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Unable to design viewpager in the layout with dynamic data

I'm new in android and want an app with viewpager. I am unable to design the viewpager in the layout. The layout fetch the data dynamatically. I want to create a matreial UI viewpager which swipes the page left or right like a paper.I have made a view which shows the data but is unable to swipe like a viewpager left or right...
The code is as below:
public class DetailNewsActivity extends AppCompatActivity {
private PullToZoomScrollViewEx scrollView;
private ArrayList<NewsItemModel> newsArr;
private TextView tvNewsTitle;
private TextView tvNewsPublishDate;
private TextView tvNewsFull;
private int newsPosition = 0;
private ImageView ivYoutubeEnable;
private SharedPreferences sharedPref;
int textSize = 16;
boolean isHighQuality = false;
private Typeface typeface;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_detail_news);
init();
AdView mAdView = (AdView) findViewById(R.id.adView);
AdRequest adRequest = new AdRequest.Builder()
.addTestDevice("5745FD6726ACCBEE8324DB158D021FA5")
.build();
mAdView.loadAd(adRequest);
}
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
View view = inflater.inflate(R.layout.activity_detail_news, container, false);
return view;
}
private void init() {
typeface = Typeface.createFromAsset(getAssets(), "AnmolUni.ttf");
// newsArr = (ArrayList<NewsItemModel>) getIntent().getSerializableExtra("newsArray");
newsArr = AppController.getAppController().getMainNewsArr();
AppController.getAppController().setMainNewsArr(null);
newsPosition = getIntent().getIntExtra("newsPosition", 0);
findViewById(R.id.iv_back).setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
finish();
}
});
findViewById(R.id.iv_share).setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
generateBranchURL(newsPosition);
}
});
sharedPref = getSharedPreferences(Constants.SHARED_PREF_NAME, Context.MODE_PRIVATE);
textSize = sharedPref.getInt("text_size", 16);
isHighQuality = sharedPref.getBoolean("isHighQuality",false);
loadViewForCode();
scrollView = (PullToZoomScrollViewEx) findViewById(R.id.scroll_view);
setNewsFromArray(newsPosition);
// ((ImageView) scrollView.getZoomView().findViewById(R.id.iv_zoom)).setImageResource(android.R.drawable.arrow_down_float);
(scrollView.getZoomView().findViewById(R.id.iv_zoom)).setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View view) {
Intent intent = new Intent(DetailNewsActivity.this, ImageVideoActivity.class);
intent.putExtra("viewType", "image");
if(isHighQuality)
intent.putExtra("imageArr", newsArr.get(newsPosition).getImage());
else
intent.putExtra("imageArr", newsArr.get(newsPosition).getMedium());
startActivity(intent);
}
});
DisplayMetrics localDisplayMetrics = new DisplayMetrics();
getWindowManager().getDefaultDisplay().getMetrics(localDisplayMetrics);
int mScreenHeight = localDisplayMetrics.heightPixels;
int mScreenWidth = localDisplayMetrics.widthPixels;
LinearLayout.LayoutParams localObject = new LinearLayout.LayoutParams(mScreenWidth, (int) (9.0F * (mScreenWidth / 16.0F)));
scrollView.setHeaderLayoutParams(localObject);
scrollView.setParallax(true);
// scrollView.getPullRootView().findViewById(R.id.container_layout).setOnTouchListener(new OnSwipeTouchListener(DetailNewsActivity.this) {
scrollView.getPullRootView().setOnTouchListener(new OnSwipeTouchListener(DetailNewsActivity.this) {
#Override
public void onSwipeLeft() {
if (newsPosition < newsArr.size() - 1) {
newsPosition++;
setNewsFromArray(newsPosition);
} else {
CommonUtils.showToast(DetailNewsActivity.this, "No more news");
}
}
#Override
public void onSwipeRight() {
if (newsPosition > 0) {
newsPosition--;
setNewsFromArray(newsPosition);
} else {
CommonUtils.showToast(DetailNewsActivity.this, "This is the first news");
}
}
});
scrollView.setOnPullZoomListener(new PullToZoomBase.OnPullZoomListener() {
#Override
public void onPullZooming(int newScrollValue) {
Log.d("MainActivity", "onPullZooming: " + newScrollValue);
// Intent intent = new Intent(DetailNewsActivity.this, ImageVideoActivity.class);
// intent.putExtra("viewType", "image");
// intent.putExtra("imageArr", newsArr.get(newsPosition).getImage());
// startActivity(intent);
}
#Override
public void onPullZoomEnd() {
}
});
}
void setNewsFromArray(int position) {
if (position >= newsArr.size()) {
finish();
return;
}
if (!newsArr.get(position).getMedium().get(0).isEmpty()) {
if(isHighQuality)
Picasso.with(DetailNewsActivity.this).load(newsArr.get(position).getImage().get(0)).placeholder(R.drawable.logo).error(R.drawable.logo).
