Develop Reference

android-amazing-listview, how Can I update the new page load by passing data to the URL

On the auto load, I need to be able to load more items from the URL. Where I am getting my Data via Json.
in my API call class I need to add to this nuber 10 as:
pairs.add(new BasicNameValuePair("limit", "10"));
Whenever the list view finish loading the currently data, then changes the value above and check again.
I though I needed to create a method in PaginationDemoActivity where it check for if more pages, then use intent to pass a new variable to overwrite ("limit", "10")) in the JSONfunctions class
Any advice ? Thanks guys
JSONfunctions
public class JSONfunctions extends Activity{
public static JSONObject getJSONfromURL(String url) {
InputStream is = null;
String result = "";
JSONObject jArray = null;
// Download JSON data from URL
try {
HttpClient httpclient = new DefaultHttpClient();
HttpPost httppost = new HttpPost(url);
//Add URL Encoding by sending post data
List<NameValuePair> pairs = new ArrayList<NameValuePair>();
pairs.add(new BasicNameValuePair("c","getlist"));
pairs.add(new BasicNameValuePair("page","1"));
pairs.add(new BasicNameValuePair("limit", "10"));
UrlEncodedFormEntity entity = new UrlEncodedFormEntity(pairs,HTTP.UTF_8);
httppost.setEntity(entity);
// end Add URL Encoding by sending post data
HttpResponse httpResponse = httpclient.execute(httppost);
HttpEntity httpEntity = httpResponse.getEntity();
is = httpEntity.getContent();
//end test
/*
HttpResponse response = httpclient.execute(httppost);
HttpEntity entity = response.getEntity();
is = entity.getContent();
*/
} catch (Exception e) {
Log.e("log_tag", "Error in http connection " + e.toString());
}
// Convert response to string
try {
BufferedReader reader = new BufferedReader(new InputStreamReader(
is, "iso-8859-1"), 8);
StringBuilder sb = new StringBuilder();
String line = null;
while ((line = reader.readLine()) != null) {
sb.append(line + "\n");
}
is.close();
result = sb.toString();
} catch (Exception e) {
Log.e("log_tag", "Error converting result " + e.toString());
}
try {
jArray = new JSONObject(result);
} catch (JSONException e) {
Log.e("log_tag", "Error parsing data " + e.toString());
}
return jArray;
}
}
Data
public class Data {
static String URL = " my api url";
static String itemsPerPage = "20";
public static final String TAG = Data.class.getSimpleName();
public static List<Pair<String, List<Composer>>> getAllData() {
List<Pair<String, List<Composer>>> res = new ArrayList<Pair<String, List<Composer>>>();
for (int i = 0; i < 4; i++) {
res.add(getOneSection(i));
}
return res;
}
public static List<Composer> getFlattenedData() {
List<HashMap<String, String>> arraylist;
JSONObject jsonobject;
JSONArray jsonarray;
List<Composer> res = new ArrayList<Composer>();
//Pair<String, List<Composer>> mydata;
arraylist = new ArrayList<HashMap<String, String>>();
// Retrieve JSON Objects from the given URL address
jsonobject = JSONfunctions.getJSONfromURL(URL);
Log.e("check", jsonobject.toString());
try {
// Locate the array name in JSON
jsonarray = jsonobject.getJSONArray("data");
for (int i = 0; i < jsonarray.length(); i++) {
HashMap<String, String> map = new HashMap<String, String>();
jsonobject = jsonarray.getJSONObject(i);
// Retrive JSON Objects
map.put("id", jsonobject.getString("id"));
map.put("title", jsonobject.getString("title"));
map.put("s_desc", jsonobject.getString("s_desc"));
map.put("img", jsonobject.getString("img"));
// Set the JSON Objects into the array
arraylist.add(map);
Composer s = new Composer(
jsonobject.getString("title"),
jsonobject.getString("s_desc"),
jsonobject.getString("id"),
jsonobject.getString("img"));
res.add(s);
}
} catch (JSONException e) {
Log.e("Error", e.getMessage());
e.printStackTrace();
}
return res;
}
protected void updateUrlItems()
{
}
public static Pair<Boolean, List<Composer>> getRows(int page) {
List<Composer> flattenedData = getFlattenedData();
if (page == 1) {
return new Pair<Boolean, List<Composer>>(true, flattenedData.subList(0, 5));
} else {
SystemClock.sleep(2000); // simulate loading
return new Pair<Boolean, List<Composer>>(page * 5 < flattenedData.size(),
flattenedData.subList((page - 1) * 5, Math.min(page * 5, flattenedData.size())));
