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How to show interstitial ad when navigating back to the main fragment in bottom navigation

i have four fragments Home, Warning, Donate, and About, Home is the first one shown on launch, what i need is that when users are on any of these fragments (Donate, About, and Caution), and when they go back to the Home fragment using backstack only, I want to show an interstitial ad before showing the home fragment.
I don't want to show the ad when the home fragment launch for first time
Main Activity
public class MainActivity extends AppCompatActivity {
public BottomNavigationView bottomNavigationView;
Deque<Integer> integerDeque = new ArrayDeque<>(3);
boolean flag = true;
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
Window window = this.getWindow();
window.setStatusBarColor(this.getResources().getColor(R.color.black));
bottomNavigationView = findViewById(R.id.bottomNavigationView);
bottomNavigationView.setItemIconTintList(null);
integerDeque.push(R.id.home_icon);
loadFragments(new Home_Fragment());
bottomNavigationView.setSelectedItemId(R.id.home_icon);
bottomNavigationView.setOnNavigationItemSelectedListener(
item -> {
int id = item.getItemId();
if (integerDeque.contains(id)) {
if (id == R.id.home_icon) {
integerDeque.size();
if (flag) {
integerDeque.addFirst(R.id.home_icon);
flag = false;
}
}
integerDeque.remove(id);
}
integerDeque.push(id);
loadFragments(getFragment(item.getItemId()));
return true;
}
);
}
#SuppressLint("NonConstantResourceId")
private Fragment getFragment(int itemId) {
switch (itemId) {
case R.id.home_icon:
bottomNavigationView.getMenu().getItem(0).setChecked(true);
return new Home_Fragment();
case R.id.guide_icon:
bottomNavigationView.getMenu().getItem(1).setChecked(true);
return new Cuation_Fragment();
case R.id.donate_icon:
bottomNavigationView.getMenu().getItem(2).setChecked(true);
return new Donate_Fragment();
case R.id.about_icon:
bottomNavigationView.getMenu().getItem(3).setChecked(true);
return new About_Fragment();
}
bottomNavigationView.getMenu().getItem(0).setChecked(true);
return new Home_Fragment();
}
public void loadFragments(Fragment fragment) {
if (fragment != null) {
getSupportFragmentManager().beginTransaction()
.replace(R.id.fragment_container, fragment, fragment.getClass().getSimpleName())
.commit();
}
}
#Override
public void onBackPressed() {
integerDeque.pop();
if (!integerDeque.isEmpty()) {
bottomNavigationView.setSelectedItemId(integerDeque.peek());
} else {
finish();
}
}
}

Go back from a fragment to main fragment

This is my main activity where I am calling my fragments:
public class what extends AppCompatActivity {
private DrawerLayout mDrawerLayout;
private ActionBarDrawerToggle mToggle;
private ListView mDrawerList;
private ArrayAdapter<String> mAdapter;
private FragmentTransaction fragmentTransaction;
NavigationView navigationView;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_what);
mDrawerLayout=(DrawerLayout)findViewById(R.id.drawer_layout);
mToggle=new ActionBarDrawerToggle(this, mDrawerLayout, R.string.open, R.string.close);
mDrawerLayout.addDrawerListener(mToggle);
mToggle.syncState();
fragmentTransaction= getSupportFragmentManager().beginTransaction();
fragmentTransaction.add(R.id.main_content,new mainfrag());
fragmentTransaction.commit();
ActionBar actionBar= getSupportActionBar();
actionBar.setDisplayHomeAsUpEnabled(true);
navigationView=(NavigationView)findViewById(R.id.nav_view);
navigationView.getMenu().getItem(1).setChecked(false);
navigationView.getMenu().getItem(0).setChecked(true);
navigationView.getMenu().getItem(2).setChecked(false);
navigationView.getMenu().getItem(3).setChecked(false);
navigationView.setNavigationItemSelectedListener(new NavigationView.OnNavigationItemSelectedListener() {
#Override
public boolean onNavigationItemSelected(#NonNull MenuItem item) {
switch (item.getItemId()) {
case R.id.nav_main:
navigationView.getMenu().getItem(1).setChecked(false);
navigationView.getMenu().getItem(2).setChecked(false);
navigationView.getMenu().getItem(3).setChecked(false);
navigationView.setCheckedItem(R.id.nav_main);
mDrawerLayout.closeDrawers();
fragmentTransaction=getSupportFragmentManager().beginTransaction();
fragmentTransaction.replace(R.id.main_content, new mainfrag());
fragmentTransaction.commit();
getSupportActionBar().setTitle(("SGPA and CGPA Calculator"));
item.setChecked(true);
break;
case R.id.nav_savedcal:
navigationView.getMenu().getItem(0).setChecked(false);
navigationView.getMenu().getItem(2).setChecked(false);
navigationView.getMenu().getItem(3).setChecked(false);
navigationView.setCheckedItem(R.id.nav_savedcal);
mDrawerLayout.closeDrawers();
fragmentTransaction=getSupportFragmentManager().beginTransaction();
fragmentTransaction.replace(R.id.main_content, new savedFragment());
fragmentTransaction.commit();
getSupportActionBar().setTitle(("Saved Calculations"));
item.setChecked(true);
break;
case R.id.nav_upldoc:
navigationView.getMenu().getItem(0).setChecked(false);
navigationView.getMenu().getItem(1).setChecked(false);
navigationView.getMenu().getItem(3).setChecked(false);
navigationView.setCheckedItem(R.id.nav_upldoc);
mDrawerLayout.closeDrawers();
fragmentTransaction=getSupportFragmentManager().beginTransaction();
fragmentTransaction.replace(R.id.main_content, new uploadedfragment());
fragmentTransaction.commit();
getSupportActionBar().setTitle(("Uploaded documents"));
item.setChecked(true);
break;
case R.id.nav_site:
navigationView.getMenu().getItem(0).setChecked(false);
navigationView.getMenu().getItem(1).setChecked(false);
navigationView.getMenu().getItem(2).setChecked(false);
navigationView.setCheckedItem(R.id.nav_site);
mDrawerLayout.closeDrawers();
fragmentTransaction=getSupportFragmentManager().beginTransaction();
fragmentTransaction.replace(R.id.main_content, new resultsite());
fragmentTransaction.commit();
getSupportActionBar().setTitle(("VTU Results"));
item.setChecked(true);
break;
}
return false;
}
});
}
public boolean onOptionsItemSelected(MenuItem item ){
if(mToggle.onOptionsItemSelected(item)){
return true;
}
return super.onOptionsItemSelected(item);
}
#Override
public void onBackPressed() {
DialogInterface.OnClickListener dialogClickListener = new DialogInterface.OnClickListener() {
#Override
public void onClick(DialogInterface dialog, int which) {
switch (which) {
case DialogInterface.BUTTON_POSITIVE: {
finish();
}
break;
case DialogInterface.BUTTON_NEGATIVE:
break;
}
}
};
AlertDialog.Builder builder = new AlertDialog.Builder(this);
builder.setMessage("Are you sure you want to exit?").setPositiveButton("Yes", dialogClickListener)
.setNegativeButton("No", dialogClickListener).show();
return;
}
}
This is my default fragment :
public class mainfrag extends Fragment {
private View view;
private AdView adView;
private Button button10;
private Button button11;
public mainfrag() {
// Required empty public constructor
}
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
view = inflater.inflate(R.layout.fragment_mainfrag, container, false);
adView = view.findViewById(R.id.adView);
button10 = (Button) view.findViewById(R.id.button10);
button10.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
openmainactivity();
}
});
button11 = (Button) view.findViewById(R.id.button11);
button11.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
openscheme();
}
});
return view;
}
public void openmainactivity() {
Intent intent = new Intent(getContext(), MainActivity.class);
startActivity(intent);
}
public void openscheme(){
Intent intent=new Intent(getContext(), scheme.class);
startActivity(intent);
}
}
This is one of the other fragments:
public class savedFragment extends Fragment {
RecyclerView recyclerview;
adapter_sgpa recyclerAdapter;
ArrayList<POJO> sgpaArrayList;
public savedFragment() {
// Required empty public constructor
}
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
FragmentTransaction tx = getChildFragmentManager().beginTransaction();
tx.replace(R.id.container, new sgpa_frag());
tx.commit();
}
private BottomNavigationView.OnNavigationItemSelectedListener mOnNavigationItemSelectedListener
= new BottomNavigationView.OnNavigationItemSelectedListener() {
#Override
public boolean onNavigationItemSelected(#NonNull MenuItem item) {
int id = item.getItemId();
Fragment fragment = null;
switch (id) {
case R.id.navigation_sgpa:
sgpa_frag sf = new sgpa_frag();
FragmentManager fragmentManager = getChildFragmentManager();
fragmentManager.beginTransaction().replace(R.id.container, sf).commit();
return true;
case R.id.navigation_cgpa:
cgpa_frag cf = new cgpa_frag();
fragmentManager = getChildFragmentManager();
fragmentManager.beginTransaction().replace(R.id.container, cf).commit();
return true;
}
return false;
}
};
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
final View v = inflater.inflate(R.layout.fragment_saved, container, false);
BottomNavigationView nav = (BottomNavigationView) v.findViewById(R.id.bottom_navigation);
nav.setOnNavigationItemSelectedListener(mOnNavigationItemSelectedListener);
return v;
}
}
What changes should I make in this code so that I am able to move back from the other fragments to the main fragment on pressing back button ?