into((ImageView) scrollView.getZoomView().findViewById(R.id.iv_zoom));
else
Picasso.with(DetailNewsActivity.this).load(newsArr.get(position).getMedium().get(0)).placeholder(R.drawable.logo).error(R.drawable.logo).
into((ImageView) scrollView.getZoomView().findViewById(R.id.iv_zoom));
} else {
((ImageView) scrollView.getZoomView().findViewById(R.id.iv_zoom)).setImageResource(R.drawable.logo);
}
tvNewsTitle.setText(newsArr.get(position).getTitle());
tvNewsPublishDate.setText(newsArr.get(position).getPublish_dt());
//String style = "<html><body style='text-align:justify'>";
//Log.i("RAJEEV",style + newsArr.get(position).getFullnews());
tvNewsFull.setText(Html.fromHtml( newsArr.get(position).getFullnews()));
if (newsArr.get(position).getYoutube_video().isEmpty()) {
ivYoutubeEnable.setVisibility(View.GONE);
} else {
ivYoutubeEnable.setVisibility(View.VISIBLE);
}
ivYoutubeEnable.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
Intent intent = new Intent(DetailNewsActivity.this, ImageVideoActivity.class);
intent.putExtra("viewType", "youtube");
intent.putExtra("youtube_code", newsArr.get(newsPosition).getYoutube_video());
startActivity(intent);
}
});
}
private void loadViewForCode() {
PullToZoomScrollViewEx scrollView = (PullToZoomScrollViewEx) findViewById(R.id.scroll_view);
View headView = LayoutInflater.from(this).inflate(R.layout.ptz_head_view, null, false);
View zoomView = LayoutInflater.from(this).inflate(R.layout.ptz_zoom_view, null, false);
View contentView = LayoutInflater.from(this).inflate(R.layout.ptz_content_view, null, false);
scrollView.setHeaderView(headView);
scrollView.setZoomView(zoomView);
scrollView.setScrollContentView(contentView);
tvNewsTitle = (TextView) scrollView.getPullRootView().findViewById(R.id.tv_news_title);
tvNewsPublishDate = (TextView) scrollView.getPullRootView().findViewById(R.id.tv_news_publish_date);
tvNewsFull = (TextView) scrollView.getPullRootView().findViewById(R.id.tv_news_full);
tvNewsFull.setTextSize(textSize);
if (!AppController.isPunjabiSupported()) {
tvNewsTitle.setTypeface(typeface);
tvNewsFull.setTypeface(typeface);
}
ivYoutubeEnable = (ImageView) scrollView.getHeaderView().findViewById(R.id.iv_youtube_header);
}
void generateBranchURL(final int newsPosition) {
// String imageUrl = "";
// if (newsArr.get(newsPosition).getMedium().size() <= 1)
// imageUrl = newsArr.get(newsPosition).getMedium().get(0);
BranchUniversalObject branchUniversalObject = new BranchUniversalObject()
.setCanonicalIdentifier("NewsDetails")
///.setCanonicalUrl("https://branch.io/deepviews")
//.setTitle("" + newsArr.get(newsPosition).getTitle())
//.setContentDescription("" + newsArr.get(newsPosition).getIntro())
//.setContentImageUrl("" + imageUrl)
// You use this to specify whether this content can be discovered publicly - default is public
.setContentIndexingMode(BranchUniversalObject.CONTENT_INDEX_MODE.PUBLIC);
// Here is where you can add custom keys/values to the deep link data
//.addContentMetadata("property1", "blue")
//.addContentMetadata("property2", "red");
LinkProperties linkProperties = new LinkProperties()
.addControlParameter("$desktop_url", "http://www.newsnumber.com/news/share/" + newsArr.get(newsPosition).getFn_id())
.addControlParameter("$ios_url", "itms-apps://itunes.apple.com/us/app/newsnumber/id1022442357?mt=8")
.addControlParameter("NewsId", "" + newsArr.get(newsPosition).getFn_id())
.addControlParameter("CatId", "" + newsArr.get(newsPosition).getCat_id())
.addControlParameter("$og_title", newsArr.get(newsPosition).getTitle())
.addControlParameter("$og_description", newsArr.get(newsPosition).getIntro())
.addControlParameter("$og_image_url", newsArr.get(newsPosition).getImage().get(0))
.addControlParameter("$twitter_title", newsArr.get(newsPosition).getTitle())
.addControlParameter("$twitter_description", newsArr.get(newsPosition).getIntro())
.addControlParameter("$twitter_image_url", newsArr.get(newsPosition).getImage().get(0))
;
branchUniversalObject.generateShortUrl(this, linkProperties, new Branch.BranchLinkCreateListener() {
#Override
public void onLinkCreate(String url, BranchError error) {
if (error == null) {
Log.i("MyApp", "got my Branch link to share: " + url);
Intent sharingIntent = new Intent(Intent.ACTION_SEND);
sharingIntent.setType("text/plain");
sharingIntent.putExtra(Intent.EXTRA_SUBJECT, "News Number\n");
sharingIntent.putExtra(Intent.EXTRA_TEXT, url);
startActivity(Intent.createChooser(sharingIntent, "Share via"));
}
}
});
}
}
can anyone help??
thanks in advance.

