyName = jCountry.getJSONObject("currency").getString("currencyname");
String details = currencyName ;
country.put("flag", R.drawable.blank);
country.put("flag_path", flag);
country.put("details", details);
} catch (JSONException e) {
e.printStackTrace();
}
return country;
}
public static Object optJSONObject(int arg2) {
// TODO Auto-generated method stub
return null;
}
public static boolean isNull(int arg2) {
// TODO Auto-generated method stub
return false;
}
}
Add these code into your dewnloadurl method.
String jsonString = null;
HttpURLConnection linkConnection = null;
try{
URL linkur1 = new URL(url);
linkConnection = (HttpURLConnection) linkur1.openConnection();
int responseCode = linkConnection.getResponseCode();
if(responseCode == HttpURLConnection.HTTP_OK){
InputStream linkingStream = linkConnection.getInputStream();
ByteArrayOutputStream baos = new ByteArrayOutputStream();
int j = 0;
while ((j = linkingStream.read()) != -1) {
baos.write(j);
}
byte[] data = baos.toByteArray();
jsonString = new String(data);
}
}catch(Exception e){
e.printStackTrace();
}finally{
if(linkConnection != null){
linkConnection.disconnect();
}
}
return jsonString;
Than Use it to get single item
public void onItemClick(AdapterView<?> arg0, View arg1, int position,
long id) {
View item = arg0.getChildAt(position);
}
I got all the data ... But I am not able to use webview url(UrlWeb) , i mean when i click on list item then it will open in web view. when i click any list it should pass corresponding url to the WebView activity.So how to achieve this, how to store corresponding url?? please someone help me..
My MainActivity :
public class MainActivity extends Activity {
ListView mListView;
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
// URL to the JSON data
String strUrl = "http://www.mulnivasisangh.com/aman/listweb.json";
// Creating a new non-ui thread task to download json data
DownloadTask downloadTask = new DownloadTask();
// Starting the download process
downloadTask.execute(strUrl);
// Getting a reference to ListView of activity_main
mListView = (ListView) findViewById(R.id.lv_countries);
}
/** 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;
}
/** AsyncTask to download json data */
private class DownloadTask extends AsyncTask<String, Integer, String>{
String data = null;
#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) {
// The parsing of the xml data is done in a non-ui thread
ListViewLoaderTask listViewLoaderTask = new ListViewLoaderTask();
// Start parsing xml data
listViewLoaderTask.execute(result);
}
}
/** AsyncTask to parse json data and load ListView */
private class ListViewLoaderTask extends AsyncTask<String, Void, SimpleAdapter>{
JSONObject jObject;
// Doing the parsing of xml data in a non-ui thread
#Override
protected SimpleAdapter doInBackground(String... strJson) {
try{
jObject = new JSONObject(strJson[0]);
CountryJSONParser countryJsonParser = new CountryJSONParser();
countryJsonParser.parse(jObject);
}catch(Exception e){
Log.d("JSON Exception1",e.toString());
}
// Instantiating json parser class
CountryJSONParser countryJsonParser = new CountryJSONParser();
// A list object to store the parsed countries list
List<HashMap<String, Object>> countries = null;
try{
// Getting the parsed data as a List construct
countries = countryJsonParser.parse(jObject);
}catch(Exception e){
Log.d("Exception",e.toString());
}
// Keys used in Hashmap
String[] from = { "country","flag","details", "URL"};
// Ids of views in listview_layout
int[] to = { R.id.tv_country,R.id.iv_flag,R.id.tv_country_details,R.id.tv_URL};
// Instantiating an adapter to store each items
// R.layout.listview_layout defines the layout of each item
SimpleAdapter adapter = new SimpleAdapter(getBaseContext(), countries, R.layout.lv_layout, from, to);
return adapter;
}
/** Invoked by the Android on "doInBackground" is executed */
protected void onPostExecute(SimpleAdapter adapter) {
// Setting adapter for the listview
mListView.setAdapter(adapter);
for(int i=0;i<adapter.getCount();i++){
HashMap<String, Object> hm = (HashMap<String, Object>) adapter.getItem(i);
String imgUrl = (String) hm.get("flag_path");
ImageLoaderTask imageLoaderTask = new ImageLoaderTask();
HashMap<String, Object> hmDownload = new HashMap<String, Object>();
hm.put("flag_path",imgUrl);
hm.put("position", i);
// Starting ImageLoaderTask to download and populate image in the listview
imageLoaderTask.execute(hm);
}
mListView.setOnItemClickListener(new OnItemClickListener() {
#Override
public void onItemClick(AdapterView<?> arg0, View view, int arg2,
