Android Handling back press when using fragments in Android

Question

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.

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

super-qua · Accepted Answer · 2014-03-21 08:15:20Z

up vote 46 down vote accepted

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;}});}

answered Mar 21 '14 at 8:15

super-qua

2,512 1 13 26

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

show 7 more comments

Matt Tester · Answer 2 · 2015-08-21 02:56:32Z

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;}});}

Raj Kumar · Answer 3 · 2016-03-21 10:32:42Z

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;}});

score 1 · Answer 4

        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;

Android Handling back press when using fragments in Android

4 Answers