It seems like you might be trying to make a new Activity for each "page" of a ViewPager. The Android support library already has their own ViewPager that uses fragments.
You basically need three things to use a ViewPager:
The ViewPager itself
An adapter for the ViewPager
The fragment that will be used in the ViewPager (esentially the "template" that will be used for each "page" in the ViewPager)
First, we'll create the fragment. This is just a simple example that uses only one TextView, but it will work for any amount of views and data. You'll notice that static method "newInstance()" that creates and returns an instance of this fragment. Google recommends using this method to instantiate new Fragments for a ViewPager as it makes passing data to the fragment much easier. All fragments have a "setArguments()" method that lets you pass in a Bundle when you instantiate it with whatever data you want. The method "getArguments()" can be used to access that bundle and get the values out of it in onCreate() or onCreateView(). This is how you pass in an object or objects to bind its data to the views. In this example, were just passing in a String and setting that String to a TextView. You'll see how it's used when we create the adapter for the ViewPager.
//You should be using android.support.v4.app.Fragment here
public class ExampleFragment extends Fragment {
private static final String DAY_NAME_KEY = "day_name";
private TextView dayName;
#Nullable
#Override
public View onCreateView(LayoutInflater inflater,
#Nullable ViewGroup container, #Nullable Bundle savedInstanceState) {
View fragmentView = inflater.inflate(R.layout.fragment_example, container, false);
dayName = (TextView) fragmentView.findViewById(R.id.day_name);
return fragmentView;
}
#Override
public void onActivityCreated(#Nullable Bundle savedInstanceState) {
super.onActivityCreated(savedInstanceState);
//Set the name of the day to the dayName TextView
String day = getArguments().getString(DAY_NAME_KEY);
dayName.setText(day);
}
public static ExampleFragment newInstance(String day) {
Bundle bundle = new Bundle();
bundle.putString(DAY_NAME_KEY, day);
ExampleFragment fragment = new ExampleFragment();
fragment.setArguments(bundle);
return fragment;
}
}
Now, we need to make an adapter that will create the views when the ViewPager is swiped. You need to extend either FragmentPagerAdapter or FragmentStatePagerAdapter. FragmentPagerAdapter is used for a small number of static fragments and it will use more memory. So you only want to use this if you have 4 or 5 pages and aren't adding any more dynamically.
For your case, it sounds like you want to swipe through a variable number of pages that are dynamically added, so you want to use FragmentStatePagerAdapter. It's optimized for memory efficiency and it will handle the saving and restoring of the fragments' state for you.
The adapter is simple.
First, you need to make your constructor match the super class's constructor. What that means is that your constructor must have a FragmentManager parameter. All you do with that is pass it to the super class. (You'll see below.)
Secondly, you have to implement just 2 methods from the FragmentStatePagerAdapter class:
public Fragment getItem(int position)
and
public int getCount()
getItem will be automatically called by the ViewPager when it is swiped. You just have to tell it what type of fragment to return. We'll be using the newInstance() method from the ExampleFragment class here.
getCount is the number of views that your ViewPager will be using. For example, I will have an ArrayList that will contain 7 strings (one for each day of the week). I want each one of those strings to be displayed on a different page of my ViewPager. So I'm just going to return the size of the ArrayList for this method.
Here's the class:
public class ViewPagerAdapter extends FragmentStatePagerAdapter {
//A reference to the array of data that will be used to populate
//each fragment. In this case it's an array of Strings, but it
//could be any type of object. The Strings within this array are what
//we'll be passing to the newInstance() method of each fragment.
private ArrayList<String> days;
//Constructor must take a FragmentManager to match the superclass.
public ViewPagerAdapter(FragmentManager fm, ArrayList<String> days) {
//All you have to do with the fragment manager is pass it to super
super(fm);
//The array will be passed in when we create the Adapter in our Activity
this.days = days;
}
#Override
public Fragment getItem(int position) {
/*
Automatically called when another page is needed.
The adapter will keep track of the position of the current page
so the first time this is called, it will be 0, then when a
swipe occurs, it will be one. If it is swiped backward, it will go back to 0.
So when the position is 0, a new Fragment will be created and the
String at days.get(0) ("Monday") will be passed to it.
*/
return ExampleFragment.newInstance(days.get(position));
}
#Override
public int getCount() {
return days.size();
}
}
Now we just have to set the adapter for the ViewPager in our Activity and it will automatically handle swipes for us.
public class MainActivity extends AppCompatActivity {
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
ArrayList<String> daysOfWeek = new ArrayList<>();
daysOfWeek.add("Monday");
daysOfWeek.add("Tuesday");
daysOfWeek.add("Wednesday");
daysOfWeek.add("Thursday");
daysOfWeek.add("Friday");
daysOfWeek.add("Saturday");
daysOfWeek.add("Sunday");
ViewPager pager = findViewById(R.id.view_pager);
//Pass the activity's fragmentmanager by calling getSupportFragmentManager().
ViewPagerAdapter adapter = new ViewPagerAdapter(getSupportFragmentManager(), daysOfWeek);
pager.setAdapter(adapter);
}
}
This is what we get (I've added some padding and color to make it clear):
As for changing the way the pages "turn" (for example, like a newspaper), you need to look into PageTransformer