long arg3) {
// TODO Auto-generated method stub
String URL = ((TextView) view.findViewById(R.id.tv_URL)).getText().toString();//this will take the value of the invincible textView
Intent i = new Intent(MainActivity.this, WebViewActivity.class);
i.putExtra("URL", URL);
startActivity(i);
}
});
}
}
/** AsyncTask to download and load an image in ListView */
private class ImageLoaderTask extends AsyncTask<HashMap<String, Object>, Void, HashMap<String, Object>>{
#Override
protected HashMap<String, Object> doInBackground(HashMap<String, Object>... hm) {
InputStream iStream=null;
String imgUrl = (String) hm[0].get("flag_path");
int position = (Integer) hm[0].get("position");
URL url;
try {
url = new URL(imgUrl);
// 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();
// Getting Caching directory
File cacheDirectory = getBaseContext().getCacheDir();
// Temporary file to store the downloaded image
File tmpFile = new File(cacheDirectory.getPath() + "/wpta_"+position+".png");
// The FileOutputStream to the temporary file
FileOutputStream fOutStream = new FileOutputStream(tmpFile);
// Creating a bitmap from the downloaded inputstream
Bitmap b = BitmapFactory.decodeStream(iStream);
// Writing the bitmap to the temporary file as png file
b.compress(Bitmap.CompressFormat.PNG,100, fOutStream);
// Flush the FileOutputStream
fOutStream.flush();
//Close the FileOutputStream
fOutStream.close();
// Create a hashmap object to store image path and its position in the listview
HashMap<String, Object> hmBitmap = new HashMap<String, Object>();
// Storing the path to the temporary image file
hmBitmap.put("flag",tmpFile.getPath());
// Storing the position of the image in the listview
hmBitmap.put("position",position);
// Returning the HashMap object containing the image path and position
return hmBitmap;
}catch (Exception e) {
e.printStackTrace();
}
return null;
}
#Override
protected void onPostExecute(HashMap<String, Object> result) {
// Getting the path to the downloaded image
String path = (String) result.get("flag");
// Getting the position of the downloaded image
int position = (Integer) result.get("position");
// Getting adapter of the listview
SimpleAdapter adapter = (SimpleAdapter ) mListView.getAdapter();
// Getting the hashmap object at the specified position of the listview
HashMap<String, Object> hm = (HashMap<String, Object>) adapter.getItem(position);
// Overwriting the existing path in the adapter
hm.put("flag",path);
// Noticing listview about the dataset changes
adapter.notifyDataSetChanged();
}
}
#Override
public boolean onCreateOptionsMenu(Menu menu) {
getMenuInflater().inflate(R.menu.activity_main, menu);
return true;
}
}
My CountryJSONParser :
public class CountryJSONParser {
// Receives a JSONObject and returns a list
public List<HashMap<String,Object>> parse(JSONObject jObject){
JSONArray jCountries = null;
try {
// Retrieves all the elements in the 'countries' array
jCountries = jObject.getJSONArray("webs");
} catch (JSONException e) {
e.printStackTrace();
}
// Invoking getCountries with the array of json object
// where each json object represent a country
return getCountries(jCountries);
}
private List<HashMap<String, Object>> getCountries(JSONArray jCountries){
int countryCount = jCountries.length();
List<HashMap<String, Object>> countryList = new ArrayList<HashMap<String,Object>>();
HashMap<String, Object> country = null;
// Taking each country, parses and adds to list object
for(int i=0; i<countryCount;i++){
try {
// Call getCountry with country JSON object to parse the country
country = getCountry((JSONObject)jCountries.get(i));
countryList.add(country);
} catch (JSONException e) {
e.printStackTrace();
}
}
return countryList;
}
// Parsing the Country JSON object
private HashMap<String, Object> getCountry(JSONObject jCountry){
HashMap<String, Object> country = new HashMap<String, Object>();
String countryName = "";
String flag="";
String language = "";
String capital = "";
String web ="";
try {
countryName = jCountry.getString("Nom");
flag = jCountry.getString("UrlImatge");
language = jCountry.getString("Descripcio");
capital = jCountry.getString("Id");
web = jCountry.getString("UrlWeb");
String details = "Descripcio : " + language + "\n" +
"Id : " + capital + "\n" + "URL: " + web + "\n";
country.put("country", countryName);
country.put("UrlImatge", R.drawable.blank);
country.put("flag_path", flag);
country.put("details", details);
country.put("URL", web);
} catch (JSONException e) {
e.printStackTrace();
}
return country;
}
}
Thanks in advance..
