Can't communicate with fragments in ViewPager after orientation change - android

I have a tab that holds a view pager with 5 fragments in it.
When onPageSelected is called then I tell the current fragment to animate up using
((ItemFragment) pagerAdapter.getItem(position)).animateUp();
and Inside the fragment
public void animateUp(){
if(linearLayout != null){
linearLayout.animate().translationYBy(-75));
}
}
Everything seems to work fine until I rotate the device. The fragments are shown and I can move them but the animateUp() method doesn't do anything. It seems like the viewpager doesn't have a reference to the fragments being shown.
Edit: onCreate is empty, here is onCreateView
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
ViewGroup rootView = (ViewGroup) inflater.inflate(R.layout.fragment_explore_tab, container, false);
pager = (MultiViewPager)rootView.findViewById(R.id.pager);
List<Fragment> fragmentsList = new ArrayList<>();
for(int i = 0; i < header.length; i++){
ItemFragment fragment = new ItemFragment();
Bundle bundle = new Bundle();
bundle.putInt(ItemFragment.IMAGE_KEY, header[i]);
fragment.setArguments(bundle);
fragmentsList.add(fragment);
}
pager.addOnPageChangeListener(new OnPageChangeListener() {
#Override
public void onPageScrolled(int position, float positionOffset, int positionOffsetPixels) {
}
#Override
public void onPageSelected(int position) {
((ItemFragment) pagerAdapter.getItem(position)).animateUp();
}
#Override
public void onPageScrollStateChanged(int state) {
}
});
pagerAdapter = new BaseFragmentPagerAdapter(getChildFragmentManager(), fragmentsList);
pager.setAdapter(pagerAdapter);
return rootView;
}

if(linearLayout != null){ *your listener change to null when you rotate device*
linearLayout.animate().translationYBy(-75)); }
You must subscribe listener once more. Try to do this in onResume

Related

Android: Fragments inside the ViewPager not showing

I have a Fragment. This fragment contains a view pager where the view page has multiple fragments. I can scroll the pages but seeing nothing even though getItem did call when scroll and initialised the fragment.
I have changed the code with support.v4.app.Fragment and support.v4.app.FragmentManager and change the main activity to FragmentActivity. In addition, I use getChildFragmentManager to the adapter but still can't showing anything.
I also change the line below to return true always but it can show the first fragment. Subsequent fragment aren't showing and behave badly when start paging it.
#Override
public boolean isViewFromObject(View view, Object object) {
return true;
}
Below is the code I implement the ViewPager.
public class AppsPagerAdapter extends FragmentPagerAdapter {
private int appsSize;
private int appsPerPage = 12;
private Activity activity;
public AppsPagerAdapter (Activity activity1, FragmentManager manager, int size)
{
super(manager);
appsSize = size;
activity = activity1;
}
#Override
public int getCount() {
int offset = appsSize % appsPerPage;
int pageExtra = (offset > 0)? 1: 0;
return appsSize / appsPerPage + pageExtra;
}
#Override
public boolean isViewFromObject(View view, Object object) {
return view == object;
}
public Fragment getItem(int position) {
Bundle bundle = new Bundle();
bundle.putInt (AppPageFragment.PAGE_NUMBER_PARAMS, position);
return Fragment.instantiate(activity, AppPageFragment.class.getName(), bundle);
}
}
Outer Fragment:
#Override
public View onCreateView (LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState)
{
View view = inflater.inflate (R.layout.fragment_all_app, container, false);
ViewPager appsPager = (ViewPager) view.findViewById(R.id.grid_allapps);
//adapter = new AppsPagerAdapter(((AppCompatActivity)getActivity()).getSupportFragmentManager(), GlobalData.getInstance().getApps().getAll().size());
adapter = new AppsPagerAdapter(getActivity(), getChildFragmentManager(), GlobalData.getInstance().getApps().getAll().size());
appsPager.setAdapter(adapter);
appsPager.addOnPageChangeListener(pageChangeListener);
return view;

How to get current page index in fragment of viewpager?