Access fragment variable outside of Fragment in view pager

enter image description here
Before reading the question, please refer to image.
I am using viewpager to show the fragment.
Problem
In the fragment, I have used two edittext lets say editText1, editText2 now the problem is how I will get the editText data. I can only get the editText values when user click on next button but the next button is outside of fragment. How do I access the editText outside the fragment.
Before downvoting the question, let me know the reason so that I can improve my question.
Fragment java class
// newInstance constructor for creating fragment with arguments
public static BpDetails newInstance(int page) {
BpDetails fragmentFirst = new BpDetails();
Bundle args = new Bundle();
args.putInt("someInt", page);
fragmentFirst.setArguments(args);
return fragmentFirst;
}
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
page = getArguments().getInt("someInt", 0);
}
// Inflate the view for the fragment based on layout XML
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
final View view = inflater.inflate(R.layout.bp_details, container, false);
Log.i("View ",view.toString());
Log.i("DOB is ",Long.toString(Constants.dob));
systolic =(EditText) view.findViewById(R.id.systolic);
diastolic =(EditText) view.findViewById(R.id.diastolic);
return view;
}
ViewPager Activity
vpPager = (ViewPager) findViewById(R.id.view_pager);
adapterViewPager = new MyPagerAdapter(getSupportFragmentManager());
vpPager.setAdapter(adapterViewPager);
Fragment fragment=adapterViewPager.getItem(prevPage);
if (fragment.getClass().equals(BpDetails.class)){
Log.i("Call ","Yes");
}
findViewById(R.id.btn_prev).setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
// checking for last page
// if last page home screen will be launched
int current = getItem(-1);
if (current!=0)
prevPage=current-1;
if (current < 4) {
// move to next screen
vpPager.setCurrentItem(current);
} else {
//final reached.
}
}
});
findViewById(R.id.btn_next).setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
// checking for last page
// if last page home screen will be launched
int current = getItem(+1);
if (current!=0)
prevPage=current-1;
System.out.println("Prev page "+prevPage);
if (current < 4) {
// move to next screen
Fragment prevFragment=adapterViewPager.getItem(prevPage);
} else {
//final reached.
}
}
});
}
private int getItem(int i) {
return vpPager.getCurrentItem() + i;
}
public static class MyPagerAdapter extends FragmentPagerAdapter {
private static int NUM_ITEMS = 4;
private static int mSelectedPosition;
public MyPagerAdapter(FragmentManager fragmentManager) {
super(fragmentManager);
//mSelectedPosition=selectedPosition;
}
// Returns total number of pages
#Override
public int getCount() {
return NUM_ITEMS;
}
// Returns the fragment to display for that page
#Override
public Fragment getItem(int position) {
switch (position) {
case 0: // Fragment # 0 - This will show FirstFragment
return BasicDetails.newInstance(0);
case 1:
return BpDetails.newInstance(1);
case 2:
return BslDetails.newInstance(2);
case 3:
return Summary.newInstance(3);
default:
return null;
}
}
}

Create two getters inside your fragment like this.
public String getSystolic(){
return this.systolic.getText().toString();
}
public String getDiastolic(){
return this.diastolic.getText().toString();
}
BpDetails fr = (BpDetails)myAdapter.getItem(myViewPager.getCurrentItem());
String systolicString = fr.getSystolic();

I had a similar issue. .getItem() instantiates a new Fragment, so upon calling myAdapter.getItem(...) you would be getting null for all elements in the Fragment, but not null for the Fragment.
When I fixed this, what I had to do was create another method inside of MyPagerAdapter called getInstantiatedFragment:
public Fragment getInstantiatedFragment(int position)
{
return fragments.get(position);
}
fragments is a new field for the class:
private ArrayList<Fragment> fragments = new ArrayList<>();
I would override getItem() (as you have done already) and change it to:
#Override
public Fragment getItem(int position)
{
switch (position) {
case 0:
BasicDetails basicDetails = BasicDetails.newInstance(0);
fragments.add(basicDetails);
return basicDetails;
...
}
where you're adding the fragment to fragments before returning, then you would call:
BpDetails fr = (BpDetails)myAdapter.getInstantiatedItem(myViewPager.getCurrentItem());
to get the instance of the created fragment and then call
String systolicString = fr.getSystolic();
if you're using the previous answer's method.
This is so that you can keep track of the instantiated fragments in fragments. I'm sure there are better ways.

Viewpager Adapter getItem always called for index 0 and 1

I was just wondering if it is the normal behaviour of viewpager and its adapter to always call the getItem() method for index 0 and 1, even if I immediately set a current position.
Here is my code:
mNewsPagerAdapter = new NewsDetailPagerAdapter(getChildFragmentManager());
mNewsPagerAdapter.updateNewsList(news);
mViewPager = (ViewPager) mView.findViewById(R.id.horizontal_view_pager);
mViewPager.setPageMargin(2);
mViewPager.setPageMarginDrawable(R.color.black);
mViewPager.setAdapter(mNewsPagerAdapter);
mViewPager.setCurrentItem(mCurrentPositionPager, false);
If I switch from my overview activity to my detail activity with this viewpager, the adapter always calls the getItem() method for position 0 and 1 and after that the getItem() method for the position of mOriginalPosition and its neighbors. I was wondering if this is the correct behaviour or if I missed something to implement it in a right way. Thanks for your help :)
Edit: Added my adapter code
public class NewsDetailPagerAdapter extends FragmentStatePagerAdapter {
private SparseArray<Fragment> mPageReferenceMap = new SparseArray<Fragment>();
private ArrayList<News> mNewsList;
public NewsDetailPagerAdapter(FragmentManager fm) {
super(fm);
}
/**
* Setzt die neuen News.
**/
public void updateNewsList(ArrayList<News> list) {
mNewsList = list;
}
#Override
public Fragment getItem(int position) {
Log.d("debug", "getItem position:" + position);
News newsItem = mNewsList.get(position);
NavigationFragment fragment = new NavigationFragment();
mPageReferenceMap.put(position, fragment);
return fragment;
}
#Override
public int getCount() {
return mNewsList.size();
}
#Override
public int getItemPosition(Object object) {
return POSITION_NONE;
}
public Fragment getFragment(int position) {
return mPageReferenceMap.get(position);
}
}

