Fragment re-created on bottom navigation view item selected

Question

Following is my code for bottom navigation view item selected

bottomNavigationView.setOnNavigationItemSelectedListener(new BottomNavigationView.OnNavigationItemSelectedListener() {  
@Override
public boolean onNavigationItemSelected(@NonNull MenuItem item) {
    Fragment fragment = null;
    switch (item.getItemId()) {
        case R.id.action_one:
            // Switch to page one
            fragment = FragmentA.newInstance();
            break;
        case R.id.action_two:
            // Switch to page two
            fragment = FragmentB.newInstance();
            break;
        case R.id.action_three:
            // Switch to page three
            fragment = FragmentC.newInstance();
            break;
    }
    getSupportFragmentManager().beginTransaction().replace(R.id.container,fragment,"TAG").commit();
    return true;
}
});

Now my problem is every time fragment is re-created and don't want fragment to be recreated every time I also tried adding addToBackStack(null) but it this case on back button press keeps popping fragments from stack which I don't want.

Is there any way to display fragments on bottom navigation bar selected without re-creating fragment

To avoid that, I have create a map : `Map` and each fragment have a static id. I create all Fragment in `onCreate` of the `Activity`. But it's not recommended. You can add the fragment in the `backstack` with a unique tag like `Fragment.class.getSimpleName()`, then find it with `findFragmentByTag` and commit him again. Be sure to add each `Fragment` one time to the `backstack` — Raphael Teyssandier, Feb 21 '17 at 09:13
Hi Raphael as I said I don't want to add to it to backstack since it disturbs on back press implementation — amodkanthe, Feb 21 '17 at 09:15
For that you can Override `onBackPressed()` in your `Activity`. Comment `super.onBackPressed()` — Raphael Teyssandier, Feb 21 '17 at 09:17
no but there are some fragments other than these which will be added to stack if user performs action. I just don't want to add fragments associated with bottom navvigation view to backstack at same time dont want to recreate them — amodkanthe, Feb 21 '17 at 09:20
You don't want to recreate them for the view or something else in there code ? — Raphael Teyssandier, Feb 21 '17 at 09:24
Oh, I see, I just install Google NewsStand, and what you talking about it's the menu on the bottom right ? — Raphael Teyssandier, Feb 21 '17 at 10:13
no click on bottom navigation bar items see it does not creates fragments again and again — amodkanthe, Feb 21 '17 at 10:26
@amodkanthe will please share me the idea , how to retain the state of click Bottom Nevigation item while on backpressed.? — Rahul Kushwaha, Oct 30 '19 at 07:17
if you use the android navigation architecture component, see this: https://stackoverflow.com/a/69308302/6139861 — rafsanahmad007, Sep 24 '21 at 00:51

Viven · Answer 1 · 2018-06-12T06:01:02.750

26

With support library v26 you can do this

FragmentTransaction fragmentTransaction = mFragmentManager.beginTransaction();

Fragment curFrag = mFragmentManager.getPrimaryNavigationFragment();
if (curFrag != null) {
    fragmentTransaction.detach(curFrag);
}

Fragment fragment = mFragmentManager.findFragmentByTag(tag);
if (fragment == null) {
    fragment = new YourFragment();
    fragmentTransaction.add(container.getId(), fragment, tag);
} else {
    fragmentTransaction.attach(fragment);
}

fragmentTransaction.setPrimaryNavigationFragment(fragment);
fragmentTransaction.setReorderingAllowed(true);
fragmentTransaction.commitNowAllowingStateLoss();

edited Jun 12 '18 at 06:01

answered Jul 25 '17 at 10:48

Viven

627
7
14

2

For a complete example you can look at this git repo https://github.com/okaybroda/FragmentStateManager – Viven Jul 25 '17 at 10:49
2

Would you say this is the best way to handle navigation between three destinations when you want to keep the state/list positions etc when moving back and forth? Are there any caveats to using this method? Possible memory leaks or anything to be aware of? I'm not 100% sound on lifecycle quite yet – Burkely91 Oct 27 '17 at 10:24
1

