Develop Reference

Fragment with ViewPager issue

I want to create soemthing like this:
The ViewPager is attached to an adapter which has 2 fragments. One to list the upcoming orders and the other to list the past orders.
So the image shown above has a main fragment which hosts the ViewPager, and the adapter creates 2 fragments as children of the main fragment.
For sake of simplicity I'll call the main fragment as "Parent fragment" and the two fragments supplied by the adapter as "children fragments".
Once the parent fragment is created or resumed it has to fetch a list of data from the server and pass it to the two children fragment(The children fragments will process the list of data and display the necessary data). Both the children fragments have a listView, and each listView row item is clickable.
Now, the data fetched by the parent fragment has to be passed to the children fragments before the ViewPager is attached to the adapter. So I do not attach the adapter to the ViewPager in the onCreate method of the parent fragment, but rather once the list of data is fetched, I attach the adapter to the ViewPager in the onPostExecute method of the async task after the data is fetched.
This works fine the first time, but once I click on a listView row item of the child fragment and then press the back button, the getItem() method of the adapter is not called, but the onResume methods of the children fragments are called even before the data is fetched from the server.
So I guess the android framework remembers that the children fragment have already been created, and does not recreate them again.
How do I ensure that the children fragments are created/called only after the data is fetched from the server in the parent fragment?
I am adding some code for clarity.
BookingHistory.java(Parent Fragment)
public class BookingHistory extends android.support.v4.app.Fragment {
ViewPager mPager;
SlidingTabLayout mTabs;
Toolbar toolBar;
View view;
private ProgressDialog progress;
private OrderTask mOrderTask = null;
UserFunctions userFunctions = null;
OrderFunctions orderFunctions = null;
private BookingHistoryListener mListener;
private List<Order> mOrderList;
PlacedOrders upcomingOrders;
PlacedOrders pastOrders;
public BookingHistory() {
// Required empty public constructor
}
#Override
public void onResume() {
super.onResume();
mOrderList = null;
mPager = null;
mTabs = null;
upcomingOrders = null;
pastOrders = null;
progress = new ProgressDialog(getActivity());
fetchOrders();
}
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
view = inflater.inflate(R.layout.fragment_booking_history, container, false);
toolBar = (Toolbar) view.findViewById(R.id.toolbar_s);
if (toolBar != null) {
TextView tv = (TextView) view.findViewById(R.id.toolbar_title);
toolBar.setTitle("");
tv.setText("History");
}
return view;
}
class MyPagerAdapter extends FragmentPagerAdapter {
String tabs[] = {"Upcoming", "Past"};
public MyPagerAdapter(android.support.v4.app.FragmentManager fm) {
super(fm);
}
#Override
public android.support.v4.app.Fragment getItem(int position) {
if (position == 0) {
upcomingOrders = PlacedOrders.newInstance(Constants.DATE_TODAY_FUTURE);
upcomingOrders.getOrderList(mOrderList);
return upcomingOrders;
} else {
pastOrders = PlacedOrders.newInstance(Constants.DATE_PAST);
pastOrders.getOrderList(mOrderList);
return pastOrders;
}
}
#Override
public CharSequence getPageTitle(int position) {
return tabs[position];
}
#Override
public int getCount() {
return 2;
}
}
public void fetchOrders() {
if (mOrderTask != null) {
return;
}
progress.show();
mOrderTask = new OrderTask(getActivity());
mOrderTask.execute((Void) null);
}
public class OrderTask extends AsyncTask<Void, Void, Boolean> {
private final Activity mActivity;
OrderTask(Activity activity) {
mActivity = activity;
}
#Override
protected Boolean doInBackground(Void... params) {
userFunctions = new UserFunctions();
orderFunctions = new OrderFunctions();
return orderFunctions.getList(userFunctions.getToken(mActivity));
}
#Override
protected void onPostExecute(final Boolean success) {
mOrderTask = null;
progress.dismiss();
if (success) {
mOrderList = UserProfile.getOrders();
//attaching the view pager to adapter here!