}
}
public static Pair<String, List<Composer>> getOneSection(int index) {
String[] titles = {"", "", "", ""};
Composer[][] composerss = {
{
new Composer("", "", "", ""),
},
};
return new Pair<String, List<Composer>>(titles[index], Arrays.asList(composerss[index]));
}
}
PaginationDemoActivity
public class PaginationDemoActivity extends Activity {
AmazingListView lsComposer;
PaginationComposerAdapter adapter;
ImageLoader imageLoader;
// Flag for current page
static Integer current_page = 10;
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_pagination_demo);
imageLoader = new ImageLoader(this);
lsComposer = (AmazingListView) findViewById(R.id.lsComposer);
lsComposer.setLoadingView(getLayoutInflater().inflate(R.layout.loading_view, null));
lsComposer.setAdapter(adapter = new PaginationComposerAdapter());
adapter.notifyMayHaveMorePages();
}
public void bRefresh_click(View v) {
adapter.reset();
adapter.resetPage();
adapter.notifyMayHaveMorePages();
}
class PaginationComposerAdapter extends AmazingAdapter {
List<Composer> list = Data.getRows(1).second;
private AsyncTask<Integer, Void, Pair<Boolean, List<Composer>>> backgroundTask;
public void reset() {
if (backgroundTask != null) backgroundTask.cancel(false);
list = Data.getRows(1).second;
notifyDataSetChanged();
}
#Override
public int getCount() {
return list.size();
}
#Override
public Composer getItem(int position) {
return list.get(position);
}
#Override
public long getItemId(int position) {
return position;
}
#Override
protected void onNextPageRequested(int page) {
Log.d(TAG, "Got onNextPageRequested page=" + page);
if (backgroundTask != null) {
backgroundTask.cancel(false);
}
backgroundTask = new AsyncTask<Integer, Void, Pair<Boolean, List<Composer>>>() {
#Override
protected Pair<Boolean, List<Composer>> doInBackground(Integer... params) {
int page = params[0];
Log.e("more page", "page: " + page);
return Data.getRows(page);
}
#Override
protected void onPostExecute(Pair<Boolean, List<Composer>> result) {
if (isCancelled()) return;
Log.e("onPostExecute", "result: " + result.first);
list.addAll(result.second);
nextPage();
notifyDataSetChanged();
if (result.first) {
// still have more pages
notifyMayHaveMorePages();
} else {
notifyNoMorePages();
}
};
}.execute(page);
}
#Override
protected void bindSectionHeader(View view, int position, boolean displaySectionHeader) {
}
#Override
public View getAmazingView(int position, View convertView, ViewGroup parent) {
View res = convertView;
if (res == null) res = getLayoutInflater().inflate(R.layout.item_composer, null);
// we don't have headers, so hide it
res.findViewById(R.id.header).setVisibility(View.GONE);
TextView lName = (TextView) res.findViewById(R.id.lName);
TextView lYear = (TextView) res.findViewById(R.id.lYear);
TextView lId = (TextView) res.findViewById(R.id.lId);
// Locate the ImageView in listview_item.xml
ImageView lImg = (ImageView) res.findViewById(R.id.lImg);
Composer composer = getItem(position);
lName.setText(composer.name);
lYear.setText(composer.year);
lId.setText(composer.id);
Log.e("getAmazingView PRINT THE URL 1111111111", "URL: " + composer.img);
// Capture position and set results to the ImageView
// Passes img images URL into ImageLoader.class
imageLoader.DisplayImage(composer.img, lImg);
Log.e("222","333");
//khen
lsComposer.setOnItemClickListener(new OnItemClickListener() {
#Override
public void onItemClick(AdapterView<?> parent, View v, int position, long id) {
// TODO Auto-generated method stub
if(id > -1){
Composer composer = adapter.getItem(position);
Intent intent = new Intent();
intent.setClass(getApplicationContext(), SingleItemView.class);
Bundle bundle = new Bundle();
bundle.putString("id", composer.id);
bundle.putString("name", composer.name);
bundle.putString("year", composer.year);
bundle.putString("img", composer.img);
intent.putExtras(bundle);
startActivity(intent);
}
}
});
//end khen
return res;
}
#Override
public void configurePinnedHeader(View header, int position, int alpha) {
}
#Override
public int getPositionForSection(int section) {
return 0;
}
#Override
public int getSectionForPosition(int position) {
return 0;
}
#Override
public Object[] getSections() {
return null;
}
}
}

