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Swipe between fragments with help of BottomNavigationBar

I have trouble finding a good example on how to swipe between fragments with help of bottom navigatiom bar. Since FragmentStatePagerAdapter is deprecated and a new ViewPager2 is now recommended instead of the old ViewPager I want to use ViewPager2 and FragmentStateAdapter in my code instead. I have found an example of how to combine BottomNavigationBar and ViewPager here and I want to do something similar. My code have many similarities to the one in the example with the only difference that I have my code in a fragment instead of an activity. Here is a picture of how my FrontendFragment display look like. I can switch between the views using the bottomnavigationbar but I also want to be able to swipe between the views. Can someone help me or at least direct me on the right way? Here is my code:
FragmentPagerAdapter Class:
public class FragmentPagerAdapter extends FragmentStateAdapter {
private static final int mFragmentCount = 5;
public FragmentPagerAdapter(#NonNull Fragment fragment) {
super(fragment);
}
#NonNull
#Override
public Fragment createFragment(int position) {
switch (position){
case 0:
return new HomeFragment();
case 1:
return new SearchFragment();
case 2:
return new AddFragment();
case 3:
return new MessageFragment();
case 4:
return new ProfileFragment();
}
return null;
}
#Override
public int getItemCount() {
return mFragmentCount;
}
}
FrontendFragment Class:
public class FrontendFragment extends Fragment implements BottomNavigationView.OnNavigationItemSelectedListener{
private BottomNavigationView mBottomNavigationView;
private ViewPager2 mViewPager2;
private FragmentPagerAdapter mFragmentPagerAdapter;
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
// Inflate the layout for this fragment
View v = inflater.inflate(R.layout.fragment_frontend, container, false);
loadFragment(new HomeFragment());
mBottomNavigationView = v.findViewById(R.id.bottomNavigationBar);
mBottomNavigationView.setOnNavigationItemSelectedListener(this);
return v;
}
#Override
public boolean onNavigationItemSelected(#NonNull MenuItem item) {
Fragment selectedFragment = null;
switch (item.getItemId()) {
case R.id.home_icon:
selectedFragment = new HomeFragment();
break;
case R.id.search_icon:
selectedFragment = new SearchFragment();
break;
case R.id.add_icon:
selectedFragment = new AddFragment();
break;
case R.id.message_icon:
selectedFragment = new MessageFragment();
break;
case R.id.profile_icon:
selectedFragment = new ProfileFragment();
break;
}
return loadFragment(selectedFragment);
}
private boolean loadFragment(Fragment selectedFragment) {
if(selectedFragment != null){
MainActivity.sFm.beginTransaction().replace(R.id.relLayoutMiddle, selectedFragment).commit();
return true;
}
return false;
}
}
Thanks in advance!