Would it be better to do this or somehow restore instance state is what I really want to know I think! – Burkely91 Oct 27 '17 at 10:45
It did not seem to hold fragments in memory; it just somehow made page fragments look layered (page1 looked through below page2). – Damn Vegetables Dec 17 '17 at 05:11
I'd like to improve your nice snippet with the condition: if (curFrag != null && curFrag != fragment ). In you code, if a fragment is already on screen, when I click the same bottom button, fragment will be detached showing a black page – marco Jun 10 '18 at 14:01
@marco thanks for the highlight. I have made edits to the snippet by detaching first before attaching. – Viven Jun 12 '18 at 06:02
1

using `show` `hide` instead of `attach` `detach` works better. It won't restart fragment's lifecycle – osrl Sep 22 '18 at 17:23
@osrl that works too but it will hold up the views in memory – Viven Sep 26 '18 at 07:31
Yes that's what I've wanted in the first place :) thank you for your answers, it helped @Viven – osrl Sep 26 '18 at 08:56

score 16 · Answer 2 · answered Sep 06 '18 at 22:56

I faced the same problem and finally i i found the solution, you can try this code. it's work for me.

import android.support.annotation.NonNull;
import android.support.design.widget.BottomNavigationView;
import android.support.v4.app.Fragment;
import android.support.v4.app.FragmentManager;
import android.support.v4.app.FragmentTransaction;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.view.MenuItem;
import android.widget.FrameLayout;
import android.widget.Toast;

public class MainActivity extends AppCompatActivity {
public BottomNavigationView bv;
public home_fragment home;
public account_fragment afrag;
public other_fragment other;
public FrameLayout fr;
android.support.v4.app.Fragment current;
//public FragmentTransaction frt;
    public static int temp=0;
    final Fragment fragment11 = new account_fragment();
    final Fragment fragment22 = new home_fragment();
    final Fragment fragment33 = new other_fragment();
    final FragmentManager fm = getSupportFragmentManager();
    Fragment active = fragment11;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        bv=(BottomNavigationView) findViewById(R.id.navigationView);


        fm.beginTransaction().add(R.id.main_frame, fragment33, "3").hide(fragment33).commit();
        fm.beginTransaction().add(R.id.main_frame, fragment22, "2").hide(fragment22).commit();
        fm.beginTransaction().add(R.id.main_frame,fragment11, "1").commit();
bv.setOnNavigationItemSelectedListener(new BottomNavigationView.OnNavigationItemSelectedListener() {

            @Override
            public boolean onNavigationItemSelected(@NonNull MenuItem item) {
                switch (item.getItemId()) {
                    case R.id.account:
                        fm.beginTransaction().hide(active).show(fragment11).commit();
                        active = fragment11;
                        return true;

                    case R.id.home1:
                        fm.beginTransaction().hide(active).show(fragment22).commit();
                        active = fragment22;
                        return true;

                    case R.id.other:
                        fm.beginTransaction().hide(active).show(fragment33).commit();
                        active = fragment33;
                        return true;
                }
                return false;
            }
        });
      bv.setOnNavigationItemReselectedListener(new BottomNavigationView.OnNavigationItemReselectedListener() {
          @Override
          public void onNavigationItemReselected(@NonNull MenuItem item) {
              Toast.makeText(MainActivity.this, "Reselected", Toast.LENGTH_SHORT).show();

          }
      });


    }

}

Hat's off to you man! Really appreciate your work. You made my day. Thank you! — Gourav, Jul 04 '20 at 09:48
Definitely the cleanest solution I think. And it's flexible - if you need to recreate the fragment, you just re-assign the relevant fragment variable. Thanks a lot! — Gary Allen, Jul 23 '20 at 12:38
But this solution is not scalable. You will have to modify your code every time you want to add a new fragment. — Laura Galera, Jun 04 '21 at 08:54
with this code navigation between specified fragments is flawless but we have to handle many other things if using nav components — Uzair Mughal, Jul 26 '23 at 07:59

score 15 · Answer 3 · edited Oct 23 '19 at 12:20

This seemed to work well for me. Instead of attaching and detaching, i use show or hide to maintain fragment state.

