How to implement onBackPressed in Fragments

Question

Is there a way in which we can implement onBackPressed   in Android Fragment similar to the way in which we implement in Android Activity   As the Fragment lifecycle do not have onBackPressed    Is there any other alternative method to over ride onBackPressed   in Android 3 0 fragments

User · Answer

Override public void onResume         super onResume         getView   setFocusableInTouchMode true       getView   requestFocus        getView   setOnKeyListener new View OnKeyListener              Override         public boolean onKey View v  int keyCode  KeyEvent event                if  event getAction      KeyEvent ACTION UP  amp  amp  keyCode    KeyEvent KEYCODE BACK                       handle back button                 replaceFragmentToBackStack getActivity    WelcomeFragment newInstance bundle   tags                    return true                             return false

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onBackPressed   cause Fragment to be detach from Activity   According to  Sterling Diaz answer I think he is right  BUT some situation will be wrong   ex  Rotate Screen   So  I think we could detect whether isRemoving   to achieve goals   You can write it at onDetach   or onDestroyView    It is work      Override public void onDetach         super onDetach        if isRemoving                onBackPressed             Override public void onDestroyView         super onDestroyView        if isRemoving                onBackPressed

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In activity life cycle  always android back button deals with FragmentManager transactions when we used FragmentActivity or AppCompatActivity  To handle the backstack we don t need to handle its backstack count or tag anything but we should keep focus while adding or replacing a fragment  Please find the following snippets to handle the back button cases       public void replaceFragment Fragment fragment             FragmentTransaction transaction   getSupportFragmentManager   beginTransaction            if    fragment instanceof HomeFragment                 transaction addToBackStack null                     transaction replace R id activity menu fragment container  fragment  commit            Here  I won t add back stack for my home fragment because it s home page of my application  If add addToBackStack to HomeFragment then app will wait to remove all the frament in acitivity then we ll get blank screen so I m keeping the following condition   if    fragment instanceof HomeFragment                 transaction addToBackStack null       Now  you can see the previously added fragment on acitvity and app will exit when reaching HomeFragment  you can also look on the following snippets    Override public void onBackPressed          if  mDrawerLayout isDrawerOpen Gravity LEFT             closeDrawer          else           super onBackPressed

User · Answer

This line of code will do the trick from within any fragment  it will pop the current fragment on the backstack   getActivity   getSupportFragmentManager   popBackStack

User · Answer

Just follow these steps   Always while adding a fragment    fragmentTransaction add R id fragment container  detail fragment   Fragment tag   addToBackStack null  commit      Then in the main activity  override onBackPressed    if  getSupportFragmentManager   getBackStackEntryCount    gt  0        getSupportFragmentManager   popBackStack      else       finish        To handle the back button in your app   Fragment f   getActivity   getSupportFragmentManager   findFragmentByTag  Fragment tag    if  f instanceof FragmentName        if  f    null           getActivity   getSupportFragmentManager   beginTransaction   remove f  commit                      That s it

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If you use EventBus   it is probably a far more simpler solution       In your Fragment      Override public void onAttach Activity activity        super onAttach activity       EventBus getDefault   register this       Override public void onDetach         super onDetach        EventBus getDefault   unregister this          This method will be called when a MessageEvent is posted public void onEvent BackPressedMessage type       getSupportFragmentManager   popBackStack        and in your Activity class you can define     Override public void onStart         super onStart        EventBus getDefault   register this       Override public void onStop         EventBus getDefault   unregister this       super onStop          This method will be called when a MessageEvent is posted public void onEvent BackPressedMessage type       super onBackPressed        Override public void onBackPressed         EventBus getDefault   post new BackPressedMessage true        BackPressedMessage java is just a POJO object  This is super clean and there is no interface implementation hassle

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public class MyActivity extends Activity        protected OnBackPressedListener onBackPressedListener       public interface OnBackPressedListener           void doBack               public void setOnBackPressedListener OnBackPressedListener onBackPressedListener            this onBackPressedListener   onBackPressedListener              Override     public void onBackPressed             if  onBackPressedListener    null              onBackPressedListener doBack            else             super onBackPressed                 Override     protected void onDestroy             onBackPressedListener   null          super onDestroy              in your fragment add the following  dont forget to implement mainactivity s interface   public class MyFragment extends Framgent implements MyActivity OnBackPressedListener        Override     public void onViewCreated View view  Bundle savedInstanceState            super onViewCreated view  savedInstanceState              MyActivity  getActivity    setOnBackPressedListener this           Override public void doBack           BackPressed in activity will call this

