Develop Reference

Viewpager optimization with custom views

Scenario - I am working on an app that shows events respective to particular dates in a viewpager, where each page represents a day(i.e 24 hrs in a vertical manner, similar to google calendar). Each page/fragment contains a vertical scrollview(it has a framelayout inside it) and based on list of events i am dynamically creating custom-views(view position and dimension is based on the corresponding event timing and duration) and adding it to the scrollview. User can drag and drop events between dates.
Issue - I have successfully achieved the view creation part, now the issue is with performance. Sometimes vewpager(using FragmentStatePagerAdapter) lags while swiping through pages.
Someone please suggest me how to reduce the lag or any better ways to achieve this

Yes I had a similar performance with viewpager and FragmentStatePagerAdapter, the problem with viewpager is that pre creates the views either side of the current view to speed up the swipe to next view.
This works well for static views but for views with dynamic data the pre-created view was usually out of date and needed to be regenerated when the user swiped to it.
Thus it was having to call onCreateView on 3 views while the user swiped between views leading to lag sometimes.
I thought of 2 improvements for performance, though only used one.
1) The view holder/model pattern e.g. https://www.androidcode.ninja/android-viewholder-pattern-example/ and https://developer.android.com/topic/libraries/architecture/viewmodel where the inflation and finding items re-used / separated from onCreateView activities.
I did not use this method
2) Create bare bones views for the dynamic ones (The first view was static and then there were 2 dynamic ones at positions 1 and 2 that contained listviews of different aspects of the dynamic data.)
The listviews were inflated and had an adapter set to an empty list in onCreateView of these views thus they were fast to create.
Then I added an on OnPageChangeListener which notified the adapter backing the ViewPager that the pages had changed
mViewPager.addOnPageChangeListener(new ViewPager.OnPageChangeListener() {
#Override
public void onPageSelected(int position) {
if (position == 1 || position == 2)
{
mSectionsPagerAdapter.notifyDataSetChanged();
}
}
#Override
public void onPageScrolled(int position, float positionOffset, int positionOffsetPixels) {
// Code goes here
}
#Override
public void onPageScrollStateChanged(int state) {
// Code goes here
}
});
The notifyDataSetChanged causes the viewPager to call getItemPosition in the FragmentStatePagerAdapter class to work out if the page position has changed and it if need to re-create it in the a new position.
Then in FragmentStatePagerAdapter extended class I overrode getItemPosition with
#Override
public int getItemPosition(Object object) {
if (object instanceof LogFragment) {
LogFragment f = (LogFragment) object;
if (f != null) {
f.update();
}
} else if (object instanceof SummaryFragment){
SummaryFragment f = (SummaryFragment) object;
if (f != null) {
f.update();
}
} else {
return POSITION_UNCHANGED;
}
return super.getItemPosition(object);
}
This allowed me to get the Fragment object and then call the update method on it but still returning POSITION_UNCHANGED so the viewpager did not try and re-create the Fragments.
Then in the update method of the Fragment I get the listview adapter and update the data.
public void update(){
adapter.clear();
adapter.addAll(datasource.getData());
}
Thus the more costly getting and display the dynamic data is only done when the page is actually display, NOT when it is pre-created by viewPager (because that pre-created view would be old out of date data anyway and would need to be updated)
There is one downside to this approach, the screen shown during the swipe is still the old data (either empty or data from when that page was last updated), this was acceptable to me.