    public void changeFragment(Fragment fragment, String tagFragmentName) {

        FragmentManager mFragmentManager = getSupportFragmentManager();
        FragmentTransaction fragmentTransaction = mFragmentManager.beginTransaction();

        Fragment currentFragment = mFragmentManager.getPrimaryNavigationFragment();
        if (currentFragment != null) {
            fragmentTransaction.hide(currentFragment);
        }

        Fragment fragmentTemp = mFragmentManager.findFragmentByTag(tagFragmentName);
        if (fragmentTemp == null) {
            fragmentTemp = fragment;
            fragmentTransaction.add(R.id.frame_layout, fragmentTemp, tagFragmentName);
        } else {
            fragmentTransaction.show(fragmentTemp);
        }

        fragmentTransaction.setPrimaryNavigationFragment(fragmentTemp);
        fragmentTransaction.setReorderingAllowed(true);
        fragmentTransaction.commitNowAllowingStateLoss();
    }

And this is how i use it

     private void initViews() {
        BottomNavigationView bottomNavigationView = findViewById(R.id.navigation);
        bottomNavigationView.setOnNavigationItemSelectedListener
                (new BottomNavigationView.OnNavigationItemSelectedListener() {
                    @Override
                    public boolean onNavigationItemSelected(@NonNull MenuItem item) {
                        Fragment selectedFragment = null;
                        switch (item.getItemId()) {
                            case R.id.explore:
                                changeFragment(new ExploreFragment(), ExploreFragment.class
                                        .getSimpleName());
                                toggleViews(true, "");
                                break;
                            case R.id.favorite:
                                changeFragment(new FavoriteFragment(), FavoriteFragment.class
                                        .getSimpleName());
                                toggleViews(false, "Favorites");
                                break;
                            case R.id.venue:
                                changeFragment(new VenueFragment(), VenueFragment.class.getSimpleName());
                                toggleViews(false, "Venues");
                                break;
                            case R.id.profile:
                                changeFragment(new ProfileFragment(), ProfileFragment.class
                                        .getSimpleName());
                                toggleViews(false, "Profile");
                                break;
                        }
                        return true;
                    }
                });

        //Manually displaying the first fragment - one time only
        changeFragment(new ExploreFragment(), ExploreFragment.class
                .getSimpleName());

    }

score 12 · Answer 4 · edited May 13 '21 at 13:39

12

This solution stops a fragment from being re-created when the currently selected nav button is clicked again. However, a new fragment will be created every time the user clicks a different nav button.

Just add this line to avoid re-created Fragment from BottomNavigationView

 bottomNavigation.setOnNavigationItemReselectedListener(new BottomNavigationView.OnNavigationItemReselectedListener() {
            @Override
            public void onNavigationItemReselected(@NonNull MenuItem item) {
             // do nothing here   
            }
        });

Or with a lambda:

bottomNavigation.setOnNavigationItemReselectedListener(item -> { });

edited May 13 '21 at 13:39

tronman

9,862
10
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answered Mar 02 '20 at 06:42

Nikunj Paradva

15,332
5
54
65

1

And you are real hero! you are life sever! – Dilip Hirapara Jun 15 '21 at 14:56
@DilipHirapara Dhanyawad mitra.. :D – Nikunj Paradva Jun 15 '21 at 17:01
2

`setOnNavigationItemReselectedListener` is deprecated, change to `setOnItemReselectedListener` – Asad Aug 27 '21 at 10:42

Maxwell · Answer 5 · 2020-04-20T15:22:59.397

8

Be careful when using replace. Even if providing a fragment that already exists in memory, replace will restart the fragment's lifecycle. To avoid a restart, the transaction object's methods includes add, show, and hide, which can be used to show the correct fragment without restarting it.

private fun switchFragment(selectedTabIndex: Int) {
    val previousTabIndex = this.currentTabIndex
    this.currentTabIndex = selectedTabIndex

    val transaction = supportFragmentManager.beginTransaction()
    val tag = fragments[this.currentTabIndex].tag