As I'm already using BottomNav with ViewPager2 in one of my app, I can help.
Your code is partially correct which means your FragmentPagerAdapter is fine, but not your FrontEndFragment.
See, the FragmentPagerAdapter has to be set to a ViewPager2 as
//this here is the FrontEndFragment
mViewPager2.setAdapter(new FragmentPagerAdapter(this));
Then, You don't have to do the FragmentTransaction at all, you just have to change the ViewPager2's current item position through the BottomNavigationBar as
#Override
public boolean onNavigationItemSelected(#NonNull MenuItem item) {
switch (item.getItemId()) {
case R.id.home_icon:
mViewPager2.setCurrentItem(0);
break;
case R.id.search_icon:
mViewPager2.setCurrentItem(1);
break;
case R.id.add_icon:
mViewPager2.setCurrentItem(2);
break;
case R.id.message_icon:
mViewPager2.setCurrentItem(3);
break;
case R.id.profile_icon:
mViewPager2.setCurrentItem(4);
break;
}
return false;
}
This is all, you don't have to deal with Fragments at all apart from the FragmentPagerAdapter. Also, don't forget to remove the loadFragment(new HomeFragment()); which is not required, nor the function loadFragment() is required.
(Optional), Furthermore, if you want to disable the Swipe Action of the ViewPager2 and want the Fragments to be selected based on the Selected BottomNav item only, then you can set setUserInputEnabled() property of ViewPager2 as false.
Next, to set the BottomNavigationBar's item as selected based on the swipe of the ViewPager2, what you've to do is,
Create a global var
MenuItem previousMenuItem;
Then, set a default item (first) to be selected of BottomNav on activity start as
mBottomNavigationView.getMenu().getItem(0).setChecked(true);
Finally, set an OnPageSelected() callback on ViewPager2 to update the selected Menu Item as:
mViewPager2.registerOnPageChangeCallback(new ViewPager2.OnPageChangeCallback() {
#Override
public void onPageScrolled(int position, float positionOffset, int positionOffsetPixels) {
super.onPageScrolled(position, positionOffset, positionOffsetPixels);
}
#Override
public void onPageSelected(int position) {
super.onPageSelected(position);
if (previousMenuItem != null) {
previousMenuItem.setChecked(false);
}
else {
mBottomNavigationView.getMenu().getItem(0).setChecked(false);
}
mBottomNavigationView.getMenu().getItem(position).setChecked(true);
previousMenuItem = mBottomNavigationView.getMenu().getItem(position);
}
#Override
public void onPageScrollStateChanged(int state) {
super.onPageScrollStateChanged(state);
}
});
What you're doing here is that you're setting default item to previousMenuItem and then on swiping to a different page, deselecting the previousMenuItem and selecting the new one, which means updating the BottomNav based on ViewPager's current item. This is the complete code you require to acheive your objective.

If you want to swipe between views, a simple solution would be to store all views in your parent view, but set all layouts for views except the initial view to android:visibility="gone". Make sure to set the initial view layout to android:visibility="visible" though. Now on you button clicks, you will have to implement onClick such that they turn on/ off view visibilities accordingly. For example, store views in order and control them via array index. But the whole thing you're trying to do is generally not a good design pattern in my opinion.
Why don't you load another Activity onClick instead of crowding your single activity? This will cause load time issues. Even if the views are non-visible, it's just an overall hassle to maintain all that in one place.

How to fix bottom navigation bar not showing correctly

I'm having the problem that when I trying to switch between the menu item. The menu item will not pointing to the correct icon.
here is the flow when i found this problem
starting at the (Home)fragment,then press on the second menu item (Features )
case R.id.nav_home:
//home fragment transaction
actionBar.setTitle("Home");
HomeFragment fragment1 = new HomeFragment();
FragmentTransaction fragmentTransaction1 = getSupportFragmentManager().beginTransaction();
fragmentTransaction1.replace(R.id.content, fragment1, "");
fragmentTransaction1.commit();
break;
second menu item (features) will go to features activity
case R.id.nav_features:
//features fragment transaction
startActivity(new Intent(DashboardActivity.this, FeaturesActivity.class));
break;
close features activity and back to (Home) fragment
onBackPressed();
bottom navigation still pointing to second menu item (features).
how can I make the system point to the correct menu item ?

You should return a boolean for this method:
#Override
public boolean onNavigationItemSelected(#NonNull MenuItem item) {
//...
}
do this :
case R.id.nav_home:
//home fragment transaction
actionBar.setTitle("Home");
HomeFragment fragment1 = new HomeFragment();
FragmentTransaction fragmentTransaction1 =
getSupportFragmentManager().beginTransaction();
fragmentTransaction1.replace(R.id.content, fragment1, "");
fragmentTransaction1.commit();
return true; // add this line and remove break;
if you don't want to select icon after click, you can return false.