I use this trick when I want to pass data from listview to another activity.
1- I add a textView to my item-list.xml which is R.layout.lv_layout in your case and make its visibility gone. android:visibility="gone"
2- add the URL String to this textView, it wont be shown in the listview, because it has no visibility.
String[] from = { "country","flag","details", "URL"};
// Ids of views in listview_layout
int[] to = { R.id.tv_country,R.id.iv_flag,R.id.tv_country_details, R.id.tv_country_URL};//the forth one is the textView you set it as gone.
3- in OnItemClick function just add the following:
String URL = ((TextView) view.findViewById(R.id.tv_country_URL)).getText().toString();//this will take the value of the invincible textView
Intent i = new Intent(MainActivity.this, WebView.class);
i.putExtra("URL", URL);
startActivity(i);
4- use getIntent in your webView Activity to get the URL and load it.
if it is still vague please inform me. hope you got the idea.
Edit
you dont need getURL function anymore, I thought getCountries doesnt return a hashMap for URL.
so all you have to do is create a invisible textView in your lv_layout and put each URL in it.
follow the 4 steps above.
for step 3 in Post:
protected void onPostExecute(SimpleAdapter adapter) {
// Setting adapter for the listview
mListView.setAdapter(adapter);
for(int i=0;i<adapter.getCount();i++){
HashMap<String, Object> hm = (HashMap<String, Object>) adapter.getItem(i);
String imgUrl = (String) hm.get("flag_path");
ImageLoaderTask imageLoaderTask = new ImageLoaderTask();
HashMap<String, Object> hmDownload = new HashMap<String, Object>();
hm.put("flag_path",imgUrl);
hm.put("position", i);
// Starting ImageLoaderTask to download and populate image in the listview
imageLoaderTask.execute(hm);
}
mListView.setOnItemClickListener(new OnItemClickListener() {
#Override
public void onItemClick(AdapterView<?> arg0, View view, int arg2,
long arg3) {
// TODO Auto-generated method stub
String URL = ((TextView) view.findViewById(R.id.tv_URL)).getText().toString();//this will take the value of the invincible textView
Intent i = new Intent(MainActivity.this, WebView.class);
i.putExtra("URL", URL);
startActivity(i);
}
Edit
for webViewActivity you need to get extra from the previous activity as the following:
public class WebViewActivity extends Activity{
private WebView webView;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.web_view);
webView = (WebView) findViewById(R.id.webview);
webView.setWebViewClient(new MyWebViewClient());
String url = getIntent().getExtras().getString("URL")
if (null != url) {
webView.getSettings().setJavaScriptEnabled(true);
webView.loadUrl(url);
}
}
private class MyWebViewClient extends WebViewClient {
#Override
public boolean shouldOverrideUrlLoading(WebView view, String url) {
view.loadUrl(url);
return true;
}
}
}
public class TopMovie extends Activity
{
GridView lv;
Vibrator vibrator;
private Object params;
public static String movie_Id;
#Override
protected void onCreate(Bundle savedInstanceState) {
// TODO Auto-generated method stub
super.onCreate(savedInstanceState);
Log.i("Category", MainActivity.movie_Category);
setContentView(R.layout.new_movie);
LayoutInflater inflater = getLayoutInflater();
View view = inflater.inflate(R.layout.customtoast,
(ViewGroup) findViewById(R.id.custom_toast_layout));
Toast toast = new Toast(getApplicationContext());
toast.setDuration(Toast.LENGTH_LONG);
toast.setGravity(Gravity.CENTER_HORIZONTAL, 0, 0);
toast.setView(view);
toast.show();
vibrator = (Vibrator) getSystemService(Context.VIBRATOR_SERVICE);
lv = (GridView) findViewById(R.id.grid_view);
// URL to the JSON data
String strUrl = "http://vaibhavtech.com/work/android/movie_list.php?category="
+ MainActivity.movie_Category + "&sub_category=other";
DownloadTask downloadTask = new DownloadTask();
downloadTask.execute(strUrl);
lv.setOnItemClickListener(new OnItemClickListener() {
#Override
public void onItemClick(AdapterView<?> arg0, View arg1, int arg2,
long arg3) {
// // TODO Auto-generated method stub
vibrator.vibrate(40);
LayoutInflater inflater = getLayoutInflater();
View view = inflater.inflate(R.layout.customtoast,