Can get information from JSON API

im trying to get some information from a site BayFiles.net using their API.
The call URL is: http://api.bayfiles.net/v1/account/files?session=SESSION-ID
The error i get is:
07-04 13:54:39.525: E/log_tag(588): Error parsing data org.json.JSONException: Value at error of type java.lang.String cannot be converted to JSONArray
The JSON output when correct sessionID is something like this:
{
"error": "",
"S8tf": {
"infoToken": "wCfhXe",
"deleteToken": "gzHTfGcF",
"size": 122484,
"sha1": "8c4e2bbc0794d2bd4f901a36627e555c068a94e6",
"filename": "Screen_Shot_2013-07-02_at_3.52.23_PM.png"
},
"S29N": {
"infoToken": "joRm6p",
"deleteToken": "IL5STLhq",
"size": 129332,
"sha1": "b4a03897121d0320b82059c36f7a10a8ef4c113d",
"filename": "Stockholmsyndromet.docx"
}
}
however i cant get to catch the respons and show it in a listview.
This is my activity:
public class FilesActivity extends SherlockListActivity implements
OnClickListener {
private ProgressDialog mDialog;
ActionBar ABS;
TextView session;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.dblist);
getSupportActionBar().setDisplayHomeAsUpEnabled(true);
getSupportActionBar().setTitle("Files");
JsonAsync asyncTask = new JsonAsync();
// Using an anonymous interface to listen for objects when task
// completes.
asyncTask.setJsonListener(new JsonListener() {
#Override
public void onObjectReturn(JSONObject object) {
handleJsonObject(object);
}
});
// Show progress loader while accessing network, and start async task.
mDialog = ProgressDialog.show(this, getSupportActionBar().getTitle(),
getString(R.string.loading), true);
asyncTask.execute("http://api.bayfiles.net/v1/account/files?session=" + PreferenceManager.getDefaultSharedPreferences(getBaseContext()).getString("sessionID", "defaultStringIfNothingFound"));
//session = (TextView)findViewById(R.id.textView1);
//session.setText(PreferenceManager.getDefaultSharedPreferences(getBaseContext()).getString("sessionID", "defaultStringIfNothingFound"));
}
#Override
public void onClick(View v) {
// TODO Auto-generated method stub
}
private void handleJsonObject(JSONObject object) {
ArrayList<HashMap<String, String>> mylist = new ArrayList<HashMap<String, String>>();
try {
JSONArray shows = object.getJSONArray("error");
for (int i = 0; i < shows.length(); i++) {
HashMap<String, String> map = new HashMap<String, String>();
JSONObject e = shows.getJSONObject(i);
//map.put("video_location", "" + e.getString("video_location"));
mylist.add(map);
}
} catch (JSONException e) {
Log.e("log_tag", "Error parsing data " + e.toString());
}
ListAdapter adapter = new SimpleAdapter(this, mylist, R.layout.dbitems,
new String[] { "video_title", "video_location" }, new int[] { R.id.item_title,
R.id.item_subtitle });
setListAdapter(adapter);
final ListView lv = getListView();
lv.setTextFilterEnabled(true);
lv.setOnItemClickListener(new OnItemClickListener() {
#Override
public void onItemClick(AdapterView<?> parent, View view,
int position, long id) {
#SuppressWarnings("unchecked")
HashMap<String, String> o = (HashMap<String, String>) lv
.getItemAtPosition(position);
//Intent myIntent = new Intent(ListShowsController.this,
// TestVideoController.class);
//myIntent.putExtra("video_title", o.get("video_title"));
//myIntent.putExtra("video_channel", o.get("video_channel"));
//myIntent.putExtra("video_location", o.get("video_location"));
//startActivity(myIntent);
}
});
if (mDialog != null && mDialog.isShowing()) {
mDialog.dismiss();
}
}
}
and my JSONfunctions:
public class JSONfunctions {
public static JSONObject getJSONfromURL(String url){
InputStream is = null;
String result = "";
JSONObject jArray = null;
//http post
try{
HttpClient httpclient = new DefaultHttpClient();
HttpPost httppost = new HttpPost(url);
try {
// Add your data
/*List<NameValuePair> nameValuePairs = new ArrayList<NameValuePair>(2);
nameValuePairs.add(new BasicNameValuePair("key", "stianxxs"));
nameValuePairs.add(new BasicNameValuePair("secret", "mhfgpammv9f94ddayh8GSweji"));
httppost.setEntity(new UrlEncodedFormEntity(nameValuePairs)); */
// Execute HTTP Post Request
HttpResponse response = httpclient.execute(httppost);
//HttpResponse response = httpclient.execute(httppost);
HttpEntity httpEntity = response.getEntity();
is = httpEntity.getContent();
} catch (ClientProtocolException e) {
// TODO Auto-generated catch block
} catch (IOException e) {
// TODO Auto-generated catch block
}
}catch(Exception e){
Log.e("log_tag", "Error in http connection "+e.toString());
}
//convert response to string
try{
BufferedReader reader = new BufferedReader(new InputStreamReader(is,"iso-8859-1"),8);
StringBuilder sb = new StringBuilder();
String line = null;
while ((line = reader.readLine()) != null) {
sb.append(line + "\n");
}
is.close();
result=sb.toString();
}catch(Exception e){
Log.e("log_tag", "Error converting result "+e.toString());
}
try{
jArray = new JSONObject(result);
}catch(JSONException e){
Log.e("log_tag", "Error parsing data "+e.toString());
}
return jArray;
}
}
Any help is much appreciated!

As 'error' is not JSONArray it is giving you parsing error.
JSONArray shows = object.getJSONArray("error");
Change you line to
String shows = object.getString("error");
You can refer to these link for JSON Parsing.
https://stackoverflow.com/a/16938507/1441666

