How to determine when Fragment becomes visible in ViewPager

Question

Problem  Fragment onResume   in ViewPager is fired before the fragment becomes actually visible   For example  I have 2 fragments with ViewPager and FragmentPagerAdapter  The second fragment is only available for authorized users and I need to ask the user to log in when the fragment becomes visible  using an alert dialog    BUT the ViewPager creates the second fragment when the first is visible in order to cache the second fragment and makes it visible when the user starts swiping   So the onResume   event is fired in the second fragment long before it becomes visible  That s why I m trying to find an event which fires when the second fragment becomes visible to show a dialog at the appropriate moment   How can this be done

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May be very late  This is working for me  I slightly updated the code from  Gobar and  kris Solutions  We have to update the code in our PagerAdapter  setPrimaryItem is called every time when a tab is visible and returns its position  If the position are same means we are unmoved  If position changed and current position is not our clicked tab set as -1  private int mCurrentPosition   -1    Override public void setPrimaryItem  NotNull ViewGroup container  int position   NotNull Object object           This is what calls setMenuVisibility   on the fragments     super setPrimaryItem container  position  object       if  position    mCurrentPosition            return            if  object instanceof YourFragment            YourFragment fragment    YourFragment  object          if  fragment isResumed                  mCurrentPosition   position              fragment doYourWork     Update your function                 else           mCurrentPosition   -1

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I support SectionsPagerAdapter with child fragments so after a lot of headache I finally got working version based on solutions from this topic   public abstract class BaseFragment extends Fragment        private boolean visible      private boolean visibilityHintChanged                  Called when the visibility of the fragment changed             protected void onVisibilityChanged View view  boolean visible                private void triggerVisibilityChangedIfNeeded boolean visible            if  this visible    visible    getActivity      null    getView      null                return                    this visible   visible          onVisibilityChanged getView    visible               Override     public void onCreate  Nullable Bundle savedInstanceState            super onCreate savedInstanceState           if   visibilityHintChanged                setUserVisibleHint false                         Override     public void onResume             super onResume            if  getUserVisibleHint    amp  amp   isHidden                  triggerVisibilityChangedIfNeeded true                         Override     public void onHiddenChanged boolean hidden            super onHiddenChanged hidden           triggerVisibilityChangedIfNeeded  hidden               Override     public void setUserVisibleHint boolean isVisibleToUser            super setUserVisibleHint isVisibleToUser           visibilityHintChanged   true          if  isVisibleToUser  amp  amp  isResumed    amp  amp   isHidden                  triggerVisibilityChangedIfNeeded true             else if   isVisibleToUser                triggerVisibilityChangedIfNeeded false                         Override     public void onPause             super onPause            triggerVisibilityChangedIfNeeded false               Override     public void onStop             super onStop            triggerVisibilityChangedIfNeeded false              protected boolean isReallyVisible             return visible

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Override Fragment onHiddenChanged   for that   public  void  onHiddenChanged boolean  hidden  Called when the hidden state  as returned by isHidden    of the fragment has changed  Fragments start out not hidden  this will be called whenever the fragment changes state from that  Parameters  hidden - boolean  True if the fragment is now hidden  false if it is not visible

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In ViewPager2 and ViewPager from version androidx fragment fragment 1 1 0 you can just use onPause and onResume callbacks to determine which fragment is currently visible for the user  onResume callback is called when fragment became visible and onPause when it stops to be visible    In case of ViewPager2 it is default behavior but the same behavior can be enabled for old good ViewPager easily    To enable this behavior in the first ViewPager you have to pass FragmentPagerAdapter BEHAVIOR RESUME ONLY CURRENT FRAGMENT parameter as second argument of FragmentPagerAdapter constructor   FragmentPagerAdapter fragmentManager  BEHAVIOR RESUME ONLY CURRENT FRAGMENT    Note  setUserVisibleHint   method and FragmentPagerAdapter constructor with one parameter are now deprecated in the new version of Fragment from android jetpack

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A simple way of implementing that is checking whether user is logged in before going to the fragment   In your MainActivity you may do something like this inside the onNavigationItemSelected method    case R id nav profile side                    if  User is logged in                         fragmentManager beginTransaction                                replace R id content frame                                       new FragmentProfile                                 commit                     else                        ShowLoginOrRegisterDialog fragmentManager                                       break    However  if you are using navigation drawer  the selection in the drawer will have changed to Profile though we have not gone to the ProfileFragment   To reset the selection to the current selection run the code below          navigationView getMenu   getItem 0  setChecked true

