Fragments within Fragments

Question

I m wondering if this is actually a bug in the Android API   I have a setup like so    --------------                      1      2             -------                              3       --------------     Is a menu which loads fragment  2  A search screen  in the right pane  Is a search screen which contains fragment  3  which is a result list  The result list is used in several places  including as a functioning high level fragment in it s own right     This functionality works perfectly well on a phone  Where 1  amp  2 and 3 are ActivityFragments     However  when I used this code       FragmentTransaction transaction   getSupportFragmentManager   beginTransaction               Fragment frag   new FragmentNumber2        if toLoad    null  frag setArguments toLoad       transaction replace R id rightPane  frag             transaction commit      Where R id leftPane and R id rightPane are  lt fragment gt s in a horizontal linear layout   It is my understanding that the above code removes the fragment which is resident and then replaces it with a new fragment  Brilliant    Obviously that isn t what happens because when this code runs the second time you get the following exception   07-27 15 22 55 940  ERROR AndroidRuntime 8105   Caused by  java lang IllegalArgumentException  Binary XML file line  57  Duplicate id 0x7f080024  tag null  or parent id 0x0 with another fragment for FragmentNumber3   This is caused because the the container for FragmentNumber3 has been duplicated and it no longer has a unique ID  The initial Fragment hasn t been destroyed     before the new one is added  in my mind that means it hasn t been replaced    Can someone tell me if this is possible  this answer suggests it isn t  or is it a bug

User · Answer

you can cleanup your nested fragment in the parent fragment s destroyview method    Override     public void onDestroyView            try          FragmentTransaction transaction   getSupportFragmentManager                    beginTransaction             transaction remove nestedFragment            transaction commit           catch Exception e                    super onDestroyView

User · Answer

Nested fragments are not currently supported   Trying to put a fragment within the UI of another fragment will result in undefined and likely broken behavior      Update  Nested fragments are supported as of Android 4 2  and Android Support Library rev 11    http   developer android com about versions android-4 2 html NestedFragments   NOTE  as per this docs    Note  You cannot inflate a layout into a fragment when that layout includes a  lt fragment gt   Nested fragments are only supported when added to a fragment dynamically

User · Answer

I ve faced with the same problem  have struggled a couple of day with it and should say that the most easiest way to overcome I found this is to use fragment hide     fragment show   when tab is selected unselected      public void onTabUnselected ActionBar Tab tab  FragmentTransaction ft        if  mFragment    null          ft hide mFragment       When screen rotation occurs all parent and child fragments get correctly destroyed    This approach has also one additional advantage - using hide   show   does not cause fragment views to loose their state  so there is no need to restore the previous scroll position for ScrollViews for example   The problem is that I don t know whether it is correct to not detach fragments when they are not visible  I think the official example of TabListener is designed with a thought in mind that fragments are reusable and you should not pollute with them memory  however  I think if you have just a few tabs and you know that users will be switching between them frequently it will be appropriate to keep them attached to the current activity   I would like to hear comments from more experienced developers

User · Answer

I have an application that I am developing that is laid out similar with Tabs in the Action Bar that launches fragments  some of these Fragments have multiple embedded Fragments within them   I was getting the same error when I tried to run the application  It seems like if you instantiate the Fragments within the xml layout after a tab was unselected and then reselected I would get the inflator error    I solved this replacing all the fragments in xml with Linearlayouts and then useing a Fragment manager  fragment transaction to instantiate the fragments everything seems to working correctly at least on a test level right now   I hope this helps you out

User · Answer

If you find your nested fragment not being removed or being duplicated  eg  on Activity restart  on screen rotate  try changing   transaction add R id placeholder  newFragment     to  transaction replace R id placeholder  newFragment     If above doesn t help  try   Fragment f   getChildFragmentManager   findFragmentById R id placeholder    FragmentTransaction transaction   getChildFragmentManager   beginTransaction     if  f    null        Log d TAG   onCreateView  fragment doesn t exist        newFragment  new MyFragmentType        transaction add R id placeholder  newFragment     else       Log d TAG   onCreateView  fragment already exists        transaction replace R id placeholder  f     transaction commit      Learnt here

User · Answer

Nested fragments are supported in android 4 2 and later   The Android Support Library also now supports nested fragments  so you can implement nested fragment designs on Android 1 6 and higher   To nest a fragment  simply call getChildFragmentManager   on the Fragment in which you want to add a fragment  This returns a FragmentManager that you can use like you normally do from the top-level activity to create fragment transactions  For example  here   s some code that adds a fragment from within an existing Fragment class   Fragment videoFragment   new VideoPlayerFragment    FragmentTransaction transaction   getChildFragmentManager   beginTransaction    transaction add R id video fragment  videoFragment  commit      To get more idea about nested fragments  please go through these tutorials  Part 1  Part 2  Part 3   and here is a SO post which discuss about best practices for nested fragments

[android] Fragments within Fragments

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