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Providing custom back navigation by handling onBackPressed is now more easy with callbacks inside the fragment   class MyFragment   Fragment         override fun onCreate savedInstanceState  Bundle             super onCreate savedInstanceState          val onBackPressedCallback   object   OnBackPressedCallback true                override fun handleOnBackPressed                     if  true    conditionForCustomAction                        myCustomActionHere                     else  NavHostFragment findNavController this MyFragment  navigateUp                            requireActivity   onBackPressedDispatcher addCallback          this  onBackPressedCallback                   If you want the default back action based on some condition  you can use    NavHostFragment findNavController this MyFragment  navigateUp

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Well I done it like this  and it work for me  Simple interface  FragmentOnBackClickInterface java  public interface FragmentOnBackClickInterface       void onClick        Example implementation   MyFragment java   public class MyFragment extends Fragment implements FragmentOnBackClickInterface       other stuff  public void onClick               what you want to call onBackPressed      then just override onBackPressed in activity       Override public void onBackPressed         int count   getSupportFragmentManager   getBackStackEntryCount        List lt Fragment gt  frags   getSupportFragmentManager   getFragments        Fragment lastFrag   getLastNotNull frags         nothing else in back stack    nothing in back stack is instance of our interface     if  count    0      lastFrag instanceof FragmentOnBackClickInterface             super onBackPressed          else             FragmentOnBackClickInterface  lastFrag  onClick             private Fragment getLastNotNull List lt Fragment gt  list       for  int i  list size  -1 i gt  0 i--           Fragment frag   list get i           if  frag    null               return frag                      return null

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I have used another approach as follows    An Otto event bus to communicate between the Activity and its Fragments A Stack in the Activity containing custom back actions wrapped in a Runnable that the calling fragment defines When onBackPressed is called in the controlling Activity  it pops the most recent custom back action and executes its Runnable  If there s nothing on the Stack  the default super onBackPressed   is called   The full approach with sample code is included here as an answer to this other SO question

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since this question and some of the answers are over five years old  let me share my solution  This is a follow-up and modernization to the answer from  oyenigun  UPDATE  At the bottom of this article  I added an alternative implementation using an abstract Fragment extension that won t involve the Activity at all  which would be useful for anyone with a more complex fragment hierarchy involving nested fragments that require different back behavior   I needed to implement this because some of the fragments I use have smaller views that I would like to dismiss with the back button  such as small information views that pop up  etc  but this is good for anyone who needs to override the behavior of the back button inside fragments   First  define an Interface  public interface Backable       boolean onBackPressed        This interface  which I call Backable  I m a stickler for naming conventions   has a single method onBackPressed   that must return a boolean value  We need to enforce a boolean value because we will need to know if the back button press has  absorbed  the back event  Returning true means that it has  and no further action is needed  otherwise  false says that the default back action still must take place  This interface should be it s own file  preferably in a separate package named interfaces   Remember  separating your classes into packages is good practice   Second  find the top fragment  I created a method that returns the last Fragment object in the back stack  I use tags    if you use ID s  make the necessary changes  I have this static method in a utility class that deals with navigation states  etc    but of course  put it where it best suits you  For edification  I ve put mine in a class called NavUtils   public static Fragment getCurrentFragment Activity activity        FragmentManager fragmentManager   activity getFragmentManager        if  fragmentManager getBackStackEntryCount    gt  0            String lastFragmentName   fragmentManager getBackStackEntryAt                  fragmentManager getBackStackEntryCount   - 1  getName            return fragmentManager findFragmentByTag lastFragmentName             return null      Make sure the back stack count is greater than 0  otherwise an ArrayOutOfBoundsException could be thrown at runtime  If it isn t greater than 0  return null  We ll check for a null value later     Third  Implement in a Fragment  Implement the Backable interface in whichever fragment where you need to override the back button behavior  Add the implementation method   public class SomeFragment extends Fragment implements          FragmentManager OnBackStackChangedListener  Backable              Override     public boolean onBackPressed                 Logic here            if  backButtonShouldNotGoBack                whateverMethodYouNeed                return true                    return false             In the onBackPressed   override  put whatever logic you need  If you want the back button to not pop the back stack  the default behavior   return true  that your back event has been absorbed  Otherwise  return false   Lastly  in your Activity     Override the onBackPressed   method and add this logic to it    Override public void onBackPressed             Get the current fragment using the method from the second step above        Fragment currentFragment   NavUtils getCurrentFragment this           Determine whether or not this fragment implements Backable        Do a null check just to be safe     if  currentFragment    null  amp  amp  currentFragment instanceof Backable             if    Backable  currentFragment  onBackPressed                     If the onBackPressed override in your fragment                 did absorb the back event  returned true   return             return            else                  Otherwise  call the super method for the default behavior             super onBackPressed                            Any other logic needed           call super method to be sure the back button does its thing        super onBackPressed        We get the current fragment in the back stack  then we do a null check and determine if it implements our Backable interface  If it does  determine if the event was absorbed  If so  we re done with onBackPressed   and can return  Otherwise  treat it as a normal back press and call the super method   Second Option to not involve the Activity  At times  you don t want the Activity to handle this at all  and you need to handle it directly within the fragment  But who says you can t have Fragments with a back press API  Just extend your fragment to a new class   Create an abstract class that extends Fragment and implements the View OnKeyListner interface     import android app Fragment  import android os Bundle  import android view KeyEvent  import android view View   public abstract class BackableFragment extends Fragment implements View OnKeyListener         Override     public void onViewCreated View view  Bundle savedInstanceState            super onViewCreated view  savedInstanceState           view setFocusableInTouchMode true           view requestFocus            view setOnKeyListener this               Override     public boolean onKey View v  int keyCode  KeyEvent event            if  event getAction      KeyEvent ACTION UP                if  keyCode    KeyEvent KEYCODE BACK                    onBackButtonPressed                    return true                                   return false             public abstract void onBackButtonPressed        As you can see  any fragment that extends BackableFragment will automatically capture back clicks using the View OnKeyListener interface  Just call the abstract onBackButtonPressed   method from within the implemented onKey   method using the standard logic to discern a back button press  If you need to register key clicks other than the back button  just be sure to call the super method when overriding onKey   in your fragment  otherwise you ll override the behavior in the abstraction   Simple to use  just extend and implement   public class FragmentChannels extends BackableFragment                  Override     public void onBackButtonPressed             if  doTheThingRequiringBackButtonOverride                   do the thing           else               getActivity   onBackPressed                                 Since the onBackButtonPressed   method in the super class is abstract  once you extend you must implement onBackButtonPressed    It returns void because it just needs to perform an action within the fragment class  and does not need to relay the absorption of the press back to the Activity  Make sure you do call the Activity onBackPressed   method if whatever you re doing with the back button doesn t require handling  otherwise  the back button will be disabled    and you don t want that   Caveats As you can see  this sets the key listener to the root view of the fragment  and we ll need to focus it  If there are edit texts involved  or any other focus-stealing views  in your fragment that extends this class   or other inner fragments or views that have the same   you ll need to handle that separately  There s a good article on extending an EditText to lose focus on a back press   I hope someone finds this useful  Happy coding