RecyclerView onBindViewHolder called only once inside Tab layout

I've four tabs and four fragments (each one for each tab).
Each fragment has a vertical recycler view. Since all fragments view look similar I'm re-using the same layout file, same recycler view items and same adapter.
The issue is that only one item is loaded under the first tab and third tab and fourth tab, While the second tab successfully loads the entire data.
I hope image added below gives better understanding regarding the issue.
Here is my adapter code
public class OthersAdapter extends RecyclerView.Adapter<OthersAdapter.OthersViewHolder> {
private final Context context;
private final ArrayList<LocalDealsDataFields> othersDataArray;
private LayoutInflater layoutInflater;
public OthersAdapter(Context context, ArrayList<LocalDealsDataFields> othersDataArray) {
this.context = context;
this.othersDataArray = othersDataArray;
if (this.context != null) {
layoutInflater = LayoutInflater.from(this.context);
}
}
class OthersViewHolder extends RecyclerView.ViewHolder implements View.OnClickListener {
TextView othersSmallTitleTextView;
ImageView othersImageView;
OthersViewHolder(View itemView) {
super(itemView);
othersSmallTitleTextView = (TextView) itemView.findViewById(R.id.others_small_title);
othersImageView = (ImageView) itemView.findViewById(R.id.others_image);
itemView.setOnClickListener(this);
}
#Override
public void onClick(View view) {
Intent couponDetailsItem = new Intent(context, LocalDealsActivity.class);
Bundle extras = new Bundle();
extras.putString(Constants.SECTION_NAME, context.getString(R.string.local_deals_section_title));
// Add the offer id to the extras. This will be used to retrieve the coupon details
// in the next activity
extras.putInt(Constants.COUPONS_OFFER_ID, othersDataArray.get(
getAdapterPosition()).getLocalDealId());
couponDetailsItem.putExtras(extras);
context.startActivity(couponDetailsItem);
}
}
#Override
public OthersViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
View view = layoutInflater.inflate(R.layout.others_items, parent, false);
return new OthersViewHolder(view);
}
#Override
public void onBindViewHolder(OthersViewHolder holder, int position) {
String lfImage = othersDataArray.get(position).getLocalDealImage();
String lfCategoryName = othersDataArray.get(position).getLocalDealSecondTitle();
if (lfCategoryName != null) {
// Set the second title
holder.othersSmallTitleTextView.setText(lfCategoryName);
}
if (lfImage != null) {
if (!lfImage.isEmpty()) {
// Get the Uri
Uri lfUriImage = Uri.parse(lfImage);
// Load the Image
Picasso.with(context).load(lfUriImage).into(holder.othersImageView);
}
}
}
#Override
public int getItemCount() {
return othersDataArray.size();
}
}
I like to point out couple of things -
I've checked other answers on Stack Overflow. They talk about setting the recycler view layout_height to wrap_content. This isn't the issue as the layout_height is already wrap_content and also the second tab loads all the data as expected.
And some others answers mentioned to used same versions for all support libraries and I'm already using 25.1.0 version for all the support libraries.
Size of the data array is 20 and returning 20 from the adapter's getItemCount() method.
The data array has the expected number of items in it and they are not null or empty.
Clean build, invalidate/caches doesn't work either.
Finally, I'm using FragmentStatePagerAdapter to load the fragments when the tabs are in focus.