It is normal (and intelligent in my opinion).
ViewPager class has one property named mOffscreenPageLimit with default value of 1. This number determines how many pages on the left and on the right of the current page that the Viewpager will preload. For instance, you have 10 pages, current position is 5 and mOffcreenPageLimit is 1, the page at position 4 and 6 will be loaded.
You could change this property by calling this method
viewpager. setOffscreenPageLimit(int)
If you pass in an integer that is smaller than 1, it has no effect.

Yes, this is the normal behaviour of the ViewPager, because it will always try to stay ahead of the user by rendering tabs that limit with the drawing area. I personally don't recommend creating a custom ViewPager as you are almost sure to break functionality unless you really know what you are doing. Your adapter class should look something like this:
public class YourCustomPagerAdapter extends FragmentStatePagerAdapter {
private List<Fragment> fragmentList = new ArrayList<>();
private List<String> titleList = new ArrayList<>();
public WizardPagerAdapter(FragmentManager fm) {
super(fm);
}
public void addFragment(Fragment fragment, String title) {
fragmentList.add(fragment);
titleList.add(title);
}
#Override
public Fragment getItem(int position) {
return fragmentList.get(position);
}
#Override
public CharSequence getPageTitle(int position) {
super.getPageTitle(position);
return titleList.get(position);
}
#Override
public int getCount() {
return fragmentList.size();
}
}
and you should add your fragments as such:
#Override
public void onCreate(Bundle savedInstanceState) {
...
YourCustomPagerAdapter adapter = new YourCustomPagerAdapter (getSupportFragmentManager());
adapter.addFragment(FragmentOne.newInstance(), "Frag 1");
adapter.addFragment(FragmentTwo.newInstance(), "Frag 2");
viewPager.setAdapter(adapter);
...
}

Actually this is the normale behavior. In fact, as soos as you associate the ViewPager with the adapter, the adapter creates the first visibile layout (index 0) end the next one (index 1). This is done by default in the "setAdapter". Then, when you set a different position, the adapter will instantiate the fragment at the selected index, the previous one and the next one.
This is the usual ViewPager setAdapter code:
public void setAdapter(PagerAdapter adapter) {
if (mAdapter != null) {
mAdapter.setViewPagerObserver(null);
mAdapter.startUpdate(this);
for (int i = 0; i < mItems.size(); i++) {
final ItemInfo ii = mItems.get(i);
mAdapter.destroyItem(this, ii.position, ii.object);
}
mAdapter.finishUpdate(this);
mItems.clear();
removeNonDecorViews();
mCurItem = 0;
scrollTo(0, 0);
}
final PagerAdapter oldAdapter = mAdapter;
mAdapter = adapter;
mExpectedAdapterCount = 0;
if (mAdapter != null) {
if (mObserver == null) {
mObserver = new PagerObserver();
}
mAdapter.setViewPagerObserver(mObserver);
mPopulatePending = false;
final boolean wasFirstLayout = mFirstLayout;
mFirstLayout = true;
mExpectedAdapterCount = mAdapter.getCount();
if (mRestoredCurItem >= 0) {
mAdapter.restoreState(mRestoredAdapterState, mRestoredClassLoader);
setCurrentItemInternal(mRestoredCurItem, false, true);
mRestoredCurItem = -1;
mRestoredAdapterState = null;
mRestoredClassLoader = null;
} else if (!wasFirstLayout) {
populate();
} else {
requestLayout();
}
}
if (mAdapterChangeListener != null && oldAdapter != adapter) {
mAdapterChangeListener.onAdapterChanged(oldAdapter, adapter);
}
}
In order to change the ViewPager behavior, you could extend the classic ViewPager overriding the setAdapter method and set the mCurrItem to the desired position.
I hope it helped
Edit:
After different tests, we found a solution.
If the ViewPager adapter is set after ViewPager layout become visible, items 0 and 1 are load.
If you want to avoid this behavior but you can't set the adapter before the layout become visible (because you are waiting for data), than you can use this workaround:
1) Set the ViewPager visibility initially to GONE
2) After you receive all the data, you update the adapter and you set the current item value
3) Finally you set the ViewPager visibility to VISIBLE
Here you can find an example:
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
View v = inflater.inflate(R.layout.detail_overview_fragment, container, false);
final int position = getArguments().getInt("position");
final ViewPager viewPager = (ViewPager) v.findViewById(R.id.viewpager);
viewPager.setVisibility(View.GONE);
Handler handler = new Handler();
handler.postDelayed(new Runnable() {
#Override
public void run() {
viewPager.setAdapter(new PagerAdapter(getChildFragmentManager()));
viewPager.setCurrentItem(position);
viewPager.setVisibility(View.VISIBLE);
}
},5000);
return v;
}

i think the error is the adapter:
/**
* Setzt die neuen News.
**/
public void updateNewsList(ArrayList<News> list) {
//mNewsList = list;
mNewsList.clear();
mNewsList.addAll(list);
/**
* Notifies the attached observers that the underlying data has been changed
* and any View reflecting the data set should refresh itself.
*/
this.notifyDataSetChanged();
}
error reason :this list is diffent entity for that adapter.

