Fragment pressing back button

Question

I am now having an activity containing fragments

[1] , [2] , [3] , [4]

If pressing buttons , [3] , it can be redirected to [4]

I would like to implement the back button as shown follow..

when pressing back at [4] , it return to [3]

when pressing back at [3] , it return to [2]

when pressing back at [1] , the activity finishes();

When it comes to the current implementation, it finish the activity instead of popping up the Fragment. Would you please tell me what I should do or keep in mind ?

@Override
public boolean onKeyDown(int keyCode, KeyEvent event) {

    if( keyCode==KeyEvent.KEYCODE_BACK) 
    {   

        finish();
    }       

        return super.onKeyDown(keyCode, event); 

}

score 92 · Answer 1 · answered Feb 07 '14 at 18:53

92

This worked for me.

-Add .addToBackStack(null) when you call the new fragment from activity.

    FragmentTransaction mFragmentTransaction = getFragmentManager()
                .beginTransaction();
    ....
    mFragmentTransaction.addToBackStack(null);

-Add onBackPressed() to your activity

    @Override
public void onBackPressed() {
    if (getFragmentManager().getBackStackEntryCount() == 0) {
        this.finish();
    } else {
        getFragmentManager().popBackStack();
    }
}

answered Feb 07 '14 at 18:53

Kamel

1,077
8
4

4

This is the best and easiest solution from SO, imho – Andrei Drynov May 21 '14 at 21:41
This is working without orientation change,But After Orientation change I am getting Blank Screen if i press back button – kavie Sep 19 '14 at 09:29
This works but I wonder if someone can explain to me why this isnt the default behaviour like it is with an `Activity` ? – wal Oct 02 '15 at 03:33
I would prefer to call super.onBackPressed(); – benleung Dec 07 '15 at 03:23
I have an issue with this : Frag1 [back stack-true]-> frag2 [true]-> frag 3[true] for this backpressed work perfect but Frag1 [back stack-true]-> frag2 [true]-> frag 3[true]->frag 4[false]->Frag1 [back stack-true]-> frag2 [true]-> frag 3[true] then if i backpressed from frag 3 it directly go to frag 1 intead of frag 2.please help.. – Anil Prajapati Apr 26 '16 at 04:03
My Fragment is initialized as " Fragment ff= new SubFirstFragment();" and i am opening a fragment like " getActivity().getSupportFragmentManager().beginTransaction().replace(R.id.bglayout,ff,"SubFragment").addToBackStack("SubFragment").commit(); " thus my backstackcount is always becoming 0 due to which on every back pressed my activity is finished ! Please guide me through it . – Yash Agrawal Oct 10 '16 at 16:19

Hiren Patel · Answer 2 · 2016-03-03T10:36:49.863

Easiest way ever:

onResume():

@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 && keyCode == KeyEvent.KEYCODE_BACK) {
                // handle back button's click listener
                Toast.makeText(getActivity(), "Back press", Toast.LENGTH_SHORT).show();
                return true;
            }
            return false;
        }
    });

}

Edit 1: If fragment having EditText.

private EditText editText;

onCreateView():

editText = (EditText) rootView.findViewById(R.id.editText);

onResume():

@Override
public void onResume() {
    super.onResume();

    editText.setOnKeyListener(new View.OnKeyListener() {
        @Override
        public boolean onKey(View v, int keyCode, KeyEvent event) {
            if (keyCode == KeyEvent.KEYCODE_BACK) {
                editText.clearFocus();
            }
            return false;
        }
    });

    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 && keyCode == KeyEvent.KEYCODE_BACK) {
                // handle back button's click listener
                Toast.makeText(getActivity(), "Back press", Toast.LENGTH_SHORT).show();
                return true;
            }
            return false;
        }
    });

}

Note: It will work if you have EditText in fragment.

Done

but if you have an EditText in you fragment view. so that will not work all the time. e.g : if the keyboard was shown and the editext request focus. — david, Oct 02 '15 at 11:16
@HirenPatel I need to implement for many fragments, so I mad BaseFragment for it. I can't access edit text in BaseFragment. How can I solve this? — Kishan Vaghela, May 23 '16 at 14:09
I found that in Android P, you have to re-focus root View after clear editText focus. — Yu-Hsuan, Jun 25 '18 at 05:41

savepopulation · Answer 3 · 2017-06-15T19:59:46.507

9

This is a working solution for me:

dialog.setOnKeyListener(new DialogInterface.OnKeyListener() {
                    @Override
                    public boolean onKey(DialogInterface dialog, int keyCode, KeyEvent event) {
                        if (keyCode == KeyEvent.KEYCODE_BACK) {
                            // DO WHAT YOU WANT ON BACK PRESSED
                            return true;
                        }
                        return false;
                    }
                });

Edit: You can replace dialog with getView() for fragments.

edited Jun 15 '17 at 19:59

answered Oct 05 '14 at 22:44

savepopulation

11,736
4
55
80

3

what is dialog? and how is it related to the fragment? – behelit Mar 21 '16 at 02:04
It's an alert dialog or dialog fragment. ı'm not sure i need to check the code. – savepopulation Mar 21 '16 at 08:47

score 9 · Answer 4 · answered Aug 06 '17 at 14:35

Try this simple solution:

In your activity implement onBackPressed

 @Override
    public void onBackPressed() {
       if (getSupportFragmentManager().getBackStackEntryCount() > 1) {
            getSupportFragmentManager().popBackStack();
        } else {
            finish();
        }
    }

This will work if you want to pop the top fragment on each back press. Note:- While adding fragment to activity always do add the transaction to back stack for this to work

score 5 · Answer 5 · edited Jun 20 '20 at 09:12

Solution for Pressing or handling back button in Fragment.