(ViewGroup) findViewById(R.id.custom_toast_layout));
Toast toast = new Toast(getApplicationContext());
toast.setDuration(Toast.LENGTH_LONG);
toast.setGravity(Gravity.CENTER_HORIZONTAL, 0, 0);
toast.setView(view);
toast.show();
MainActivity.movie_Id = ((TextView) arg1
.findViewById(R.id.tv_girdview_content_id)).getText()
.toString();
Log.i("Name is", MainActivity.movie_Id);
startActivity(new Intent(TopMovie.this, MovieDescription.class));
}
});
}
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;
}
/** AsyncTask to download json data */
private class DownloadTask extends AsyncTask<String, Integer, String> {
String data = null;
#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) {
// The parsing of the xml data is done in a non-ui thread
ListViewLoaderTask listViewLoaderTask = new ListViewLoaderTask();
// Start parsing xml data
listViewLoaderTask.execute(result);
}
}
/** AsyncTask to parse json data and load ListView */
private class ListViewLoaderTask extends
AsyncTask<String, Void, SimpleAdapter> {
JSONObject jObject;
// Doing the parsing of xml data in a non-ui thread
#Override
protected SimpleAdapter doInBackground(String... strJson) {
try {
jObject = new JSONObject(strJson[0]);
MovieParser countryJsonParser = new MovieParser();
countryJsonParser.parse(jObject);
} catch (Exception e) {
Log.d("JSON Exception1", e.toString());
}
// Instantiating json parser class
MovieParser countryJsonParser = new MovieParser();
// A list object to store the parsed countries list
List<HashMap<String, Object>> countries = null;
try {
// Getting the parsed data as a List construct
countries = countryJsonParser.parse(jObject);
} catch (Exception e) {
Log.d("Exception", e.toString());
}
// Keys used in Hashmap
String[] from = { "image", "id", "year", "duration", "name" };
// Ids of views in listview_layout
// int[] to = {
// R.id.iv_radio_data_image,R.id.tv_radio_data_id,R.id.tv_radio_data_like,R.id.tv_radio_data_rating,R.id.tv_radio_data_listner,R.id.tv_radio_data_radio_url,R.id.tv_radio_data_name};
int[] to = { R.id.iv_girdview_content_image,
R.id.tv_girdview_content_id, R.id.tv_girdview_content_like,
R.id.tv_girdview_content_listner,
R.id.tv_girdview_content_name };
SimpleAdapter adapter = new SimpleAdapter(getBaseContext(),
countries, R.layout.grid_view_content, from, to);
return adapter;
}
/** Invoked by the Android on "doInBackground" is executed */
#Override
protected void onPostExecute(SimpleAdapter adapter) {
// Setting adapter for the listview
lv.setAdapter(adapter);
for (int i = 0; i < adapter.getCount(); i++) {
HashMap<String, Object> hm = (HashMap<String, Object>) adapter
.getItem(i);
String imgUrl = (String) hm.get("flag_path");
ImageLoaderTask imageLoaderTask = new ImageLoaderTask();
HashMap<String, Object> hmDownload = new HashMap<String, Object>();
hm.put("flag_path", imgUrl);
hm.put("position", i);
// Starting ImageLoaderTask to download and populate image in
// the listview
imageLoaderTask.execute(hm);
}
}
}
/** AsyncTask to download and load an image in ListView */
private class ImageLoaderTask extends
AsyncTask<HashMap<String, Object>, Void, HashMap<String, Object>> {
#Override
protected HashMap<String, Object> doInBackground(
HashMap<String, Object>... hm) {
InputStream iStream = null;
String imgUrl = (String) hm[0].get("flag_path");
int position = (Integer) hm[0].get("position");
URL url;
try {
url = new URL(imgUrl);
// 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();
// Getting Caching directory
File cacheDirectory = getBaseContext().getCacheDir();
// Temporary file to store the downloaded image
File tmpFile = new File(cacheDirectory.getPath() + "/wpta_"
+ position + ".png");
// The FileOutputStream to the temporary file
FileOutputStream fOutStream = new FileOutputStream(tmpFile);
// Creating a bitmap from the downloaded inputstream
Bitmap b = BitmapFactory.decodeStream(iStream);
// Writing the bitmap to the temporary file as png file
b.compress(Bitmap.CompressFormat.PNG, 100, fOutStream);
// Flush the FileOutputStream
fOutStream.flush();
// Close the FileOutputStream
fOutStream.close();
// Create a hashmap object to store image path and its position