EDIT:
This is how I'm parsing the JSON data received
private void parseLocalDeals(String stringResponse) throws JSONException {
JSONArray localJSONArray = new JSONArray(stringResponse);
// If the array length is less than 10 then display to the end of the JSON data or else
// display 10 items.
int localArrayLength = localJSONArray.length() <= 20 ? localJSONArray.length() : 20;
for (int i = 0; i < localArrayLength; i++) {
// Initialize Temporary variables
int localProductId = 0;
String localSecondTitle = null;
String localImageUrlString = null;
JSONObject localJSONObject = localJSONArray.getJSONObject(i);
if (localJSONObject.has(JSONKeys.KEY_LOCAL_DEAL_ID)) {
localProductId = localJSONObject.getInt(JSONKeys.KEY_LOCAL_DEAL_ID);
}
if (localJSONObject.has(JSONKeys.KEY_LOCAL_DEAL_CATEGORY)) {
localSecondTitle = localJSONObject.getString(JSONKeys.KEY_LOCAL_DEAL_CATEGORY);
}
if (localJSONObject.has(JSONKeys.KEY_LOCAL_DEAL_IMAGE)) {
localImageUrlString = localJSONObject.getString(JSONKeys.KEY_LOCAL_DEAL_IMAGE);
}
if (localImageUrlString != null) {
if (!localImageUrlString.isEmpty()) {
// Remove the dots at the start of the Product Image String
while (localImageUrlString.charAt(0) == '.') {
localImageUrlString = localImageUrlString.replaceFirst(".", "");
}
// Replace the spaces in the url with %20 (useful if there is any)
localImageUrlString = localImageUrlString.replaceAll(" ", "%20");
}
}
LocalDealsDataFields localDealsData = new LocalDealsDataFields();
localDealsData.setLocalDealId(localProductId);
localDealsData.setLocalDealSecondTitle(localSecondTitle);
localDealsData.setLocalDealImage(localImageUrlString);
localDealsDataArray.add(localDealsData);
}
// Initialize the Local Deals List only once and notify the adapter that data set has changed
// from second time. If you initializeRV the localDealsRVAdapter at an early instance and only
// use the notifyDataSetChanged method here then the adapter doesn't update the data. This is
// because the adapter won't update items if the number of previously populated items is zero.
if (localDealsCount == 0) {
if (localArrayLength != 0) {
// Populate the Local Deals list
// Specify an adapter
localDealsRVAdapter = new OthersAdapter(context, localDealsDataArray);
localDealsRecyclerView.setAdapter(localDealsRVAdapter);
} else {
// localArrayLength is 0; which means there are no rv elements to show.
// So, remove the layout
contentMain.setVisibility(View.GONE);
// Show no results layout
showNoResultsIfNoData(localArrayLength);
}
} else {
// Notify the adapter that data set has changed
localDealsRVAdapter.notifyDataSetChanged();
}
// Increase the count since parsing the first set of results are returned
localDealsCount = localDealsCount + 20;
// Remove the progress bar and show the content
prcVisibility.success();
}
parseLocalDeals method is inside a helper class and it is called by using initializeHotels.initializeRV();
initializeRV() initializes the Recycler view, makes a network call to the server and the received data is passed to the parseLocalDeals method. initializeHotels being an instance variable of the Helper class.
EDIT 2:
For those who wants to explore the code in detail, I've moved the part of the code to another project and shared it on Github. Here is the link https://github.com/gSrikar/TabLayout and to understand the hierarchy check out the README file.
Can anyone tell me what I'm missing?