    // if the fragment has not yet been added to the container, add it first
    if (supportFragmentManager.findFragmentByTag(tag) == null) {
        transaction.add(R.id.container, fragments[this.currentTabIndex], tag)
    }

    transaction.hide(fragments[previousTabIndex])
    transaction.show(fragments[this.currentTabIndex])
    transaction.commit()
}

edited Apr 20 '20 at 15:22

answered Aug 09 '17 at 15:35

Maxwell

6,532
4
37
55

3

You used slightly confusing wording there, just to clarify: replace doesn't restart a fragments's life cycle as it is added to the UI - it ends the fragment currently attached then adds the new frag, which we can only assume was previously destroyed if removed or it's being added for the first time. So it will surely be starting over yes but not because replace is forcing it to. Essentially replace = remove(oldFrag) then add(newFrag). – Burkely91 Oct 27 '17 at 10:16
What is `currentTabPosition`? `android.support.design.widget.BottomNavigationView` does not seem to have that property. – Damn Vegetables Dec 17 '17 at 05:22
One should be very careful while using findFragmentByTag ... it's better to avoid it altogether :P – sandpat Aug 09 '19 at 13:35
@Maxwell can you clarify the above comments please? What is the index and currentTabPosition and what if this switchFragment method is in BaseActivity. Can you post an example with small activity or git gist. Thanks as this answer seems to be incomplete. – shivamDev31 Sep 08 '19 at 18:20

score 7 · Answer 6 · answered Feb 21 '17 at 10:35

Try this :

bottomNavigationView.setOnNavigationItemSelectedListener(new BottomNavigationView.OnNavigationItemSelectedListener() {
                @Override
                public boolean onNavigationItemSelected(@NonNull MenuItem item) {
                    Fragment fragment = null;
                    Fragment currentFragment = getSupportFragmentManager().findFragmentById(R.id.container);
                    switch (item.getItemId()) {
                        case R.id.action_one:
                            // Switch to page one
                            if (!(currentFragment instanceof FragmentA)) {
                                fragment = FragmentA.newInstance();
                            }
                            break;
                        case R.id.action_two:
                            // Switch to page two
                            if (!(currentFragment instanceof FragmentB)) {
                                fragment = FragmentB.newInstance();
                            }
                            break;
                        case R.id.action_three:
                            // Switch to page three
                            if (!(currentFragment instanceof FragmentC)) {
                                fragment = FragmentC.newInstance();
                            }
                            break;
                    }
                    getSupportFragmentManager().beginTransaction().replace(R.id.container, fragment, "TAG").commit();
                    return true;
                }
            });

That will get the current fragment in your container and if you click again on this fragment that will not re add the fragment.

How i can redirect to home page when i click on back button...please help me sir — Gowthaman M, Jun 04 '17 at 18:55
You can `Override` the fucntion `onBackPressed` on your main `Activity`. — Raphael Teyssandier, Jun 05 '17 at 15:04
In your code, If first FragmentA loaded, After click on second than second fragment loaded, after that If user click on firstFragment then is also recreate. — Mitesh Vanaliya, Nov 22 '17 at 07:34
@MiteshVanaliya Yes, if you want to not recreate every time the fragment, store the variable, or put all the fragment inside a `ViewPager`and change the current item. — Raphael Teyssandier, Nov 22 '17 at 09:41

score 7 · Answer 7 · answered Jun 02 '17 at 10:44

7

setOnNavigationItemReselectedListener would be a better solution for that

answered Jun 02 '17 at 10:44

akaMahesh

383
2
9

I do agree with you – Odai A. Ali Sep 14 '19 at 11:32

Zack · Answer 8 · 2019-12-20T11:45:50.687

The best way i found to do it.

private void replace_fragment(Fragment fragment) {

        String tag = fragment.getClass().getSimpleName();
        FragmentTransaction tr = getSupportFragmentManager().beginTransaction();

        Fragment curFrag = getSupportFragmentManager().getPrimaryNavigationFragment();
        Fragment cacheFrag = getSupportFragmentManager().findFragmentByTag(tag);

        if (curFrag != null)
            tr.hide(curFrag);

        if (cacheFrag == null) {
            tr.add(R.id.main_frame, fragment, tag);
        } else {
            tr.show(cacheFrag);
            fragment = cacheFrag;
        }

        tr.setPrimaryNavigationFragment(fragment);
        tr.commit();

