Programmatically go back to the previous fragment in the backstack

Question

Say I have an activity that has fragments added programmatically   private void animateToFragment Fragment newFragment  String tag        FragmentTransaction ft   getFragmentManager   beginTransaction        ft replace R id fragment container  newFragment  tag       ft addToBackStack null       ft commit        What is the best way to return to the previous fragment that was visible   I found Trigger back-button functionality on button click in Android but I m thinking simulating a back key event isn t the right way to go about it  and I can t get it to work either    dispatchKeyEvent new KeyEvent KeyEvent ACTION DOWN  KeyEvent KEYCODE BACK      Calling finish   just closes the activity which I m not interested in   Is there a better way to go about this

User · Answer

This solution works perfectly for bottom bar based fragment navigation when you want to close the app when back pressed in primary fragment.

On the other hand when you are opening the secondary fragment (fragment in fragment) which is defined as "DetailedPizza" in my code it will return the previous state of primary fragment. Cheers !

Inside activities on back pressed put this:

Fragment home = getSupportFragmentManager().findFragmentByTag("DetailedPizza");

if (home instanceof FragmentDetailedPizza && home.isVisible()) {
    if (getFragmentManager().getBackStackEntryCount() != 0) {
        getFragmentManager().popBackStack();
    } else {
        super.onBackPressed();
    }
} else {
    //Primary fragment
    moveTaskToBack(true);
}

And launch the other fragment like this:

Fragment someFragment = new FragmentDetailedPizza();
FragmentTransaction transaction = getFragmentManager().beginTransaction();
transaction.replace(R.id.container_body, someFragment, "DetailedPizza");
transaction.addToBackStack("DetailedPizza");
transaction.commit();

User · Answer

Android studio 4 0 1 Kotlin 1 3 72 Android Navigation architecture component  The following code works for me  findNavController   popBackStack

User · Answer

To make that fragment come again  just add that fragment to backstack which you want to come on back pressed  Eg   button setOnClickListener new View OnClickListener          Override     public void onClick View v            Fragment fragment   new LoginFragment              replacing the fragment         if  fragment    null                FragmentTransaction ft     FragmentActivity getContext    getSupportFragmentManager   beginTransaction                ft replace R id content frame  fragment               ft addToBackStack  SignupFragment                ft commit                          In the above case  I am opening LoginFragment when Button button is pressed  right now the user is in SignupFragment  So if addToBackStack TAG  is called  where TAG    SignupFragment   then when back button is pressed in LoginFragment  we come back to SignUpFragment    Happy Coding

User · Answer

These answers does not work if i don t have addToBackStack   added to my fragment transaction but  you can use   getActivity   onBackPressed      from your any fragment to go back one step

User · Answer

To elaborate on the other answers provided  this is my solution  placed in an Activity     Override public void onBackPressed        FragmentManager fm   getFragmentManager        if  fm getBackStackEntryCount    gt  0            Log i  MainActivity    popping backstack            fm popBackStack          else           Log i  MainActivity    nothing on backstack  calling super            super onBackPressed

User · Answer

By adding fragment tran addToBackStack null  on last fragment  I am able to do come back on last fragment   adding new fragment   view findViewById R id changepass  setOnClickListener new View OnClickListener              Override         public void onClick View v                FragmentTransaction transaction   getActivity   getSupportFragmentManager   beginTransaction                transaction replace R id container  new ChangePassword                 transaction addToBackStack null               transaction commit

User · Answer

Add those line to your onBackPressed   Method  popBackStackImmediate   method will get you back to the previous fragment if you have any fragment on back stack    if getFragmentManager   getBackStackEntryCount    gt  0        getFragmentManager   popBackStackImmediate      else      super onBackPressed

User · Answer

Look at the getFragmentManager   popBackStack   methods  there are several to choose from   http   developer android com reference android app FragmentManager html popBackStack

User · Answer

16 July 2020 - Kotlin Answer  First  call Fragment Manager  After  to use onBackPressed   method   Coding in Android Studio 4 0 with Kotlin  fragmentManager  popBackStack    Happy coding   canerkaseler

User · Answer

I came here looking or the same idea  and in the meantime i came up with own  which I believe is not that bad and works if with ViewPager   So what I did  is to override the onBackPressed method in the parent activity that holds the viewPager  and set it to always go back minus 1 position until it reaches the first fragment  then closes the activity     Override public void onBackPressed         if viewPager getCurrentItem   gt 0           viewPager setCurrentItem viewPager getCurrentItem  -1         else           super onBackPressed            this close             private void close        this finish        This might have a downfalls  like it only goes back one way left each time  so it might not work great if there are tabs and you switch positions with fragments skipped    going from 0 to 2  and then pressing back would put you on 1  instead of 0   For my case tho  with 2 fragments in viewPager without tabs  it does the job nicely

User · Answer

When we are updating add the fragments   Should Include the  addToBackStack     getSupportFragmentManager   beginTransaction        add detailFragment   detail      Add this transaction to the back stack  name is an optional name for this back stack state  or null        addToBackStack null       commit      After that if we give the getFragments popBackStackImmediate   will return true if we add update the fragments  and move back to the current screen

User · Answer

Programmatically go back to the previous fragment using following code   if   getFragmentManager   getBackStackEntryCount    gt  0               getFragmentManager   popBackStack              return    super onBackPressed

User · Answer

Try below code    Override     public void onBackPressed             Fragment myFragment   getSupportFragmentManager   findFragmentById R id container           if  myFragment    null  amp  amp  myFragment instanceof StepOneFragment                finish              else               if  getSupportFragmentManager   getBackStackEntryCount    gt  0                    getSupportFragmentManager   popBackStack                  else                   super onBackPressed

[android] Programmatically go back to the previous fragment in the backstack

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