My app is an icon view like app drawer
Each page has 12 icons, if more than 12 icons, other icons will display in next page.
I use viewpager and gridview to implement this interface, Each fragment of viewpager has a gridview to display items.
In FragmentActivity, I can get the current page index by adding OnPageChangeListener to viewpager.
viewPager.addOnPageChangeListener(new ViewPager.OnPageChangeListener() {
#Override
public void onPageScrolled(int position, float positionOffset, int positionOffsetPixels) {
}
#Override
public void onPageSelected(int position) {
}
#Override
public void onPageScrollStateChanged(int state) {
}
});
But I cannot get the index in fragment
public class MyFragment extends Fragment {
public static final String EXTRA_MESSAGE = "EXTRA_MESSAGE";
public static final MyFragment newInstance(String message)
{
MyFragment f = new MyFragment();
Bundle bdl = new Bundle(1);
bdl.putString(EXTRA_MESSAGE, message);
f.setArguments(bdl);
return f;
}
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
String message = getArguments().getString(EXTRA_MESSAGE);
View v = inflater.inflate(R.layout.fragment, container, false);
//suppose the list has 15 items now
ArrayList list=new ArrayList();
list.add(1);
list.add(2);
list.add(3);
list.add(4);
list.add(5);
list.add(6);
list.add(7);
list.add(8);
list.add(9);
list.add(10);
list.add(11);
list.add(12);
list.add(13);
list.add(14);
list.add(15);
GridView gridview = (GridView) v.findViewById(R.id.gridview);
int currentIndex=??? //how to get index?
if(currentIndex==0){
gridview.setAdapter(new GridViewAdapter(list.subList(0,12));
} else if (currentIndex==1) {
gridview.setAdapter(new GridViewAdapter(list.subList(12,15));
}
return v;
}
}
The fragment in different page should display different sub list of items, how get index in fragment?
There is a method named getItem(int position) you will have to override when you create your FragmentPagerAdapter. You can pass the index there.
Since you have this:
public static final MyFragment newInstance(String message)
{
MyFragment f = new MyFragment();
Bundle bdl = new Bundle(1);
bdl.putString(EXTRA_MESSAGE, message);
f.setArguments(bdl);
return f;
}
You can put your index in your bdl and get it later in your onCreate()
You should get reference to viewPager in your fragment and just read it.
viewPager.getCurrentItem()
http://developer.android.com/reference/android/support/v4/view/ViewPager.html#getCurrentItem%28%29

ViewPager inside fragment, how to retain state?