how to maintain scroll position of listview when it updates

I have read plenty of examples ,but if I wish to maintain my scroll position after a ListView is updated from JSON ,then can I do that without using an AsyncTask instance ???
the code for my list is
String wrd;
//ArrayList<HashMap<String,String>> mylist;
#Override
public void onCreate(Bundle savedInstanceState) {
// TODO Auto-generated method stub
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
Intent i2=getIntent();
wrd=i2.getStringExtra("entrd");
Log.v("keyis",wrd);
final Handler handler = new Handler();
Runnable runable = new Runnable() {
#Override
public void run() {
//call the function
LoadData();
//also call the same runnable
handler.postDelayed(this, 40000);
}
};
handler.postDelayed(runable, 10);
}public void LoadData(){
JSONObject j2=JSONfunctions.getJSONfromURL("/webservice_search.php?keyword="+wrd+"&format=json");
ArrayList<HashMap<String,String>> mylist = new ArrayList<HashMap<String,String>>();
try{JSONArray jray=j2.getJSONArray("listings");
for(int i=0;i<jray.length();i++){
Log.v("state","json data being read");
JSONObject j3= jray.getJSONObject(i);
String first=j3.getString("listing");
Log.v("sublist", first);
JSONObject j4=j3.getJSONObject("listing");
String sec=j4.getString("links");
int maxLength = (sec.length() < 30)?sec.length():27;
sec.substring(0, maxLength);
String cutsec=sec.substring(0,maxLength);
Log.v("links are",cutsec);
String img=j4.getString("image_name");
Log.v("image name is ",img);
//Uri dimg=Uri.parse("http://zeesms.info/android_app_images/Koala.jpg");
HashMap<String,String> map=new HashMap<String,String>();
map.put("Id",String.valueOf(i));
map.put(Li_nk,cutsec);
map.put(Image_name,j4.getString("image_name"));
map.put(KEY_THUMB_URL,"http://zeesms.info/android_app_images/"+img);
mylist.add(map);
}
}
catch(JSONException e){
Log.e("loG_tag","Error parsing"+e.toString());
}
LazyAdapter adapter = new LazyAdapter(this,mylist);
adapter.notifyDataSetChanged();
ListView list=(ListView)findViewById(R.id.lv1);
list.setEmptyView(findViewById(R.id.empty));
list.setAdapter(adapter);
list.setItemsCanFocus(false);
and my adapter is
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());
}
#Override
public int getCount() {
// TODO Auto-generated method stub
return data.size();
}
#Override
public Object getItem(int position) {
// TODO Auto-generated method stub
return position;
}
#Override
public long getItemId(int position) {
// TODO Auto-generated method stub
return position;
}
#Override
public View getView(int position, View convertView, ViewGroup parent) {
View vi=convertView;
if(convertView==null)
vi = inflater.inflate(R.layout.custom_row_view1, null);
TextView title = (TextView)vi.findViewById(R.id.linkname); // merchnts name
TextView artist = (TextView)vi.findViewById(R.id.imagename); // address
//TextView duration = (TextView)vi.findViewById(R.id); // distance
ImageView thumb_image=(ImageView)vi.findViewById(R.id.mClogo); // logo
HashMap<String, String> jsn = new HashMap<String, String>();
jsn = data.get(position);
// Setting all values in listview
title.setText(jsn.get(Second.Li_nk));
artist.setText(jsn.get(Second.Image_name));
//duration.setText(song.get(CustomizedListView.KEY_DURATION));
imageLoader.DisplayImage(jsn.get(Second.KEY_THUMB_URL), thumb_image);
return vi;
}
and finally the class being used for json parsing is
public class JSONfunctions {
public static JSONObject getJSONfromURL(String url){
InputStream is = null;
String result = "";
JSONObject jArray = null;
String str1="http://zeesms.info"+url;
// ArrayList<NameValuePair> namevaluepairs = new ArrayList<NameValuePair>();
Log.v("url result",url);
//namevaluepairs.add(new BasicNameValuePair("location",str1));
//http post
try{
HttpClient httpclient= new DefaultHttpClient();
HttpGet request = new HttpGet();
request.setURI(new URI(str1));
HttpResponse response = httpclient.execute(request);
is = response.getEntity().getContent();
if(is==null){
Log.v("url result","is null");
}
else
{
Log.v("url result","is not null");
}
/* BufferedReader buf = new BufferedReader(new InputStreamReader(is,"UTF-8"));
StringBuilder sb = new StringBuilder();
String s;
while(true )
{
s = buf.readLine();
if(s==null || s.length()==0)
break;
sb.append(s);
}
buf.close();
is.close();
sb.toString(); */
// httppost.setEntity(new UrlEncodedFormEntity(namevaluepairs));
//HttpResponse response=httpclient.execute(httppost);
//HttpEntity entity=response.getEntity();
//is=entity.getContent();
/*
HttpClient httpclient = new DefaultHttpClient();
HttpPost httppost = new HttpPost(url);
HttpResponse response = httpclient.execute(httppost);
HttpEntity entity = response.getEntity();
is = entity.getContent();
*/
}catch(Exception e){
Log.v("log_tag", "Error in http connection "+e.toString());
AlertDialog.Builder alert=new AlertDialog.Builder(null);
alert.setMessage("Invalid Keyword").setPositiveButton("Ok", new OnClickListener(){
#Override
public void onClick(DialogInterface arg0, int arg1) {
// TODO Auto-generated method stub
}
});
}
//convert response to string
try{
Log.v("url result","getting result starts");
BufferedReader reader = new BufferedReader(new InputStreamReader(is,"iso-8859-1"),8);
StringBuilder sb = new StringBuilder();
String line = null;
Log.v("url result","getting result");
while ((line = reader.readLine()) != null) {
Log.v("url result","getting result");
sb.append(line + "\n");
}
is.close();
result=sb.toString();
Log.v("url result",result);
}catch(Exception e){
Log.e("log_tag", "Error converting result "+e.toString());
}
try{
jArray = new JSONObject(result);
}catch(JSONException e){
Log.e("log_tag", "Error parsing data "+e.toString());
}
return jArray;
}
}
along with this if the data is updated from the webpage, what would be the simplest way to show the updated item on top ??

It is easier to maintain scroll position by calling notifydatasetchanged() only. The problem there is that you are creating a new adapter every time the data gets updated... you should do something like this:
if(listView.getAdapter()==null)
listView.setAdapter(myAdapter);
else{
myAdapter.updateData(myNewData); //update adapter's data
myAdapter.notifyDataSetChanged(); //notifies any View reflecting data to refresh
}
This way, your listview will mantain the scrolling position.
In case you want to scroll to a new position, use:
list.smoothScrollToPosition(int position);

In case for some reason you don't want to call notifyDataSetChanged(), the you can maintain the position by using setSelectionFromTop()
Before updating the adaptor:
lastViewedPosition = listView.getFirstVisiblePosition();
//get offset of first visible view
View v = listView.getChildAt(0);
topOffset = (v == null) ? 0 : v.getTop();
After updating the adaptor:
listView.setSelectionFromTop(lastViewedPosition, topOffset);

list.smoothScrollToPosition(int position); //my favorite :)
It may also help you to scroll nice'n'smooth to a particular item

listview.setSelection( i );
this will help you to set particular row at top

For overall picture:
In your API response callback, call this function(example) below:
MyAdapter mAdapter;
ArrayList<Users> mUsers;
private void updateListView(ArrayList<Users> users) {
mUsers.addAll(users);
if(mAdapter == null) {
mAdapter = new MyAdapter(getContext(), mUsers);
mListView.setAdapter(mAdapter);
}
mAdapter.notifyDataSetChanged(); // Add this one
}

If you're using an ArrayAdapter (or a subclass of it), the problem may be caused by that the adapter updates the list when you clean it before adding the new items:
adapter.clear();
adapter.addAll(...);
You can fix it by wrapping the code that modifies the adapter like this:
adapter.setNotifyOnChange(false); // Disable calling notifyDatasetChanged() on modification
adapter.clear();
adapter.addAll(...); // Notify the adapter about that data has changed. Note: it will re-enable notifyOnChange
adapter.notifyDataSetChanged();