mPager = (ViewPager) view.findViewById(R.id.pager);
mTabs = (SlidingTabLayout) view.findViewById(R.id.sliding_tabs);
mTabs.setDistributeEvenly(true);
mTabs.setCustomTabColorizer(new SlidingTabLayout.TabColorizer() {
#Override
public int getIndicatorColor(int position) {
return getResources().getColor(R.color.white);
}
});
mPager.setAdapter(new MyPagerAdapter(getChildFragmentManager()));
mTabs.setViewPager(mPager);
} else {
//Error handling stuff
}
}
}
}
PlacedOrders.java(Children Fragments)
public class PlacedOrders extends android.support.v4.app.Fragment {
private static String flag;
private int dateFlag;
private PlacedOrdersListener mListener;
UserFunctions userFunctions = null;
OrderFunctions orderFunctions = null;
private PlacedOrdersAdapter ordersAdapter;
private ProgressDialog progress;
private List<Order> mOrderList;
private List<Order> mPendingOrderList;
private List<Order> mCompletedOrderList;
public static PlacedOrders newInstance(int date) {
PlacedOrders fragment = new PlacedOrders();
Bundle args = new Bundle();
args.putInt(flag, date);
fragment.setArguments(args);
return fragment;
}
public void getOrderList(List<Order> orderList) {
this.mOrderList = orderList;
}
public PlacedOrders() {
// Required empty public constructor
}
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
if (getArguments() != null) {
dateFlag = getArguments().getInt(flag);
}
}
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
mPendingOrderList = new ArrayList<Order>();
mCompletedOrderList = new ArrayList<Order>();
return inflater.inflate(R.layout.fragment_placed_orders, container, false);
}
#Override
public void onResume() {
super.onResume();
displayOrders();
}
private void displayOrders() {
if (isVisible() && (mOrderList != null)) {
mPendingOrderList.clear();
mCompletedOrderList.clear();
ListView listViewOrder = (ListView) getView().findViewById(R.id.orderList);
if(dateFlag == Constants.DATE_TODAY_FUTURE) {
for(int i = 0; i < mOrderList.size(); i++) {
String status = mOrderList.get(i).status;
if(status.equals("PENDING") || status.equals("PROCESSING")) {
mPendingOrderList.add(mOrderList.get(i));
ordersAdapter = new PlacedOrdersAdapter(mPendingOrderList, getActivity().getLayoutInflater());
listViewOrder.setAdapter(ordersAdapter);
}
}
}
else if(dateFlag == Constants.DATE_PAST) {
for(int i = 0; i < mOrderList.size(); i++) {
String status = mOrderList.get(i).status;
if(status.equals("COMPLETE")) {
mCompletedOrderList.add(mOrderList.get(i));
ordersAdapter = new PlacedOrdersAdapter(mCompletedOrderList, getActivity().getLayoutInflater());
listViewOrder.setAdapter(ordersAdapter);
}
}
}
listViewOrder.setOnItemClickListener(new AdapterView.OnItemClickListener() {
//Display a new fragment on clicking
});
}
}
}

I had same issue and this was my solution :
In container fragment (fragment that contains tabs) in onViewCreated() method I created startFetch() method:
#Override
public void onViewCreated(View v, Bundle savedInstanceState) {
super.onViewCreated(v, savedInstanceState);
mViewPager = (ViewPager) v.findViewById(R.id.home_tab_pager);
mTabsHost= (TabLayout) getActivity().findViewById(R.id.appTabs);
startFetch();
}
Then in startFetch method i use Volley request and in onResponse method i update data and then add tabs :
public void startFetch(){
//Create volley request
String url = BuildConfig.API_GET_CATEGORIES;
final RequestQueue queue = VolleyService.getInstance(this.getContext()).getRequestQueue();
StringRequest request = new StringRequest(url, new Response.Listener<String>() {
#Override
public void onResponse(String response) {
// we got the response, now our job is to handle it
try {
updateCategoryData(response);
} catch (RemoteException | OperationApplicationException e) {
e.printStackTrace();
}
}
}, new Response.ErrorListener() {
#Override
public void onErrorResponse(VolleyError error) {
//something happened, treat the error.