In my application the fragment activity holds two fragments, Fragment A and Fragment B. Fragment B is a view pager that contains 3 fragments.
In my activity, to prevent that the fragment is recreated on config changes:
if(getSupportFragmentManager().findFragmentByTag(MAIN_TAB_FRAGMENT) == null) {
getSupportFragmentManager().beginTransaction().replace(R.id.container, new MainTabFragment(), MAIN_TAB_FRAGMENT).commit();
}
Code for Fragment B:
public class MainTabFragment extends Fragment {
private PagerSlidingTabStrip mSlidingTabLayout;
private LfPagerAdapter adapter;
private ViewPager mViewPager;
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setRetainInstance(true);
}
#Nullable
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
return inflater.inflate(R.layout.fragment_tab, container, false);
}
#Override
public void onViewCreated(View view, Bundle savedInstanceState) {
this.adapter = new LfPagerAdapter(getChildFragmentManager());
this.mViewPager = (ViewPager) view.findViewById(R.id.viewpager);
this.mViewPager.setAdapter(adapter);
this.mSlidingTabLayout = (PagerSlidingTabStrip) view.findViewById(R.id.sliding_tabs);
this.mSlidingTabLayout.setViewPager(this.mViewPager);
}
}
Code for the adapter:
public class LfPagerAdapter extends FragmentPagerAdapter {
private static final int NUM_ITEMS = 3;
private FragmentManager fragmentManager;
public LfPagerAdapter(FragmentManager fm) {
super(fm);
this.fragmentManager = fm;
}
#Override
public int getCount() {
return NUM_ITEMS;
}
#Override
public Fragment getItem(int position) {
Log.d("TEST","TEST");
switch (position) {
case 1:
return FragmentC.newInstance();
case 2:
return FragmentD.newInstance();
default:
return FragmentE.newInstance();
}
}
}
My problem is that I am not able to retain the state of the view pager an its child fragments on orientation changes.
Obviously this is called on every rotation:
this.adapter = new LfPagerAdapter(getChildFragmentManager());
which will cause the whole pager to be recreated, right? As a result
getItem(int position)
will be called on every rotation and the fragment will be created from scratch and losing his state:
return FragmentC.newInstance();
I tried solving this with:
if(this.adapter == null)
this.adapter = new LfPagerAdapter(getChildFragmentManager());
in onViewCreated but the result was that on rotation the fragments inside the pager where removed.
Any ideas how to correctly retain the state inside the pager?
You will need to do 2 things to resolve the issue:
1) You should use onCreate method instead of onViewCreated to instantiate LfPagerAdapter;
i.e.:
public class MainTabFragment extends Fragment {
private PagerSlidingTabStrip mSlidingTabLayout;
private LfPagerAdapter adapter;
private ViewPager mViewPager;
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setRetainInstance(true);
this.adapter = new LfPagerAdapter(getChildFragmentManager());
}
#Nullable
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
return inflater.inflate(R.layout.fragment_tab, container, false);
}
#Override
public void onViewCreated(View view, Bundle savedInstanceState) {
this.mViewPager = (ViewPager) view.findViewById(R.id.viewpager);
this.mViewPager.setAdapter(adapter);
this.mSlidingTabLayout = (PagerSlidingTabStrip) view.findViewById(R.id.sliding_tabs);
this.mSlidingTabLayout.setViewPager(this.mViewPager);
}
}
2) You will need to extend FragmentStatePagerAdapter instead of FragmentPagerAdapter
Android will automatically recreate your activity on configuration without this line android:configChanges="keyboardHidden|orientation|screenSize" in you manifest so that you can handle onConfiguration change yourself.
The only way then is to use onSaveInstanceState() in both your activityFragement to save viewPager state(current position for example) and in fragments where you need to save stuff
Example on how you can save current position of viewpager and restore it onConfiguration change
#Override
public void onSaveInstanceState(Bundle outState) {
super.onSaveInstanceState(outState);
int position = mViewPager.getCurrentItem();
outState.Int("Key", position );
}
#Override //then restore in on onCreate();
public void onCreated(Bundle savedInstanceState) {
super.onCreated(savedInstanceState);
// do stuff
if (savedInstanceState != null) {
int position= savedInstanceState.getInt("Key");
mViewPager.setCurrentItem(position)
}
}
Of course, this is a very basic example.
Ps: to restore in fragment use onActivityCreated() instead of onCreate() method.
Here is another example on how to retain state : Click me!