    }

private BottomNavigationView.OnNavigationItemSelectedListener mOnNavigationItemSelectedListener
            = new BottomNavigationView.OnNavigationItemSelectedListener() {

        @Override
        public boolean onNavigationItemSelected(@NonNull MenuItem item) {

            switch (item.getItemId()) {
                case R.id.nav_posts:
                    replace_fragment(new PostsFragment());
                    return true;
                case R.id.nav_stores:
                    replace_fragment(new StoresFragment());
                    return true;
                case R.id.nav_chats:
                    replace_fragment(new DiscussionsFragment());
                    return true;
                case R.id.nav_account:
                    replace_fragment(new ProfileFragment());
                    return true;
            }
            return false;
        }
    };

score 3 · Answer 9 · edited Dec 04 '17 at 04:31

3

Use setOnNavigationItemReselectedListener like this:

private BottomNavigationView.OnNavigationItemReselectedListener onNavigationItemReselectedListener
            = new BottomNavigationView.OnNavigationItemReselectedListener() {

        @Override
        public void onNavigationItemReselected(@NonNull MenuItem item) {
            Toast.makeText(MainActivity.this, "Reselected", Toast.LENGTH_SHORT).show();
        }
    };

and call it using:

navigation.setOnNavigationItemReselectedListener(onNavigationItemReselectedListener);

edited Dec 04 '17 at 04:31

Pang

9,564
146
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answered Dec 03 '17 at 16:55

Akshay Sahai

2,121
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8

How does this answer the question? – Timuçin Jul 15 '18 at 16:48
@Timuçin whatever you perform inside this function, it will be performed on item reselect, so if you do not wish to create a new fragment then leave it empty. – Akshay Sahai Jul 29 '18 at 17:09
Not even going inside the reselect function. – Harminder Singh Oct 23 '18 at 05:10
2

@Timuçin when the reselect listener is set, the normal one won't be fired on item reselection. – couceirof Mar 20 '19 at 16:48
1

In 2019, item reselection is only triggered when you select the current item on are on again. Probably useful for something like scroll to top if the current fragment houses a vertical list. – Eaweb Jun 27 '19 at 10:02

score 1 · Answer 10 · answered Sep 22 '18 at 17:48

I've improved @Viven's answers and written it with Kotlin. My version instantiates fragment only for the first time, hides/shows. I'm new at Kotlin so tell me if I can improve anything.

We need to hold a id to tag map:

private val fragmentTags = hashMapOf(
        R.id.action_home to "home_fragment",
        R.id.action_profile to "profile_fragment"
)

The listener code:

bottomNavigation.run {
    setOnNavigationItemSelectedListener { menuItem ->
        supportFragmentManager.beginTransaction()
                .let { transaction ->
                    // hide current fragment
                    supportFragmentManager.primaryNavigationFragment?.let {
                        // if selected fragment's tag is same, do nothing.
                        if (it.tag == fragmentTags[menuItem.itemId]) {
                            return@setOnNavigationItemSelectedListener true
                        }

                        transaction.hide(it)
                    }

                    var fragment  = supportFragmentManager.findFragmentByTag(fragmentTags[menuItem.itemId])

                    if (fragment == null) {
                        // instantiate fragment for the first time
                        fragment = when(menuItem.itemId) {
                            R.id.action_home -> HomeFragment()
                            R.id.action_profile -> ProfileFragment()
                            else -> null
                        }?.also {
                            // and add it 
                            transaction.add(R.id.frame, it, fragmentTags[menuItem.itemId])
                        }
                    } else {
                        // if it's found show it 
                        transaction.show(fragment)
                    }


                    transaction
                            .setPrimaryNavigationFragment(fragment)
                            .setReorderingAllowed(true)
                }.commitNowAllowingStateLoss()

        return@setOnNavigationItemSelectedListener true
    }

    //bottomNavigation things
    itemIconTintList = null
    selectedItemId = R.id.action_home
}

ivan8m8 · Answer 11 · 2018-11-07T14:11:35.267

I solved this problem by adding a ViewPager to which I delegated all my navigation fragments. Its adapter (FragmentPagerAdapter) doesn't recreate the fragments instances when the user navigates through the BotoomNavigationView.