Maintain one boolean variable to check current fragment is MainFragment or not.
if its not MainFragment -> replace MainFragment
Else -> super.onBackPressed()
ex:
private boolean isMainFragment=true; //make it false when move to other fragment
#Override
public void onBackPressed() {
if(!isMainFragment){
isMainFragment=true;
//replace your MainFragment
}
else{
//your logic show dialog or super.onBackPressed()
}
}

Ithink I know what you need. have a look at the last part of this documentation
"You can add a fragment transaction to the back stack. The back stack keeps track of actions in your app which can be backtracked when the user clicks Android's standard "back" button on the device. If you add a fragment transaction to the back stack then the transaction can be backtracked (reversed) with a click on the back button on the device" quotet from Jenkov
simply do fragmentTransaction.addToBackStack(null) on your main activity before you do the commit this will allow you to travel back using the back button
if you always want to travel back to the main fragment then you want to only add the main fragment to the backstack that way on pressing the back button you will always land there
in this part of your oncreate:
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_what);
mDrawerLayout=(DrawerLayout)findViewById(R.id.drawer_layout);
mToggle=new ActionBarDrawerToggle(this, mDrawerLayout, R.string.open, R.string.close);
mDrawerLayout.addDrawerListener(mToggle);
mToggle.syncState();
fragmentTransaction= getSupportFragmentManager().beginTransaction();
fragmentTransaction.add(R.id.main_content,new mainfrag());
//HERE YOU PUT THE CODE V
fragmentTransaction.addToBackStack(null);
//HERE YOU PUT THE CODE ^
fragmentTransaction.commit();
ActionBar actionBar= getSupportActionBar();
actionBar.setDisplayHomeAsUpEnabled(true);
// ALL THE OTHER STUFF COMMING AFTER