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I overrode the Count method of the associated FragmentStatePagerAdapter and have it return the total count minus the number of pages to hide    public class MyAdapter   Android Support V13 App FragmentStatePagerAdapter            private List lt Fragment gt   fragments        public int TrimmedPages   get  set          public MyAdapter Android App FragmentManager fm    base fm            public MyAdapter Android App FragmentManager fm  List lt Android App Fragment gt  fragments    base fm                   fragments   fragments            TrimmedPages   0               public override int Count                   get   return  fragments Count             get   return  fragments Count - TrimmedPages                So  if there are 3 fragments initially added to the ViewPager  and only the first 2 should be shown until some condition is met  override the page count by setting TrimmedPages to 1 and it should only show the first two pages   This works good for pages on the end  but wont really help for ones on the beginning or middle  though there are plenty of ways of doing this

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Another solution posted here overriding setPrimaryItem in the pageradapter by kris larson almost worked for me  But this method is called multiple times for each setup  Also I got NPE from views  etc  in the fragment as this is not ready the first few times this method is called  With the following changes this worked for me   private int mCurrentPosition   -1    Override public void setPrimaryItem ViewGroup container  int position  Object object        super setPrimaryItem container  position  object        if  position    mCurrentPosition            return             if  object instanceof MyWhizBangFragment            MyWhizBangFragment fragment    MyWhizBangFragment  object           if  fragment isResumed                  mCurrentPosition   position              fragment doTheThingYouNeedToDoOnBecomingVisible

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UPDATE  Android Support Library  rev 11  finally fixed the user visible hint issue  now if you use support library for fragments  then you can safely use getUserVisibleHint   or override setUserVisibleHint   to capture the changes as described by gorn s answer   UPDATE 1 Here is one small problem with getUserVisibleHint    This value is by default true      Hint provided by the app that this fragment is currently visible to the user  boolean mUserVisibleHint   true    So there might be a problem when you try to use it before setUserVisibleHint   was invoked  As a workaround you might set value in onCreate method like this   public void onCreate  Nullable Bundle savedInstanceState        setUserVisibleHint false       The outdated answer   In most use cases  ViewPager only show one page at a time  but the pre-cached fragments are also put to  visible  state  actually invisible  if you are using FragmentStatePagerAdapter in Android Support Library pre-r11   I override    public class MyFragment extends Fragment        Override     public void setMenuVisibility final boolean visible            super setMenuVisibility visible           if  visible                                                     To capture the focus state of fragment  which I think is the most suitable state of the  visibility  you mean  since only one fragment in ViewPager can actually place its menu items together with parent activity s items

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This seems to restore the normal onResume   behavior that you would expect   It plays well with pressing the home key to leave the app and then re-entering the app   onResume   is not called twice in a row    Override public void setUserVisibleHint boolean visible        super setUserVisibleHint visible       if  visible  amp  amp  isResumed                    Only manually call onResume if fragment is already visible           Otherwise allow natural fragment lifecycle to call onResume         onResume              Override public void onResume         super onResume        if   getUserVisibleHint                  return               INSERT CUSTOM CODE HERE

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Only this worked for me   and setUserVisibleHint      is now deprecated  I attached docs at end   which means any other answer is deprecated  -  public class FragmentFirewall extends Fragment                  Required cause  quot setMenuVisibility      quot  is not guaranteed to be        called after  quot onResume   quot  and or  quot onCreateView      quot  method              protected void didVisibilityChange             Activity activity   getActivity            if  isResumed    amp  amp  isMenuVisible                     Once resumed and menu is visible  at last                our Fragment is really visible to user                        Override     public void onResume             super onResume            didVisibilityChange                Override     public void setMenuVisibility boolean visible            super setMenuVisibility visible           didVisibilityChange             Tested and works with NaviagationDrawer as well  there isMenuVisible   will always return true  and onResume   seems enough  but we want to support ViewPager too    setUserVisibleHint is deprecated  If overriding this method  behavior implemented when passing in true should be moved to Fragment onResume    and behavior implemented when passing in false should be moved to Fragment onPause