To achieve this, you have to complete 5 easy steps:

add a ViewPager to your layout;

implement its adapter:

class YourNavigationViewPagerAdapter(fm: FragmentManager,
                                     private val param1: Int,
                                     private val param2: Int)

    : FragmentPagerAdapter(fm) {

    override fun getItem(p0: Int) = when(p0) {
        0 -> NavigationFragment1.newInstance(param1, param2)
        1 -> NavigationFragment2.newInstance(param1, param2)
        2 -> NavigationFragment3.newInstance(param1, param2)
        else -> null
    }

    override fun getCount() = 3
}

don't forget to set the new adapter:

yourViewPager.adapter = YourNavigationViewPagerAdapter(supportFragmentManager, param1, param2)

set a OnNavigationItemSelectedListener to your BottomNavigationView like the following:

yourBottomNavigationView.setOnNavigationItemSelectedListener {

    when(it.itemId) {

        R.id.yourFirstFragmentMenuItem -> {
            yourViewPager.currentItem = 0
            true
        }

        R.id.yourSecondFragmentMenuItem -> {
            yourViewPager.currentItem = 1
            true
        }

        R.id.yourThirdFragmentMenuItem -> {
            yourViewPager.currentItem = 2
            true
        }


        else -> false
    }
}

set a OnPageChangeListener to your ViewPager like the following:

yourViewPager.addOnPageChangeListener(object : 
ViewPager.OnPageChangeListener {
    override fun onPageScrollStateChanged(p0: Int) {

    }

    override fun onPageScrolled(p0: Int, p1: Float, p2: Int) {

    }

    override fun onPageSelected(p0: Int) {
        yourBottomNavigationView.menu.getItem(p0).isChecked = true
    }

})

enjoy :)

score 1 · Answer 12 · answered May 14 '19 at 06:05

I wrote an Extension function in Kotlin for the same.

fun FragmentManager.switch(containerId: Int, newFrag: Fragment, tag: String) {

var current = findFragmentByTag(tag)
beginTransaction()
    .apply {

        //Hide the current fragment
        primaryNavigationFragment?.let { hide(it) }

        //Check if current fragment exists in fragmentManager
        if (current == null) {
            current = newFrag
            add(containerId, current!!, tag)
        } else {
            show(current!!)
        }
    }
    .setTransition(FragmentTransaction.TRANSIT_FRAGMENT_OPEN)
    .setPrimaryNavigationFragment(current)
    .setReorderingAllowed(true)
    .commitNowAllowingStateLoss()
}

score 0 · Answer 13 · answered Jun 06 '18 at 06:34

There are several test cases involved in proper navigation , I am pasting my code with all test cases checked.

FragmentTransaction fragmentTransaction = fragmentManager.beginTransaction();
        switch (item.getItemId()) {
            case R.id.dashboard:
                Fragment fragment;
                fragment = fragmentManager.findFragmentByTag(DashboardFragment.TAG);

                if (fragment == null) {
                    fragment = new DashboardFragment();
                    fragmentTransaction.add(R.id.frame, fragment, DashboardFragment.TAG);
                } else {
                    fragmentTransaction.detach(fragmentManager.getPrimaryNavigationFragment());
                    fragmentTransaction.attach(fragment);
                }
                fragmentTransaction.setPrimaryNavigationFragment(fragment);
                fragmentTransaction.commitNow();
                return true;
            case R.id.expenses:
                fragment = fragmentManager.findFragmentByTag(ExpenseFragment.TAG);
                if (fragment == null) {
                    fragment = new ExpenseFragment();
                    fragmentTransaction.add(R.id.frame, fragment, ExpenseFragment.TAG);
                } else {
                    fragmentTransaction.detach(fragmentManager.getPrimaryNavigationFragment());
                    fragmentTransaction.attach(fragment);
                }
                fragmentTransaction.setPrimaryNavigationFragment(fragment);
                fragmentTransaction.commitNow();
                return true;
            case R.id.vehicle_parts:
                Bundle bundle = new Bundle();
                bundle.putInt("odometer", vehicle.getOdometer());
                bundle.putString("vehicle_id", vehicle.get_id());
                fragment = fragmentManager.findFragmentByTag(PartsFragment.TAG);
                if (fragment == null) {
                    fragment = new PartsFragment();
                    fragment.setArguments(bundle);
                    fragmentTransaction.add(R.id.frame, fragment, PartsFragment.TAG);