Log.e("ErrorFETCH", error.networkResponse.toString());
}
});
queue.add(request);
}
My udpateCategory() method :
public void updateCategoryData(final String stream) throws RemoteException, OperationApplicationException {
//Update the data to SQLITE
setupTabs();
}
My setupTabs() method :
public void setUpTabs(){
ArrayList<Category> categories = new ArrayList<>();
Cursor data = getActivity().getContentResolver().query(
Category.Entry.CONTENT_URI, // URI
Category.PROJECTION, // Projection
Category.Entry.COLUMN_NAME_PARENT_ID + " = ?", // Selection
new String[]{"0"}, // Selection args
null);
if (data != null) {
while(data.moveToNext()){
categories.add(new Category(data));
}
}
TabsPagerAdapter mAdapter = new TabsPagerAdapter(getActivity().getSupportFragmentManager(), this.getActivity(), categories);
mViewPager.setAdapter(mAdapter);
mTabsHost.setupWithViewPager(mViewPager);
}

Fragments inside ViewPager is not refreshing contents or its views

MainActivity.java
public class MainActivity extends ActionBarActivity {
Toolbar toolbar;
ViewPager pager;
ViewPagerAdapter adapter;
SlidingTabLayout tabs;
private ArrayList<String> mLanguagesArray = null;
int Numboftabs;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
if (savedInstanceState == null) {
Bundle extras = getIntent().getExtras();
if (extras != null) {
mLanguagesArray = new ArrayList<String>();
mLanguagesArray.addAll(extras.getStringArrayList("languages"));
Numboftabs = mLanguagesArray.size();
}
}
toolbar = (Toolbar) findViewById(R.id.tool_bar);
setSupportActionBar(toolbar);
getSupportActionBar().setIcon(R.drawable.ic_launcher);
adapter = new ViewPagerAdapter(getSupportFragmentManager(),
mLanguagesArray, Numboftabs, MainActivity.this);
pager = (ViewPager) findViewById(R.id.pager);
pager.setAdapter(adapter);
// Assiging the Sliding Tab Layout View
tabs = (SlidingTabLayout) findViewById(R.id.tabs);
tabs.setViewPager(pager);
tabs.setOnPageChangeListener(new ViewPager.OnPageChangeListener() {
#Override
public void onPageScrollStateChanged(int arg0) {
}
#Override
public void onPageScrolled(int arg0, float arg1, int arg2) {
}
#Override
public void onPageSelected(int arg0) {
refreshListInFragment(arg0);
}
});
}
protected void refreshListInFragment(int position) {
String currentLanguage = mLanguagesArray.get(position);
FragmentManager fm = getSupportFragmentManager();
ListviewFragment fragment = (ListviewFragment) fm
.findFragmentById(R.id.pager);
fragment.loadListview(currentLanguage);
}
}
ViewPagerAdapter.java
import java.util.ArrayList;
import android.content.Context;
import android.support.v4.app.Fragment;
import android.support.v4.app.FragmentManager;
import android.support.v4.app.FragmentStatePagerAdapter;
public class ViewPagerAdapter extends FragmentStatePagerAdapter {
ArrayList<String> Titles;
int NumbOfTabs;
Context mContext;
public ViewPagerAdapter(FragmentManager fm,
ArrayList<String> mLanguagesArray, int mNumbOfTabsumb,
Context context) {
super(fm);
Titles = new ArrayList<String>();
this.Titles = mLanguagesArray;
this.NumbOfTabs = mNumbOfTabsumb;
this.mContext = context;
}
#Override
public Fragment getItem(int position) {
ListviewFragment listfragment = new ListviewFragment(mContext);
return listfragment;
}
#Override
public CharSequence getPageTitle(int position) {
return Titles.get(position);
}
#Override
public int getCount() {
return NumbOfTabs;
}
}
ListviewFragment.java
import android.support.v4.app.Fragment;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.Button;
import android.widget.ListView;
import android.widget.ProgressBar;
public class ListviewFragment extends Fragment {
ProgressBar progressbar;
ListView list;
ArrayList<RStore> mRstoreList = null;
RadioListAdapter adapter;
Context mContext;
Button tryagain;
String mCurrentLanguage = null;
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
View v = inflater.inflate(R.layout.listviewfragment, container, false);