User · Answer

This is just a small code that will do the trick    getActivity   onBackPressed      Hope it helps someone

User · Answer

Try this one  if you really want to enable onBackPressed   in Fragment  After wasting an hour of time  I made this solution which exactly fits over the needs  from my prior experiences  You just need to focus on the value of private int STATUS FRAGMENT 0  which suffices the need of addToBackStack   in fragments  import android view MenuItem  import android view View   import androidx annotation NonNull  import androidx appcompat app AppCompatActivity  import androidx fragment app Fragment   import com example growfast NavigationItemsFolder CoreFragments Cart  import com example growfast NavigationItemsFolder CoreFragments HelpDesk  import com example growfast NavigationItemsFolder CoreFragments Home  import com example growfast NavigationItemsFolder CoreFragments ProfileDetails  import com example growfast R  import com google android material bottomnavigation BottomNavigationView   public class BusinessManagement extends AppCompatActivity        public BottomNavigationView bottomNavigationView      private int STATUS FRAGMENT 0        Override     protected void onCreate Bundle savedInstanceState            super onCreate savedInstanceState           setContentView R layout activity base layout           setBottomNavigationMenu                private void setBottomNavigationMenu             bottomNavigationView   findViewById R id navigation           bottomNavigationView setVisibility View VISIBLE            bottomNavigationView setOnNavigationItemSelectedListener new BottomNavigationView OnNavigationItemSelectedListener                  Fragment fragment   null                Override             public boolean onNavigationItemSelected  NonNull MenuItem item                     switch  item getItemId                           case R id action home                          fragment   new Home                            break                       case R id action profile                          fragment   new ProfileDetails                            break                      case R id action cart                          fragment   new Cart                            break                      case R id action favourites menu                          fragment   new HelpDesk                            break                                     return loadFromFragment fragment                                      bottomNavigationView setSelectedItemId R id action home              private boolean loadFromFragment Fragment fragment            if  fragment    null                getSupportFragmentManager   beginTransaction   replace R id my container  fragment                       commit                STATUS FRAGMENT 1              return true                    return false              Override     public void onBackPressed             if  STATUS FRAGMENT  1                bottomNavigationView setSelectedItemId R id action home               STATUS FRAGMENT 0              bottomNavigationView setVisibility View VISIBLE                     else              super onBackPressed

User · Answer

Inside the fragment s onCreate method add the following    Override public void onCreate Bundle savedInstanceState        super onCreate savedInstanceState        OnBackPressedCallback callback   new OnBackPressedCallback true             Override         public void handleOnBackPressed                   Handle the back pressed                      requireActivity   getOnBackPressedDispatcher   addCallback this  callback