button not change on back button press in BottomNavigationView

i use three fragment in dashbordActivity on bottom navigation bar. On back button press previous fragment view properly but bottom navigation button not changing.
in first image home fragment is already selected after i select profile from bottom navigation and press backbutton. fragment changes but bottom navigation item does not change.
this is my bottom navigation view .....
private BottomNavigationView.OnNavigationItemSelectedListener mOnNavigationItemSelectedListener
= new BottomNavigationView.OnNavigationItemSelectedListener() {
#Override
public boolean onNavigationItemSelected(#NonNull MenuItem item) {
switch (item.getItemId()) {
case R.id.navigation_home:
setTitle("Home");
fragment = new FirstFragment();
loadFragment(fragment);
return true;
case R.id.navigation_favorite:
setTitle("favourite");
fragment = new MyFavoriteAdsFragment();
loadFragment(fragment);
return true;
case R.id.navigation_profile:
setTitle("Profile");
fragment = new ProfileFragment();
loadFragment(fragment);
return true;
case R.id.navigation_myads:
setTitle("Chat");
fragment = new MyAdsFragment();
loadFragment(fragment);
return true;
case R.id.navigation_chat:
// mTextMessage.setText(R.string.title_chat);
setTitle("Chat");
fragment = new TabFragmentChatUserList();
loadFragment(fragment);
/* Intent i=new Intent(getApplicationContext(),Chat.class);
startActivity(i);*/
return true;
}
return false;
}
};
private void loadFragment(Fragment fragment) {
// load fragment
transaction = getSupportFragmentManager().beginTransaction();
transaction.replace(R.id.frame_container, fragment);
transaction.addToBackStack("TAG");
transaction.commit();
/* fragmentManager.beginTransaction().replace(R.id.home_container, frag).addToBackStack(null).commit();*/
}
ob back press i tryed...
#Override
public void onBackPressed()
{
// if your using fragment then you can do this way
int fragments
=getSupportFragmentManager().getBackStackEntryCount();
if (fragments == 1) {
new AlertDialog.Builder(this)
.setMessage("Are you sure you want to exit?")
.setCancelable(false)
.setPositiveButton("Yes", new DialogInterface.OnClickListener() {
public void onClick(DialogInterface dialog, int id) {
finish();
}
})
.setNegativeButton("No", null)
.show();
} else {
if (getFragmentManager().getBackStackEntryCount() > 1) {
getFragmentManager().popBackStack();
if(navigation.getSelectedItemId () != R.id.navigation_favorite)
{
navigation.setSelectedItemId(R.id.navigation_favorite);
}
else if(navigation.getSelectedItemId () != R.id.navigation_chat)
{
navigation.setSelectedItemId(R.id.navigation_chat);
}
else if(navigation.getSelectedItemId () != R.id.navigation_profile)
{
navigation.setSelectedItemId(R.id.navigation_profile);
}
else
{
super.onBackPressed();
}
} else {
super.onBackPressed();
}
}

You need to check your backstack and add listener to your fragment manager, after that based on your fragment you need to set particular button check based on your fragment.
fragmentManager.addOnBackStackChangedListener(new FragmentManager.OnBackStackChangedListener() {
#Override
public void onBackStackChanged() {
// If the stack decreases it means I clicked the back button
if( fragmentManager.getBackStackEntryCount() <= count){
//check your position based on selected fragment and set it accordingly.
navigation.getMenu().getItem(your_pos).setChecked(true);
}
}
});

You can customize your onBackPressed in this way:
#Override
public void onBackPressed() {
// if your using fragment then you can do this way
int fragments
= getSupportFragmentManager().getBackStackEntryCount();
if (fragments == 1) {
new AlertDialog.Builder(this)
.setMessage("Are you sure you want to exit?")
.setCancelable(false)
.setPositiveButton("Yes", new DialogInterface.OnClickListener() {
public void onClick(DialogInterface dialog, int id) {
finish();
}
})
.setNegativeButton("No", null)
.show();
} else {
if (getSupportFragmentManager().getBackStackEntryCount() > 1) {
getSupportFragmentManager().popBackStack();
Fragment selectedFragment = null;
List<Fragment> fragments = getSupportFragmentManager.getFragments();
for (Fragment fragment : fragments) {
if (fragment != null && fragment.isVisible()) {
selectedFragment = fragment;
break;
}
}
if (selectedFragment instanceof yourFirstFragment) {
navigation.setSelectedItemId(R.id.your_first_item);
} if (selectedFragment instanceof yourSecondFragment) {
navigation.setSelectedItemId(R.id.your_second_item);
} if (selectedFragment instanceof yourThirdFragment) {
navigation.setSelectedItemId(R.id.your_third_item);
} else {
super.onBackPressed();
}
} else {
super.onBackPressed();
}
}

Android bottom navigation bar when press back go to previous fragment

Here is my navigation bar :
There are 4 items in my bottom nav bar , I want it to back to previous fragment when I press the back button,
Here`s my xml :
<android.support.design.widget.BottomNavigationView
android:id="#+id/bottomnav"
android:layout_width="382dp"
android:layout_height="52dp"
android:layout_marginBottom="0dp"
app:itemBackground="#color/backbeyez"
app:itemIconTint="#drawable/nav_items_color"
app:itemTextColor="#drawable/nav_items_color"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintLeft_toLeftOf="parent"
app:layout_constraintRight_toRightOf="parent"
app:menu="#menu/navigation"
tools:layout_editor_absoluteY="515dp">
</android.support.design.widget.BottomNavigationView>
Here`s the code for MainActivity :
public class MainActivity extends AppCompatActivity {
public void switchorders() {
FragmentManager manager = getSupportFragmentManager();
manager.beginTransaction().replace(R.id.container, new OrdersLayout()).commit();
}
public void switchcredits() {
FragmentManager manager = getSupportFragmentManager();
manager.beginTransaction().replace(R.id.container, new CreditLayout()).commit();
}
public void switchworks() {
FragmentManager manager = getSupportFragmentManager();
manager.beginTransaction().replace(R.id.container, new ListLayout()).commit();
}
public void switchprofile() {
FragmentManager manager = getSupportFragmentManager();
manager.beginTransaction().replace(R.id.container, new ProfileLayout()).commit();
}
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
switchorders();
BottomNavigationView bottomNavigationView = (BottomNavigationView) findViewById(R.id.bottomnav);
BottomNavigationViewHelper.disableShiftMode(bottomNavigationView);
bottomNavigationView.setOnNavigationItemSelectedListener(new BottomNavigationView.OnNavigationItemSelectedListener() {
#Override
public boolean onNavigationItemSelected(#NonNull MenuItem item) {
switch (item.getItemId()) {
case R.id.navigation_orders:
switchorders();
break;
case R.id.navigation_credit:
switchcredits();
break;
case R.id.navigation_works:
switchworks();
break;
case R.id.navigation_profile:
switchprofile();
break;
}
return true;
}
});
}
I also tried defining a back button with the statements below but they didn`t work :
public void aboutback(View view) {
if (getSupportFragmentManager().getBackStackEntryCount() > 0)
{
boolean done = getSupportFragmentManager().popBackStackImmediate();
}
}
and also "popbackstack()" and "popbackstackImmediate()" did not work!