// in the listview
HashMap<String, Object> hmBitmap = new HashMap<String, Object>();
// Storing the path to the temporary image file
hmBitmap.put("image", tmpFile.getPath());
// Storing the position of the image in the listview
hmBitmap.put("position", position);
// Returning the HashMap object containing the image path and
// position
return hmBitmap;
} catch (Exception e) {
e.printStackTrace();
}
return null;
}
#Override
protected void onPostExecute(HashMap<String, Object> result) {
// Getting the path to the downloaded image
String path = (String) result.get("image");
// Getting the position of the downloaded image
int position = (Integer) result.get("position");
// Getting adapter of the listview
SimpleAdapter adapter = (SimpleAdapter) lv.getAdapter();
// Getting the hashmap object at the specified position of the
// listview
HashMap<String, Object> hm = (HashMap<String, Object>) adapter
.getItem(position);
// Overwriting the existing path in the adapter
hm.put("image", path);
adapter.notifyDataSetChanged();
}
}
}
My application is debugging but not running.RejectedExecutionException: Task android.os.AsyncTas rejected from java.util.concurrent.
Submitting tasks to a thread-pool gives RejectedExecutionException
how to resolve threadpool exception in gridview android
You can change the executor the asynctask uses if you extend the asynctask class.
Check this example from docs where they download multiple images and use a custom asynctask to control the concurrency.
I had the same problem you are having and used that project to fix it.
public class NewMovie extends Activity {
GridView lv;
Vibrator vibrator;
SimpleAdapter adapter;
Button b;
#Override
protected void onCreate(Bundle savedInstanceState) {
// TODO Auto-generated method stub
super.onCreate(savedInstanceState);
Log.i("Category", MainActivity.movie_Category);
setContentView(R.layout.new_movie);
vibrator = (Vibrator) getSystemService(Context.VIBRATOR_SERVICE);
lv = (GridView) findViewById(R.id.grid_view);
// URL to the JSON data
String strUrl = "http://vaibhavtech.com/work/android/movie_list.php?category="
+ MainActivity.movie_Category + "&sub_category=new";
// Creating a new non-ui thread task to download json data
DownloadTask downloadTask = new DownloadTask();
// Starting the download processt
downloadTask.execute(strUrl);
// Getting a reference to ListView of activity_main
lv.setOnItemClickListener(new OnItemClickListener() {
#Override
public void onItemClick(AdapterView<?> arg0, View arg1, int arg2,
long arg3) {
// // TODO Auto-generated method stub
vibrator.vibrate(40);
LayoutInflater inflater = getLayoutInflater();
View view = inflater.inflate(R.layout.customtoast,
(ViewGroup) findViewById(R.id.custom_toast_layout));
Toast toast = new Toast(getApplicationContext());
toast.setDuration(Toast.LENGTH_LONG);
toast.setGravity(Gravity.CENTER_HORIZONTAL, 0, 0);
toast.setView(view);
toast.show();
MainActivity.movie_Id = ((TextView) arg1
.findViewById(R.id.tv_girdview_content_id)).getText()
.toString();
Log.i("Name is", MainActivity.movie_Id);
startActivity(new Intent(NewMovie.this, MovieDescription.class));
}
});
}
/** 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;
}
/** AsyncTask to download json data */
private class DownloadTask extends AsyncTask<String, Integer, String> {
String data = null;
#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) {
// The parsing of the xml data is done in a non-ui thread
ListViewLoaderTask listViewLoaderTask = new ListViewLoaderTask();
// Start parsing xml data
listViewLoaderTask.execute(result);
}
}
/** AsyncTask to parse json data and load ListView */
private class ListViewLoaderTask extends
AsyncTask<String, Void, SimpleAdapter> {
JSONObject jObject;
// Doing the parsing of xml data in a non-ui thread
#Override
protected SimpleAdapter doInBackground(String... strJson) {
try {
jObject = new JSONObject(strJson[0]);
MovieParser countryJsonParser = new MovieParser();
countryJsonParser.parse(jObject);
} catch (Exception e) {
Log.d("JSON Exception1", e.toString());
}
// Instantiating json parser class
MovieParser countryJsonParser = new MovieParser();