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Fragment  Make a BaseFragment placing a method     public boolean onBackPressed      Activity    Override public void onBackPressed         List lt Fragment gt  fragments   getSupportFragmentManager   getFragments        if  fragments    null            for  Fragment fragment   fragments                if   fragment isVisible    continue               if  fragment instanceof BaseFragment  amp  amp    BaseFragment  fragment  onBackPressed                      return                                     super onBackPressed        Your activity will run over the attached and visible fragments and call onBackPressed   on each one of them and abort if one of them returns  true   meaning that it has been handled  so no further actions

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this is my solution      in MyActivity java    public interface OnBackClickListener           boolean onBackClick               private OnBackClickListener onBackClickListener   public void setOnBackClickListener OnBackClickListener onBackClickListener            this onBackClickListener   onBackClickListener          Override     public void onBackPressed             if  onBackClickListener    null  amp  amp  onBackClickListener onBackClick                  return                    super onBackPressed               and in Fragment      MyActivity  getActivity    setOnBackClickListener new MyActivity OnBackClickListener          Override     public boolean onBackClick             if  condition                return false                        some codes          return true

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I had the same problem and I created a new listener for it and used in my fragments   1 - Your activity should have a listener interface and a list of listeners in it  2 - You should implement methods for adding and removing the listeners  3 - You should override the onBackPressed method to check that any of the listeners use the back press or not  public class MainActivity                       Back press listener list  Used for notifying fragments when onBackPressed called             private Stack lt BackPressListener gt  backPressListeners   new Stack lt BackPressListener gt                               Adding new listener to back press listener stack         param backPressListener             public void addBackPressListener BackPressListener backPressListener            backPressListeners add backPressListener                         Removing the listener from back press listener stack         param backPressListener             public void removeBackPressListener BackPressListener backPressListener            backPressListeners remove backPressListener                  Overriding onBackPressed to check that is there any listener using this back press      Override     public void onBackPressed                 checks if is there any back press listeners use this press         for BackPressListener backPressListener   backPressListeners                if backPressListener onBackPressed    return                        if not returns in the loop  calls super onBackPressed         super onBackPressed               4 - Your fragment must implement the interface for back press  5 - You need to add the fragment as a listener for back press  6 - You should return true from onBackPressed if the fragment uses this back press  7 - IMPORTANT - You must remove the fragment from the list onDestroy  public class MyFragment extends Fragment implements MainActivity BackPressListener                   Override     public void onAttach Activity activity            super onCreate savedInstanceState               adding the fragment to listener list           MainActivity  activity  addBackPressListener this                        Override     public void onDestroy             super onDestroy                removing the fragment from the listener list           MainActivity  getActivity    removeBackPressListener this                        Override     public boolean onBackPressed                 you should check that if this fragment is the currently used fragment or not            if this fragment is not used at the moment you should return false         if  isThisFragmentVisibleAtTheMoment  return false           if  isThisFragmentUsingBackPress                   do what you need to do             return true                    return false            There is a Stack used instead of the ArrayList to be able to start from the latest fragment  There may be a problem also while adding fragments to the back stack  So you need to check that the fragment is visible or not while using back press  Otherwise one of the fragments will use the event and latest fragment will not be closed on back press   I hope this solves the problem for everyone

User · Answer

Easy way to handle onBackPressed   in Fragments  Step 1  Create a static boolean in activity   public static Fragment one    Step 2  On MainActivity Activity that holds fragment   in On Create method  declare   Fragment one true    Step 3  Override onBackPressed   in MainActivity   Override public void onBackPressed          if Fragment one           Back key pressed on fragment one       else           Back key pressed on fragment two           Step 4  On fragment one     onCreateView method declare  MainActivity Fragment one true    Step 5  On fragment two     onCreateView method declare  MainActivity Fragment one false    Note  This method can be only applicable to TWO fragments

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Do not implement ft addToBackStack   method so that when you pressed back button your activity will be finished   proAddAccount   new ProfileAddAccount    FragmentManager fragmentManager   getSupportFragmentManager    FragmentTransaction fragmentTransaction   fragmentManager beginTransaction    fragmentTransaction replace R id fragment container  proAddAccount     fragmentTransaction addToBackStack null   fragmentTransaction commit

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How about using onDestroyView      Override public void onDestroyView         super onDestroyView

