Android Handling back press when using fragments in Android

In MainActivity:

getSupportFragmentManager().beginTransaction().replace(R.id.gif_contents, gifPageTwoFragment, "gifPageTwoFragment").addToBackStack("gifPageTwoFragment").commit();

In GifPageTwoFragment:

@Override
    public void onActivityCreated(Bundle savedInstanceState) {
        super.onActivityCreated(savedInstanceState);
        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) {
                    Log.e("gif--","fragment back key is clicked");
                    getActivity().getSupportFragmentManager().popBackStack("gifPageTwoFragment", FragmentManager.POP_BACK_STACK_INCLUSIVE);
                    return true;
                }
                return false;
            }
        });
    }

In your oncreateView() method you need to write this code and in KEYCODE_BACk condition you can write whatever the functionality you want

  View v = inflater.inflate(R.layout.xyz, container, false);
    //Back pressed Logic for fragment
    v.setFocusableInTouchMode(true);
    v.requestFocus();
    v.setOnKeyListener(new View.OnKeyListener() {
        @Override
        public boolean onKey(View v, int keyCode, KeyEvent event) {
            if (event.getAction() == KeyEvent.ACTION_DOWN) {
                if (keyCode == KeyEvent.KEYCODE_BACK) {
                    getActivity().finish();
                    Intent intent = new Intent(getActivity(), MainActivity.class);
                    startActivity(intent);

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

 view.setFocusableInTouchMode(true);
        view.requestFocus();
        view.setOnKeyListener(new View.OnKeyListener() {
        @Override
        public boolean onKey(View v, int keyCode, KeyEvent event)   {
        if (keyCode == KeyEvent.KEYCODE_BACK) {

            Fragment NameofFragment = new NameofFragment;

            FragmentTransaction  transaction=getFragmentManager().beginTransaction();
            transaction.replace(R.id.frame_container,NameofFragment);

            transaction.commit();

            return true;
        }
        return false;
    }
});

return view;

繁琐的方法:

I am using Android Sliding Menu using Navigation Drawer in my application and Fragments are used in the app instead of Activities. When I open the drawer, click on an item a Fragment appears. I move from one fragment to another fragment using the following code:

Fragment fragment = null;
fragment = new GalleryFragment(selectetdMainMenu.getCategoryID());
                    FragmentTransaction ft = getFragmentManager().beginTransaction();
                    ft.addToBackStack("menuFrag");
                    ft.add(R.id.frame_container, fragment, "menuFrag");
                    ft.setTransition(FragmentTransaction.TRANSIT_FRAGMENT_FADE);
                    ft.commit();

In this way I can go from one fragment to another but I fail to come to the previous fragment on back button press. I managed to come up with this code to handle back press in MainActivity where Drawer is Initialized:

@Override
public boolean onKeyDown(int keyCode, KeyEvent event) {
    super.onKeyDown(keyCode, event);
    if (keyCode == KeyEvent.KEYCODE_BACK) {
        Fragment fragment_byTag = fragmentManager.findFragmentByTag("menuFrag");
        Fragment menuFragment_by_tag = fragmentManager.findFragmentByTag("galleryFrag");
        Fragment commentsFrag_by_tag = fragmentManager.findFragmentByTag("commentsFrag");
        Fragment dealDetail = fragmentManager.findFragmentByTag("promoFrag");
            if(commentsFrag_by_tag != null){
                if (commentsFrag_by_tag.isVisible()) {
                    Log.e("comments back  ", " clicked");
                    //menuDetailsFrag.onBackPressed();
                    FragmentManager fragmentManager = getSupportFragmentManager();
                    fragmentManager.beginTransaction().remove(commentsFrag_by_tag).commit();
                    fragmentManager.beginTransaction().show(menuFragment_by_tag).commit();
                }
            }else if(menuFragment_by_tag.isVisible()){
                Log.e("menu back  ", " clicked");
                menuDetailsFrag.onBackPressed();
                FragmentManager fragmentManager = getSupportFragmentManager();
                fragmentManager.beginTransaction().remove(menuFragment_by_tag).commit();
                fragmentManager.beginTransaction().show(fragment_byTag).commit();
            }
        }

    return false;
}

This works at times but fails most of the time. I would greatly appreciate if a better way to navigate back can be shown.

9down votefavorite

14

I am using Android Sliding Menu using Navigation Drawer in my application and Fragments are used in the app instead of Activities. When I open the drawer, click on an item a Fragment appears. I move from one fragment to another fragment using the following code:

Fragment fragment =null;
fragment =newGalleryFragment(selectetdMainMenu.getCategoryID());FragmentTransaction ft = getFragmentManager().beginTransaction();
                    ft.addToBackStack("menuFrag");
                    ft.add(R.id.frame_container, fragment,"menuFrag");
                    ft.setTransition(FragmentTransaction.TRANSIT_FRAGMENT_FADE);
                    ft.commit();

In this way I can go from one fragment to another but I fail to come to the previous fragment on back button press. I managed to come up with this code to handle back press in MainActivity where Drawer is Initialized:

@Overridepublicboolean onKeyDown(int keyCode,KeyEventevent){super.onKeyDown(keyCode,event);if(keyCode ==KeyEvent.KEYCODE_BACK){Fragment fragment_byTag = fragmentManager.findFragmentByTag("menuFrag");Fragment menuFragment_by_tag = fragmentManager.findFragmentByTag("galleryFrag");Fragment commentsFrag_by_tag = fragmentManager.findFragmentByTag("commentsFrag");Fragment dealDetail = fragmentManager.findFragmentByTag("promoFrag");if(commentsFrag_by_tag !=null){if(commentsFrag_by_tag.isVisible()){Log.e("comments back  "," clicked");//menuDetailsFrag.onBackPressed();FragmentManager fragmentManager = getSupportFragmentManager();
                    fragmentManager.beginTransaction().remove(commentsFrag_by_tag).commit();
                    fragmentManager.beginTransaction().show(menuFragment_by_tag).commit();}}elseif(menuFragment_by_tag.isVisible()){Log.e("menu back  "," clicked");
                menuDetailsFrag.onBackPressed();FragmentManager fragmentManager = getSupportFragmentManager();
                fragmentManager.beginTransaction().remove(menuFragment_by_tag).commit();
                fragmentManager.beginTransaction().show(fragment_byTag).commit();}}returnfalse;}

This works at times but fails most of the time. I would greatly appreciate if a better way to navigate back can be shown.

android android-fragments navigation back navigation-drawer

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asked Mar 21 '14 at 7:41 TharakaNirmana 6,22673160

Check this one out .. stackoverflow.com/questions/22552653/… – J.Ajendra Mar 21 '14 at 7:45

1

add this ft.addToBackStack(null);ft.commit(); add the fragments to the backstack and pop them. stackoverflow.com/questions/22550420/… – Raghunandan Mar 21 '14 at 7:45 

@Raghunandan. The easiest solution I found is yours. – YuDroid Nov 29 '14 at 12:21

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4 Answers

activeoldestvotes

up vote46down voteaccepted

I usually set an onKeyListener to the View in onResume. From what I learned you have to take care to set setFocusableInTouchMode() and requestFocus on the View.

This is a sample of what I use for this purpose:

@Overridepublicvoid onResume(){super.onResume();

    getView().setFocusableInTouchMode(true);
    getView().requestFocus();
    getView().setOnKeyListener(newView.OnKeyListener(){@Overridepublicboolean onKey(View v,int keyCode,KeyEventevent){if(event.getAction()==KeyEvent.ACTION_UP && keyCode ==KeyEvent.KEYCODE_BACK){// handle back buttonreturntrue;}returnfalse;}});}

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answered Mar 21 '14 at 8:15 super-qua 2,51211326

where do I place this code? fragment or main activity> – TharakaNirmana Mar 21 '14 at 8:16

The code goes in the fragment. Hope this helps – super-qua Mar 21 '14 at 8:17

This worked. I added getActivity().getSupportFragmentManager().popBackStack(); to handle back press. – TharakaNirmana Mar 24 '14 at 5:02

1

@super-qua, superb solution for fragment – Hiren Patel Nov 26 '14 at 8:54

5

This will stop working if you have a child view within the fragment that can gain focus. For example if you have a "list state" and "edit state" in the fragment, you go into the "edit state" that has an EditText within it, select the EditText, the main view will lose focus and the onKey() will stop functioning unless you manually regain focus of the base view. – wchristiansen Dec 1 '15 at 21:10

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up vote5down vote

Try these methods. To me, the most useful solution is as follows:

In MainActivity:

getSupportFragmentManager().beginTransaction().replace(R.id.gif_contents, gifPageTwoFragment,"gifPageTwoFragment").addToBackStack("gifPageTwoFragment").commit();

In GifPageTwoFragment:

@Overridepublicvoid onActivityCreated(Bundle savedInstanceState){super.onActivityCreated(savedInstanceState);
        getView().setFocusableInTouchMode(true);
        getView().requestFocus();
        getView().setOnKeyListener(newView.OnKeyListener(){@Overridepublicboolean onKey(View v,int keyCode,KeyEventevent){if(event.getAction()==KeyEvent.ACTION_UP && keyCode ==KeyEvent.KEYCODE_BACK){Log.e("gif--","fragment back key is clicked");
                    getActivity().getSupportFragmentManager().popBackStack("gifPageTwoFragment",FragmentManager.POP_BACK_STACK_INCLUSIVE);returntrue;}returnfalse;}});}

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edited Aug 21 '15 at 2:56 Matt Tester 2,15321829

answered Aug 21 '15 at 2:09 renhui 5112

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up vote2down vote

In your oncreateView() method you need to write this code and in KEYCODE_BACk condition you can write whatever the functionality you want

View v = inflater.inflate(R.layout.xyz, container,false);//Back pressed Logic for fragment
    v.setFocusableInTouchMode(true);
    v.requestFocus();
    v.setOnKeyListener(newView.OnKeyListener(){@Overridepublicboolean onKey(View v,int keyCode,KeyEventevent){if(event.getAction()==KeyEvent.ACTION_DOWN){if(keyCode ==KeyEvent.KEYCODE_BACK){
                    getActivity().finish();Intent intent =newIntent(getActivity(),MainActivity.class);
                    startActivity(intent);returntrue;}}returnfalse;}});

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answered Mar 21 '16 at 10:32 Raj Kumar 286312

This was perfect for me – Adi May 18 '16 at 12:41

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up vote1down vote

view.setFocusableInTouchMode(true); view.requestFocus(); view.setOnKeyListener(newView.OnKeyListener(){@Overridepublicboolean onKey(View v,int keyCode,KeyEventevent){if(keyCode ==KeyEvent.KEYCODE_BACK){FragmentNameofFragment=newNameofFragment;FragmentTransaction transaction=getFragmentManager().beginTransaction(); transaction.replace(R.id.frame_container,NameofFragment); transaction.commit();returntrue;}returnfalse;}});return view;