// A list object to store the parsed countries list
List<HashMap<String, Object>> countries = null;
try {
// Getting the parsed data as a List construct
countries = countryJsonParser.parse(jObject);
} catch (Exception e) {
Log.d("Exception", e.toString());
}
// Keys used in Hashmap
String[] from = { "image", "id", "year", "duration", "name" };
// Ids of views in listview_layout
// int[] to = {
// R.id.iv_radio_data_image,R.id.tv_radio_data_id,R.id.tv_radio_data_like,R.id.tv_radio_data_rating,R.id.tv_radio_data_listner,R.id.tv_radio_data_radio_url,R.id.tv_radio_data_name};
int[] to = { R.id.iv_girdview_content_image,
R.id.tv_girdview_content_id, R.id.tv_girdview_content_like,
R.id.tv_girdview_content_listner,
R.id.tv_girdview_content_name };
// Instantiating an adapter to store each items
// R.layout.listview_layout defines the layout of each item
adapter = new SimpleAdapter(getBaseContext(), countries,
R.layout.grid_view_content, from, to);
return adapter;
// lv.setAdapter(new ListAdapter(getApplicationContext()));
}
/** Invoked by the Android on "doInBackground" is executed */
#Override
protected void onPostExecute(SimpleAdapter adapter) {
// Setting adapter for the listview
lv.setAdapter(adapter);
for (int i = 0; i < adapter.getCount(); i++) {
HashMap<String, Object> hm = (HashMap<String, Object>) adapter
.getItem(i);
String imgUrl = (String) hm.get("flag_path");
ImageLoaderTask imageLoaderTask = new ImageLoaderTask();
HashMap<String, Object> hmDownload = new HashMap<String, Object>();
hm.put("flag_path", imgUrl);
hm.put("position", i);
// Starting ImageLoaderTask to download and populate image in
// the listview
imageLoaderTask.execute(hm);
}
// }
}
/** AsyncTask to download and load an image in ListView */
private class ImageLoaderTask
extends
AsyncTask<HashMap<String, Object>, Void, HashMap<String, Object>> {
#Override
protected HashMap<String, Object> doInBackground(
HashMap<String, Object>... hm) {
InputStream iStream = null;
String imgUrl = (String) hm[0].get("flag_path");
int position = (Integer) hm[0].get("position");
URL url;
try {
url = new URL(imgUrl);
// 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();
// Getting Caching directory
File cacheDirectory = getBaseContext().getCacheDir();
// Temporary file to store the downloaded image
File tmpFile = new File(cacheDirectory.getPath() + "/wpta_"
+ position + ".png");
// The FileOutputStream to the temporary file
FileOutputStream fOutStream = new FileOutputStream(tmpFile);
// Creating a bitmap from the downloaded inputstream
Bitmap b = BitmapFactory.decodeStream(iStream);
// Writing the bitmap to the temporary file as png file
b.compress(Bitmap.CompressFormat.PNG, 100, fOutStream);
// Flush the FileOutputStream
fOutStream.flush();
// Close the FileOutputStream
fOutStream.close();
// Create a hashmap object to store image path and its
// position in the listview
HashMap<String, Object> hmBitmap = new HashMap<String, Object>();
// Storing the path to the temporary image file
hmBitmap.put("image", tmpFile.getPath());
// Storing the position of the image in the listview
hmBitmap.put("position", position);
// Returning the HashMap object containing the image path
// and position
return hmBitmap;
} catch (Exception e) {
e.printStackTrace();
}
return null;
}
#Override
protected void onPostExecute(HashMap<String, Object> result) {
// Getting the path to the downloaded image
String path = (String) result.get("image");
// Getting the position of the downloaded image
int position = (Integer) result.get("position");
// Getting adapter of the listview
adapter = (SimpleAdapter) lv.getAdapter();
// Getting the hashmap object at the specified position of the
// listview
HashMap<String, Object> hm = (HashMap<String, Object>) adapter
.getItem(position);
// Overwriting the existing path in the adapter
hm.put("image", path);
// lv.invalidateViews();
adapter.notifyDataSetChanged();
}
}
}
---------*********************-------------------------------------------
PLZ help i found this ans from loag time i want loading more image from server when scrolling like facebook app style. above my code plz help me.