If you want to handle backpress in fragment than you should add addToBackStack() when adding or replacing a fragment
try to add like that in your all fragment
public void switchorders() {
FragmentManager manager = getSupportFragmentManager();
manager.beginTransaction().replace(R.id.container, new OrdersLayout()).addToBackStack("TAG").commit();
}
It will be handle by default.
You can also handle in onBackPress() in activity if you want

Following code will set the icon of the home fragment icon of the bottom navigation to active, use accordingly to make active each icon on back press:
final BottomNavigationView mBottomNav = findViewById(R.id.nav_view);
MenuItem homeItem = mBottomNav.getMenu().getItem(0);
mBottomNav.setSelectedItemId(homeItem.getItemId());

Use AlertDialog On BackPressed try this,
#Override
public void onBackPressed() {
new AlertDialog.Builder(this)
.setTitle("Really Exit?")
.setMessage("Are you sure you want to exit?")
.setNegativeButton(android.R.string.no, null)
.setPositiveButton(android.R.string.yes, new OnClickListener() {
public void onClick(DialogInterface arg0, int arg1) {
WelcomeActivity.super.onBackPressed();
}
}).create().show();
}
I hope this may help you..

How to handle bottom navigation perfectly with back pressed

I am working on a bottom navigation bar, but I am not getting perfectly bottom navigation bar.
My MainActivity class:
public class MainActivity extends AppCompatActivity {
private static final String SELECTED_ITEM = "selected_item";
private BottomNavigationView bottomNavigationView;
private Toolbar toolbar;
private MenuItem menuItemSelected;
private int mMenuItemSelected;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
toolbar = (Toolbar) findViewById(R.id.toolbar);
setSupportActionBar(toolbar);
bottomNavigationView = (BottomNavigationView) findViewById(R.id.bottom_navigation);
bottomNavigationView.setOnNavigationItemSelectedListener(new BottomNavigationView.OnNavigationItemSelectedListener() {
#Override
public boolean onNavigationItemSelected(#NonNull MenuItem item) {
selectFragment(item);
return true;
}
});
//Always load first fragment as default
FragmentTransaction fragmentTransaction = getSupportFragmentManager().beginTransaction();
fragmentTransaction.replace(R.id.frameLayout, new AnnouncementFragment());
fragmentTransaction.commit();
if (savedInstanceState != null) {
mMenuItemSelected = savedInstanceState.getInt(SELECTED_ITEM, 0);
menuItemSelected = bottomNavigationView.getMenu().findItem(mMenuItemSelected);
} else {
menuItemSelected = bottomNavigationView.getMenu().getItem(0);
}
selectFragment(menuItemSelected);
}
private void selectFragment(MenuItem item) {
Fragment fragment = null;
Class fragmentClass;
switch (item.getItemId()) {
case R.id.action_announcement:
fragmentClass = AnnouncementFragment.class;
break;
case R.id.action_menu:
fragmentClass = MenuFragment.class;
break;
case R.id.action_menu_reports:
fragmentClass = ReportFragment.class;
break;
case R.id.action_setting:
fragmentClass = SettingFragment.class;
break;
default:
fragmentClass = AnnouncementFragment.class;
}
try {
fragment = (Fragment) fragmentClass.newInstance();
} catch (Exception e) {
e.printStackTrace();
}
FragmentManager fragmentManager = getSupportFragmentManager();
fragmentManager.beginTransaction().replace(R.id.frameLayout, fragment).commit();
}
#Override
protected void onSaveInstanceState(Bundle outState) {
outState.putInt(SELECTED_ITEM, mMenuItemSelected);
super.onSaveInstanceState(outState);
}
And my back pressed also not working properly:
#Override
public void onBackPressed() {
MenuItem homeItem = bottomNavigationView.getMenu().getItem(0);
if (mMenuItemSelected != homeItem.getItemId()) {
selectFragment(homeItem);
} else {
super.onBackPressed();
}
}
How should I do that because bottom menu has uneven distribution on bar. How to properly maintain the menu space without uneven distribution.
Here I am attaching my result which I obtain on AVD

According to the guidelines for Material Design
On Android, the Back button does not navigate between bottom
navigation bar views.
EDIT: Material Design link no longer mentions back button behavior.
Pressing the back button you can quit the application, which is the default behavior, such as in Google Photo...
FragmentManager fragmentManager = getFragmentManager();
FragmentTransaction fragmentTransaction = fragmentManager.beginTransaction();
fragmentTransaction.replace(R.id.content, fragment);
// note: there is NOT a addToBackStack call
fragmentTransaction.commit();
...or lead the user to the home section and then, if pushed again, at the exit.
Personally I find this last pattern much better.
To get it without override onBackPressed you need to identify the home fragment and differentiate it from all the others
navigation = (BottomNavigationView) findViewById(R.id.navigation);
navigation.setOnNavigationItemSelectedListener(new BottomNavigationView.OnNavigationItemSelectedListener() {
#Override
public boolean onNavigationItemSelected(#NonNull MenuItem item) {
switch (item.getItemId()) {
case R.id.navigation_home:
viewFragment(new HomeFragment(), FRAGMENT_HOME);
return true;
case R.id.navigation_page_1:
viewFragment(new OneFragment(), FRAGMENT_OTHER);
return true;
case R.id.navigation_page_2:
viewFragment(new TwoFragment(), FRAGMENT_OTHER);
return true;
}
return false;
}
});
What you have to do now is write the viewfragment method that have to:
Know how many fragments there are in the stack before the commit
If the fragment is not "home type", save it to the stack before
the commit
Add an OnBackStackChangedListener that when the stack decreases,
(i.e. when I pressed back ), delete all the fragments that are
not "home type" (POP_BACK_STACK_INCLUSIVE) , bringing us to the home fragment
Below the full method with comments
private void viewFragment(Fragment fragment, String name){
final FragmentManager fragmentManager = getFragmentManager();
FragmentTransaction fragmentTransaction = fragmentManager.beginTransaction();
fragmentTransaction.replace(R.id.content, fragment);
// 1. Know how many fragments there are in the stack
final int count = fragmentManager.getBackStackEntryCount();
// 2. If the fragment is **not** "home type", save it to the stack
if( name.equals( FRAGMENT_OTHER) ) {
fragmentTransaction.addToBackStack(name);
}
// Commit !
fragmentTransaction.commit();
// 3. After the commit, if the fragment is not an "home type" the back stack is changed, triggering the
// OnBackStackChanged callback
fragmentManager.addOnBackStackChangedListener(new FragmentManager.OnBackStackChangedListener() {
#Override
public void onBackStackChanged() {
// If the stack decreases it means I clicked the back button
if( fragmentManager.getBackStackEntryCount() <= count){
// pop all the fragment and remove the listener
fragmentManager.popBackStack(FRAGMENT_OTHER, POP_BACK_STACK_INCLUSIVE);
fragmentManager.removeOnBackStackChangedListener(this);
// set the home button selected
navigation.getMenu().getItem(0).setChecked(true);
}
}
});
}