How to get last Fragment used when pressing back button

I have a simple fragment with this code:
private BottomNavigationView.OnNavigationItemSelectedListener navListener =
new BottomNavigationView.OnNavigationItemSelectedListener() {
#Override
public boolean onNavigationItemSelected(#NonNull MenuItem menuItem) {
Fragment selectedFragment= null;
switch (menuItem.getItemId()){
case R.id.nav_home:
selectedFragment= new HomeFragment();
setTitle("Beranda");
break;
case R.id.nav_message:
selectedFragment= new MessageFragment();
setTitle("Pesan");
break;
case R.id.nav_transaction:
selectedFragment= new TransactionFragment();
setTitle("Transaksi");
break;
case R.id.nav_profile:
selectedFragment= new ProfileFragment();
setTitle("Profil");
if(sessionLevel.equals("admin")){
setTitle("Admin");
}
break;
}
getSupportFragmentManager().beginTransaction().replace(R.id.fragment_container, selectedFragment).commit();
return true;
}
};
Most of the fragment are just some kind of holder for Intent Activity. And the Activity itself doesnt have some fancy code.
The problem is that when i do Intent on Profile menu and then press back, the fragment shown is HomeActivity but the selected button is Profile.
I dont know about the other 2 fragment since im not there yet, but probably they do the same thing.

You can do this like the following:
#Override
public void onBackPressed() {
super.onBackPressed();
Fragment frag = YourActivity.this.getSupportFragmentManager().findFragmentById(R.id.fragment_container);
if(frag!=null && frag instanceof yourFragment)
{}
}
The following will give you count
int count = getSupportFragmentManager().getBackStackEntryCount();
You can make condition, If count is great than 1 then have more than 1 fragments else you have atleast 1 fragment and that will be last fragment. If count 0 then no more fragment available on stack as all have been poped out of stack.

Create an interface:
public interface IOnBackPressed {
boolean onBackPressed();
}
In Fragment implement IOnBackPressed like:
public class FAQFragment extends Fragment implements IOnBackPressed {
public boolean onBackPressed() {
return false
}
}
On Main Activity Backpress use
#Override
public void onBackPressed(){
if (getSupportFragmentManager().getBackStackEntryCount() > 0) {
getSupportFragmentManager().popBackStack();
}
}

How to set back activity to Fragment classes?

I am developing an Android Application with navigation activity and there are some list of options in navigation drawer and my First page is also in this activity. I am navigating to another page through the options present in the navigation drawer which are Fragment classes. I need to come back to the first page if I press back button on device. But it goes to pages which I visited before. My Target is to come back to First page from the respective Fragment class.
At times when I hit back button, it also comes to my splash screen, Kindly help me to fix this. Thanks in advance.
This is the code of my FirstPage from where I am navigating to another pages through drawer. I need to come back to this same page again from the drawer (FirsPage)
public void selectDrawerItem(MenuItem menuItem) {
switch(menuItem.getItemId()) {
//1.User Profile
case R.id.navigation_item_attachment:
fragmentClass = ProfileTab.class;
// finish();
break;
//2.FeedBack
//case R.id.navigation_item_images:
/* fragmentClass = SearchHistoryTab.class;
break;*/
case R.id.navigation_refer:
fragmentClass = ReferFrndz.class;
// finish();
break;
case R.id.navigation_daily:
fragmentClass = DailyUsage.class;
break;
//4.About Us
case R.id.navigation_about:
fragmentClass = AboutJc.class;
break;
//4.Contact Us
case R.id.navigation_item_location:
fragmentClass = ContactJc.class;
break;
default:
break;
}
try {
fragment = (Fragment) fragmentClass.newInstance();
}
catch (Exception e) {
e.printStackTrace();
}
FragmentManager fragmentManager = getSupportFragmentManager();
fragmentManager.beginTransaction().replace(R.id.search_layout, fragment).commit();
menuItem.setChecked(true);
setTitle(menuItem.getTitle());
mDrawerLayout.closeDrawers();
}
I used Finish() but it didn't work. It terminating my entire application.
Splash Screen Code:
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
Thread mythread = new Thread() {
public void run(){
try{
sleep(3000);
}catch(InterruptedException e){
e.printStackTrace();
}
finally {
.....
}
}
}
};
mythread.start();
}

Update your Fragmenttransaction code to add ProfileTab (FirstPage) in backstack entry.' So you get ProfileTab (FirstPage) back after click back button.
FragmentManager fragmentManager = getSupportFragmentManager();
if(fragment.equals(ProfileTab.class)){
fragmentManager.beginTransaction().replace(R.id.search_layout, fragment).addToBackStack("fragment_tag").commit();
//Only add backstack entry for first page so you get after click on back button
}
else
{
fragmentManager.beginTransaction().replace(R.id.search_layout, fragment).commit();
}
menuItem.setChecked(true);
setTitle(menuItem.getTitle());
mDrawerLayout.closeDrawers();
Use this solution and share your feedback with replay will help us to improve solution.