progressbar = (ProgressBar) v.findViewById(R.id.progressbar);
list = (ListView) v.findViewById(R.id.listview);
if (ListviewFragment.this.isMenuVisible()) {
if (mRstoreList == null) {
loadListview("English");
}
}
return v;
}
public void loadListview(final String currentlanguage) {
this.mCurrentLanguage = currentlanguage;
mRstoreList = new ArrayList<RStore>();
new AsyncTask<Void, Void, String>() {
private String jsonStr;
#Override
protected void onPreExecute() {
list.setVisibility(View.GONE);
progressbar.setVisibility(View.VISIBLE);
tryagain.setVisibility(View.GONE);
super.onPreExecute();
}
#Override
protected String doInBackground(Void... arg0) {
try {
String URL = ServiceUrls.MUSIC_PHP;
CustomHttpClient sh = new CustomHttpClient();
JSONObject jsonobjpost = new JSONObject();
jsonobjpost.put("languages", currentlanguage);
jsonStr = sh.makeServiceCall(URL, CustomHttpClient.POST,
jsonobjpost.toString());
System.out.println("MUSIC_PHP_Response " + jsonStr);
} catch (Exception e) {
e.printStackTrace();
}
return jsonStr;
}
#Override
protected void onPostExecute(String result) {
if (result == null || result.trim().equalsIgnoreCase("null")
|| result.trim().equalsIgnoreCase("")) {
progressbar.setVisibility(View.GONE);
super.onPostExecute(result);
return;
}
try {
String DUMMYJASON = result.toString();
JSONObject jsonObject = new JSONObject(DUMMYJASON);
JSONArray jsonArray = jsonObject.getJSONArray("Language");
for (int i = 0; i < jsonArray.length(); i++) {
JSONObject obj = jsonArray.getJSONObject(i);
String id = obj.getString("id");
String language = obj.getString("language");
String tittle = obj.getString("Tittle");
String link = obj.getString("link");
RStore storecon = new RStore();
storecon.setId(id);
storecon.setLanguage(language);
storecon.setTitle(tittle);
storecon.setLink(link);
mRstoreList.add(storecon);
}
} catch (JSONException e) {
e.printStackTrace();
}
adapter = new RadioListAdapter(mContext, mRstoreList);
list.setAdapter(adapter);
list.setVisibility(View.VISIBLE);
progressbar.setVisibility(View.GONE);
super.onPostExecute(result);
}
}.executeOnExecutor(AsyncTask.THREAD_POOL_EXECUTOR);
}
public ListviewFragment(Context context) {
this.mContext = context;
}
}
I'm creating number of fragments dynamically using one fragment class called ListviewFragment and setting it as view page adapter. ListviewFragment contains listview which is populated dynamically from service. With my code everything is working fine the only problem is, sometimes the datas inside the fragments are not refreshing or updating with new values. In my case the listview is showing the previously loaded data but in background the service is called and the listview Adapter is updated but the updated listview is not showing in the fragment. Please see my code, and correct me if i made any mistake..Thanks in advance

Instead of calling a method with (currentLanguage) as a parameter in fragment from activity using findFragmentById, I've just passed (currentLanguage) as bundle in ViewPagerAdapter getItem() method and in ListviewFragment class onCreateView i got (currentlanguage) value using getArguments and passed it to (loadListview) method. Now everything works fine and clean.
ViewPagerAdapter.java
#Override
public Fragment getItem(int position) {
Bundle args = new Bundle();
args.putString("language", Titles.get(position));
ListviewFragment f = new ListviewFragment(mContext);
f.setArguments(args);
return f;
}
ListviewFragment.java
private void getarugs() {
Bundle args = getArguments();
mCurrentLanguage = args.getString("language");
loadListview(mCurrentLanguage);
}

Viewpager adapter in android

Why does my pager adapter doesn't want to start from my first item. When I start ContainerIspiti activity, and show first fragment, the view pager dones't show the right element. Insted of first, view pager shows the second element, and I can't to swipe to first element of my array list. Does anybody have solution.