Try this
#Override
public void onBackPressed() {
BottomNavigationView bottomNavigationView = (BottomNavigationView) findViewById(R.id.navigation);
int seletedItemId = bottomNavigationView.getSelectedItemId();
if (R.id.home != seletedItemId) {
setHomeItem(MainActivity.this);
} else {
super.onBackPressed();
}
}
public static void setHomeItem(Activity activity) {
BottomNavigationView bottomNavigationView = (BottomNavigationView)
activity.findViewById(R.id.navigation);
bottomNavigationView.setSelectedItemId(R.id.home);
}

#Override
public void onBackPressed() {
BottomNavigationView mBottomNavigationView = findViewById(R.id.navigation);
if (mBottomNavigationView.getSelectedItemId() == R.id.navigation_home)
{
super.onBackPressed();
finish();
}
else
{
mBottomNavigationView.setSelectedItemId(R.id.navigation_home);
}
}

This is maybe a little late but I think the best way to do it is as simple as this.
#Override
public void onBackPressed() {
if (mBottomNavigationView.getSelectedItemId() == R.id.action_home) {
super.onBackPressed();
} else {
mBottomNavigationView.setSelectedItemId(R.id.action_home);
}
}
I hope it helps and happy coding :)

onBackPressed did not worked for me. So this I used.
#Override
protected void onResume() {
super.onResume();
bottomNavigationView.getMenu().getItem(0).setChecked(true);
}

The best way is: when in home button the app is closed and when in another button back in home button.
Below I put my code :
first i'm load home button in navigation View :
private void loadFragment(Fragment fragment) {
Toast.makeText(this, "load", Toast.LENGTH_SHORT).show();
FragmentTransaction transaction = getSupportFragmentManager().beginTransaction();
transaction.replace(R.id.frame_container, fragment, TAG_FRAGMENT);
transaction.commit();
}
and remember dont call addToBackStack() .
and then handle the situation by onBackPressed() :
#Override
public void onBackPressed() {
if (navigation.getSelectedItemId() == R.id.bottomAkhbar) {
super.onBackPressed();
} else {
navigation.setSelectedItemId(R.id.bottomAkhbar);
}
}

I had the same problem so I solved my problem using this method:
In my main activity, I have a bottom nav bar and a nav drawer, I need to sync items in my drawer and bottom nav:
I created a method for my main fragment and the others:
my main fragment replacer:
public void MainFragmentChanger(final Fragment fragment, final String TAG){
if (main_page_fragment != null){
fragmentTransaction = myFragmentManager.beginTransaction();
fragmentTransaction.remove(main_page_fragment).commit();
}
if (main_drawer.isDrawerOpen()){
main_drawer.closeDrawer();
}
new Handler().post(new Runnable() {
#Override
public void run() {
main_page_fragment = fragment;
main_page_fragment.setRetainInstance(true);
fragmentTransaction = myFragmentManager.beginTransaction();
fragmentTransaction.replace(R.id.main_container, main_page_fragment,TAG);
fragmentTransaction.setTransition(FragmentTransaction.TRANSIT_FRAGMENT_FADE);
fragmentTransaction.commitAllowingStateLoss();
}
});
}
and this is for my other fragment replacer:
public void changeBottomFragment(final Fragment fragment, final String TAG){
if (main_drawer.isDrawerOpen()){
main_drawer.closeDrawer();
}
new Handler().post(new Runnable() {
#Override
public void run() {
main_page_fragment = fragment;
main_page_fragment.setRetainInstance(true);
fragmentTransaction = myFragmentManager.beginTransaction();
fragmentTransaction.replace(R.id.main_container, main_page_fragment);
fragmentTransaction.addToBackStack(null);
fragmentTransaction.setTransition(FragmentTransaction.TRANSIT_FRAGMENT_FADE);
fragmentTransaction.commitAllowingStateLoss();
}
});
}
so after that, I need to sync items in both drawer and bar:
Note I use material navigation drawer by Mike Penz, and com.ashokvarma.bottomnavigation.BottomNavigationBar for nav bar.
here is the method for that purpose:
public void changeNavAndBarStats(String tag){
if (tag == "flash"){
bottomNavigationBar.selectTab(2,false);
main_drawer.setSelection(flashcards.getIdentifier(),false);
}else if (tag == "dic"){
bottomNavigationBar.selectTab(3,false);
main_drawer.setSelection(dictionary.getIdentifier(),false);
}else if (tag == "Home"){
bottomNavigationBar.selectTab(0,false);
main_drawer.setSelection(home.getIdentifier(),false);
}
}
So I call my fragments Like this:
MainFragmentChanger(new MainPageFragment(),"Home");
bottomNavigationBar.selectTab(0,false);
changeBottomFragment(new FlashCardFragment(),"flash");
bottomNavigationBar.selectTab(2,false);
changeBottomFragment(new TranslateFragment(),"dic");
bottomNavigationBar.selectTab(3,false);
At the end I call changeNavAndBarStatus in my fragment's onResume method:
((MainPageActivity)getContext()).changeNavAndBarStats("flash");
That's it! you are good to go!