Fragment in ViewPager not restored after popBackStack

Problem
A Fragment is not reattached to its hosting ViewPager after returning from another fragment.
Situation
One Activity hosting a Fragment whose layout holds a ViewPager (PageListFragment in the example below). The ViewPager is populated by a FragmentStateViewPagerAdapter. The single Fragments hosted inside the pager (PageFragment in the example below) can open sub page lists, containing a new set of pages.
Behaviour
All works fine as long as the back button is not pressed. As soon as the user closes one of the sub PageLists the previous List is recreated, but without the Page that was displayed previously. Swiping through the other pages on the parent PageList still works.
Code
A sample application can be found on github:
Activity
public class MainActivity extends FragmentActivity {
private static final String CURRENT_FRAGMENT = MainActivity.class.getCanonicalName() + ".CURRENT_FRAGMENT";
public static final String ARG_PARENTS = "Parents";
public void goInto(String mHostingLevel, String mPosition) {
Fragment hostingFragment = newHostingFragment(mHostingLevel, mPosition);
addFragment(hostingFragment);
}
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
addBaseFragment();
}
private void addBaseFragment() {
Fragment hostingFragment = newHostingFragment("", "");
addFragment(hostingFragment);
}
private Fragment newHostingFragment(String mHostingLevel, String oldPosition) {
Fragment hostingFragment = new PageListFragment();
Bundle args = new Bundle();
args.putString(ARG_PARENTS, mHostingLevel + oldPosition +" > ");
hostingFragment.setArguments(args);
return hostingFragment;
}
private void addFragment(Fragment hostingFragment) {
FragmentTransaction transaction = getSupportFragmentManager().beginTransaction();
transaction.replace(R.id.fragmentSpace, hostingFragment, CURRENT_FRAGMENT);
transaction.addToBackStack(null);
transaction.commit();
}
}
PageListFragment
public class PageListFragment extends Fragment {
private String mParentString;
public PageListFragment() {
// Required empty public constructor
}
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
}
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
// Inflate the layout for this fragment
return inflater.inflate(R.layout.fragment_hosting, container, false);
}
#Override
public void onResume() {
mParentString = getArguments().getString(MainActivity.ARG_PARENTS);
ViewPager viewPager = (ViewPager) getView().findViewById(R.id.viewPager);
viewPager.setAdapter(new SimpleFragmentStatePagerAdapter(getFragmentManager(),mParentString));
super.onResume();
}
private static class SimpleFragmentStatePagerAdapter extends FragmentStatePagerAdapter {
private String mHostingLevel;
public SimpleFragmentStatePagerAdapter(FragmentManager fm, String hostingLevel) {
super(fm);
this.mHostingLevel = hostingLevel;
}
#Override
public android.support.v4.app.Fragment getItem(int position) {
PageFragment pageFragment = new PageFragment();
Bundle args = new Bundle();
args.putString(MainActivity.ARG_PARENTS, mHostingLevel);
args.putInt(PageFragment.ARG_POSITION, position);
pageFragment.setArguments(args);
return pageFragment;
}
#Override
public int getCount() {
return 5;
}
}
}
PageFragment
public class PageFragment extends Fragment {
public static final String ARG_POSITION = "Position";
private String mHostingLevel;
private int mPosition;
public PageFragment() {
// Required empty public constructor
}
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
View contentView = inflater.inflate(R.layout.fragment_page, container, false);
setupTextView(contentView);
setupButton(contentView);
return contentView;
}
private void setupTextView(View contentView) {
mPosition = getArguments().getInt(ARG_POSITION);
mHostingLevel = getArguments().getString(MainActivity.ARG_PARENTS);
TextView text = (TextView) contentView.findViewById(R.id.textView);
text.setText("Parent Fragments " + mHostingLevel + " \n\nCurrent Fragment "+ mPosition);
}
private void setupButton(View contentView) {
Button button = (Button) contentView.findViewById(R.id.button);
button.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
openNewLevel();
}
});
}
protected void openNewLevel() {
MainActivity activity = (MainActivity) getActivity();
activity.goInto(mHostingLevel, Integer.toString(mPosition));
}
}

After a lengthy investigation it turns out to be a problem with the fragment manager.
When using a construct like the one above the fragment transaction to reattach the fragment to the page list is silently discarded. It is basically the same problem that causes a
java.lang.IllegalStateException: Recursive entry to executePendingTransactions
when trying to alter the fragments inside the FragmentPager.
The same solution, as for problems with this error, is also applicable here. When constructing the FragmentStatePagerAdapter supply the correct child fragment manager.
Instead of
viewPager.setAdapter(new SimpleFragmentStatePagerAdapter(getFragmentManager(),mParentString));
do
viewPager.setAdapter(new SimpleFragmentStatePagerAdapter(getChildFragmentManager(),mParentString));
See also: github

What Paul has failed to mention is, if you use getChildFragmentManager, then you will suffer the "blank screen on back pressed" issue.