Here is my code for ConainterIspiti
public class ContainerIspiti extends FragmentActivity{
private Button next, previous, odgovori, informacije;
private TextView textPitanja, brojPitanja;
private ViewPager pager;
private PagerAdapter mPagerAdapter;
public static ArrayList<Pitanja> getAllPitanja;
public static ArrayList<Pitanje_has_Slika> getAllImages;
private Intent intent;
private DBTools db = new DBTools(this);
private ProgressDialog pDialog;
private int broj;
#Override
protected void onCreate(Bundle arg0) {
super.onCreate(arg0);
setContentView(R.layout.activity_container_pitanja);
Bundle bundle = new Bundle();
intent = getIntent();
Dohvati d = new Dohvati();
d.execute();
textPitanja = (TextView) findViewById(R.id.kategorijaTextViewPitanjeActivity);
brojPitanja = (TextView) findViewById(R.id.brojPitanjaTextViewPitanjeActivity);
pager = (ViewPager) findViewById(R.id.pagerPitanja);
pager.setCurrentItem(0, true);
bundle.putString("NAZIV_KATEGORIJE", intent.getStringExtra("NAZIV_KATEGORIJE"));
}
private class ScreenSlidePagerAdapter extends FragmentStatePagerAdapter {
public ScreenSlidePagerAdapter(FragmentManager fm) {
super(fm);
}
#Override
public Fragment getItem(int position) {
Log.i("Position je sljedeci ", String.valueOf(position));
return PitanjaFragment.create(position);
}
#Override
public int getCount() {
Log.i("Velicina polja je ", String.valueOf(getAllPitanja.size()));
Log.i("Prvi eleemnt liste je", getAllPitanja.get(0).getTextPitanja());
return getAllPitanja.size();
}
}
private class Dohvati extends AsyncTask<String, String, String>{
#Override
protected void onPreExecute() {
super.onPreExecute();
pDialog = new ProgressDialog(ContainerIspiti.this);
pDialog.setCancelable(false);
pDialog.setIndeterminate(false);
pDialog.show();
}
#Override
protected String doInBackground(String... params) {
getAllPitanja = db
.getAllPitanja(intent.getStringExtra("id_kategorije"));
Log.i("Ovoliki je get all pitanja", String.valueOf(getAllPitanja.size()));
getAllImages = db.getAllPitanjaImages();
Log.i("ovoliko je slika", String.valueOf(getAllImages.size()));
return null;
}
#Override
protected void onPostExecute(String result) {
pDialog.dismiss();
mPagerAdapter = new ScreenSlidePagerAdapter(getSupportFragmentManager());
pager.setAdapter(mPagerAdapter);
pager.setOnPageChangeListener(new ViewPager.SimpleOnPageChangeListener(){
#Override
public void onPageSelected(int position) {
invalidateOptionsMenu();
brojPitanja.setText(String.valueOf(position) + "/" + String.valueOf(getAllPitanja.size()));
broj = position;
}
});
textPitanja.setText(intent.getStringExtra("NAZIV_KATEGORIJE"));
brojPitanja.setText(String.valueOf(broj) + "/" + getAllPitanja.size());
}
}
}
and here is my fragment activity
public class PitanjaFragment extends Fragment implements API{
public static final String ARG_PAGE = "page";
private int broj;
private ImageView image;
private TextView textPitanja;
private String uri;
private View view;
private ListView listView;
private Typeface custom_font;
private boolean odgovoreno, tocno;
private ArrayList<Odgovor> odgovorList;
private PitanjaAdapter adapter;
private DBTools db;
private List<Integer> kliknuti;
private HashMap<Integer, List<Integer>> odgBrojPitanja;
public static PitanjaFragment create(int pageNumber) {
PitanjaFragment fragment = new PitanjaFragment();
Bundle args = new Bundle();
args.putInt(ARG_PAGE, pageNumber);
fragment.setArguments(args);
return fragment;
}
public PitanjaFragment() {
}
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
broj = getArguments().getInt(ARG_PAGE);
}
#Override
public View onCreateView(LayoutInflater inflater,
#Nullable ViewGroup container, #Nullable Bundle savedInstanceState) {
// TODO Auto-generated method stub
View view = inflater.inflate(R.layout.fragment_pitanja, container, false);
image = (ImageView) view.findViewById(R.id.imageSlikaImageView);
image.setOnClickListener(this);
textPitanja = (TextView) view.findViewById(R.id.textPitanjaTextViewPitanjaActivity);
db = new DBTools(getActivity());
listView = (ListView) view.findViewById(R.id.listView);
updateDisplay((broj+1));
return view;
}
public void updateDisplay(int z) {
odgovoreno = false;
tocno = true;
textPitanja.setText(stripHtml(String.valueOf(ContainerIspiti.getAllPitanja.get(z).getTextPitanja())));