Try this to achieve the following:
on back press:
from home fragment exit the app.
from other fragments goto home fragment.
//On Back Press if we are at a Fragment other than the Home Fragment it will navigate back to the
// Home Fragment. From Home Fragment it will exit the App.
#Override
public void onBackPressed() {
int backStackEntryCount = getSupportFragmentManager().getBackStackEntryCount();
if (backStackEntryCount == 0) {
super.onBackPressed();
} else {
goHome();
}
}
public void goHome() {
//Following code will set the icon of the bottom navigation to active
final BottomNavigationView mBottomNav = findViewById(R.id.nav_view);
MenuItem homeItem = mBottomNav.getMenu().getItem(0);
mBottomNav.setSelectedItemId(homeItem.getItemId());
getSupportFragmentManager().popBackStackImmediate();
//To delete all entries from back stack immediately one by one.
int backStackEntry = getSupportFragmentManager().getBackStackEntryCount();
for (int i = 0; i < backStackEntry; i++) {
getSupportFragmentManager().popBackStackImmediate();
}
//To navigate to the Home Fragment
final HomeFragment homeFragment = new HomeFragment();
FragmentTransaction myFragmentTransaction = getSupportFragmentManager().beginTransaction();
myFragmentTransaction.replace(R.id.nav_host_fragment, homeFragment, "HomeFrag Tag");
myFragmentTransaction.commit();
}

You can try this /
its worked for me
public class MainActivity extends BaseActivity {
private HomeFragment homeFragment = new HomeFragment();
private CartFragment cartFragment = new CartFragment();
private ProfileFragment profileFragment = new ProfileFragment();
private BottomNavigationView bottomNavigationView;
#Override
protected void onCreate(#Nullable Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
if (savedInstanceState == null){
setContentView(R.layout.activity_main);
bottomNavigationView = findViewById(R.id.bottom_nav);
bottomNavigationView.setSelectedItemId(R.id.btnHome);
FragmentTransaction homeFm = getSupportFragmentManager().beginTransaction();
homeFm.replace(R.id.fragment_container, homeFragment);
homeFm.commit();
setupView();
}
}
private void setupView() {
bottomNavigationView.setOnNavigationItemSelectedListener(item -> {
{
switch (item.getItemId()) {
case R.id.btnHome:
loadFragment(homeFragment);
return true;
case R.id.btnCart:
loadFragment(cartFragment);
return true;
case R.id.btnProfile:
loadFragment(profileFragment);
return true;
}
return false;
}
});
}
private void loadFragment(Fragment fragment) {
FragmentTransaction transaction = getSupportFragmentManager().beginTransaction();
transaction.replace(R.id.fragment_container, fragment);
transaction.addToBackStack(null);
transaction.commit();
}
#Override
public void onBackPressed() {
if (bottomNavigationView.getSelectedItemId() == R.id.btnHome)
{
finish();
}
else
{
bottomNavigationView.setSelectedItemId(R.id.btnHome);
}
}}

Use addToBackStack Method when calling a fragment like this,
getSupportFragmentManager().beginTransaction().addToBackStack(null).add(R.id.content_home_nav,newFragment).commit();
Use this code in your onBackPressed Method
if (getSupportFragmentManager().getBackStackEntryCount() > 0 ){
getFragmentManager().popBackStack();
} else {
super.onBackPressed();
}

For your requirement you would be working with fragments on navigation for this you can use Tablayout with view pager and make bottom navigation.
<android.support.design.widget.TabLayout
android:id="#+id/tab_layout"
android:layout_width="match_parent"
android:layout_height="60dp"></android.support.design.widget.TabLayout>
and then setup viewpager with tab layout and add icon to tablayout in your activity
tabLayout = (TabLayout) findViewById(R.id.tab_layout);
viewPager = (ViewPager) findViewById(R.id.controller_pager);
viewPager.setAdapter(new ViewPagerAdapter(getSupportFragmentManager()));
viewPager.setOffscreenPageLimit(4);
tabLayout.setupWithViewPager(viewPager);
tabLayout.getTabAt(0).setIcon(R.drawable.selector_home);
tabLayout.getTabAt(1).setIcon(R.drawable.selector_contact);
tabLayout.getTabAt(2).setIcon(R.drawable.selector_profile);
tabLayout.getTabAt(3).setIcon(R.drawable.selector_settings);
now handle all things on the click of tablayout and it will work fine
tabLayout.addOnTabSelectedListener(this);

I was facing the same problem but after doing this I got the solution
First Paste this code in your main activity (where you are using Bottom navigation bar)
BottomNavigationView bottomNavigationView = (BottomNavigationView) findViewById(R.id.navigation);
BottomNavigationViewHelper.disableShiftMode(bottomNavigationView);
And then create a class named BottomNavigationViewHelper and paste the following code.
public class BottomNavigationViewHelper {
public static void disableShiftMode(BottomNavigationView view) {
BottomNavigationMenuView menuView = (BottomNavigationMenuView) view.getChildAt(0);
try {
Field shiftingMode = menuView.getClass().getDeclaredField("mShiftingMode");
shiftingMode.setAccessible(true);
shiftingMode.setBoolean(menuView, false);
shiftingMode.setAccessible(false);
for (int i = 0; i < menuView.getChildCount(); i++) {
BottomNavigationItemView item = (BottomNavigationItemView) menuView.getChildAt(i);
//noinspection RestrictedApi
item.setShiftingMode(false);
// set once again checked value, so view will be updated
//noinspection RestrictedApi
item.setChecked(item.getItemData().isChecked());
}
} catch (NoSuchFieldException e) {
Log.e("BNVHelper", "Unable to get shift mode field", e);
} catch (IllegalAccessException e) {
Log.e("BNVHelper", "Unable to change value of shift mode", e);
}
}
}
Hope It helps