The hierarchy in my case was:
MainActivity->MainFragment->TabLayout+ViewPager->AccountsFragment+SavingsFragment+InvestmentsFragment etc.
The problem I had was that I couldn't use childFragmentManagerfor the reason that a click on the item Account view (who resides inside one of the Fragments of the ViewPager) needed to replace MainFragment i.e. the entire screen.
Using MainFragments host Fragment i.e. passing getFragmentManager() enabled the replacing, BUT when popping the back-stack, I ended up with this screen:
This was apparent also by looking at the layout inspector where the ViewPager is empty.
Apparently looking at the restored Fragments you would notice that their View is restored but will not match the hierarchy of the popped state. In order to make the minimum impact and not force a re-creation of the Fragments I re-wrote FragmentStatePagerAdapter with the following changes:
I copied the entire code of FragmentStatePagerAdapter and changed
#NonNull
#Override
public Object instantiateItem(#NonNull ViewGroup container, int position) {
// If we already have this item instantiated, there is nothing
// to do. This can happen when we are restoring the entire pager
// from its saved state, where the fragment manager has already
// taken care of restoring the fragments we previously had instantiated.
if (mFragments.size() > position) {
Fragment f = mFragments.get(position);
if (f != null) {
return f;
}
}
...
}
with
#NonNull
#Override
public Object instantiateItem(#NonNull ViewGroup container, int position) {
// If we already have this item instantiated, there is nothing
// to do. This can happen when we are restoring the entire pager
// from its saved state, where the fragment manager has already
// taken care of restoring the fragments we previously had instantiated.
if (mFragments.size() > position) {
Fragment f = mFragments.get(position);
if (f != null) {
if (mCurTransaction == null) {
mCurTransaction = mFragmentManager.beginTransaction();
}
mCurTransaction.detach(f);
mCurTransaction.attach(f);
return f;
}
}
...
}
This way I am effectively making sure that that the restored Fragments are re-attached to the ViewPager.

Delete all page fragments, enabling them to be re-added later
The page fragments are not attached when you return to the viewpager screen as the FragmentStatePagerAdapter is not re-connecting them. As a work-around, delete all the fragments in the viewpager after popbackstack() is called, which will allow them to be re-added by your initial code.
[This example is written in Kotlin]
//Clear all fragments from the adapter before they are re-added.
for (i: Int in 0 until adapter.count) {
val item = childFragmentManager.findFragmentByTag("f$i")
if (item != null) {
adapter.destroyItem(container!!, i, item)
}
}