image.setImageBitmap(null);
//info = ContainerIspiti.getAllPitanja.get(z).getInfo();
Log.d("Postoji", ContainerIspiti.getAllImages.get(z).getNazivSlike() + ", ");
for (int j = 0; j < ContainerIspiti.getAllImages.size(); j++) {
if (ContainerIspiti.getAllImages.get(j).getIdPitanja() == ContainerIspiti.getAllPitanja.get(z)
.getIdPitanja()
&& ContainerIspiti.getAllImages.get(j).getNazivSlike() != null) {
Log.i("Id pitanja slike + idpitanja pitanja + idSlike",
ContainerIspiti.getAllImages.get(j).getIdPitanja()
+ ", "
+ String.valueOf(ContainerIspiti.getAllPitanja.get(z)
.getIdPitanja()
+ ", "
+ ContainerIspiti.getAllImages.get(j).getIdSlika()));
image.setVisibility(View.VISIBLE);
//povecalo.setImageResource(R.drawable.gumb_pretrazi);
//povecalo.setEnabled(true);
uri = PregledZnakova.PHOTOS_BASE_URL
+ ContainerIspiti.getAllImages.get(j).getNazivSlike();
int rounded_value = 40;
DisplayImageOptions options = new DisplayImageOptions.Builder().showImageForEmptyUri(R.drawable.placeholder).showStubImage(R.drawable.placeholder).cacheInMemory().cacheOnDisc().displayer(new RoundedBitmapDisplayer(rounded_value)).build();
ImageLoaderConfiguration config = new ImageLoaderConfiguration.Builder(getActivity().getApplicationContext()).defaultDisplayImageOptions(options).build();
ImageLoader.getInstance().init(config);
ImageLoader.getInstance().displayImage(uri, image,options);
break;
// }
} else {
image.setVisibility(View.GONE);
//povecalo.setImageResource(R.drawable.gumb_pretrazi_neaktivno);
//povecalo.setEnabled(false);
}
}
odgovorList = db.getAllOdgovore(Integer.toString(ContainerIspiti.getAllPitanja.get(z)
.getIdPitanja()));
adapter = new PitanjaAdapter(getActivity(),
R.layout.pitanja_entry, odgovorList);
listView.setAdapter(adapter);
for (int i=0;i<ContainerIspiti.getAllPitanja.size();i++){
if (ContainerIspiti.getAllPitanja.get(i).isTocno()){
Log.i("Ovo pitanje je tocno", ContainerIspiti.getAllPitanja.get(i).getTextPitanja());
}
}
}
#Override
public int getItemBroj() {
return broj;
}
#Override
public int getPosition() {
return broj;
}
#Override
public void setPosition(int position) {
this.broj = position;
}
#Override
public Fragment getFragment() {
return this;
}
}
Thanks for your time and your help.

In the onCreateView() method of your PitanjaFragment class, replace:
updateDisplay((broj+1));
with
updateDisplay(broj);
Try this. It should work.

Android Fragment Content Lost

i have a problem on android eclipse with fragments in a viewpager. When an home activity starts i show an actionbar tabs and first fragment on the screen. When i swipe to next fragment and then back to first fragment, first fragment contents are still on the screen. But on the other hand if a swipe 2 times to right and go back first fragment, its contents are lost and blank screen is shown. My codes are below. How to retain each fragment content either it is shown or is visible ? any help is appreciated. Thanx in advance.
HomeActivity.java
public class HomeActivity extends FragmentActivity implements TabListener {
private String[] menuItems = null;
private ActionBar bar = null;
private ViewPager viewPager = null;
private TabsAdapter tabsAdapter = null;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_home);
viewPager = (ViewPager) findViewById(R.id.viewPager);
viewPager.setPageMargin(10);
menuItems = getResources().getStringArray(R.array.menuTitles);
bar = getActionBar();
bar.setNavigationMode(ActionBar.NAVIGATION_MODE_TABS);
tabsAdapter = new TabsAdapter(this, viewPager);
for (int i = 0; i < menuItems.length; i++) {
switch (i) {
case 0:
tabsAdapter.addTab(bar.newTab().setText(menuItems[i]),
NewsFeedActivity.class, null);
break;
case 1:
tabsAdapter.addTab(bar.newTab().setText(menuItems[i]),
NotificationActivity.class, null);
break;
case 2:
tabsAdapter.addTab(bar.newTab().setText(menuItems[i]),
NewsFeedActivity.class, null);
break;
case 3:
tabsAdapter.addTab(bar.newTab().setText(menuItems[i]),
NotificationActivity.class, null);
break;
case 4:
tabsAdapter.addTab(bar.newTab().setText(menuItems[i]),
NewsFeedActivity.class, null);
break;
default:
break;
}
}
if (savedInstanceState != null) {
bar.setSelectedNavigationItem(savedInstanceState.getInt("tab", 0));
}
}
#Override
