I'm currently developing a Android studio App using fragment and a bottom navigation bar.
When I click on a navigation bar's item, it's replacing the current fragment by another one which correspond the fragment I wanted for this item.
The problem is, the objects in my fragment are all reset after replacing fragment.
I'm not removing the fragment from the container so I don't really understand why all the objects are reset after doing this.
Here is my code to add and replace fragment to my FrameLayout :
private void setFragment(Fragment fragment) {
FragmentTransaction fragmentTransaction = getSupportFragmentManager().beginTransaction();
fragmentTransaction.setCustomAnimations(android.R.anim.slide_in_left, android.R.anim.fade_out);
if (getSupportFragmentManager().findFragmentById(R.id.main_frame) == null) {
fragmentTransaction.add(R.id.main_frame, fragment);
}
else
{
fragmentTransaction.replace(R.id.main_frame, fragment);
}
fragmentTransaction.addToBackStack(null);
fragmentTransaction.commit();
}
and here is the bottom navigation bar code to execute the previous function and change the displayed fragment:
homeFragment = new HomeFragment();
programFragment = new ProgramFragment();
bluetoothFragment = new BluetoothFragment();
mMainNav.setOnNavigationItemSelectedListener(new BottomNavigationView.OnNavigationItemSelectedListener() {
#Override
public boolean onNavigationItemSelected(#NonNull MenuItem item) {
test = mMainNav.getMenu().getItem(2);
switch (item.getItemId()) {
case R.id.nav_home:
//mMainNav.setItemBackgroundResource(R.color.colorPrimary);
HQ_logo_IV.setVisibility(View.VISIBLE);
setFragment(homeFragment);
return true;
case R.id.nav_program:
//mMainNav.setItemBackgroundResource(R.color.colorAccent);
HQ_logo_IV.setVisibility(View.INVISIBLE);
setFragment(programFragment);
return true;
case R.id.nav_bluetooth:
//mMainNav.setItemBackgroundResource(R.color.colorPrimaryDark);
HQ_logo_IV.setVisibility(View.INVISIBLE);
setFragment(bluetoothFragment);
return true;
default:
return false;
}
}
});
I found the way to stop this thing.
I used an AsyncTask to refresh my fragment state.
I just put new "yourAsyncTaskName"().execute() at the beginning of my onCreate() method to refresh the fragment when it's created or replaced.
Hope this will help.
Related
I was trying to implement the bottom navigation with fragment inside an activity.
I have done that and it was successful.
To replace the fragment on click each navigation item, I use the following code.
private BottomNavigationView.OnNavigationItemSelectedListener mOnNavigationItemSelectedListener
= new BottomNavigationView.OnNavigationItemSelectedListener() {
#Override
public boolean onNavigationItemSelected(#NonNull MenuItem item) {
switch (item.getItemId()) {
case R.id.navigation_notifications:
loadFragment(new NotificationsFragment());
return true;
case R.id.navigation_notes:
loadFragment(new NotesFragment());
return true;
case R.id.navigation_about:
loadFragment(new AboutFragment());
return true;
}
return false;
}
};
private void loadFragment(Fragment fragment) {
// load fragment
FragmentTransaction transaction = getSupportFragmentManager().beginTransaction();
transaction.replace(R.id.frame_container, fragment);
transaction.addToBackStack(null);
transaction.commit();
}
Now the problem is that when I click on a navigation in the bottom navigation bar multiple times, the fragment is also getting added to the back stack multiple times.
So when I click the back button the fragment is again loaded, not exiting or loading the previous fragment.
So, How can I prevent the fragment getting added to the back stack multiple times?
Remove
transaction.addToBackStack(null);
or add
transaction.disallowAddToBackStack();
I have a setup of 3 Fragments inside my main activity and want to navigate them using the BottomNavigationView. I want to add them once and then just switch between them without actually destroying the Fragments. Everything works fine except that the first fragment added to the SupportFragmentManager always disappears (tried changing the order so the problem is not with the Fragments themselves). Actually, it doesn't disappear but the last Fragment that occupied the container shows up.