Control single row in ListView

I'm trying to add an animation to my ListView so text will fade into separate rows as results come in from an HTTP GET request. I know how to do the fade in effect and i already have a custom ListView adapter but the problem is that the ListView updates all the rows each time a result comes in, thus triggering the fade in effect each time for the entire list.
How would I be able to control a single row so the ListView won't animate every row on each data change?
This is the code i use to fill the ListView:
private class CustomAdapter extends ArrayAdapter<Row> {
public CustomAdapter() {
super(Results.this, R.layout.row, dataList);
}
public View getView(int position, View convertView, ViewGroup parent) {
View row = convertView;
RowHolder holder = null;
if (row == null) {
LayoutInflater inflater = getLayoutInflater();
row = inflater.inflate(R.layout.row, parent, false);
holder = new RowHolder(row);
row.setTag(holder);
} else {
holder = (RowHolder) row.getTag();
}
try {
holder.populateRow(dataList.get(position));
} catch (NullPointerException e) {
e.printStackTrace();
}
return row;
}
}
private class RowHolder {
private TextView label = null;
private TextView count = null;
private TextView result = null;
public RowHolder(View row) {
label = (TextView) row.findViewById(R.id.list_label);
count = (TextView) row.findViewById(R.id.list_count);
result = (TextView) row.findViewById(R.id.list_result);
}
public void populateRow(Row r) {
label.setText(r.getLabel());
count.setText(r.getCount());
result.setText(r.getResult());
label.startAnimation(fadeIn);
count.startAnimation(fadeIn);
result.startAnimation(fadeIn);
}
}
Any help is appreciated, thank you in advance!
Edit 1:
My AsyncTask:
private class CheckSource extends AsyncTask<String, Void, String> {
protected void onPreExecute() {
results.setUnixTime(getUnixTime());
results.setLabel(getString(R.string.label));
results.setCount(null);
results.setResult(null);
results.setResultLabel("");
results.setShowProgress(true);
results.setIconType(null);
results.setShowIcon(false);
results.setHasResults(false);
adapter.notifyDataSetChanged();
}
#Override
protected String doInBackground(String... params) {
String query = params[0];
String httpResults = null;
try {
httpResults = getResults(query, "source");
jsonObject = new JSONObject(httpResults);
} catch (IllegalStateException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
} catch (JSONException e) {
e.printStackTrace();
} catch (URISyntaxException e) {
e.printStackTrace();
}
return httpResults;
}
protected void onPostExecute(String results) {
try {
parseJSON(results);
} catch (JSONException e) {
e.printStackTrace();
results.setResultLabel("<br />"
+ getString(R.string.source_not_available) + "<br />");
}
results.setShowProgress(false);
adapter.notifyDataSetChanged();
}
// Parse the retrieved json results
private void parseJSON(String jsonResults) throws JSONException {
if (jsonResults == null) {
results.setResult(null);
results.setHasResults(false);
results.setResultLabel("<br />"
+ getString(R.string.source_not_available) + "<br />");
return;
}
jsonObject = new JSONObject(jsonResults);
String result = null;
String resultLabel = null;
switch (jsonObject.getInt("count")) {
case -1:
results.setCount(null);
results.setHasResults(false);
resultLabel = getString(R.string.no_results);
break;
case 0:
results.setCount(null);
results.setHasResults(false);
resultLabel = getString(R.string.no_results);
break;
case 1:
results.setHasResults(true);
results.setCount(jsonObject.get("count").toString() + " "
+ getString(R.string.one_result));
result = jsonObject.get("url").toString();
resultLabel = getString(R.string.hyperlink_text);
break;
default:
results.setHasResults(true);
results.setCount(jsonObject.get("count").toString() + " "
+ getString(R.string.multiple_results));
result = jsonObject.get("url").toString();
resultLabel = getString(R.string.hyperlink_text);
break;
}
results.setResult(result);
results.setResultLabel("<br />" + resultLabel + "<br />");
}
}
The method that executes the HTTP request:
private String getResults(String query, String source)
throws IllegalStateException, IOException, URISyntaxException {
/* Method variables */
StringBuilder builder = new StringBuilder();
String URL = "url";
URI uri;
String phrase = "phrase";
List<NameValuePair> params = new ArrayList<NameValuePair>();
/* HTTP variables */
HttpGet httpGet;
DefaultHttpClient httpClient;
HttpResponse httpResponse;
HttpEntity httpEntity;
HttpParams httpParams;
int socketTimeout = 10000;
int connectionTimeout = 10000;
// Set the socket and connection timeout values
httpParams = new BasicHttpParams();
HttpConnectionParams
.setConnectionTimeout(httpParams, connectionTimeout);
HttpConnectionParams.setSoTimeout(httpParams, socketTimeout);
httpClient = new DefaultHttpClient(httpParams);
// Add parameters to the GET request
params.add(new BasicNameValuePair("query", query));
params.add(new BasicNameValuePair("type", source));
String paramString = URLEncodedUtils.format(params, "utf-8");
uri = new URI(URL + paramString);
httpGet = new HttpGet(uri);
// Execute the GET request
httpResponse = httpClient.execute(httpGet);
/* Read http response if http status = 200 */
if (httpResponse.getStatusLine().getStatusCode() == HttpStatus.SC_OK) {
httpEntity = httpResponse.getEntity();
InputStream content = httpEntity.getContent();
BufferedReader reader = new BufferedReader(new InputStreamReader(
content));
String line;
while ((line = reader.readLine()) != null) {
builder.append(line);
}
}
return builder.toString();
}

As Romain Guy explained a while back during the Google I/O session, the most efficient way to only update one view in a list view is something like the following (this one update the whole view data):
ListView list = getListView();
int start = list.getFirstVisiblePosition();
for(int i=start, j=list.getLastVisiblePosition();i<=j;i++)
if(target==list.getItemAtPosition(i)){
View view = list.getChildAt(i-start);
list.getAdapter().getView(i, view, list);
break;
}
Assuming target is one item of the adapter.
This code retrieve the ListView, then browse the currently shown views, compare the target item you are looking for with each displayed view items, and if your target is among those, get the enclosing view and execute the adapter getView on that view to refresh the display.
As a side note invalidate doesn't work like some people expect and will not refresh the view like getView does, notifyDataSetChanged will rebuild the whole list and end up calling getview for every displayed items and invalidateViews will also affect a bunch.
One last thing, one can also get extra performance if he only needs to change a child of a row view and not the whole row like getView does. In that case, the following code can replace list.getAdapter().getView(i, view, list); (example to change a TextView text):
((TextView)view.findViewById(R.id.myid)).setText("some new text");
In code we trust.