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Using Navigation component you can do it like this      Java   public class MyFragment extends Fragment     Override public void onCreate  Nullable Bundle savedInstanceState        super onCreate savedInstanceState           This callback will only be called when MyFragment is at least Started      OnBackPressedCallback callback   new OnBackPressedCallback true    enabled by default                Override         public void handleOnBackPressed                    Handle the back button event                       requireActivity   getOnBackPressedDispatcher   addCallback this  callback           The callback can be enabled or disabled here or in handleOnBackPressed                Kotlin   class MyFragment   Fragment      override fun onCreate savedInstanceState  Bundle         super onCreate savedInstanceState          This callback will only be called when MyFragment is at least Started      val callback   requireActivity   onBackPressedDispatcher addCallback this               Handle the back button event               The callback can be enabled or disabled here or in the lambda

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If you wanted that sort of functionality you would need to override it in your activity  and then add a YourBackPressed interface to all your fragments  which you call on the relevant fragment whenever the back button is pressed   Edit  I d like to append my previous answer   If I were to do this today  I d use a broadcast  or possibly a ordered broadcast if I expected other panels to update in unison to the master main content panel   LocalBroadcastManager in the Support Library can help with this  and you just send the broadcast in onBackPressed and subscribe in your fragments that care  I think that Messaging is a more decoupled implementation and would scale better  so it would be my official implementation recommendation now  Just use the Intent s action as a filter for your message  send your newly created ACTION BACK PRESSED  send it from your activity and listen for it in the relevant fragments

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This worked for me  https   stackoverflow com a 27145007 3934111   Override public void onResume         super onResume         if getView      null           return             getView   setFocusableInTouchMode true       getView   requestFocus        getView   setOnKeyListener new View OnKeyListener              Override         public boolean onKey View v  int keyCode  KeyEvent event                 if  event getAction      KeyEvent ACTION UP  amp  amp  keyCode    KeyEvent KEYCODE BACK                      handle back button s click listener                 return true                            return false

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Override    public boolean onKeyDown int keyCode  KeyEvent event               if   keyCode    KeyEvent KEYCODE BACK                  finish                 return super onKeyDown keyCode  event           Just Comment Any Key down related method now addToBackStack will work   thanks

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I know it s too late but I had the same problem last week  None of the answers helped me  I then was playing around with the code and this worked  since I already added the fragments   In your Activity  set an OnPageChangeListener for the ViewPager so that you will know when the user is in the second activity  If he is in the second activity  make a boolean true as follows       mSectionsPagerAdapter   new SectionsPagerAdapter getSupportFragmentManager            Set up the ViewPager with the sections adapter      mViewPager    ViewPager  findViewById R id pager       mViewPager setAdapter mSectionsPagerAdapter       mViewPager setCurrentItem 0       mViewPager addOnPageChangeListener new OnPageChangeListener               Override         public void onPageSelected int position                   TODO Auto-generated method stub                 mSectionsPagerAdapter instantiateItem mViewPager  position                   if position    1                      inAnalytics   true                  else if position    0                      inAnalytics   false                      Override         public void onPageScrolled int position  float arg1  int arg2                   TODO Auto-generated method stub                     Override         public void onPageScrollStateChanged int arg0                   TODO Auto-generated method stub                      Now check for the boolean whenever back button is pressed and set the current item to your first Fragment    Override public void onBackPressed         if inAnalytics          mViewPager setCurrentItem 0  true       else          super onBackPressed

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You should add interface to your project like below   public interface OnBackPressed         void onBackPressed        And then  you should implement this interface on your fragment   public class SampleFragment extends Fragment implements OnBackPressed         Override     public void onBackPressed               on Back Pressed            And you can trigger this onBackPressed event under your activities onBackPressed event like below   public class MainActivity extends AppCompatActivity           Override         public void onBackPressed                     Fragment currentFragment   getSupportFragmentManager   getFragments   get getSupportFragmentManager   getBackStackEntryCount   - 1                   if  currentFragment instanceof OnBackPressed                            OnBackPressed  currentFragment  onBackPressed                                      super onBackPressed

User · Answer

Simply do it in onKeyUp       Override public boolean onKeyUp int keyCode  KeyEvent event         if  keyCode    KeyEvent KEYCODE BACK               do something         return true      return true if back handled  false otherwise            return super onKeyUp keyCode  event

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According to the AndroidX release notes  androidx activity 1 0 0-alpha01 is released and introduces ComponentActivity  a new base class of the existing FragmentActivity and AppCompatActivity  And this release brings us a new feature    You can now register an OnBackPressedCallback via addOnBackPressedCallback to receive onBackPressed   callbacks without needing to override the method in your activity

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You can use onBackPressedDispatcher of parent activity like this  val backpress   requireActivity   onBackPressedDispatcher addCallback viewLifecycleOwner  true                   here dispatcher works for any action when back pressed    you can also enable disable backpress button from fragment any time like this  backpress isEnabled   true false