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How to determine when Fragment becomes visible in ViewPager   You can do the following by overriding setUserVisibleHint in your Fragment   public class MyFragment extends Fragment        Override     public void setUserVisibleHint boolean isVisibleToUser            super setUserVisibleHint isVisibleToUser           if  isVisibleToUser                      else

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Override setPrimaryItem   in the FragmentPagerAdapter subclass  I use this method  and it works well    Override public void setPrimaryItem ViewGroup container  int position  Object object           This is what calls setMenuVisibility   on the fragments     super setPrimaryItem container  position  object        if  object instanceof MyWhizBangFragment            MyWhizBangFragment fragment    MyWhizBangFragment  object          fragment doTheThingYouNeedToDoOnBecomingVisible

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I encountered this problem when I was trying to get a timer to fire when the fragment in the viewpager was on-screen for the user to see    The timer always started just before the fragment was seen by the user  This is because the onResume   method in the fragment is called before we can see the fragment   My solution was to do a check in the onResume   method  I wanted to call a certain method  foo    when fragment 8 was the view pagers current fragment     Override public void onResume         super onResume        if viewPager getCurrentItem      8           foo              Your code here  Executed when fragment is seen by user            Hope this helps  I ve seen this problem pop up a lot  This seems to be the simplest solution I ve seen  A lot of others are not compatible with lower APIs etc

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Note that setUserVisibleHint false  is not called on activity   fragment stop   You ll still need to check start stop to properly register unregister any listeners etc   Also  you ll get setUserVisibleHint false  if your fragment starts in a non-visible state  you don t want to unregister there since you ve never registered before in that case    Override public void onStart         super onStart         if  getUserVisibleHint                 register           Override public void onStop         if  getUserVisibleHint                 unregister            super onStop        Override public void setUserVisibleHint boolean isVisibleToUser        super setUserVisibleHint isVisibleToUser        if  isVisibleToUser  amp  amp  isResumed                 register          if   mHasBeenVisible                mHasBeenVisible   true                  else if  mHasBeenVisible              unregister

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I had the same issue  ViewPager executes other fragment life cycle events and I could not change that behavior  I wrote a simple pager using fragments and available animations  SimplePager

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setUserVisibleHint   gets called sometimes before onCreateView   and sometimes after which causes trouble    To overcome this you need to check isResumed   as well inside setUserVisibleHint   method  But in this case i realized setUserVisibleHint   gets called only if Fragment is resumed and visible  NOT when Created   So if you want to update something when Fragment is visible  put your update function both in onCreate   and setUserVisibleHint      Override public View onCreateView                   myUIUpdate                              Override public void setUserVisibleHint boolean visible       super setUserVisibleHint visible       if  visible  amp  amp  isResumed             myUIUpdate              UPDATE  Still i realized myUIUpdate   gets called twice sometimes  the reason is  if you have 3 tabs and this code is on 2nd tab  when you first open 1st tab  the 2nd tab is also created even it is not visible and myUIUpdate   is called  Then when you swipe to 2nd tab  myUIUpdate   from if  visible  amp  amp  isResumed    is called and as a result myUIUpdate   may get called twice in a second    The other problem is  visible in setUserVisibleHint gets called both 1  when you go out of fragment screen and 2  before it is created  when you switch to fragment screen first time   Solution    private boolean fragmentResume false  private boolean fragmentVisible false  private boolean fragmentOnCreated false        Override public View onCreateView                     Initialize variables     if   fragmentResume  amp  amp  fragmentVisible       only when first time fragment is created         myUIUpdate                              Override public void setUserVisibleHint boolean visible       super setUserVisibleHint visible       if  visible  amp  amp  isResumed          only at fragment screen is resumed         fragmentResume true          fragmentVisible false          fragmentOnCreated true          myUIUpdate         else  if  visible             only at fragment onCreated         fragmentResume false          fragmentVisible true          fragmentOnCreated true            else if  visible  amp  amp  fragmentOnCreated     only when you go out of fragment screen         fragmentVisible false          fragmentResume false            Explanation    fragmentResume fragmentVisible  Makes sure myUIUpdate   in onCreateView   is called only when fragment is created and visible  not on resume  It also solves problem when you are at 1st tab  2nd tab is created even if it is not visible  This solves that and checks if fragment screen is visible when onCreate   fragmentOnCreated  Makes sure fragment is not visible  and not called when you create fragment first time  So now this if clause only gets called when you swipe out of fragment   Update You can put all this code in BaseFragment code like this and override method