Try this.
getSupportFragmentManager().addOnBackStackChangedListener(new FragmentManager.OnBackStackChangedListener() {
#Override
public void onBackStackChanged() {
// Gets the previous global stack count
int previousStackCount = mPreviousStackCount;
// Gets a FragmentManager instance
FragmentManager localFragmentManager = getSupportFragmentManager();
// Sets the current back stack count
int currentStackCount = localFragmentManager.getBackStackEntryCount();
// Re-sets the global stack count to be the current count
mPreviousStackCount = currentStackCount;
boolean popping = currentStackCount < previousStackCount;
if(popping){
bottomNavigationView.getMenu().getItem(0).setChecked(true);
}
}
});

Please try this solution.
I have made changes in your code given in question.
I have assumed that on back pressing first time your app will come back to home fragment (in your case Announcement fragment) and if you back press again, the app will close.
This flow will also reflect in bottom navigation bar.
public class MainActivity extends AppCompatActivity {
private static final String BACK_STACK_ROOT_TAG = "root_home_fragment";
private static final String SELECTED_ITEM = "selected_item";
private Fragment fragment;
private FragmentManager fragmentManager;
private BottomNavigationView bottomNavigationView;
private Toolbar toolbar;
private MenuItem menuItemSelected;
private int mMenuItemSelected;
private BottomNavigationView.OnNavigationItemSelectedListener mOnNavigationItemSelectedListener
= new BottomNavigationView.OnNavigationItemSelectedListener() {
#Override
public boolean onNavigationItemSelected(#NonNull MenuItem item) {
boolean selected = false;
switch (item.getItemId()) {
case R.id.action_announcement:
fragment = AnnouncementFragment.newInstance();
selected = true;
break;
case R.id.action_menu:
fragment = MenuFragment.newInstance();
selected = true;
break;
case R.id.action_menu_reports:
fragment = ReportFragment.newInstance();
selected = true;
break;
case R.id.action_setting:
fragment = SettingFragment.newInstance();
selected = true;
}
if(fragment !=null){
fragmentManager = getFragmentManager();
switch (item.getItemId()) {
case R.id.action_announcement:
// Pop every fragment from backstack including home fragment.
fragmentManager.popBackStack(BACK_STACK_ROOT_TAG, FragmentManager.POP_BACK_STACK_INCLUSIVE);
fragmentManager.beginTransaction()
.replace(R.id.content, fragment)
.addToBackStack(BACK_STACK_ROOT_TAG)
.commit();
break;
default:
fragmentManager.beginTransaction()
.replace(R.id.content, fragment)
.addToBackStack(null)
.commit();
break;
}
}
return selected;
}
};
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
toolbar = (Toolbar) findViewById(R.id.toolbar);
setSupportActionBar(toolbar);
bottomNavigationView = (BottomNavigationView) findViewById(R.id.bottom_navigation);
bottomNavigationView.setOnNavigationItemSelectedListener(mOnNavigationItemSelectedListener);
//Always load first fragment as default
bottomNavigationView.setSelectedItemId(R.id.action_announcement);
if (savedInstanceState != null) {
mMenuItemSelected = savedInstanceState.getInt(SELECTED_ITEM, 0);
menuItemSelected = bottomNavigationView.getMenu().findItem(mMenuItemSelected);
} else {
menuItemSelected = bottomNavigationView.getMenu().getItem(0);
}
}
#Override
protected void onSaveInstanceState(Bundle outState) {
outState.putInt(SELECTED_ITEM, mMenuItemSelected);
super.onSaveInstanceState(outState);
}
public void onBackPressed() {
int count = getFragmentManager().getBackStackEntryCount();
if(count >1){
// We have lots of fragment on backstack to be popped.
// Pop till the root fragment.
getFragmentManager().popBackStack(BACK_STACK_ROOT_TAG, FragmentManager.POP_BACK_STACK_INCLUSIVE);
bottomNavigationView.setSelectedItemId(R.id.action_announcement);
}
else{
// Close the application when we are on home fragment.
supportFinishAfterTransition();
}
}
}

Most time when you, press back button, old fragment in the back stack,
are recalled. therefore the system call this onCreateView() method
there add this code
val bottomNav = activity?.findViewById<BottomNavigationView>(R.id.activity_main_bottom_navigation)
bottomNav?.selectedItemId = R.id.the_id_of_the_icon__that_represent_the_fragment

I did this after trying all and everything and at last it worked -_- .I have pasted this 2 override method in my each and every activity that i am surfing through my bottom navigation.
#Override
protected void onResume() {
super.onResume();
bottomNavigationView = (BottomNavigationView) findViewById(R.id.bottom_navigation_Menu_name);
bottomNavigationView.getMenu().getItem(Menu_item_position).setChecked(true);
}
#Override
protected void onRestart() {
super.onRestart();
bottomNavigationView = (BottomNavigationView) findViewById(R.id.bottom_navigation_Menu_name);
bottomNavigationView.getMenu().getItem(Menu_item_position).setChecked(true);
}

Late answer but here it goes.
Let's say you have a BottomNavigation inside MainActivity with 4 Fragments.
FragmentA
FragmentB
FragmentC
FragmentD
If your are adding each fragment to backstack like so:
With kotlin:
main_bottom_navigation.setOnNavigationItemSelectedListener { item ->
var fragment: Fragment? = null
when (item.itemId) {
R.id.nav_a -> fragment = FragmentA()
R.id.nav_b -> fragment = FragmentB()
R.id.nav_c -> fragment = FragmentC()
R.id.nav_d -> fragment = FragmentD()
}
supportFragmentManager
.beginTransaction()
.setCustomAnimations(R.anim.abc_fade_in, R.anim.abc_fade_out)
.replace(R.id.home_content, fragment!!)
.addToBackStack(fragment.tag)
.commit()
true
}
You dont really need to override onBackPressed() inside the MainActivity but explicitly cast on each fragment and assigning the BottomNavigation like this:
FragmentA.kt
override fun onViewCreated(view: View, savedInstanceState: Bundle?) {
super.onViewCreated(view, savedInstanceState)
(activity as MainActivity).main_bottom_navigation.menu.getItem(0).isChecked = true
}
FragmentB.kt
override fun onViewCreated(view: View, savedInstanceState: Bundle?) {
super.onViewCreated(view, savedInstanceState)
(activity as MainActivity).main_bottom_navigation.menu.getItem(1).isChecked = true
}
FragmentC.kt
override fun onViewCreated(view: View, savedInstanceState: Bundle?) {
super.onViewCreated(view, savedInstanceState)
(activity as MainActivity).main_bottom_navigation.menu.getItem(2).isChecked = true
}
FragmentD.kt
override fun onViewCreated(view: View, savedInstanceState: Bundle?) {
super.onViewCreated(view, savedInstanceState)
(activity as MainActivity).main_bottom_navigation.menu.getItem(3).isChecked = true
}
Like this the fragment backstack will properly pop and even exit application when it reaches 0.