Method notifyDataSetChanged force to call getView method to all visible elements of the ListView. If you want update only 1 specific item of the ListView you need to path this item to the AsynhTask.

Android: Making a dynamic listview

I'm having a JSON file which is populated to a listview.
I wanna make the list view dynamic. That means, I only need one Activity for the click action on the list I have. And the source of the content (picture,title,description) which is populated to the Activity comes from a JSON file on the web.
For example, I have 13 projects on the list, whenever I click one of them it goes to ONE activity containing different picture,title,and description depends on the item I click.
I need somebody to improve the codes I provide below.
Projects.java
public class Projects {
public String title;
public String keyword;
public String description;
public String smallImageUrl;
public String bigImageUrl;
public int cost;
#Override
public String toString()
{
return "Title: "+title+ " Keyword: "+keyword+ " Image: "+smallImageUrl;
}
}
ProjectsAdapter.java
Public class ProjectsAdapter extends ArrayAdapter<Projects> {
int resource;
String response;
Context context;
//Initialize adapter
public ProjectsAdapter(Context context, int resource, List<Projects> items) {
super(context, resource, items);
this.resource=resource;
}
#Override
public View getView(int position, View convertView, ViewGroup parent)
{
LinearLayout projectView;
//Get the current alert object
Projects pro = getItem(position);
//Inflate the view
if(convertView==null)
{
projectView = new LinearLayout(getContext());
String inflater = Context.LAYOUT_INFLATER_SERVICE;
LayoutInflater vi;
vi = (LayoutInflater)getContext().getSystemService(inflater);
vi.inflate(resource, projectView, true);
}
else
{
projectView = (LinearLayout) convertView;
}
TextView Title =(TextView)projectView.findViewById(R.id.title);
try {
ImageView i = (ImageView)projectView.findViewById(R.id.image);
Bitmap bitmap = BitmapFactory.decodeStream((InputStream)new URL(pro.smallImageUrl).getContent());
i.setImageBitmap(bitmap);
} catch (MalformedURLException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
}
//Assign the appropriate data from our alert object above
//Image.setImageDrawable(pro.smallImageUrl);
Title.setText(pro.title);
return projectView;
}
}
Main.java
public class Main extends Activity {
/** Called when the activity is first created. */
//ListView that will hold our items references back to main.xml
ListView lstTest;
//Array Adapter that will hold our ArrayList and display the items on the ListView
ProjectsAdapter arrayAdapter;
//List that will host our items and allow us to modify that array adapter
ArrayList<Projects> prjcts=null;
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
//Initialize ListView
lstTest= (ListView)findViewById(R.id.lstText);
//Initialize our ArrayList
prjcts = new ArrayList<Projects>();
//Initialize our array adapter notice how it references the listitems.xml layout
arrayAdapter = new ProjectsAdapter(Main.this, R.layout.listitems,prjcts);
//Set the above adapter as the adapter of choice for our list
lstTest.setAdapter(arrayAdapter);
//Instantiate the Web Service Class with he URL of the web service not that you must pass
WebService webService = new WebService("http://pre.spendino.de/test/android/projects.json");
//Pass the parameters if needed , if not then pass dummy one as follows
Map<String, String> params = new HashMap<String, String>();
params.put("var", "");
//Get JSON response from server the "" are where the method name would normally go if needed example
// webService.webGet("getMoreAllerts", params);
String response = webService.webGet("", params);
try
{
//Parse Response into our object
Type collectionType = new TypeToken<ArrayList<Projects>>(){}.getType();
//JSON expects an list so can't use our ArrayList from the lstart
List<Projects> lst= new Gson().fromJson(response, collectionType);
//Now that we have that list lets add it to the ArrayList which will hold our items.
for(Projects l : lst)
{
prjcts.add(l);
}
//Since we've modified the arrayList we now need to notify the adapter that
//its data has changed so that it updates the UI
arrayAdapter.notifyDataSetChanged();
}
catch(Exception e)
{
Log.d("Error: ", e.getMessage());
}
lstTest.setOnItemClickListener(new OnItemClickListener() {
public void onItemClick(AdapterView<?> parent, View view, int position, long id) {
#SuppressWarnings("unchecked")
Projects p = (Projects ) lstTest.getItemAtPosition(position);
//Do your logic and open up a new Activity.
Intent care = new Intent(Main.this, Organization.class);
startActivity(care);
}
});
}
}
WebService.java (I don't think we need to edit this one)
public class WebService{
DefaultHttpClient httpClient;
HttpContext localContext;
private String ret;
HttpResponse response1 = null;
HttpPost httpPost = null;
HttpGet httpGet = null;
String webServiceUrl;
//The serviceName should be the name of the Service you are going to be using.
public WebService(String serviceName){
HttpParams myParams = new BasicHttpParams();
HttpConnectionParams.setConnectionTimeout(myParams, 10000);
HttpConnectionParams.setSoTimeout(myParams, 10000);
httpClient = new DefaultHttpClient(myParams);
localContext = new BasicHttpContext();
webServiceUrl = serviceName;
}
//Use this method to do a HttpPost\WebInvoke on a Web Service
public String webInvoke(String methodName, Map<String, Object> params) {
JSONObject jsonObject = new JSONObject();
for (Map.Entry<String, Object> param : params.entrySet()){
try {
jsonObject.put(param.getKey(), param.getValue());
}
catch (JSONException e) {
Log.e("Groshie", "JSONException : "+e);
}
}
return webInvoke(methodName, jsonObject.toString(), "application/json");
}
private String webInvoke(String methodName, String data, String contentType) {
ret = null;
httpClient.getParams().setParameter(ClientPNames.COOKIE_POLICY, CookiePolicy.RFC_2109);
httpPost = new HttpPost(webServiceUrl + methodName);
response1 = null;
StringEntity tmp = null;
//httpPost.setHeader("User-Agent", "SET YOUR USER AGENT STRING HERE");
httpPost.setHeader("Accept",
"text/html,application/xml,application/xhtml+xml,text/html;q=0.9,text/plain;q=0.8,image/png,*/*;q=0.5");
if (contentType != null) {
httpPost.setHeader("Content-Type", contentType);
} else {
httpPost.setHeader("Content-Type", "application/x-www-form-urlencoded");
}
try {
tmp = new StringEntity(data,"UTF-8");
} catch (UnsupportedEncodingException e) {
Log.e("Groshie", "HttpUtils : UnsupportedEncodingException : "+e);
}
httpPost.setEntity(tmp);
Log.d("Groshie", webServiceUrl + "?" + data);
try {
response1 = httpClient.execute(httpPost,localContext);
if (response1 != null) {
ret = EntityUtils.toString(response1.getEntity());
}