Benji helped me here.
public class EndlessScrollListener implements OnScrollListener {
private int visibleThreshold = 5;
private int currentPage = 0;
private int previousTotal = 0;
private boolean loading = true;
public EndlessScrollListener() {
}
public EndlessScrollListener(int visibleThreshold) {
this.visibleThreshold = visibleThreshold;
}
#Override
public void onScroll(AbsListView view, int firstVisibleItem,
int visibleItemCount, int totalItemCount) {
if (loading) {
if (totalItemCount > previousTotal) {
loading = false;
previousTotal = totalItemCount;
currentPage++;
}
}
if (!loading && (totalItemCount - visibleItemCount) <= (firstVisibleItem + visibleThreshold)) {
// I load the next page of gigs using a background task,
// but you can call any function here.
new LoadGigsTask().execute(currentPage + 1);
loading = true;
}
}
#Override
public void onScrollStateChanged(AbsListView view, int scrollState) {
}
}
Check this out
I've made gridview application that get path of image from json. it work find but when it load it's so slow. and i try to find solution and they recommended me to use ViewHolder but I don't know how to use in my gridview application.
How can I use ViewHolder in my application? how I speed up my application?
This code work find but it load so slow.
public class MainActivity extends Activity {
String strUrl = "http://192.168.10.104/adchara1/";
GridView gridView;
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
// Creating a new non-ui thread task to download json data
DownloadTask downloadTask = new DownloadTask();
// Starting the download process
downloadTask.execute(strUrl);
gridView = (GridView) findViewById(R.id.lv_countries);
gridView.setOnItemClickListener(new OnItemClickListener() {
public void onItemClick(AdapterView<?> parent, View v, int positon,
long id) {
HashMap<String, Object> hm = (HashMap<String, Object>) gridView.getAdapter().getItem(positon);
String imgPath = (String) hm.get("photo"); //get downloaded image path
Intent i = new Intent(MainActivity.this, DisplayActivity.class); //start new Intent to another Activity.
i.putExtra("ClickedImagePath", imgPath ); //put image link in intent.
startActivity(i);
}
});
}
/** A method to download json data from url */
private String downloadUrl(String strUrl) throws IOException{
String data = "";
InputStream iStream = null;
HttpClient httpClient = new DefaultHttpClient();
HttpPost httpPost = new HttpPost(strUrl);
ArrayList<NameValuePair> param = new ArrayList<NameValuePair>();
try {
httpPost.setEntity(new UrlEncodedFormEntity(param));
HttpResponse httpResponse = httpClient.execute(httpPost);
HttpEntity httpEntity = httpResponse.getEntity();
iStream = httpEntity.getContent();
} catch (Exception e) {
Log.e("log_tag", "Error in http connection " + e.toString());
}
try {
BufferedReader br = new BufferedReader(new InputStreamReader(iStream));
StringBuilder sb = new StringBuilder();
String line = "";
while((line = br.readLine()) != null){
sb.append(line + "\n");
}
iStream.close();
data = sb.toString();
} catch (Exception e) {
Log.e("log_tag", "Error converting result " + e.toString());
}
return data;
}
/** AsyncTask to download json data */
private class DownloadTask extends AsyncTask<String, Integer, String>{
String data = null;
#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) {
// The parsing of the xml data is done in a non-ui thread
GridViewLoaderTask gridViewLoaderTask = new GridViewLoaderTask();
// Start parsing xml data
gridViewLoaderTask.execute(result);
}
}
/** AsyncTask to parse json data and load ListView */
private class GridViewLoaderTask extends AsyncTask<String, Void, SimpleAdapter>{
JSONObject jObject;
// Doing the parsing of xml data in a non-ui thread
#Override
protected SimpleAdapter doInBackground(String... strJson) {
try{
jObject = new JSONObject(strJson[0]);
CountryJSONParser countryJsonParser = new CountryJSONParser();
countryJsonParser.parse(jObject);
}catch(Exception e){
Log.d("JSON Exception1",e.toString());
}
// Instantiating json parser class
CountryJSONParser countryJsonParser = new CountryJSONParser();
// A list object to store the parsed countries list
List<HashMap<String, Object>> countries = null;
try{
// Getting the parsed data as a List construct
countries = countryJsonParser.parse(jObject);