Not much of an answer but too long for a comment.
I have duplicated (almost) your adapter code and it fully works for me. I believe I have done the same as you. I'm using the same layout file, the same item & same adapter for all tabs. I think there are no problems with your adapter code.
I say 'almost' because I had to change a couple of things since I don't have access to your data. I changed your LocalDealsDataField model to include a BitmapDrawable & I changed onBindViewHolder() to handle it.
BitmapDrawable lfImage = othersDataArray.get(position).getLocalDealImage();
holder.othersImageView.setBackground(lfImage);
Since there seems to be no problem with your adapter, I would focus on getting the data or setting up the adapter as your problem. Sorry I can't be of help beyond that.
FYI, here's how I setup the adapter in onCreateView()
rootView = inflater.inflate(R.layout.recycler_view, container, false);
mRecyclerView = (RecyclerView) rootView.findViewById(R.id.recyclerview);
mRecyclerView.setLayoutManager(new LinearLayoutManager(getActivity()));
mAdapter = new OthersAdapter(this.getContext(), list);
mRecyclerView.setAdapter(mAdapter);

Summary
Solved the layout issue at point 1 replacing a LinearLayout by a RelativeLayout, inverting visibility logic to avoid ghost effect and catching exceptions and preventing them when the related view is not found.
Added point 2 to demonstrate that the visual defect is only present on Marshmallow and Nougat devices.
Finally FragmentStatePagerAdapter loads pages before getting focus so a fix is proposed at point 3 (load all pages and update them when are selected).
Further information in the comments below and #d4h answer.
The fourth page is not using the same layout, only the same RecyclerView and id, perhaps a work in progress. The layout issue can be solved using the same layout that previous pages but I consider this change out of scope.
1. Partially fixed for Marshmallow and Nougat devices. Work in progress.
Update2 Changing LinearLayout by RelativeLayout and inverting visibility logic solves layout issue:
Update: Commenting initializeTrending in all the fragment initializations also works onApi23+
I'll check it later, seems as deals are correctly loaded but then trending is loaded and deals are lost. WIP here.
If trending array empty and trending view gone, deals are not shown, but using invisible are shown
2. You are loading a wrong page on Marshmallow and Nougat devices
FragmentStatePagerAdapter first call to getItem() wrong on Nougat devices
This ended up having nothing to do with the FragmentStatePagerAdapter
code. Rather, in my fragment, I grabbed a stored object from an array
using the string ("id") that I passed to the fragment in init. If I
grabbed that stored object by passing in the position of the object in
the array, there was no problem. Only occurs in devices with Android 7.
FragmentStatePagerAdapter - getItem
A FragmentStatePager adapter will load the current page, and one page
either side. That is why it logs 0 and 1 at the same time. When you
switch to page 2, it will load page 3 and keep page 1 in memory. Then
when you get to page 4 it will not load anything, as 4 was loaded when
you scrolled to 3 and there is nothing beyond that. So the int that
you're being given in getItem() is NOT the page that is currently
being viewed, is the one being loaded into memory. Hope that clears
things up for you
These comments are confirmed in this branch and commit
All pages load correctly on Lollipop emulator, the last page has an extra issue, see OthersFragment:
3. Initialize all pages at creation and update them on selection.
Increase OffScreenPageLimit so all pages are initialised
Add on page selected/unselected/reselected listener
These changes solve the issue commented below:
/**
* Implement the tab layout and view pager
*/
private void useSlidingTabViewPager() {
// Create the adapter that will return a fragment for each of the three
// primary sections of the activity.
BottomSectionsPagerAdapter mBottomSectionsPagerAdapter = new BottomSectionsPagerAdapter(getChildFragmentManager());
// Set up the ViewPager with the sections adapter.
ViewPager mBottomViewPager = (ViewPager) rootView.findViewById(R.id.local_bottom_pager);
mBottomViewPager.setOffscreenPageLimit(mBottomSectionsPagerAdapter.getCount());
mBottomViewPager.setAdapter(mBottomSectionsPagerAdapter);
TabLayout tabLayout = (TabLayout) rootView.findViewById(R.id.tab_layout);
tabLayout.setupWithViewPager(mBottomViewPager);
tabLayout.addOnTabSelectedListener(new TabLayout.OnTabSelectedListener() {
/**
* Called when a tab enters the selected state.
*
* #param tab The tab that was selected
*/
#Override
public void onTabSelected(TabLayout.Tab tab) {
// TODO: update the selected page here
Log.i(LOG_TAG, "page " + tab.getPosition() + " selected.");
}
/**
* Called when a tab exits the selected state.
*
* #param tab The tab that was unselected
*/
#Override
public void onTabUnselected(TabLayout.Tab tab) {
// Do nothing
Log.i(LOG_TAG, "Page " + tab.getPosition() + " unselected and ");
}
/**
* Called when a tab that is already selected is chosen again by the user. Some applications
* may use this action to return to the top level of a category.
*
* #param tab The tab that was reselected.
*/
#Override
public void onTabReselected(TabLayout.Tab tab) {
// Do nothing
Log.i(LOG_TAG, "Page " + tab.getPosition() + " reselected.");
}
});
}
Previous Comments:
Check your LocalFragment getItem() method using breakpoints.
If you select one page, next page is also initialized, and you are sharing the recyclerView, etc.
I would move the initialization outside of getItem() as suggested here:
ViewPager is default to load the next page(Fragment) which you can't
change by setOffscreenPageLimit(0). But you can do something to hack.
You can implement onPageSelected function in Activity containing the
ViewPager. In the next Fragment(which you don't want to load), you
write a function let's say showViewContent() where you put in all
resource consuming init code and do nothing before onResume() method.
Then call showViewContent() function inside onPageSelected. Hope this
will help
Read these related questions (the first has possible workarounds to hack the limit to zero):
ViewPager.setOffscreenPageLimit(0) doesn't work as expected
Does ViewPager require a minimum of 1 offscreen pages?
Yes. If I am
reading the source code correctly, you should be getting a warning
about this in LogCat, something like:
Requested offscreen page limit 0 too small; defaulting to 1
viewPager.setOffscreenPageLimit(couponsPagerAdapter.getCount());
public void setOffscreenPageLimit(int limit) {
if (limit < DEFAULT_OFFSCREEN_PAGES) {
Log.w(TAG, "Requested offscreen page limit " + limit + " too small; defaulting to "
+ DEFAULT_OFFSCREEN_PAGES);
limit = DEFAULT_OFFSCREEN_PAGES;
}
if (limit != mOffscreenPageLimit) {
mOffscreenPageLimit = limit;
populate();
}
}