protected void onSaveInstanceState(Bundle outState) {
super.onSaveInstanceState(outState);
outState.putInt("tab", getActionBar().getSelectedNavigationIndex());
}
#Override
protected void onRestoreInstanceState(Bundle savedInstanceState)
{
super.onRestoreInstanceState(savedInstanceState);
// Restore selected tab
int saved = savedInstanceState.getInt("tab", 0);
if (saved != getActionBar().getSelectedNavigationIndex())
getActionBar().setSelectedNavigationItem(saved);
}
#Override
public void onTabSelected(Tab tab, FragmentTransaction ft) {
}
#Override
public void onTabUnselected(Tab tab, FragmentTransaction ft) {
}
#Override
public void onTabReselected(Tab tab, FragmentTransaction ft) {
}
public static class TabsAdapter extends FragmentPagerAdapter implements
ActionBar.TabListener, ViewPager.OnPageChangeListener {
private final Context mContext;
private final ActionBar mActionBar;
private final ViewPager mViewPager;
private final ArrayList<TabInfo> mTabs = new ArrayList<TabInfo>();
static final class TabInfo {
private final Class<?> clss;
private final Bundle args;
TabInfo(Class<?> _class, Bundle _args) {
clss = _class;
args = _args;
}
}
public TabsAdapter(FragmentActivity activity, ViewPager pager) {
super(activity.getSupportFragmentManager());
mContext = activity;
mActionBar = activity.getActionBar();
mViewPager = pager;
mViewPager.setAdapter(this);
mViewPager.setOnPageChangeListener(this);
}
public void addTab(ActionBar.Tab tab, Class<?> clss, Bundle args) {
TabInfo info = new TabInfo(clss, args);
tab.setTag(info);
tab.setTabListener(this);
mTabs.add(info);
mActionBar.addTab(tab);
notifyDataSetChanged();
}
#Override
public void onPageScrollStateChanged(int state) {
}
#Override
public void onPageScrolled(int position, float positionOffset,
int positionOffsetPixels) {
}
#Override
public void onPageSelected(int position) {
mActionBar.setSelectedNavigationItem(position);
}
#Override
public void onTabReselected(Tab tab, FragmentTransaction ft) {
Toast.makeText(mContext, "Reselected!", Toast.LENGTH_SHORT).show();
Object tag = tab.getTag();
for (int i = 0; i < mTabs.size(); i++) {
if (mTabs.get(i) == tag) {
mViewPager.setCurrentItem(i);
}
}
}
#Override
public void onTabSelected(Tab tab, FragmentTransaction ft) {
Toast.makeText(mContext, "gokay!", Toast.LENGTH_SHORT).show();
Object tag = tab.getTag();
for (int i = 0; i < mTabs.size(); i++) {
if (mTabs.get(i) == tag) {
mViewPager.setCurrentItem(i);
}
}
}
#Override
public void onTabUnselected(Tab tab, FragmentTransaction ft) {
}
#Override
public Fragment getItem(int position) {
TabInfo info = mTabs.get(position);
return Fragment.instantiate(mContext, info.clss.getName(),
info.args);
}
#Override
public int getCount() {
return mTabs.size();
}
}
}
NewsFeedActivity.java
public class NewsFeedActivity extends Fragment {
static final String URL = "http://api.androidhive.info/pizza/?format=xml";
// XML node keys
static final String KEY_ITEM = "item"; // parent node
static final String KEY_ID = "id";
static final String KEY_NAME = "name";
static final String KEY_COST = "cost";
static final String KEY_DESC = "description";
private ArrayList<String> xmlList = null;
private XMLParser parser = null;
private String xml = "";
private Document doc = null;
private NodeList nl = null;
private View view = null;
private Element e = null;
private ListView listNewsFeed = null;
private static Bundle args = null;
private static NewsFeedActivity newsFeed = null;
private ArrayAdapter<String> adapter = null;
public static NewsFeedActivity newInstance(int page, String title) {
newsFeed = new NewsFeedActivity();
args = new Bundle();
args.putInt("Page", page);
args.putString("newsFeed", title);
newsFeed.setArguments(args);
return newsFeed;
}
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
}
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
view = inflater.inflate(R.layout.activity_news_feed, container, false);
if (getActivity().getActionBar().getSelectedTab().getPosition() == 0) {
new NewsFeeder().execute("");
}
return view;
}
private class NewsFeeder extends AsyncTask<String, String, String> {
private ProgressDialog mProgressDialog = null;
#Override
protected void onPreExecute() {
super.onPreExecute();
mProgressDialog = new ProgressDialog(getActivity());