Getting Actionbar Tabs to Stick on Fragment

I currently have a MainActivity.java which should be the only activity class. Though in that activity class I have a nav-drawer which links to other fragment views.
Currently the main issue Im facing is implementing tabs under a fragment and making them just be available for only that fragment and subfragments. I ran my application and the tabs appeared, but they also appear on other fragments after I visit the TeamsAndDriversFragment.
In my MainActivity.java I have the following function which helps point to the fragments it will generate once someone clicks on them in the nav-drawer:
/**
* Diplaying fragment view for selected nav drawer list item
* */
private void displayView(int position) {
// update the main content by replacing fragments
Fragment fragment = null;
switch (position) {
case 0:
fragment = new TimeAndScoringFragment();
break;
case 1:
fragment = new ScheduleFragment();
break;
case 2:
fragment = new StandingsFragment();
break;
case 3:
fragment = new TeamsAndDriversFragment();
break;
case 4:
fragment = new NewsFragment();
break;
default:
break;
}
if (fragment != null) {
// Create a fragment transaction object to be able to switch fragments
FragmentTransaction transaction = getFragmentManager().beginTransaction();
// Replace whatever is in the fragment container view with this fragment,
// and add the transaction to the back stack
transaction.replace(R.id.frame_container, fragment);
transaction.addToBackStack(null);
// Commit the transaction
transaction.commit();
// update selected item and title, then close the drawer
mDrawerList.setItemChecked(position, true);
mDrawerList.setSelection(position);
setTitle(navMenuTitles[position]);
mDrawerLayout.closeDrawer(mDrawerList);
} else {
// error in creating fragment
Log.e("MainActivity", "Error in creating fragment");
}
}
Here is my current TeamsAndDriversFragment class where I have an actionbar navigation with tabs:
public class TeamsAndDriversFragment extends Fragment implements TabListener {
private List<Fragment> fragList = new ArrayList<Fragment>();
#Override
public void onCreate(Bundle savedInstance) {
super.onCreate(savedInstance);
ActionBar bar = getActivity().getActionBar();
bar.setNavigationMode(ActionBar.NAVIGATION_MODE_TABS);
Tab mTeamsTab = bar.newTab();
mTeamsTab.setText("Teams");
mTeamsTab.setTabListener(this);
bar.addTab(mTeamsTab);
Tab mDriversTab = bar.newTab();
mDriversTab.setText("Drivers");
mDriversTab.setTabListener(this);
bar.addTab(mDriversTab);
}
#Override
public void onTabReselected(Tab tab, FragmentTransaction ft) {
}
#Override
public void onTabSelected(Tab tab, FragmentTransaction ft) {
Fragment f = null;
TabFragment tf = null;
if(fragList.size() > tab.getPosition()) {
fragList.get(tab.getPosition());
}
if(f == null) {
tf = new TabFragment();
Bundle data = new Bundle();
data.putInt("idx", tab.getPosition());
tf.setArguments(data);
fragList.add(tf);
} else {
tf = (TabFragment) f;
}
ft.replace(android.R.id.content, tf);
}
#Override
public void onTabUnselected(Tab tab, FragmentTransaction ft) {
if(fragList.size() > tab.getPosition()) {
ft.remove(fragList.get(tab.getPosition()));
}
}
}

In the displayView() method simply remove all tabs from the ActionBar, this way you'll always have a clean ActionBar with the exception of the TeamsAndDriversFragment fragment:
private void displayView(int position) {
getSupportActionBar().removeAllTabs();
// ...
}