I have looked at your code, problem is same as explained by #ardock
Solution i would like to propose,
You have to change your code at 3 place ::
Inside all Fragment You are using in ViewPager Don't call initializeRESPECTIVEView() from onCreateView method.
Inside LocalFragment make a list of Fragments you are going to use with ViewPager and pass it to BottomSectionsPagerAdapter. and return Fragment from that list from getItem(int position) of BottomSectionsPagerAdapter.
Add Following code to LocalFragment inside useSlidingTabViewPager().
tabLayout.addOnTabSelectedListener(new TabLayout.OnTabSelectedListener() {
#Override
public void onTabSelected(TabLayout.Tab tab) {
}
#Override
public void onTabUnselected(TabLayout.Tab tab) {
}
#Override
public void onTabReselected(TabLayout.Tab tab) {
}
});
//Call Respective fragment initializeRESPECTIVEView() method from onTabSelected , you can get fragment instance from list you passed to BottomSectionsPagerAdapter

Android - ViewPager Adapter, set primary item before adapter is instantiated

I know i can do
viewPager.setCurrentItem(position)
to set my view pager at the desired position. My question is if and how i can do this before the adapter is instantiated.
Meaning that if I do
pagerAdapter = new ViewPagerAdapter(arg1,arg2....);
viewPager.setAdapter(pagerAdapter);
viewPager.setCurrentItem(position);
item 0 is first build and after that the item at the desired position is also build. Which takes double the time...In my adapter each item needs quite a lot of work to be build, so it would be best to avoid the 0 position item to be build if possible. Maybe by passing the desired position as an argument at the adapter's instantiation...?
Any way to do that?

If the time and work is what you're worry about, I'd try to avoid building the page at position 0 until the desired one has been built. You could use a variable lets say "desiredPageHasBeenBuilt" in your adapter, when requesting the item at position 0 you could return an "empty page" if the variable desiredPageHasBeenBuilt is false, when your desired page has been build set the variable to true and the page 0 can be built.

For a solution that works in Android M as well as older versions, use reflection as follows:
int currentItem = 5;
// Set initial position first...
Field field = ViewPager.class.getDeclaredField("mRestoredCurItem");
field.setAccessible(true);
field.set(mPager, currentItem);
// ...and then set adapter
mPager.setAdapter(adapter);
Using reflection is safe, because you control the ViewPager implementation (it's included with your app).
If you use Proguard, then you need to include the following in its config:
-keepclassmembers class android.support.v4.view.ViewPager {
private int mRestoredCurItem;
}
or the field mRestoredCurItem will be renamed by Proguard.

You can just set blank adapter and after that set your real adapter this way you will "trick" the viewpager and you want load any data you dont want to.
this.viewPager.setAdapter(new PagerAdapter() {
#Override
public int getCount() {
return 0;
}
#Override
public boolean isViewFromObject(View view, Object object) {
return false;
}
});
this.viewPager.setCurrentItem(imagePosition, false);
this.viewPager.setAdapter(adapter);
this.viewPager.setCurrentItem(imagePosition, false);

You can fool the viewpager to start at a given position before the adapter is set, by calling onRestoreInstanceState, like this:
int currentItem = 5;
Parcel parcel = Parcel.obtain();
writeParcelable(BaseSavedState.EMPTY_STATE, 0);
writeInt(currentItem);
writeParcelable(null, 0);
setDataPosition(0);
SavedState savedState = ViewPager.SavedState.CREATOR.createFromParcel(parcel);
mPager.onRestoreInstanceState(savedState);
mPager.setAdapter(mAdapter);

Maybe this is not the answer you're looking for, but have you tried to it as it was designed? Do not start heavy work on page fragment before it is attached to the screen. That way you'll get that behavior you want without hacking android implementation.

you can do this trick:
refactor all of your heavy work into a function, because creating a fragment is not takes much time, and only execute the function when user is going to see it by calling that function inside OnPageChangeListener listener and at the
#Override
public void onPageSelected(int position){
// call your function that do heavy working
}

Getting the current position of a ViewPager

I know with the Gallery widget I was able to use getSelectedItemPosition(); to retrieve the current position, however it doesnt seem ViewPager has that.
I know I can setup a listener and retrieve the position when the page is switched. But I want the current view position.