ViewPager with multiple fragment instances of same class

I am trying to create a ViewPager which contains 5 fragments.
5 fragments "container", so each of them contain 2 fragments.
The 4 first fragments have the same layout and belong to the same class. The fifth is from an other class, and there is no problem with that one.
The problem is that when the activity launches, only 1 fragment seem to be working (the one at position 0 in viewPager). I tried to return new Fragment() at position 0 in my PagerAdapter, but when I do that it's the 2nd fragment that is working. (By working i mean displaying the list on the left, I still haven't taken care of the details fragment on the right)
Here is some code
CustomPagerAdapter.java
public class CustomPagerAdapter extends FragmentPagerAdapter{
public CustomPagerAdapter(FragmentManager fm) {
super(fm);
}
public CustomPagerAdapter(FragmentManager fm, Context context) {
super(fm);
}
#Override
public Fragment getItem(int pos) {
if(pos == 4)
return new OtherContainerFragment();
else
return new ContainerFragment(pos);
}
#Override
public int getCount() {
return 5;
}
ContainerFragment.java
public class ContainerFragment extends Fragment {
private int CONTAINER_TYPE;
public ContainerFragment(){
}
public ContainerFragment(int type){
CONTAINER_TYPE = type;
}
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
}
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
return inflater.inflate(R.layout.fragment_container, container, false);
}
#Override
public void onViewCreated(View view, Bundle savedInstanceState) {
super.onViewCreated(view, savedInstanceState);
FragmentTransaction ft = getActivity().getSupportFragmentManager().beginTransaction();
CustomListFragment frag = new CustomListFragment(CONTAINER_TYPE);
ft.replace(R.id.replaceable_list, frag);
ft.commit();
CustomListFragment.java
public class CustomListFragment extends SuperCustomListFragment{
private ArrayList<Model> mModels;
private int TYPE;
public CustomListFragment(){
}
public CustomListFragment(int type){
TYPE = type;
}
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
}
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
return super.onCreateView(inflater, container, savedInstanceState);
}
#Override
public void onViewCreated(View view, Bundle savedInstanceState) {
super.onViewCreated(view, savedInstanceState);
mModels = new ArrayList<Model>();
if(TYPE == AppConstants.FRAGMENT_TYPE_JOURNAL){
mAdapter = AppUtils.getJournalListAdapter(getActivity(), mModels);
new syncPapers().execute();
}else if(TYPE == AppConstants.FRAGMENT_TYPE_MOVIES){
mAdapter = AppUtils.getMoviesListAdapter(getActivity(), mModels);
new syncMovies().execute();
}
if(mAdapter != null)
mListView.setAdapter(mAdapter); //mListView is defined in the superClass
Here are the constants I use :
public class AppConstants {
public static final int FRAGMENT_TYPE_AGENDA = 0; //so Fragment at position 0 should be of type agenda
public static final int FRAGMENT_TYPE_NEWS = 1; // position 1 should be of type news
public static final int FRAGMENT_TYPE_MOVIES = 2; // ...
public static final int FRAGMENT_TYPE_JOURNAL = 3; // ...
}
And the xml for the container :
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="horizontal" >
<LinearLayout
android:id="#+id/replaceable_list"
android:layout_width="match_parent"
android:layout_height="match_parent" >
</LinearLayout>
<LinearLayout
android:id="#+id/replaceable_details"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:layout_weight="1"
android:background="#drawable/background" >
</LinearLayout>
</LinearLayout>
SO this code is not working, it seems that the list on the left in the fragment container is replaced in each fragment, and only the fragment at position 0 displays it. (Currently it displays the list with the adapter of type "JOURNAL", but it should display list of type "AGENDA".
--------------------
*BUT !...*
--------------------
If I create different fragment_container layout-files, and write IF conditions in the onCreateView and onViewCreated in the ContainerFragment.java, everything works fine.
So :
ContainerFragment.java
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
if(CONTAINER_TYPE == AppConstants.FRAGMENT_TYPE_JOURNAL)
return inflater.inflate(R.layout.fragment_container_journal, container, false);
else if(CONTAINER_TYPE == AppConstants.FRAGMENT_TYPE_MOVIES)
return inflater.inflater(R.layout.fragment_container_movies, container, false);
else
return super.onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState);
}
#Override
public void onViewCreated(View view, Bundle savedInstanceState) {
super.onViewCreated(view, savedInstanceState);
FragmentTransaction ft = getActivity().getSupportFragmentManager().beginTransaction();
CustomListFragment frag = new CustomListFragment(CONTAINER_TYPE);
if(CONTAINER_TYPE == AppConstants.FRAGMENT_TYPE_JOURNAL)
ft.replace(R.id.replaceable_journal_list, frag);
else if(CONTAINER_TYPE == AppConstants.FRAGMENT_TYPE_MOVIES)
ft.replace(R.id.replaceable_movies_list, frag);
else
return;
ft.commit();
I guess that's because in each fragment, I replace the LinearLayout of the same ID ? (replaceable_list)
I thought it was possible to share the same layout file for every fragments and didn't want to create 4 layout-files that would be the same. But it looks like I must do so ?
Or am I missing something here ?
Thank you for your time,
Though a very late response but I was facing same kind of issue and I fixed the issue by using
getChildFragmentManager().beginTransaction()
instead of
getActivity().getSupportFragmentManager().beginTransaction()
As in this case we are trying to make transaction from within a fragment (one out of the list of fragments which are attached to the ViewPager, thus the Activity holding the ViewPager) so we have to use getChildFragmentManager() here for desired results.
I was able to solve this by setting the id of the layout that is inflated within each fragment to its position.
What you would have to do is simply change the method onCreateView in you ContainerFragment class to:
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
View v = inflater.inflate(R.layout.fragment_container, container, false);
v.setId(CONTAINER_TYPE)
return v;
This works because of the way the FragmentPagerAdapter implementation handles fragment tags.