The way I solved my issue I am sure it will helps you too:

1.If you don't have any Edit Text-box in your fragment you can use below code

Here MainHomeFragment is main Fragment (When I press back button from second fragment it will take me too MainHomeFragment)

    @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 && keyCode == KeyEvent.KEYCODE_BACK){

                MainHomeFragment mainHomeFragment = new SupplierHomeFragment();
                android.support.v4.app.FragmentTransaction fragmentTransaction =
                        getActivity().getSupportFragmentManager().beginTransaction();
                fragmentTransaction.replace(R.id.fragment_container, mainHomeFragment);
                fragmentTransaction.commit();

                return true;    
            }    
            return false;
        }
    }); }

2.If you have another fragment named as Somefragment and it has Edit text-box then you can do it by this way.

private EditText editText;

Then In,

onCreateView():    
editText = (EditText) view.findViewById(R.id.editText);

Then Override OnResume,

@Override
public void onResume() {
    super.onResume();

    editText.setOnKeyListener(new View.OnKeyListener() {
        @Override
        public boolean onKey(View v, int keyCode, KeyEvent event) {
            if (keyCode == KeyEvent.KEYCODE_BACK) {
                editTextOFS.clearFocus();
                getView().requestFocus();
            }
            return false;
        }
    });

    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 && keyCode == KeyEvent.KEYCODE_BACK){

                MainHomeFragment mainHomeFragment = new SupplierHomeFragment();
                android.support.v4.app.FragmentTransaction fragmentTransaction =
                        getActivity().getSupportFragmentManager().beginTransaction();
                fragmentTransaction.replace(R.id.fragment_container, mainHomeFragment);
                fragmentTransaction.commit();

                return true;

            }

            return false;
        }
    });

}

That's all folks (amitamie.com) :-) ;-)

Haider Malik · Accepted Answer · 2019-12-11T08:16:20.780

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<Fragment> f = fragmentManager.getFragments();
            Fragment frag = f.get(0);
            currentFragment = frag.getClass().getSimpleName();
        }
    });

(Nb. my fragmentManager is declared global) Now every time you change fragment the currentFragment 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.

Update : Kotlin

override fun onBackPressed() {

    when(supportFragmentManager.fragments[0].javaClass.simpleName){
        "FragmentOne" -> doActionOne()
        "FragmentTwo" -> doActionTwo()
        else -> supportFragmentManager.popBackStack()
    }
}

Wow , it was awesome , thank you sooo much . But what about when we have nested fragments ? for example we have child fragment inside another fragment ? — ParSa, Aug 19 '19 at 11:34
@parsadadras the nested fragments will be not affected as this is dependent on the fragment listener applied to the main fragment manager and not the child fragment manager. — Haider Malik, Aug 21 '19 at 02:22

score 4 · Answer 7 · answered Oct 01 '14 at 14:20

Still better solution could be to follow a design pattern such that the back-button press event gets propagated from active fragment down to host Activity. So, it's like.. if one of the active fragments consume the back-press, the Activity wouldn't get to act upon it, and vice-versa.

One way to do it is to have all your Fragments extend a base fragment that has an abstract 'boolean onBackPressed()' method.

@Override
public boolean onBackPressed() {
   if(some_condition)
      // Do something
      return true; //Back press consumed.
   } else {
      // Back-press not consumed. Let Activity handle it
      return false;
   }
}

Keep track of active fragment inside your Activity and inside it's onBackPressed callback write something like this

@Override
public void onBackPressed() {
   if(!activeFragment.onBackPressed())
      super.onBackPressed();
   }
}

This post has this pattern described in detail

Perfect solution. I always prefer clean solutions over quick&dirty ones. — Mousa, Nov 10 '15 at 08:33

score 4 · Answer 8 · answered Feb 06 '15 at 23:40

What I do in this cases is I implement the onBackPressed() function from the Activity:

@Override
public void onBackPressed() {
   super.onBackPressed();
   FragmentManager fm = getSupportFragmentManager();
   MyFragment myFragment = (MyFragment) fm.findFragmentById(R.id.my_fragment);

   if((myFragmen.isVisible()){
      //Do what you want to do
   }
}

How this works for you too.