You can use:
mViewPager.getCurrentItem()

Create a listener and set it on your viewpager:
/**
* Get the current view position from the ViewPager by
* extending SimpleOnPageChangeListener class and adding your method
*/
public class DetailOnPageChangeListener extends ViewPager.SimpleOnPageChangeListener {
private int currentPage;
#Override
public void onPageSelected(int position) {
currentPage = position;
}
public final int getCurrentPage() {
return currentPage;
}
}

Update 2019
Now you can set addOnPageChangeListener on View Pager to Observe change in Page position.
Since you wanted to setup a listener and retrieve the position when the page is switched
mViewPager.addOnPageChangeListener(object : OnPageChangeListener {
override fun onPageScrollStateChanged(state: Int) {}
override fun onPageScrolled(position: Int, positionOffset: Float, positionOffsetPixels: Int) {}
override fun onPageSelected(position: Int) {
pagePosition.setText("" + position + "/" + galleryAdapter!!.count)
}
})

My solution would only work if you have a TabLayout linked to your ViewPager.
This is how they're linked:
tabLayout.setupWithViewPager(viewPager);
And then to get current position, you can make use of:
tabLayout.getSelectedTabPosition()

I'm telling you now its a hack, so there is no reason to downvote for that reason. Meaning, it either will be helpful to you specifically or not. Either way, the description below will provide some insight and be helpful to the community. Also, this solution is good for the older APIs that don't have ViewPager.getCurrentItem().
First, a little information. If you iterate thru all children of a ViewPager with ViewPager.getChildAt(x); and print out with toString() (or getLeft()) each child View (a page) and then do this everytime you change pages, you will notice that the children will not be in the logical order that they are displayed in when you start going back pages (paging back to the beginning). Apparently, it will remove the unneeded child from the array then append the newest child to the array. So, for example, lets say you are looking at page 2 then changed to page 3, your list of children will be in this order page 2, page 3, page 4 meaning that ViewPager.getChildAt(1); will return the current page. But, if you then change back to page 2 (from page 3) your list of children will be in this order page 2, page 3, page 1 which means that ViewPager.getChildAt(1); does not return the current page. I have not yet been able to find simple logic to weed out the current page using this information. Because the order of the pages in the array behind getChildAt is in an arbitrary order based off of how the user has been paging around.
That being said, I developed a hack work-around. I have no clue if this function will work in all in environments, but it works for my current project. I would suspect if doesn't for you, then its an issue of different API level. But I dont actually suspect any issues for other environments.
Now, onto the meat. What I noticed was that the result of ViewPager.getChildAt(x).getLeft() will have some type of horizontal pixel coordinate relative to the parent. So, I used this information to weed out which view is the current one.
private int getCurrentPageIndex(ViewPager vp){
int first,second,id1,id2,left;
id1 = first = second = 99999999;
View v;
for ( int i = 0, k = vp.getChildCount() ; i < k ; ++i ) {
left = vp.getChildAt(i).getLeft();
if ( left < second ) {
if ( left < first ) {
second = first;
id2 = id1;
first = left;
id1 = i;
} else {
second = left;
id2 = i;
}
}
}
return id2;
}
This function is probably a questionable hack because it relies on the value of getLeft() to figure it all out. But, I grab the left coordinate of each child. I then compare this to the other values and store the first and second pages, returning the second page (current page) out of the function. It seems to work beautifully.
Why (might you ask) didn't I just use onClickListenter or whatever solution? Well, I was darned determined that there was a straight forward way to do this without having to include listeners, other classes, inconclusive focus, and other bloat. Unfortunately, this solution is not exactly straight forward. But, it does do away with the bloat, other classes and listeners. If I can figure out a more straight forward way, I will be rewriting this function. Or maybe, this will provide insight for someone else to have an epiphany.

ListView/ListAdapter paging

I'm trying to implement paging in a custom ListAdapter. Right now I'm just making the request for the next page when the last item in the ListView becomes visible, by checking in getView() if position is >= the size of ListAdapter.getCount().
It works fine, but I'm wondering if there's a better way (or a different way) that will only make the request once the last item in the list is actually visible to the user. Anyone know of a way?

I'm doing it almost the same way:
public static final int SCROLLING_OFFSET = 5;
// ...
private final ArrayList<T> items = new ArrayList<T>();
// ...
if (SCROLLING_OFFSET == items.size() - position) {
if (hasNextPage()) {
addNextPage();
}
}
private boolean hasNextPage() {
// basically calculates whether the last 2 pages contained the same # of items
}
private void addNextPage() {
// show spinner
// fetch next page in a background thread
// add to items
notifyDataSetChanged();
}

I think there is a better way to do it. Implementing the OnScrollListener interface. Take a look at this: Endless Scrolling ListView

Try removing the check altogether. In my experience, getView() is only called when the entry is about to come on screen.