Circular ViewPager which uses FragmentPagerAdapter

I would like to implement a ViewPager which uses Fragments and can be swiped in a curcular motion e.g. Page (A<-->B<-->C<-->A).
I have read a couple of posts on how this is done, e.g. returning a fake count of how many elements there are and setting the position at the start in the middle.
how to create circular viewpager?
These all seem to be based of a PagerAdapter. When I try to do a similar thing while extending FragmentPagerAdapter, as soon as I return a fakeCount of pages I get an exception when I Swipe through my Fragments, I only have 2 Fragments.
Exception: java.lang.IllegalStateException: Can't change tag of fragment.
I think this is caused as the FragmentManager thinks I am in position 2 but position 2 points to the fragment at position 0. Does anyone know how I can avoid this? I am thinking I should experiment with extending Fragmentmanager. Any examples or help with this would be greatly appreciated.
I know it is a bit late but this is how it worked for me:
I needed a circular swipe between 3 fragments, so I made those 3 and two more virtual to help me implement the page looping:
public static class FirstViewFragment extends Fragment {
// Empty Constructor
public FirstViewFragment() {
}
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
return inflater.inflate(R.layout.fragment_landing_1, container, false);
}
}
public static class SecondViewFragment extends Fragment {
// Empty Constructor
public SecondViewFragment() {
}
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
return inflater.inflate(R.layout.fragment_landing_2, container, false);
}
}
public static class ThirdViewFragment extends Fragment {
// Empty Constructor
public ThirdViewFragment() {
}
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
return inflater.inflate(R.layout.fragment_landing_3, container, false);
}
}
And two more virtual fragments that enabled me to swipe left from the first and right from the last. The first virtual inflates the same layout as the last actual and the last virtual the same layout as the first actual:
public static class StartVirtualFragment extends Fragment {
public StartVirtualFragment() {}
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
return inflater.inflate(R.layout.fragment_landing_3, container, false);
}
}
public static class EndVirtualFragment extends Fragment {
public EndVirtualFragment() {}
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
return inflater.inflate(R.layout.fragment_landing_1, container, false);
}
}
My Adapter:
private class ViewPagerAdapter extends FragmentPagerAdapter {
public ViewPagerAdapter(FragmentManager fm) {
super(fm);
}
#Override
public Fragment getItem(int i) {
switch (i) {
case 0:
return new StartVirtualFragment();
case 1:
if (firstViewFragment == null) {
firstViewFragment = new FirstViewFragment();
}
return firstViewFragment;
case 2:
if (secondViewFragment == null) {
secondViewFragment = new SecondViewFragment();
}
return secondViewFragment;
case 3:
if (thirdViewFragment == null) {
thirdViewFragment = new ThirdViewFragment();
}
return thirdViewFragment;
case 4:
return new EndVirtualFragment();
}
return null;
}
#Override
public int getCount() {
return 5;
}
}
And my page listener I used the onPageScrollStateChanged to set the correct page and implement the loop:
viewPager.setOnPageChangeListener(new ViewPager.OnPageChangeListener() {
#Override
public void onPageScrolled(int position, float positionOffset, int positionOffsetPixels) {
}
#Override
public void onPageSelected(int position) {
}
#Override
public void onPageScrollStateChanged(int state) {
if (state == ViewPager.SCROLL_STATE_DRAGGING) {
int pageCount = viewPager.getChildCount();
int currentItem = viewPager.getCurrentItem();
if (currentItem == 0) {
viewPager.setCurrentItem(pageCount - 2, false);
} else if (currentItem == pageCount - 1) {
viewPager.setCurrentItem(1, false);
}
}
}
});
And in the end:
viewPager.setCurrentItem(1);
Hope I helped
I have a project in the GitHub with some widgets I've created. Here it its:
https://github.com/CyberEagle/AndroidWidgets
In the following package, there are the adapters to be used with the CircularViewPager:
https://github.com/CyberEagle/AndroidWidgets/tree/master/src/main/java/br/com/cybereagle/androidwidgets/adapter
First, you will use CircularViewPager instead of ViewPager in your layout. The CircularViewPager is here: https://github.com/CyberEagle/AndroidWidgets/blob/master/src/main/java/br/com/cybereagle/androidwidgets/view/CircularViewPager.java