This is what I did to handle back press in the activity:
#Override
public void onBackPressed() {
super.onBackPressed();
if(homeFragment.isVisible()){
navView.setSelectedItemId(R.id.nav_home);
}
if(searchFragment.isVisible()){
navView.setSelectedItemId(R.id.nav_search);
}
if(myProfileFragment.isVisible()){
navView.setSelectedItemId(R.id.nav_profile);
}
}

this code is work for me:
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
OneSignal.startInit(this)
.inFocusDisplaying(OneSignal.OSInFocusDisplayOption.Notification)
.unsubscribeWhenNotificationsAreDisabled(true)
.init();
bottomNavigationView = findViewById(R.id.bottomNav);
frameLayout = findViewById(R.id.main_frame);
homeFragment = new HomeFragment();
aboutUsFragment = new AboutUsFragment();
recipesFragment = new RecipesFragment();
knowledgeFragment = new KnowledgeFragment();
contactFragment = new ContactFragment();
loadFragment(homeFragment);
bottomNavigationView.setOnNavigationItemSelectedListener(new BottomNavigationView.OnNavigationItemSelectedListener() {
#Override
public boolean onNavigationItemSelected(#NonNull MenuItem menuItem) {
switch (menuItem.getItemId()) {
case R.id.home:
//mManiNav.setItemBackgroundResource(R.color.blue);
loadFragment(homeFragment);
return true;
case R.id.deposit:
// mManiNav.setItemBackgroundResource(R.color.colorAccent);
loadFragment(recipesFragment);
return true;
case R.id.exchange:
//mManiNav.setItemBackgroundResource(R.color.colorPrimary);
loadFragment(knowledgeFragment);
return true;
case R.id.profile:
// mManiNav.setItemBackgroundResource(R.color.light_blue);
loadFragment(aboutUsFragment);
return true;
case R.id.payout:
// mManiNav.setItemBackgroundResource(R.color.light_blue);
loadFragment(contactFragment);
return true;
default:
return false;
}
}
});
}
Here the load fragment class:
private void loadFragment(Fragment fragment) {
FragmentTransaction transaction = getSupportFragmentManager().beginTransaction();
transaction.replace(R.id.main_frame, fragment);
transaction.addToBackStack(null);
transaction.commit();
}
Here is the popBackStackTillEntry method:
enter code here public void popBackStackTillEntry(int entryIndex) {
if (getSupportFragmentManager() == null) {
return;
}
if (getSupportFragmentManager().getBackStackEntryCount() <= entryIndex) {
return;
}
FragmentManager.BackStackEntry entry = getSupportFragmentManager().getBackStackEntryAt(
entryIndex);
if (entry != null) {
getSupportFragmentManager().popBackStackImmediate(entry.getId(),
FragmentManager.POP_BACK_STACK_INCLUSIVE);
}
}
Here is the backpress method:
boolean doubleBackToExitPressedOnce = false;
#Override
public void onBackPressed() {
if (doubleBackToExitPressedOnce) {
popBackStackTillEntry(0);
moveTaskToBack(true);
System.exit(0);
return;
}
this.doubleBackToExitPressedOnce = true;
loadFragment(new HomeFragment());
new Handler().postDelayed(new Runnable() {
#Override
public void run() {
doubleBackToExitPressedOnce=false;
}
}, 2000);
}

This is a simple and complete working code in Kotlin.
class MainActivity : AppCompatActivity() {
override fun onCreate(savedInstanceState: Bundle?) {
super.onCreate(savedInstanceState)
setContentView(R.layout.activity_main)
bottomNavigationView = findViewById(R.id.bottom_navigation)
bottomNavigationView.setOnItemSelectedListener {menuItem ->
when(menuItem.itemId){
R.id.navBottom_menu_1 -> nextFragment(Fragment_1())
R.id.navBottom_menu_2 -> nextFragment(Fragment_2())
R.id.navBottom_menu_3 -> nextFragment(Fragment_3())
R.id.navBottom_menu_4 -> nextFragment(Fragment_4())
else ->false
}
}
}
fun nextFragment(fm:Fragment): Boolean {
supportFragmentManager.beginTransaction().replace(R.id.linearLayout_rootFragment, fm).commit()
return true
}
fun isMenuChecked(itemIndex:Int):Boolean{
return bottomNavigationView.menu.getItem(itemIndex).isChecked
}
fun setMenuItemChecked(itemIndex:Int){
bottomNavigationView.menu.getItem(itemIndex).isChecked = true
}
override fun onBackPressed() {
when(true){
isMenuChecked(3) -> {nextFragment(Fragment_3()) ; setMenuItemChecked(2) }
isMenuChecked(2) -> {nextFragment(Fragment_2()) ; setMenuItemChecked(1) }
isMenuChecked(1) -> {nextFragment(Fragment_1()) ; setMenuItemChecked(0) }
else -> super.onBackPressed()
}
}
}

This is how I solved my,
Wrap your main widget in WillPopScope() and set a function in the onWillpop: as this
Future<bool> _onBackpress() {
if (_currentpage != 0) {
setState(() {
_currentpage--;//decreases number of pages till the fisrt page
});
} else {
// a function to close the app
}
}