} catch (Exception e) {
Log.e("Groshie", "HttpUtils: " + e);
}
return ret;
}
//Use this method to do a HttpGet/WebGet on the web service
public String webGet(String methodName, Map<String, String> params) {
String getUrl = webServiceUrl + methodName;
int i = 0;
for (Map.Entry<String, String> param : params.entrySet())
{
if(i == 0){
getUrl += "?";
}
else{
getUrl += "&";
}
try {
getUrl += param.getKey() + "=" + URLEncoder.encode(param.getValue(),"UTF-8");
} catch (UnsupportedEncodingException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
i++;
}
httpGet = new HttpGet(getUrl);
Log.e("WebGetURL: ",getUrl);
try {
response1 = httpClient.execute(httpGet);
} catch (Exception e) {
Log.e("Groshie:", e.getMessage());
}
// we assume that the response body contains the error message
try {
ret = EntityUtils.toString(response1.getEntity());
} catch (IOException e) {
Log.e("Groshie:", e.getMessage());
}
return ret;
}
public static JSONObject Object(Object o){
try {
return new JSONObject(new Gson().toJson(o));
} catch (JSONException e) {
e.printStackTrace();
}
return null;
}
public InputStream getHttpStream(String urlString) throws IOException {
InputStream in = null;
int response = -1;
URL url = new URL(urlString);
URLConnection conn = url.openConnection();
if (!(conn instanceof HttpURLConnection))
throw new IOException("Not an HTTP connection");
try{
HttpURLConnection httpConn = (HttpURLConnection) conn;
httpConn.setAllowUserInteraction(false);
httpConn.setInstanceFollowRedirects(true);
httpConn.setRequestMethod("GET");
httpConn.connect();
response = httpConn.getResponseCode();
if (response == HttpURLConnection.HTTP_OK) {
in = httpConn.getInputStream();
}
} catch (Exception e) {
throw new IOException("Error connecting");
} // end try-catch
return in;
}
public void clearCookies() {
httpClient.getCookieStore().clear();
}
public void abort() {
try {
if (httpClient != null) {
System.out.println("Abort.");
httpPost.abort();
}
} catch (Exception e) {
System.out.println("Your App Name Here" + e);
}
}
}
EDIT
What I wanna show in Organization.java is this .xml file:
<LinearLayout
xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:background="#drawable/bg"
android:orientation="vertical">
<ImageView
android:id="#+id/project_image"
android:layout_marginTop="10dp"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_gravity="center"/>
<TextView
android:id="#+id/title"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:gravity="center"
android:text="Default Title"
android:textSize="18sp"
android:textStyle="bold"
android:textColor="#78b257"/>
<LinearLayout
xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_marginTop="15dp"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:gravity="center"
android:orientation="horizontal">
<Button
android:id="#+id/btn_forward"
android:layout_marginLeft="5dp"
android:layout_gravity="left"
android:text="Weitersagen"
android:layout_height="wrap_content"
android:layout_width="wrap_content"
android:layout_marginTop="15dp"/>
<Button
android:id="#+id/btn_sms_spend"
android:layout_marginTop="15dp"
android:layout_marginRight="5dp"
android:text="Per SMS spenden"
android:layout_gravity="right"
android:layout_height="wrap_content"
android:layout_width="wrap_content"/>
</LinearLayout>
<ScrollView
android:layout_width="fill_parent"
android:layout_height="wrap_content">
<LinearLayout
xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:background="#drawable/bg_white"
android:orientation="vertical">
<TextView
android:id="#+id/description"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:layout_marginTop="5dp"
android:layout_marginLeft="5dp"
android:gravity="left"
android:text="default description"
android:textSize="18sp"
android:textColor="#000000"/>
</LinearLayout>
</ScrollView>
</LinearLayout>
and here's the JSON file:
[{
"title": "CARE Deutschland-Luxemburg e.V.",
"keyword": "CARE",
"description": "<p><b>Das CARE-Komplett-Paket für Menschen in Not</b",
"smallImageUrl": "http://cdn.spendino.de/web/img/projects/home/1284113658.jpg",
"bigImageUrl":"http://cdn.spendino.de/web/img/projects/small/1284113658.jpg",
"cost": "5"
},
{
"title": "Brot für die Welt",
"keyword": "BROT",
"description": "<p>„Brot für die Welt“ unterstützt unter der Maßgabe 'Helfen, wo die Not am größten ist' ausgewählte Projekte weltweit.",
"smallImageUrl": "http://cdn.spendino.de/web/img/projects/home/1267454286.jpg",
"bigImageUrl":"http://cdn.spendino.de/web/img/projects/small/1267454286.jpg",
"cost": "5"
},
{
"title": "Deutsche AIDS-Stiftung",
"keyword": "HIV",
"description": "<p>Die Deutsche AIDS-Stiftung unterstützt mit ihren finanziellen Mitteln seit mehr als 20 Jahren Betroffene, die an HIV und AIDS erkrankt sind.",
"smallImageUrl": "http://cdn.spendino.de/web/img/projects/home/1258365722.jpg",
"bigImageUrl":"http://cdn.spendino.de/web/img/projects/small/1258365722.jpg",
"cost": "5"
}]
Screenshot of the list view:
If these are the steps I gotta do, then I'm having trouble with number 4 & 5:
1. Have the JSON
2. construct a suitable data structure (an Array, ArrayList, whatever you like) to hold crucial data about your list view
3. Use this data structure as the source for your list view
4. when the user clicks on any row, try to find out the position of the row in the list view, and on that position in your source data structure, look for the data needed.
5. create any activity which handles these data generally
6. open that activity with the data of the row which user clicked in step 4
7. Consume this data in your new activity
ConstantData.java:
public class ConstantData extends ArrayList<Projects>{
private static final long serialVersionUID = 9100099012485622682L;
public static Object projectsList;
public ConstantData(){
}
public ConstantData(Parcel in){
}
#SuppressWarnings("unchecked")
public static final Parcelable.Creator CREATOR = new Parcelable.Creator(){
public ConstantData createFromParcel (Parcel in){
return new ConstantData(in);
}
public Object[] newArray(int arg0){
return null;
}
};
private void readFromParcel(Parcel in){
this.clear();
int size = in.readInt();
for (int i = 0; i < size; i++){
Projects p = new Projects();
p.setTitle(in.readString());
p.setKeyword(in.readString());
p.setSmallImageUrl(in.readString());
p.setBigImageUrl(in.readString());
p.setCost(in.readInt());
}
}
public int describeContents() {
return 0;
}
public void writeToParcel (Parcel dest, int flags){
int size = this.size();
dest.writeInt(size);
for (int i = 0; i < size; i++){
Projects p = this.get(i);
dest.writeString(p.getTitle());
dest.writeString(p.getKeyword());
dest.writeString(p.getDescription());
dest.writeString(p.getSmallImageUrl());
dest.writeString(p.getBigImageUrl());
dest.writeInt(p.getCost());
}
}
}
If something is not clear, please let me know.
Thank you very much