Eg. I go to position 3, Fragment 3 shows up in the container and then click on position 1, Fragment 3 will still occupy the container. But if I tap position 2 Fragment 2 will appear. How I'm adding the Fragments:
FragmentTransaction ft = getSupportFragmentManager().beginTransaction();
ft.add(R.id.container, fragment1); //whatever gets added here ends up being invisible
ft.commitAllowingStateLoss();
ft = getSupportFragmentManager().beginTransaction();
ft.add(R.id.container, fragment2);
ft.commitAllowingStateLoss();
ft = getSupportFragmentManager().beginTransaction();
ft.add(R.id.container, fragment3);
ft.commitAllowingStateLoss();
How I'm switching between them using the OnNavigationItemSelectedListener:
private BottomNavigationView.OnNavigationItemSelectedListener navigation_listener =
new BottomNavigationView.OnNavigationItemSelectedListener() {
#Override
public boolean onNavigationItemSelected(#NonNull MenuItem item) {
Fragment selectedFragment = null;
Fragment previousFragment = getSupportFragmentManager().findFragmentById(R.id.container);
switch(item.getItemId()){
case R.id.bottom_navigation_bar_position1:
selectedFragment = fragment1;
break;
case R.id.bottom_navigation_bar_position2:
selectedFragment = fragment2;
break;
case R.id.bottom_navigation_bar_position3:
selectedFragment = fragment3;
break;
}
getSupportFragmentManager().beginTransaction().hide(previousFragment).commit();
getSupportFragmentManager().beginTransaction().show(selectedFragment).commit();
return true;
}
};
The XML menu navigation:
<item
android:id="#+id/bottom_navigation_bar_position1"
android:title="Title1"
android:icon="#drawable/ic1"
/>
<item
android:id="#+id/bottom_navigation_bar_position2"
android:title="Title2"
android:icon="#drawable/ic2"
/>
<item
android:id="#+id/bottom_navigation_bar_position3"
android:title="Title3"
android:icon="#drawable/ic3"
/>
Btw. just using replace() instead of show and hide works but that's not the goal...
I've also tested whether the first added Fragment exits (and doesn't get destroyed) and it indeed exists...
Thanks!
Instead of trying to show and hide fragment I solved the problem by managing the Fragments using a ViewPager and a SectionsPageAdapter. Once you link these two, use ViewPager.setOffscreenPageLimit(3) to make sure no Fragments get destroyed. My BottomNavigationView.OnNavigationItemSelectedListener looks like this now:
private BottomNavigationView.OnNavigationItemSelectedListener navigation_listener =
new BottomNavigationView.OnNavigationItemSelectedListener() {
#Override
public boolean onNavigationItemSelected(#NonNull MenuItem item) {
switch(item.getItemId()){
case R.id.bottom_navigation_bar_position1:
tab_view_pager.setCurrentItem(0);
return true;
case R.id.bottom_navigation_bar_position2:
tab_view_pager.setCurrentItem(1);
return true;
case R.id.bottom_navigation_bar_position3:
tab_view_pager.setCurrentItem(2);
return true;
}
return false;
}
};
You have to set 0th position item selected for BottomNavigationView.OnNavigationItemSelectedListener. Find Menu bottom_navigation_bar_position1
I used this in my code, please refactor according to your needs
BottomNavigationView navigation = findViewById(R.id.navigation);
navigation.setOnNavigationItemSelectedListener(this);
Menu menu = navigation.getMenu();
this.onNavigationItemSelected(menu.findItem(R.id.navigation_doc));
Good Day,
I am facing some problem with fragments
I am displaying a fragment when user clicks on 'More', as a popup menu
but when I click the 'More' again, it would be like add one more fragment on the previous one
can someone tell me how to remove the fragment when I click on the 'More' again? Thank you!
the java code of bottom navigation menu
public class MainActivity extends AppCompatActivity {
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
BottomNavigationView bottomNavigationView = (BottomNavigationView)
findViewById(R.id.bottom_navigation);
BottomNavigationViewHelper.disableShiftMode(bottomNavigationView);
bottomNavigationView.setOnNavigationItemSelectedListener(new BottomNavigationView.OnNavigationItemSelectedListener() {
#Override
public boolean onNavigationItemSelected(#NonNull MenuItem item) {
Fragment fragment = null;
String title = "";
switch (item.getItemId()) {
case R.id.menu:
getFragmentManager().beginTransaction().replace(R.id.fragment_container, new MenuFragment()).addToBackStack(null).commit();
title = "MENU";
getSupportActionBar().setTitle(title);
break;
case R.id.promotion:
getFragmentManager().beginTransaction().replace(R.id.fragment_container, new PromotionFragment()).addToBackStack(null).commit();
title = "PROMOTION";
getSupportActionBar().setTitle(title);
break;
case R.id.order:
getFragmentManager().beginTransaction().replace(R.id.fragment_container, new OrderFragment()).addToBackStack(null).commit();
title = "ORDER";
getSupportActionBar().setTitle(title);
break;
case R.id.location:
getFragmentManager().beginTransaction().replace(R.id.fragment_container, new LocationFragment()).addToBackStack(null).commit();
title = "LOCATION";
getSupportActionBar().setTitle(title);
break;
case R.id.more:
getFragmentManager().beginTransaction().add(R.id.fragment_container, new MoreFragment()).addToBackStack(null).commit();
break;
}
return true;
}});
}
}
Do not add your Popup Fragment to the backstack while transitioning to a new one. That is the first step you should do.