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package com example com ui fragment    import android os Bundle  import android support annotation Nullable  import android support v4 app Fragment  import android view LayoutInflater  import android view View  import android view ViewGroup   import com example com R   public class SubscribeFragment extends Fragment         Override     public View onCreateView LayoutInflater inflater   Nullable ViewGroup container   Nullable Bundle savedInstanceState            View view   inflater inflate R layout fragment subscribe  container  false           return view              Override     public void setUserVisibleHint boolean isVisibleToUser            super setUserVisibleHint isVisibleToUser            if  isVisibleToUser                   called here                       Override     public void onViewCreated View view   Nullable Bundle savedInstanceState            super onViewCreated view  savedInstanceState

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setUserVisibleHint boolean visible  is now deprecated So this is the correct solution  FragmentPagerAdapter fragmentManager  BEHAVIOR RESUME ONLY CURRENT FRAGMENT    In ViewPager2 and ViewPager from version androidx fragment fragment 1 1 0 you can just use onPause   and onResume   to determine which fragment is currently visible for the user  onResume   is called when the fragment became visible and onPause when it stops to be visible   To enable this behavior in the first ViewPager you have to pass FragmentPagerAdapter BEHAVIOR RESUME ONLY CURRENT FRAGMENT parameter as the second argument of the FragmentPagerAdapter constructor

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Here is another way using onPageChangeListener     ViewPager pager    ViewPager  findByViewId R id viewpager     FragmentPagerAdapter adapter   new FragmentPageAdapter getFragmentManager     pager setAdapter adapter     pager setOnPageChangeListener new OnPageChangeListener        public void onPageSelected int pageNumber           Just define a callback method in your fragment and call it like this       adapter getItem pageNumber  imVisible            public void onPageScrolled int arg0  float arg1  int arg2           TODO Auto-generated method stub         public void onPageScrollStateChanged int arg0           TODO Auto-generated method stub

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Add following Code inside fragment   Override public void setMenuVisibility final boolean visible          super setMenuVisibility visible       if  visible  amp  amp  isResumed

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New ViewPager2   FragmentStateAdapter   onResume    in Fragment  solve the problem Old Answer  deprecated  To detect Fragment in ViewPager visible  I m quite sure that only using setUserVisibleHint is not enough  Here is my solution to check if a fragment is visible or invisible  First when launching viewpager  switch between page  go to another activity fragment  background foreground  public class BaseFragmentHelpLoadDataWhenVisible extends Fragment       protected boolean mIsVisibleToUser     you can see this variable may absolutely  lt   gt  getUserVisibleHint   but it not  Currently  after many test I find that                 This method will be called when viewpager creates fragment and when we go to this fragment background or another activity or fragment        NOT called when we switch between each page in ViewPager              Override     public void onStart             super onStart            if  mIsVisibleToUser                onVisible                          Override     public void onStop             super onStop            if  mIsVisibleToUser                onInVisible                                    This method will called at first time viewpager created and when we switch between each page        NOT called when we go to background or another activity  fragment  when we go back              Override     public void setUserVisibleHint boolean isVisibleToUser            super setUserVisibleHint isVisibleToUser           mIsVisibleToUser   isVisibleToUser          if  isResumed         fragment have created             if  mIsVisibleToUser                    onVisible                  else                   onInVisible                                       public void onVisible             Toast makeText getActivity    TAG    quot visible quot   Toast LENGTH SHORT  show               public void onInVisible             Toast makeText getActivity    TAG    quot invisible quot   Toast LENGTH SHORT  show             EXPLANATION You can check the logcat below carefully then I think you may know why this solution will work First launch Fragment1  setUserVisibleHint  isVisibleToUser false isResumed false Fragment2  setUserVisibleHint  isVisibleToUser false isResumed false Fragment3  setUserVisibleHint  isVisibleToUser false isResumed false Fragment1  setUserVisibleHint  isVisibleToUser true isResumed false    AT THIS TIME isVisibleToUser true but fragment still not created  If you do something with View here  you will receive exception Fragment1  onCreateView Fragment1  onStart mIsVisibleToUser true Fragment2  onCreateView Fragment3  onCreateView Fragment2  onStart mIsVisibleToUser false Fragment3  onStart mIsVisibleToUser false  Go to page2 Fragment1  setUserVisibleHint  isVisibleToUser false isResumed true Fragment2  setUserVisibleHint  isVisibleToUser true isResumed true  Go to page3 Fragment2  setUserVisibleHint  isVisibleToUser false isResumed true Fragment3  setUserVisibleHint  isVisibleToUser true isResumed true  Go to background  Fragment1  onStop mIsVisibleToUser false Fragment2  onStop mIsVisibleToUser false Fragment3  onStop mIsVisibleToUser true  Go to foreground Fragment1  onStart mIsVisibleToUser false Fragment2  onStart mIsVisibleToUser false Fragment3  onStart mIsVisibleToUser true  DEMO project here Hope it help