This ViewPager expects a WrapperCircularPagerAdapter, instead of a PagerAdapter. This wrapper is used to trick the ViewPager, making it to think there are a lot of items in the ViewPager, but it actually repeat your items to make the circular effect. So, instead of implementing either PagerAdapter, FragmentPagerAdapter or FragmentStatePagerAdapter, you will implement either CircularFragmentPagerAdapter, CircularFragmentStatePagerAdapter or CircularPagerAdapter. Then, you will wrap your adapter with the WrapperCircularPagerAdapter and set the wrapper in the CircularViewPager, instead of your adapter. Also, when it's time to notify dataset changed, you will call the notifyDatasetChanged() in the wrapper.
When implementing one of the circular adapter, you will notice that instead of implementing instantiateItem, you will have to implement instantiateVirtualItem. For the fragment's pager adapter, you will implement getVirtualItem instead of getItem. That is because I've created the concept of virtual items.
To make it clear, imagine a view pager with 4 items, giving that each item represents a music. When you go all the way to left, you will see the 4th item in the left of the first. Actually, it's a whole new item, but it's linked to the virtual item that represents the 4th music.
Another example: imagine there's only one music now. You will see the same music on the left and on the right. There're 3 items at a time, but only one virtual item.
So, as explained, the Wrapper is tricking the ViewPager, making it think that there are a lot of items. To make it more difficult for the user to reach one of the ends of the ViewPager (it'd take a long time anyway), everytime a change happens to the dataset, the ViewPager goes to the same virtual item, but to one of the real items near the middle.
One more important thing is that the CircularViewPager has the method setCurrentVirtualItem. This method calculates which real item is the nearest desired virtual item and then it uses the setCurrentItem to set it. You have also the option to use the getCurrentVirtualItem, that will return the index of the current virtual item. Notice that if you use getCurrentItem, you'll get a large index.
Well, this is it. I'm sorry for the lack of documentation of the project. I'm planning document it soon. I'm also planning to remove the need for the wrapper. Feel free to copy the code (respecting the Apache 2.0 license), to fork or even contribute to it.
**If you want to make 3 views visible at same time and make it circular**
public abstract class CircularPagerAdapter extends PagerAdapter{
private int count;
int[] pagePositionArray;
public static final int EXTRA_ITEM_EACH_SIDE = 2;
private ViewPager.OnPageChangeListener pageChangeListener;
private ViewPager viewPager;
public CircularPagerAdapter(final ViewPager pager, int originalCount ) {
super();
this.viewPager = pager;
count = originalCount + 2*EXTRA_ITEM_EACH_SIDE;
pager.setOffscreenPageLimit(count-2);
pagePositionArray = new int[count];
for (int i = 0; i < originalCount; i++) {
pagePositionArray[i + EXTRA_ITEM_EACH_SIDE] = i;
}
pagePositionArray[0] = originalCount - 2;
pagePositionArray[1] = originalCount -1;
pagePositionArray[count - 2] = 0;
pagePositionArray[count - 1] = 1;
pager.setOnPageChangeListener(new ViewPager.OnPageChangeListener() {
public void onPageSelected(final int position) {
if(pageChangeListener != null)
{
pageChangeListener.onPageSelected(pagePositionArray[position]);
}
pager.post(new Runnable() {
#Override
public void run() {
if (position == 1){
pager.setCurrentItem(count-3,false);
} else if (position == count-2){
pager.setCurrentItem(2,false);
}
}
});
}
public void onPageScrolled(int position, float positionOffset, int positionOffsetPixels) {
if(pageChangeListener != null)
{
pageChangeListener.onPageScrolled(pagePositionArray[position],positionOffset,positionOffsetPixels);
}
}
public void onPageScrollStateChanged(int state) {
if(pageChangeListener != null)
{
pageChangeListener.onPageScrollStateChanged(state);
}
}
});
}
#Override
public int getCount() {
return count;
}
#Override
public boolean isViewFromObject(View view, Object object) {
return false;
}
public abstract Object customInstantiateItem(ViewGroup container, int position);
public void setPageChangeListener(ViewPager.OnPageChangeListener pageChangeListener)
{
this.pageChangeListener = pageChangeListener;
}
#Override
public Object instantiateItem(ViewGroup container, int position) {
int pageId = pagePositionArray[position];
return customInstantiateItem(container,pageId);
}
#Override
public void destroyItem(View container, int position, Object object) {
((ViewPager) container).removeView((View) object);
}
public void setFirstItem()
{
viewPager.setCurrentItem(EXTRA_ITEM_EACH_SIDE - 1);
}
}

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