                } else {
                    fragmentTransaction.detach(fragmentManager.getPrimaryNavigationFragment());
                    fragmentTransaction.attach(fragment);
                }
                fragmentTransaction.setPrimaryNavigationFragment(fragment);
                fragmentTransaction.commitNow();
                return true;
            case R.id.blog:
                fragment = fragmentManager.findFragmentByTag(BlogFragment.TAG);

                if (fragment == null) {
                    fragment = new BlogFragment();
                    fragmentTransaction.add(R.id.frame, fragment, BlogFragment.TAG);

                } else {
                    fragmentTransaction.detach(fragmentManager.getPrimaryNavigationFragment());
                    fragmentTransaction.attach(fragment);
                }
                fragmentTransaction.setPrimaryNavigationFragment(fragment);
                fragmentTransaction.commitNow();
                return true;
        }
        return false;

score 0 · Answer 14 · answered Nov 08 '19 at 05:52

Use Cicerone library for handling navigation easily.

https://github.com/terrakok/Cicerone

@Override
public boolean onNavigationItemSelected(@NonNull MenuItem menuItem) {
    switch (menuItem.getItemId()) {
        case R.id.save: {
            router.replaceScreen("your fragment1");
            menuItem.setChecked(true);
            break;
        }
        case R.id.search_lessons: {
            router.replaceScreen("your fragment2");
            menuItem.setChecked(true);
            break;
        }
        case R.id.profile_student: {
            router.replaceScreen("your fragment3");
            menuItem.setChecked(true);
            break;
        }

    }
    return false;
}

Sunil Chaudhary · Answer 15 · 2020-09-07T10:26:07.640

How To stop recreating Fragment when it is Already Visible Using BottomNavigationView

Step 1--

     @Override
public boolean onNavigationItemSelected(@NonNull MenuItem item) {
    Fragment fragment = null;
    String valuestring;      
    **if (item.getItemId() == lastSelectedItemId) { // added this
        Log.e( "both id is same","LULL" );
        return true;
    }**
    switch (item.getItemId()) {
       case R.id.navigation_category:
      SetActioBarText( getString( R.string.label_actionbar_categories ) );
            fragment = new CategoryFragment();
            valuestring = "category";
            break;
        case R.id.navigation_favourite:
     SetActioBarText( getString( R.string.label_actionbar_favourites ) );
            fragment = new FavouriteFragment();
            valuestring = "favourites";
            break;
        default:
            throw new IllegalStateException( "Unexpected value: " +                  menuItem.getItemId() );
    }
    return loadFragment( fragment, valuestring ,menuItem);
}

Now Step 2---

    private boolean loadFragment(Fragment fragment, String argument,MenuItem item) {
  
    if (fragment != null) {
       
        transaction = fragmentManager.beginTransaction();
        transaction.addToBackStack( argument );
        transaction.setTransition( FragmentTransaction.TRANSIT_FRAGMENT_FADE );
        transaction.replace( R.id.frame_container, fragment,                         "demofragment").commitAllowingStateLoss();

     lastSelectedItemId= item.getItemId();
    
        return true;
    }
    return false;
}

Mohamad Alemi · Answer 16 · 2021-03-15T07:15:23.880

-1

no need to do this answers. actually what you really need is to save view in specific fragmet.

 private   View view;
if(view == null){
    view = inflater.inflate(R.layout.call_fragment_edited, container, false);

}

so any time when you create new fragment you see current state

edited Mar 15 '21 at 07:15

answered Dec 13 '20 at 08:55

Mohamad Alemi

13
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We should never cache views especially on fragments – Chetan Gupta Mar 12 '21 at 10:34

Fragment re-created on bottom navigation view item selected

16 Answers16

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