score 4 · Answer 9 · answered Feb 12 '18 at 14:27

4

if you are using webview inside a fragment than use this in your onCreateView method

webView.setOnKeyListener(new View.OnKeyListener(){

        @Override
        public boolean onKey(View view, int i, KeyEvent keyEvent) {
            if((i==KeyEvent.KEYCODE_BACK)&& webView.canGoBack()){
                webView.goBack();
                return true;
            }
            return false;
        }
    });

and import this class

import android.view.KeyEvent;

answered Feb 12 '18 at 14:27

Akshansh Jain

87
3

this type of answer has already been given by several people now. Please remove yours. – ZF007 Feb 12 '18 at 14:51
but when i tried other answers, they were not giving the result that i want. – Akshansh Jain Feb 14 '18 at 17:03

score 3 · Answer 10 · edited May 17 '16 at 15:25

3

You can use getFragmentManager().popBackStack() in basic Fragment to go back.

edited May 17 '16 at 15:25

Allan Pereira

2,572
4
21
28

answered Sep 12 '13 at 05:09

Denny

149
1
1
5

score 2 · Answer 11 · answered Jul 22 '14 at 07:22

You also need to check Action_Down or Action_UP event. If you will not check then onKey() Method will call 2 times.

getView().setFocusableInTouchMode(true);
getView().requestFocus();

getView().setOnKeyListener(new OnKeyListener() {
        @Override
        public boolean onKey(View v, int keyCode, KeyEvent event) {
                if (event.getAction() == KeyEvent.ACTION_DOWN) {
                    if (keyCode == KeyEvent.KEYCODE_BACK) {
                        Toast.makeText(getActivity(), "Back Pressed", Toast.LENGTH_SHORT).show();
                    return true;
                    }
                }
                return false;
            }
        });

Working very well for me.

but if you have a EditText in you fragment view. so that will not work all the time. e.g : if the keyboard was shown and the editext request focus. — david, Oct 02 '15 at 11:15

score 2 · Answer 12 · answered Jan 22 '20 at 11:20

you can use this one in onCreateView, you can use transaction or replace

 OnBackPressedCallback callback = new OnBackPressedCallback(true) {
                @Override
                public void handleOnBackPressed() {
                    //what you want to do 
                }
            };
    requireActivity().getOnBackPressedDispatcher().addCallback(this, callback);

score 1 · Answer 13 · answered Dec 24 '15 at 21:27

1

Make sure to add the following:

if (event.getAction()!=KeyEvent.ACTION_DOWN)
                return true;

in the onKey block of code to avoid the event calling twice.

answered Dec 24 '15 at 21:27

mossman252

462
4
3

score 0 · Answer 14 · answered Jun 30 '17 at 23:42

i use a methode to change fragments it has thw following code

 getSupportFragmentManager().beginTransaction().setCustomAnimations(R.anim.enter, R.anim.exit, R.anim.pop_enter, R.anim.pop_exit).replace(R.id.content_frame, mContent, mContent.getClass().getSimpleName()).addToBackStack(null)
                .commit();

and for the back button this .

@Override
    public void onBackPressed() {
        // note: you can also use 'getSupportFragmentManager()'
        FragmentManager mgr = getSupportFragmentManager();
        if (mgr.getBackStackEntryCount() == 1) {
            // No backstack to pop, so calling super
            finish();
        } else {
            mgr.popBackStack();
        }
    }

the important thing to note is i use 1 for checking getBackStackEntryCount this is because if you dont use it and use 0 user sees nothing for the last back button.

score 0 · Answer 15 · answered Sep 22 '20 at 09:25

use this (in kotlin)

 activity?.onBackPressedDispatcher?.addCallback(this, object : OnBackPressedCallback(true) {
        override fun handleOnBackPressed() {
            // in here you can do logic when backPress is clicked
        }
    })

i think this is the most elegant way to do it

score 0 · Answer 16 · answered Mar 05 '21 at 12:51

Try this, its helped me :)

 @Override  
    public void onResume() { //Pressed return button - returns to the results menu
        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 && keyCode == KeyEvent.KEYCODE_BACK) {
                    /*Here your code*/
                    return true;
                }
                return false;
            }
        });
    }

score 0 · Answer 17 · answered Nov 04 '22 at 09:57

just paste it in your activity main

 @Override
public void onBackPressed() {


    DrawerLayout drawer = (DrawerLayout) findViewById(R.id.drawer_layout);
    if (drawer.isDrawerOpen(GravityCompat.START)) {
        drawer.closeDrawer(GravityCompat.START);
    } else if (getSupportFragmentManager().getBackStackEntryCount() > 1) {
        getSupportFragmentManager().popBackStack();
    } else {
        finish();
    }


    
}

score 0 · Answer 18 · answered May 10 '23 at 03:14

0

Fragment Pressing Back Button - we are using popBackStack() function.

In Kotlin - write code in your activity

override fun onBackPressed() {
     super.onBackPressed()
     supportFragmentManager.popBackStack();
}

answered May 10 '23 at 03:14

Om Prakash Sharma

1

Fragment pressing back button

18 Answers18

Solution for Pressing or handling back button in Fragment.

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