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In my opinion the best solution is   JAVA SOLUTION  Create simple interface    public interface IOnBackPressed                  If you return true the back press will not be taken into account  otherwise the activity will act naturally         return true if your processing has priority if not false             boolean onBackPressed        And in your Activity  public class MyActivity extends Activity        Override public void onBackPressed         Fragment fragment   getSupportFragmentManager   findFragmentById R id main container          if    fragment instanceof IOnBackPressed        IOnBackPressed  fragment  onBackPressed                super onBackPressed                           Finally in your Fragment   public class MyFragment extends Fragment implements IOnBackPressed      Override    public boolean onBackPressed            if  myCondition                  action not popBackStack             return true             else               return false                      KOTLIN SOLUTION  1 - Create Interface  interface IOnBackPressed       fun onBackPressed    Boolean     2 - Prepare your Activity  class MyActivity   AppCompatActivity         override fun onBackPressed             val fragment               this supportFragmentManager findFragmentById R id main container           fragment as  IOnBackPressed   onBackPressed    not    let               super onBackPressed                       3 - Implement in your target Fragment  class MyFragment   Fragment    IOnBackPressed       override fun onBackPressed    Boolean           return if  myCondition                  action not popBackStack             true           else               false

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Very short and sweet answer   getActivity   onBackPressed      Explanation of whole scenario of my case   I have FragmentA in MainActivity  I am opening FragmentB from FragmentA  FragmentB is child or nested fragment of FragmentA    Fragment duedateFrag   new FragmentB     FragmentTransaction ft    getFragmentManager   beginTransaction     ft replace R id container body  duedateFrag    ft addToBackStack null    ft commit      Now if you want to go to FragmentA from FragmentB you can simply put getActivity   onBackPressed     in FragmentB

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I just use findFragmentById and cast to the fragment and call a method that handles onBackpressed   This sample shows checking if this is the first step in order process if it is pop up a dialog fragment to confirm exit order     Override     public void onBackPressed               check if first fragment in wizard is loaded  if true get abandon confirmation before going back         OrderFragment frag   OrderFragment getSupportFragmentManager   findFragmentById R id fragContainer           if  frag  null     frag  null  amp  amp  frag getOrderStage   lt 1                AlertDialogFragment show getSupportFragmentManager    R string dialog cancel order R string dialog cancel order msg  R string dialog cancel order pos R string dialog order quiz neg  DIALOG ID CANCEL            else               super onBackPressed

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Ok guys I finally found out a good solution   In your onCreate   in your activity housing your fragments add a backstack change listener like so       fragmentManager addOnBackStackChangedListener new FragmentManager OnBackStackChangedListener              Override         public void onBackStackChanged                 List lt Fragment gt  f   fragmentManager getFragments                  List lt Fragment gt  f only returns one value             Fragment frag   f get 0               currentFragment   frag getClass   getSimpleName                         Also adding my fragmenManager is declared in the activities O Now every time you change fragment the current fragment String will become the name of the current fragment  Then in the activities onBackPressed   you can control the actions of your back button as so        Override     public void onBackPressed          switch  currentFragment            case  FragmentOne                  your code here             return          case  FragmentTwo                  your code here             return          default              fragmentManager popBackStack                   default action for any other fragment  return to previous             I can confirm that this method works for me

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In my solution  Kotlin    I m using onBackAlternative function as a parameter on BaseActivity   BaseActivity  abstract class BaseActivity        var onBackPressAlternative      - gt  Unit     null      override fun onBackPressed             if  onBackPressAlternative    null                onBackPressAlternative               else               super onBackPressed                       I have a function for set onBackPressAlternative on BaseFragment   BaseFragment  abstract class BaseFragment         override fun onStart             super onStart                       setOnBackPressed null     Add this                 Method must be declared as open  for overriding in child class      open fun setOnBackPressed onBackAlternative      - gt  Unit                activity as BaseActivity lt      gt   onBackPressAlternative   onBackAlternative            Then my onBackPressAlternative is ready to use on fragments   Sub Fragments  override fun setOnBackPressed onBackAlternative      - gt  Unit           activity as BaseActivity lt      gt   onBackPressAlternative                TODO Your own custom onback function

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None of that is easy to implement nor will it function in an optimal way   Fragments have a method call onDetach that will do the job    Override     public void onDetach             super onDetach            PUT YOUR CODE HERE         THIS WILL DO THE JOB

