Using onBackPressed in Android Fragments

Question

I am working on a project and I need to be able to use the back button in each fragment to navigate between previous fragments  I have methods written to do so by using a back arrow in the action bar  however  I want to be able to use the same functionality on the back button pressed   I don t want to use the back stack   Is there a way to do this   EDIT  Rather than using the back stack I want to be able to call the go back to previous method below when the user clicks the back button  I need to used the gobackpressed method within fragments  Is this possible  I hope this is clear and concise  Apologies for any confusion caused above   Go Back to Previous  public void gobackToPreviousFragment String preFragmentTag  Fragment preFragment        FragmentManager  fm   getSupportFragmentManager         FragmentTransaction ft   fm beginTransaction        ft setCustomAnimations R animator close slide in R animator close slide out        ft show preFragment            BY REMOVING FRAGMENT  WHEN USER TRIES TO REVISIT  FRAGMENT IS BLACK        ft remove fm findFragmentByTag Misc currentContentFragmentTag        ft addToBackStack null       ft commit         Misc currentContentFragmentTag   preFragmentTag       createBar preFragment       Go Forward  public void gotoNextFragment String nextTag  Fragment nextFragment        FragmentManager  fm   getSupportFragmentManager         FragmentTransaction ft   fm beginTransaction        ft setCustomAnimations R animator enter slide in  R animator enter slide out        boolean newlyCreated   false      if nextFragment    null           nextFragment   Fragment instantiate this  nextTag           newlyCreated   true               hide current fragment     ft hide fm findFragmentByTag Misc currentContentFragmentTag         if newlyCreated           ft add R id content frame  nextFragment  nextTag             else          ft show nextFragment              ft addToBackStack null       ft commit        Misc currentContentFragmentTag   nextTag       createBar nextFragment       These are how I navigate back and forth  and I d like to be able to implement the go back method on the onBackPressed     Does this make sense

User · Answer

I didn t find any good answer about this problem  so this is my solution    If you want to get backPress in each fragment do the following    create interface OnBackPressedListener  public interface OnBackPressedListener       void onBackPressed        That each fragment that wants to be informed of backPress implements this interface   In parent activity   you can override onBackPressed     Override public void onBackPressed         List lt Fragment gt  fragmentList   getSupportFragmentManager   getFragments        if  fragmentList    null              TODO  Perform your logic to pass back press here         for Fragment fragment   fragmentList              if fragment instanceof OnBackPressedListener                    OnBackPressedListener fragment  onBackPressed

User · Answer

In the fragment where you would like to handle your back button you should attach stuff to your view in the oncreateview   Override public View onCreateView LayoutInflater inflater  ViewGroup container  Bundle savedInstanceState        View v   inflater inflate R layout second fragment  container  false       v setOnKeyListener pressed       return v        Override public boolean onKey View v  int keyCode  KeyEvent event           TODO Auto-generated method stub     if  keyCode    KeyEvent KEYCODE BACK                   back to previous fragment by tag             myfragmentclass fragment    myfragmentclass  getActivity   getSupportFragmentManager   findFragmentByTag TAG               if fragment    null                    getActivity   getSupportFragmentManager   beginTransaction    replace R id cf g1 mainframe fm  fragment  commit                              return true                    return false

User · Answer

Use this    Override public void onBackPressed         int fragments   getFragmentManager   getBackStackEntryCount        if  fragments    1            finish              super onBackPressed

User · Answer

You can try to override onCreateAnimation  parameter and catch enter  false  This will fire before every back press    Override public Animation onCreateAnimation int transit  boolean enter  int nextAnim                        if  enter                 leaving fragment             Log d TAG  leaving fragment                      return super onCreateAnimation transit  enter  nextAnim

User · Answer

Why don t you want to use the back stack  If there is an underlying problem or confusion maybe we can clear it up for you   If you want to stick with your requirement just override your Activity s onBackPressed   method and call whatever method you re calling when the back arrow in your ActionBar gets clicked   EDIT  How to solve the  black screen  fragment back stack problem   You can get around that issue by adding a backstack listener to the fragment manager  That listener checks if the fragment back stack is empty and finishes the Activity accordingly   You can set that listener in your Activity s onCreate method    Override protected void onCreate Bundle savedInstanceState        super onCreate savedInstanceState       FragmentManager fm   getFragmentManager        fm addOnBackStackChangedListener new OnBackStackChangedListener              Override         public void onBackStackChanged                 if getFragmentManager   getBackStackEntryCount      0  finish

User · Answer

For a Fragment you can simply add    getActivity   onBackPressed      to your code

User · Answer

I found a new way to do it without interfaces  You only need to add the below code to the Fragment   s onCreate   method    overriding the fragment s oncreate  override fun onCreate savedInstanceState  Bundle             super onCreate savedInstanceState             calling onBackPressedDispatcher and adding call back          requireActivity   onBackPressedDispatcher addCallback this             do stuff here

User · Answer

requireActivity   onBackPressedDispatcher addCallback viewLifecycleOwner  object   OnBackPressedCallback true                override fun handleOnBackPressed                     Log w  quot a quot   quot  quot

User · Answer

This works for me  D      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

[android] Using onBackPressed() in Android Fragments

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