}catch(Exception e){
Log.d("Exception",e.toString());
}
// Keys used in Hashmap
String[] from = { "frame","photo"};
// Ids of views in listview_layout
int[] to = { R.id.iv_frame,R.id.iv_photo};
// Instantiating an adapter to store each items
// R.layout.listview_layout defines the layout of each item
SimpleAdapter adapter = new SimpleAdapter(getBaseContext(), countries, R.layout.lv_layout, from, to);
return adapter;
}
/** Invoked by the Android on "doInBackground" is executed */
#Override
protected void onPostExecute(SimpleAdapter adapter) {
// Setting adapter for the listview
gridView.setAdapter(adapter);
for(int i=0;i<adapter.getCount();i++){
HashMap<String, Object> hm = (HashMap<String, Object>) adapter.getItem(i);
String frameUrl = (String) hm.get("frame_path");
String imgUrl = (String) hm.get("photo_path");
ImageLoaderTask imageLoaderTask = new ImageLoaderTask();
HashMap<String, Object> hmDownload = new HashMap<String, Object>();
hm.put("frame_path", frameUrl);
hm.put("photo_path",imgUrl);
hm.put("position", i);
// Starting ImageLoaderTask to download and populate image in the listview
imageLoaderTask.execute(hm);
}
}
}
/** AsyncTask to download and load an image in ListView */
private class ImageLoaderTask extends AsyncTask<HashMap<String, Object>, Void, HashMap<String, Object>>{
#Override
protected HashMap<String, Object> doInBackground(HashMap<String, Object>... hm) {
InputStream iStream = null;
String imgUrl;
String frameUrl;
imgUrl = (String) hm[0].get("photo_path");
frameUrl = (String) hm[0].get("frame_path");
int position = (Integer) hm[0].get("position");
URL url;
URL urlFrame;
try {
url = new URL(imgUrl);
urlFrame = new URL(frameUrl);
// 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();
// Getting Caching directory
File cacheDirectory = getBaseContext().getCacheDir();
// Temporary file to store the downloaded image
File tmpFile = new File(cacheDirectory.getPath() + "/wpta_"+ position + ".png");
// The FileOutputStream to the temporary file
FileOutputStream fOutStream = new FileOutputStream(tmpFile);
// Creating a bitmap from the downloaded inputstream
Bitmap b = BitmapFactory.decodeStream(iStream);
// Writing the bitmap to the temporary file as png file
b.compress(Bitmap.CompressFormat.PNG, 100, fOutStream);
// Flush the FileOutputStream
fOutStream.flush();
// Close the FileOutputStream
fOutStream.close();
// Create a hashmap object to store image path and its position in the listview
HashMap<String, Object> hmBitmap = new HashMap<String, Object>();
// Storing the path to the temporary image file
hmBitmap.put("photo", tmpFile.getPath());
hmBitmap.put("frame", tmpFile.getPath());
// Storing the position of the image in the listview
hmBitmap.put("position", position);
// Returning the HashMap object containing the image path and position
return hmBitmap;
} catch (MalformedURLException e) {
return null;
} catch (FileNotFoundException e) {
return null;
} catch (IOException e) {
return null;
}
}
#Override
protected void onPostExecute(HashMap<String, Object> result) {
// Getting the path to the downloaded image
String path = (String) result.get("photo");
String framePath = (String) result.get("frame");
// Getting the position of the downloaded image
int position = (Integer) result.get("position");
// Getting adapter of the listview
SimpleAdapter adapter = (SimpleAdapter ) gridView.getAdapter();
// Getting the hashmap object at the specified position of the listview
HashMap<String, Object> hm = (HashMap<String, Object>) adapter.getItem(position);
// Overwriting the existing path in the adapter
hm.put("photo",path);
hm.put("frame", framePath);
// Noticing listview about the dataset changes
adapter.notifyDataSetChanged();
}
}
#Override
public boolean onCreateOptionsMenu(Menu menu) {
getMenuInflater().inflate(R.menu.activity_main, menu);
return true;
}
}
you should read the slide here to improve the performance.it's contain an example of using ViewHolder.
Take a look at our Google Guys at Google I/O 2010 . They had a session hosted by Google Software Engineer in Android Team, talking about ListView and related stuffs, including how to optimize listview-usage with ViewHolder class.
I think you can learn something from that.
Here is the link Google I/O 2010 - ListView Session