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Its just simple if you have An Activity A and you make 3 fragments like B  C and D Now if you are in fragment B or C and onBackPressed you want to move on Fragment D every time  Then you have to just Override the onBackPressed   method in main Activity A and also when you jump to any fragment then pass a TAG or name  of that fragment by which you recognized that fragment in main Activity A   I am giving the example of that one by which you can easily understand that       if  savedInstanceState    null        getSupportFragmentManager   beginTransaction   add R id container  new C fragment    xyz   commit         or if you are moving from fragment B to fragment C  and on back press you want to come on Fragment D   like below  btn setOnClickListener new View OnClickListener           Override     public void onClick View view             getActivity   getSupportFragmentManager   beginTransaction   add R id container  new C frament     xyz   commit              ActionBarActivity  getActivity    getSupportActionBar   setTitle  Fragment C                Now you have to just override the onBackPressed   method in main activity    like below     Override public void onBackPressed         FragmentManager fragmentManager  getSupportFragmentManager        if    C fragment  getSupportFragmentManager   findFragmentByTag  xyz       null  amp  amp    C fragment  getSupportFragmentManager   findFragmentByTag  xyz    isVisible              Fragment fragment   new D Fragment            fragmentManager beginTransaction   replace R id container  fragment  commit            getSupportActionBar   setTitle  D fragment           else           super onBackPressed

User · Answer

To implement like this Fragment 1 -  Fragment 2 -  Fragment 3      Button btn    Button  rootView findViewById R id your button id       btn setOnClickListener new View OnClickListener              Override         public void onClick View view                 Fragment 2 nextFrag  new Fragment 2                getActivity   getSupportFragmentManager   beginTransaction                        replace R id content frame  nextFrag getTag                         addToBackStack null                       commit                         Fragment 3 -  Fragment 2 -  Fragment 1  Step 1  Create a publically accessible String in Base Activity  Step 2  Whenever a new Fragment is activated  Change the value of the String in Base Activity  Step 3  Then add onBackPressed   method And pass the String value to another Method in Which The fagments can be replaced  In the Base Activity  public static String currentFragment null    Override public void onBackPressed              displayPreviousFragment currentFragment      public void displayPreviousFragment String currentFragment          creating fragment object     Fragment fragment   null         initializing the fragment object which is selected     switch  currentFragment                case  Fragment 2         fragment   new Fargment 1        break          case  Fragment 3         fragment   new Fragment 2        break               replacing the fragment     if  fragment    null            FragmentTransaction ft   getSupportFragmentManager   beginTransaction            ft replace R id frame to replace fragment  fragment           ft commit              In Fragment 2  inside OnCreateView method   BaseActivity currentFragment  Fragment 2     In Fragment 3  inside OnCreateView method   BaseActivity currentFragment  Fragment 3

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According to  HaMMeRed answer here is pseudocode how should it works  Lets say that your main activity is called BaseActivity which has child fragments  like in SlidingMenu lib example   Here are the steps   First we need create interface and class which implements its interface to have generic method   Create class interface OnBackPressedListener  public interface OnBackPressedListener       public void doBack       Create class which implements skills of OnBackPressedListener  public class BaseBackPressedListener implements OnBackPressedListener       private final FragmentActivity activity       public BaseBackPressedListener FragmentActivity activity            this activity   activity              Override     public void doBack             activity getSupportFragmentManager   popBackStack null  FragmentManager POP BACK STACK INCLUSIVE            Since now  we will work on our code BaseActivity and its fragments Create private listener on top of your class BaseActivity  protected OnBackPressedListener onBackPressedListener   create method to set listener in BaseActivity  public void setOnBackPressedListener OnBackPressedListener onBackPressedListener        this onBackPressedListener   onBackPressedListener     in override onBackPressed implement something like that   Override public void onBackPressed         if  onBackPressedListener    null          onBackPressedListener doBack        else         super onBackPressed     in your fragment in onCreateView you should add our listener   Override public View onCreateView LayoutInflater inflater  ViewGroup container  Bundle savedInstanceState        activity   getActivity           BaseActivity activity  setOnBackPressedListener new BaseBackPressedListener activity         View view           stuff with view      return view       Voila  now when you click back in fragment you should catch your custom on back method

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I solved in this way override onBackPressed in the Activity  All the FragmentTransaction are addToBackStack before commit    Override public void onBackPressed          int count   getSupportFragmentManager   getBackStackEntryCount         if  count    0            super onBackPressed              additional code       else           getSupportFragmentManager   popBackStack

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Just add addToBackStack while you are transitioning between your fragments like below    fragmentManager beginTransaction   replace R id content frame fragment  addToBackStack  tag   commit      if you write addToBackStack null    it will handle it by itself but if you give a tag   you should handle it manually

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New and better approach  Following piece of code in a Fragment will help you to capture the back-press event   Override public void onAttach  NonNull Context context        super onAttach context        OnBackPressedCallback callback   new OnBackPressedCallback true             Override         public void handleOnBackPressed                 Toast makeText mContext   quot back pressed quot   Toast LENGTH SHORT  show                                And when you want to go back based on your condition             if  yourCondition                    this setEnabled false                   requireActivity   onBackPressed                                        requireActivity   getOnBackPressedDispatcher   addCallback this  callback