For that you need A data structure that holds all your json nodes on index and it should be accessible for all the activities you need [Reco: Use something like GlobalVariables or ConstantData where you have all your project properties and make it public static].
Like : ConstantData.projectData which may be the arraylist or array that contains only Project objects
Now from list view onItemClick method you will get an index (position that denotes on which row its clicked), pass this on your single designed activity with help of bundles and extras.
2.Fetch the index in your desired activity. Fetch the project object on that index from ConstantData.projectData.
Populate the UI components from your project object.
By doing this you can inflate same view again and again only passing the index, only populating the list can be a heavy operation, but the rest will be quicker....
Edit: Let me provide you the snippets .
for 1. on Main.java you use these line in itemClick methods
Intent care = new Intent(Main.this, Organization.class);
startActivity(care);
Add this line between startActivity and Intent initialization.
care.putExtra("yourPackageStructure.Organization.position",position);
for 2. In Organization.java
2.1 create an integer member called mPosition[or the name you like]
2.2 in onCreate() method write mPosition = getIntent().getExtras().getInt("yourPackageStructure.Organization.position");
Project project = ConstantData.projectsData.get(mPosition);
As I don't know how what is there in Organization.java and I wanted to say an array list or something that holds your Projects objects.
Here is what you can have Organization.java 's onCreate method.
onCreate(){
position = getIntent().getExtras().getInt("yourPackageStructure.Organization.position");
//Below line will get you the projects object
Projects project = ConstantData.projectsList.itemAt(position);
ImageView projectImage = (ImageView)findViewById(R.id.project_image);
Bitmap image = getImageFromUrl(this,project.bigImageUrl);
projectImage.setBitmapDrawable(image);
TextView title = (TextView)findViewById(R.id.title);
title.setText(project.title);
TextView description = (TextView)findViewById(R.id.description);
description .setText(project.description);
}
This is what i use for getImageFromUrl method
public static Bitmap getImageFromUrl(Context context, String urlString) {
try {
if (haveInternet(context)) {
URL url = new URL(urlString);
HttpURLConnection conn = (HttpURLConnection) url
.openConnection();
conn.setDoInput(true);
conn.connect();
int length = conn.getContentLength();
InputStream is = conn.getInputStream();
Bitmap bmImg = BitmapFactory.decodeStream(is);
return bmImg;
} else {
return null;
}
} catch (MalformedURLException e) {
Log.e("Problem in image", e.toString(), e);
e.printStackTrace();
} catch (Exception e) {
Log.e("Problem in image", e.toString(), e);
}
return null;
}
This is the haveInternet Method
private static boolean haveInternet(Context context) {
NetworkInfo info = getNetworkInfo(context);
if (info == null || !info.isConnected()) {
return false;
}
if (info.isRoaming()) {
// here is the roaming option you can change it if you want to
// disable internet while roaming, just return false
return true;
}
return true;
}
Hoping it helps you properly...
Added ConstantData
ConstantData.java
public class ConstantData{
//All public static members will be here
public static final long guid = A LONG VAL;
public static String licenceText = A STRING VAL;
//etc... etc... above members are just the idea that what kind of members can be there in //ConstantData... I normally use all public static properties here
//Here is the variable you probably want
public static ArrayList<Projects> projectsList = new ArrayList<Projets>();
}
if you want to populate this array list you can do it from main.java check the lines
for(Projects l : lst)
{
prjcts.add(l);
}
You can add or replace this line. ConstantData.projectsList.add(l); I recommend you to add the line rather to display the line.....