mProgressDialog.setMessage("Haber kaynağı yenileniyor..");
mProgressDialog.setCancelable(false);
mProgressDialog.setProgressStyle(ProgressDialog.STYLE_SPINNER);
mProgressDialog.show();
}
#Override
protected String doInBackground(String... params) {
xmlList = new ArrayList<String>();
try {
parser = new XMLParser();
xml = parser.getXmlFromUrl(URL); // getting XML
Log.i("gokay", xml);
doc = parser.getDomElement(xml); // getting DOM element
nl = doc.getElementsByTagName(KEY_ITEM);
return null;
} catch (Exception e) {
e.printStackTrace();
System.out.println(e.getMessage());
Log.e("gokay", e.getMessage());
return null;
}
}
#Override
protected void onPostExecute(String result) {
super.onPostExecute(result);
mProgressDialog.dismiss();
for (int i = 0; i < nl.getLength(); i++) {
e = (Element) nl.item(i);
xmlList.add(parser.getValue(e, KEY_ID));
xmlList.add(parser.getValue(e, KEY_NAME));
xmlList.add("Rs." + parser.getValue(e, KEY_COST));
xmlList.add(parser.getValue(e, KEY_DESC));
}
listNewsFeed = (ListView) view.findViewById(R.id.listView1);
adapter = new ArrayAdapter<String>(getActivity(),
android.R.layout.simple_list_item_1, xmlList);
listNewsFeed.setAdapter(adapter);
// onFoodMenuItemsDBAddFinished();
}
}
}

try using
setRetainInstance(true);
in oncreate() fragment

Handle threads inside fragments

Currently I have made 3 tabs. On each tab (fragment) there is a thread to fetch content and display it with a listview through an ArrayAdapter.
Now when you scroll through the tabs the thread gets executed again and again (not necessary).
Is there a way to stop this ? Or do I need to write the content to external storage for faster access ?
Also sometimes I see the same data on different tabs , how to avoid this ?
Thanks in advance
This is some code that I use inside my fragment which that is called multiple times when swiping :
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
View rootView;
rootView = inflater.inflate(R.layout.leadlist, container, false);
profielen = new ArrayList<Profile>();
new getLeaderboards().execute(url);
lv = (ListView) rootView.findViewById(android.R.id.list);
lbadapter = new LeaderBoardAdapter(this.getActivity(), R.layout.item_layout, profielen);
return rootView;
}
public static class getLeaderboards extends AsyncTask<String, Void, JsonObject> {
#Override
protected JsonObject doInBackground(String... urls) {
JsonObject x = parseURL.GetJSON(urls[0]);
return x;
}
#Override
protected void onPostExecute(JsonObject obj) {
Gson gson = new Gson();
System.out.println(obj.toString());
JsonArray arr = obj.get("rows").getAsJsonArray();
for (int i=0;i<10;i++) {
Profile pat = gson.fromJson( arr.get(i) , Profile.class);
profielen.add(pat);
}
lv.setAdapter(lbadapter);
}
}
My FragmentActivity :
public class LeaderboardsActivity extends FragmentActivity implements
ActionBar.TabListener {
private ViewPager viewPager;
private TabsPagerAdapter mAdapter;
private ActionBar actionBar;
private String[] tabs = { "Tab1", "Tab2", "Tab3" };
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
getWindow().requestFeature(Window.FEATURE_ACTION_BAR);
setContentView(R.layout.leaderboard);
Intent i = getIntent();
String region = i.getStringExtra("region");
viewPager = (ViewPager) findViewById(R.id.pager);
actionBar = getActionBar();
getActionBar().setDisplayShowTitleEnabled(false);
getActionBar().setDisplayShowHomeEnabled(false);
mAdapter = new TabsPagerAdapter(getSupportFragmentManager(),region);
viewPager.setAdapter(mAdapter);
actionBar.setHomeButtonEnabled(false);
actionBar.setNavigationMode(ActionBar.NAVIGATION_MODE_TABS);
for (String tab_name : tabs) {
actionBar.addTab(actionBar.newTab().setText(tab_name)
.setTabListener(this));
}
viewPager.setOnPageChangeListener(new ViewPager.OnPageChangeListener() {
#Override
public void onPageSelected(int position) {
actionBar.setSelectedNavigationItem(position);
}
#Override
public void onPageScrolled(int arg0, float arg1, int arg2) {
}
#Override
public void onPageScrollStateChanged(int arg0) {
}
});
}
#Override
public void onTabReselected(Tab tab, FragmentTransaction ft) {
}
#Override
public void onTabSelected(Tab tab, FragmentTransaction ft) {
viewPager.setCurrentItem(tab.getPosition());
}
#Override
public void onTabUnselected(Tab tab, FragmentTransaction ft) {
}
}