Next, rather than reopening the Popup on second "more" click, you should close it. Sounds like a better approach. But this would be probably better achieved by using Dialogs.
before calling transaction for 'more' add a tag with addToBackStack function(ex: moreFragment). check fragment manager and remove fragment like:
Fragment mFragment =getSupportFragmentManager().findFragmentByTag("moreFragment");
if(mFragment != null)
getSupportFragmentManager().beginTransaction().remove(mFragment);
But I think instead of removing old fragment just keep it and dont open new one if not null
To do this you have to keep track of fragment state. Lets assume a variable isFragmentOpen. In onClick you have to flip the variable and take your decision.
private boolean isFragmentOpen;
void onClick(View view) {
if (!isFragmentOpen) {
addFragment();
} else {
removeFragment();
}
// Flip the fragment state.
isFragmentOpen = !isFragmentOpen;
}
Please check how to add or delete fragment from official document Fragments
thanks for helping and now i already solve the problem^^
this is the code what i using
FragmentManager fm = getFragmentManager();
FragmentTransaction ft = fm.beginTransaction();
MoreFragment f = (MoreFragment) fm.findFragmentByTag("tag");
if(f == null) { // not added
f = new MoreFragment();
ft.add(R.id.fragment_container, f, "tag");
ft.setTransition(FragmentTransaction.TRANSIT_FRAGMENT_OPEN);
} else { // already added
ft.remove(f);
ft.setTransition(FragmentTransaction.TRANSIT_FRAGMENT_CLOSE);
}
ft.commit();
break;
Hi guys here is my code
navigationView.setNavigationItemSelectedListener(new NavigationView
.OnNavigationItemSelectedListener() {
#Override public boolean onNavigationItemSelected(#NonNull MenuItem item) {
if (item.isChecked()) {
//item already selected. Do nothing
drawerLayout.closeDrawer(GravityCompat.START);
return true;
}
switch (item.getItemId()) {
case R.id.home:
FragmentTransaction transaction = getSupportFragmentManager()
.beginTransaction();
transaction.replace(R.id.fragment, new HomeFragment())
.setTransition(FragmentTransaction.TRANSIT_FRAGMENT_FADE).commit();
break;
case R.id.other:
transaction = getSupportFragmentManager().beginTransaction();
transaction.replace(R.id.fragment, new OtherFragment())
.addToBackStack(null).setTransition(FragmentTransaction
.TRANSIT_FRAGMENT_FADE).commit();
break;
default:
break;
}
drawerLayout.closeDrawer(GravityCompat.START);
return true;
}
});
I basically only have 2 fragments and merely the HomeFragment should be added to the backstack. After switching between HomeFragment and OtherFragment for a while and clicking on the back button while on the HomeFragment, I end up with the HomeFragment getting displayed several times.
Within the HomeFragment lies a recyclerview. When I scroll up and down I can really see that the rows are displayed multiple times.
How can I make sure that the HomeFragment is added to the backstack only once.
Thanks
You could easily check your fragment with
YourFragment.isAdded
And if you have a multiple fragment you could create a new class to manage all the fragment and create state to check if fragment have been added or not.
When you click on the Home menu item try to find out whether there is any fragment in the backstack or not. If yes, call popBackStack() or replace a fragment as you do now otherwise. Use this code: if (getSupportFragmentManager().getBackStackEntryCount() > 0) {
getSupportFragmentManager().popBackStack();
}
I am using SLiding menu at My App and according to menu item , I am changing always the fragment at activity which have binded already to menu. But There is performance issue. it is freezing when i am attaching the fragments. but after the wiew created. the performance is normal. I am replacing the fragments after call the toggle function at menu.
is there anyone to have any opinion about it ?
just call it as:
#Override
public boolean onOptionsItemSelected(MenuItem item) {
// Pass the event to ActionBarDrawerToggle, if it returns
// true, then it has handled the app icon touch event
if (item.getItemId() == R.id.evnetCalender) {
if (!isToggle) {
item.setIcon(R.drawable.ic_view_list_white_24dp);
setFragment(caldroidCalendarFragment);
isToggle = true;
} else {
item.setIcon(R.drawable.ic_event_white_24dp);
setFragment(scheduleEventFragment);
isToggle = false;
}
}
and set your fragment when you toggle it
private void setFragment(Fragment fragment1) {
FragmentManager fragmentManager = getSupportFragmentManager();
FragmentTransaction fragmentTransaction =
fragmentManager.beginTransaction();
fragmentTransaction.replace(R.id.content, fragment1);
fragmentTransaction.commit();
}
this content identifier is your frame layout id in which your fragment take place