ViewPager Fragments doesn't show correct data

i'm pretty new with Fragments and ViewPager. I'm using ActionBarSherlock and ViewPageIndicator from Jack Wharton.
I've started with a standard Android MasterDetailFlow Activity and did try to modify it to use a ViewPager in the detail part.
I'm using the standard DummyContent to provide some static data but i've replaced the DummyItem with my "Survey"-Library i have to use in this app. DummyContent provides a public static ArrayList which i use to fill the list in the list activity. After i choose a survey in this list, the corresponding questions should be shown in the view pager.
Here is the code of my QuestionActivity.java which hosts the question fragments.
public class QuestionActivity extends SherlockFragmentActivity {
private QuestionsFragmentPagerAdapter mAdapter;
private PageIndicator mIndicator;
private ViewPager mPager;
private String surveyName;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.fragment_viewpager);
getSupportActionBar().setDisplayHomeAsUpEnabled(true);
surveyName = getIntent().getExtras().getString(ItemDetailFragment.ARG_SURVEY_NAME);
mAdapter = new QuestionsFragmentPagerAdapter(getSupportFragmentManager(), DummyContent.mgr.getSurvey(surveyName).getQuestions());
mPager = (ViewPager) findViewById(R.id.pager);
mPager.setAdapter(mAdapter);
mIndicator = (PageIndicator) findViewById(R.id.indicator);
mIndicator.setViewPager(mPager);
}
}
QuestionsFragmentPagerAdapter.java
public class QuestionsFragmentPagerAdapter extends FragmentPagerAdapter {
ArrayList<Question> questions;
public QuestionsFragmentPagerAdapter(FragmentManager fm, List<Question> questions) {
super(fm);
this.questions = (ArrayList<Question>) questions;
}
#Override
public Fragment getItem(int position) {
Fragment f = QuestionFragment.newInstance(questions.get(position));
return f;
}
#Override
public int getCount() {
return questions.size();
}
}
QuestionFragment.java
public class QuestionFragment extends SherlockListFragment {
protected enum QuestionType {
FT, SC, MC;
}
public final static String ARG_QUESTION_QUESTION = "question_question";
public final static String ARG_QUESTION_TYPE = "question_type";
public final static String ARG_QUESTION_ANSWERINGOPTIONS = "question_answeringptions";
private TextView lblQuestion;
private EditText txtAnswer;
private ListView listAnswers;
private ArrayAdapter<String> listAdapter;
private Question question;
private int listLayout;
/**
*
* #param question
* #return
*/
public static QuestionFragment newInstance(Question question) {
QuestionFragment fragment = new QuestionFragment();
// Creates a Bundle with all informations available in the question obj.
Bundle args = createBundleFromQuestion(question);
fragment.setArguments(args);
return fragment;
}
/**
*
*/
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
// Creates the question object from the given arguments.
// I know this isn't a good solution, i will implement the
// Parcelable asap i have solved the current issues.
//
createQuestionFromBundle(getArguments());
// String questionXml = getArguments() != null ? getArguments().getString(ARG_QUESTION_XML) : null;
// this.question = (Question) MyXmlSerializer.deserialize(questionXml, Question.class);
}
/**
* Creates a the Question object form the Bundle.
* #param extras
*/
private void createQuestionFromBundle(Bundle extras) {
// Think we don't need it here. The field question gets instantiated.
}
/**
*
*/
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
return inflater.inflate(R.layout.answer_question, null);
}
#Override
public void onActivityCreated(Bundle savedInstanceState) {
super.onActivityCreated(savedInstanceState);
initWidgets();
setCorrectLayout();
initContent();
}
private void initContent() {
String questionStr = question.getQuestion();
lblQuestion.setText(questionStr);
if(question instanceof FTQuestion) {
} else if (question instanceof ClosedQuestion) {
listAdapter = new ArrayAdapter<String>(getActivity(), listLayout);
List<Answer> answeringOptions = question.getAnswers();
for(Answer answer : answeringOptions) {
listAdapter.add(answer.getAnswer());
}
listAnswers.setAdapter(listAdapter);
}
}
/**
*
*/
private void initWidgets() {
listAnswers = getListView();
lblQuestion = (TextView) getActivity().findViewById(R.id.lblQuestion);
txtAnswer = (EditText) getActivity().findViewById(R.id.txtAnswer);
}
/**
* Sets the FT/SC/MC layout
*/
private void setCorrectLayout() {
if(question instanceof FTQuestion) {
setFtLayout();
} else if (question instanceof SCQuestion) {
setScLayout();
} else if (question instanceof MCQuestion) {
setMcLayout();
}
}
/**
*
*/
private void setFtLayout() {
if(listAnswers.getVisibility()!=ListView.INVISIBLE && listAnswers.getVisibility()!=ListView.GONE) {
listAnswers.setVisibility(ListView.GONE);
}
}
/**
*
*/
private void setScLayout() {
listLayout = R.layout.answer_question_single_choice_list_row;
listAnswers.setChoiceMode(ListView.CHOICE_MODE_SINGLE);
if(txtAnswer.getVisibility() == TextView.VISIBLE) txtAnswer.setVisibility(TextView.GONE);
}
/**
*
*/
private void setMcLayout() {
listLayout = R.layout.answer_question_multiple_choice_list_row;
listAnswers.setChoiceMode(ListView.CHOICE_MODE_MULTIPLE);
if(txtAnswer.getVisibility() == TextView.VISIBLE) txtAnswer.setVisibility(TextView.GONE);
}
}
Choosing the right survey in the list works fine, but now the questions are displayed totaly wrong.
Actually there should be now 3 pages with 3 different questions. On the first page there should be a label with a question"Eine tolle FT Frage?" and below this label an EditText. On the second page there should be a label with a question "Eine tolle SC Frage?" and below a list with the answering options. On page three the should have the question "Eine tolle MC Frage?" and also a list below it with the same answering options as on page two.
The screenshos show a transition between the pages in the order: 1 -> 2 -> 3 -> 2 -> 1 -> 2.
you can see, that it does not appear in a way i described it above. the content of the pages does also change during the transition. i believe that there could be a problem with the DummyContent because it's static?!
If i create a survey with just one question, everything works fine...

Okay i've found the answer:
i wanted to initialize the used widgets in the onCreateView Callback. But then i always got "java.lang.IllegalStateException: Content view not yet created". A closer look showed, that this was just because of the getListView() method.
Now i switched the initialization of the widgets to the onCreateView() Callback but the getListView() i left in onActivityCreated().
Now everything works fine, and the fragments are displayed correctly!
That's how it looks right now:
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
View v = inflater.inflate(R.layout.answer_question, null);
lblQuestion = (TextView) v.findViewById(R.id.lblQuestion);
txtAnswer = (EditText) v.findViewById(R.id.txtAnswer);
return v;
}
#Override
public void onActivityCreated(Bundle savedInstanceState) {
super.onActivityCreated(savedInstanceState);
listAnswers = getListView();
setCorrectLayout();
initContent();
}

Add mIndicator.setOnPageChangeListener to your indicator.And send BroadCast inside for current page.
indicator.setOnPageChangeListener(new OnPageChangeListener()
{
#Override
public void onPageSelected(int page) {
switch (page) {
case 0:
sendBroadcast(intent)// update your content.When broadcast come set correct layout.
break;
default:
break;
}
}
#Override
public void onPageScrolled(int arg0, float arg1, int arg2) {}
#Override
public void onPageScrollStateChanged(int arg0) {}
});
Implement broadcast listener to the fragment.
Move your init methods(initWidgets(),initContent())
to a OnCreateView method
It should works