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Detecting by focused view   This works for me  public static boolean isFragmentVisible Fragment fragment        Activity activity   fragment getActivity        View focusedView   fragment getView   findFocus        return activity    null              amp  amp  focusedView    null              amp  amp  focusedView    activity getWindow   getDecorView   findFocus

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I figured out that onCreateOptionsMenu and onPrepareOptionsMenu methods called only in the case of the fragment really visible  I could not found any method which behaves like these  also I tried OnPageChangeListener but it did not work for the situations  for example  I need a variable initialized in onCreate method   So these two methods can be used for this problem as a workaround  specifically for little and short jobs   I think  this is the better solution but not the best  I will use this but wait for better solution at the same time   Regards

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I encountered the same problem while working with FragmentStatePagerAdapters and 3 tabs  I had to show a Dilaog whenever the 1st tab was clicked and hide it on clicking other tabs   Overriding setUserVisibleHint   alone didn t help to find the current visible fragment   When clicking from 3rd tab -----  1st tab  It triggered twice for 2nd fragment and for 1st fragment  I combined it with isResumed   method        Override public void setUserVisibleHint boolean isVisibleToUser        super setUserVisibleHint isVisibleToUser       isVisible   isVisibleToUser          Make sure that fragment is currently visible     if   isVisible  amp  amp  isResumed                 Call code when Fragment not visible       else if  isVisible  amp  amp  isResumed                Call code when Fragment becomes visible

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We have a special case with MVP where the fragment needs to notify the presenter that the view has become visible  and the presenter is injected by Dagger in fragment onAttach     setUserVisibleHint   is not enough  we ve detected 3 different cases that needed to be addressed  onAttach   is mentioned so that you know when the presenter is available     Fragment has just been created  The system makes the following calls   setUserVisibleHint      before fragment s lifecycle calls  so presenter is null onAttach       onResume    Fragment already created and home button is pressed  When restoring the app to foreground  this is called   onResume    Orientation change   onAttach      presenter available onResume   setUserVisibleHint      We only want the visibility hint to get to the presenter once  so this is how we do it    Nullable  Override public View onCreateView LayoutInflater inflater  ViewGroup container  Bundle savedInstanceState        View root   inflater inflate R layout fragment list  container  false       setHasOptionsMenu true        if  savedInstanceState    null            lastOrientation   savedInstanceState getInt STATE LAST ORIENTATION                getResources   getConfiguration   orientation         else           lastOrientation   getResources   getConfiguration   orientation             return root      Override public void onResume         super onResume        presenter onResume         int orientation   getResources   getConfiguration   orientation      if  orientation    lastOrientation            if  getUserVisibleHint                  presenter onViewBecomesVisible                        lastOrientation   orientation      Override public void setUserVisibleHint boolean isVisibleToUser        super setUserVisibleHint isVisibleToUser       if  presenter    null  amp  amp  isResumed    amp  amp  isVisibleToUser            presenter onViewBecomesVisible              Override public void onSaveInstanceState Bundle outState        super onSaveInstanceState outState       outState putInt STATE LAST ORIENTATION  lastOrientation

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I used this and it worked    mContext getWindow   getDecorView   isShown     boolean

[android] How to determine when Fragment becomes visible in ViewPager

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