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Google has released a new API to deal with onBackPressed in Fragment  activity  onBackPressedDispatcher  addCallback viewLifecycleOwner  object   OnBackPressedCallback true                override fun handleOnBackPressed

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In your mainActivity implement interface for callback protected mainActivity OnBackPressedListener onBackPressedListener   public interface OnBackPressedListener       void doBack       public void setOnBackPressedListener mainActivity OnBackPressedListener onBackPressedListener        this onBackPressedListener   onBackPressedListener      Override public void onBackPressed         if  onBackPressedListener    null            onBackPressedListener doBack          else            super onBackPressed             on fragment implement intefrace OnBackPressedListener which we write in mainActivity like implements mainActivity OnBackPressedListener  mainActivity is my base activity write following code in your fragment onCreateView method   mainActivity  getActivity    setOnBackPressedListener this    and implement OnBackPressedListener interface method doBack  Override public void doBack           call base fragment     now call fragment which you want to call on back pressed using doBack   method

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The solution is simple   1  If you have a base fragment class that all fragments extend  then add this code to it s class  otherwise create such a base fragment class          called when on back pressed to the current fragment that is returned      public void onBackPressed             add code in super class when override      2  In your Activity class  override onBackPressed as follows   private BaseFragment  currentFragment    Override public void onBackPressed           super onBackPressed          currentFragment onBackPressed        3  In Your Fragment class  add your desired code     Override  public void onBackPressed          setUpTitle

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Best solution    import android support v4 app Fragment  import android support v4 app FragmentManager  import android support v7 app AppCompatActivity   public class BaseActivity extends AppCompatActivity        Override     public void onBackPressed              FragmentManager fm   getSupportFragmentManager            for  Fragment frag   fm getFragments                  if  frag    null                    super onBackPressed                    finish                    return                            if  frag isVisible                      FragmentManager childFm   frag getChildFragmentManager                    if  childFm getFragments      null                        super onBackPressed                        finish                        return                                    if  childFm getBackStackEntryCount    gt  0                        childFm popBackStack                        return                                    else                        fm popBackStack                        if  fm getFragments   size    lt   1                            finish                                              return

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If you re using androidx appcompat appcompat 1 1 0 or above then you can add an OnBackPressedCallback to your fragment as follows  requireActivity        onBackPressedDispatcher      addCallback this  object   OnBackPressedCallback true            override fun handleOnBackPressed                 Log d TAG   Fragment back pressed invoked                  Do custom work here                     if you want onBackPressed   to be called as normal afterwards             if  isEnabled                    isEnabled   false                 requireActivity   onBackPressed                                     See https   developer android com guide navigation navigation-custom-back

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You can register fragment in activity to handle back press   interface BackPressRegistrar       fun registerHandler handler  BackPressHandler      fun unregisterHandler handler  BackPressHandler     interface BackPressHandler       fun onBackPressed    Boolean     usage   In Fragment   private val backPressHandler   object   BackPressHandler       override fun onBackPressed    Boolean           showClosingWarning           return false          override fun onResume         super onResume        activity as  BackPressRegistrar   registerHandler backPressHandler     override fun onStop          activity as  BackPressRegistrar   unregisterHandler backPressHandler      super onStop       In Activity   class MainActivity   AppCompatActivity    BackPressRegistrar         private var registeredHandler  BackPressHandler    null     override fun registerHandler handler  BackPressHandler    registeredHandler   handler       override fun unregisterHandler handler  BackPressHandler    registeredHandler   null        override fun onBackPressed             if  registeredHandler  onBackPressed      false  super onBackPressed

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public interface IonBackPressInFrag       void backPressed       public class FragmentMainActivity extends AppCompatActivity       public IonBackPressInFrag backPressInFrag        Override     protected void onCreate Bundle savedInstanceState              Override         public void onBackPressed                  backPressInFrag backPressed                       public class FragDetailSearch extends Fragment implements IonBackPressInFrag    if getActivity     null             FragmentMainActivity  getActivity    backPressInFrag   this              Override     public void backPressed             Toast makeText getContext     backkkkkk   Toast LENGTH LONG  show

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Here is my solution for that issue   in Activity A    Override protected void onActivityResult int requestCode  int resultCode  Intent data         super onActivityResult requestCode  resultCode  data        if requestCode    REQUEST CODE                if resultCode    Activity RESULT OK                        tvTitle setText data getExtras   getString  title                             in Activity B    Override public void onBackPressed          setResult Activity RESULT OK  getIntent          super onBackPressed        activity b holds the fragment   in fragment   private void setText String text                Intent intent   new Intent            intent putExtra  title   text           getActivity   setIntent intent           in that way the Intent Object  data  in activity A will get the string from the fragment

[android] How to implement onBackPressed() in Fragments?

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