In my StartActivity the BottomNavigationBar Listener has the following setup:
private GuideFragment guideFragment = new GuideFragment();
private MapFragment mapFragment = new MapFragment();
private MoreFragment moreFragment = new MoreFragment();
private BottomNavigationView.OnNavigationItemSelectedListener mOnNavigationItemSelectedListener
= new BottomNavigationView.OnNavigationItemSelectedListener() {
#Override
public boolean onNavigationItemSelected(#NonNull MenuItem item) {
Fragment selectedFragment = null;
switch (item.getItemId()) {
case R.id.navigation_guide:
selectedFragment = guideFragment;
break;
case R.id.navigation_map:
selectedFragment = mapFragment;
break;
case R.id.navigation_more:
selectedFragment = moreFragment;
break;
}
FragmentTransaction transaction = getFragmentManager().beginTransaction();
transaction.replace(R.id.content, selectedFragment);
transaction.commit();
return true;
}
};
As I mentioned above I want to prevent that the selected fragments always reloads the sources/view.
I tried out some stuff like - in the fragments:
if (rootView == null)
inflater.inflate...
But the fragments still recreate the view and load (in my case) webresources new.
I read something that a PageView could help, especially
offScreenPageLimit
should do the magic.
My main question is where should I implement a PageViewer - Is it possible in my StartActivity?
Or can I solve the problem in an other way?
I did it boys!
There is no ViewPager necessary.
Here is my solution (all coded in StartActivity not in Fragments):
private final GuideFragment guideFragment = new GuideFragment();
private final MapFragment mapFragment = new MapFragment();
private final MoreFragment moreFragment = new MoreFragment();
private final android.app.FragmentManager fm = getFragmentManager();
Fragment active = guideFragment;
private BottomNavigationView.OnNavigationItemSelectedListener mOnNavigationItemSelectedListener
= new BottomNavigationView.OnNavigationItemSelectedListener() {
#Override
public boolean onNavigationItemSelected(#NonNull MenuItem item) {
switch (item.getItemId()) {
case R.id.navigation_guide:
if(active != guideFragment) {
fm.beginTransaction().show(guideFragment).commit();
}
else {
fm.beginTransaction().hide(active).show(guideFragment).commit();
}
active = guideFragment;
break;
case R.id.navigation_map:
fm.beginTransaction().hide(active).show(mapFragment).commit();
active = mapFragment;
break;
case R.id.navigation_more:
fm.beginTransaction().hide(active).show(moreFragment).commit();
active = moreFragment;
break;
}
return true;
}
};
and in onCreate list the transaction commits.
fm.beginTransaction().add(R.id.content,moreFragment).commit();
fm.beginTransaction().add(R.id.content, mapFragment).commit();
fm.beginTransaction().add(R.id.content, guideFragment).commit();
It is very important to commit the first tabs fragment last(fragm3,fragm2,fragm1) if you have 3 tabs.
Highly speed performance on the smartphone now by not loading every fragment new/refresh.
Related
I have a Bottom Navigation Bar Activity with changing fragments. i have done forward slide animation on fragments using 'setCustomAnimations' function but i want backward slide animations it has the same animation as for forward animation. i am unable to solve it, i have also tried many different solutions but none of them are working. can anyone help me give a solution to this
Here is the Code
public class Homepage extends AppCompatActivity {
private BottomNavigationView mainNav;
private FrameLayout mainFrame;
private HomeFragment homeFragment;
private GamesFragment gamesFragment;
private ExerciseFragment exerciseFragment;
private GalleryFragment galleryFragment;
private MoreFragment moreFragment;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_homepage);
mainNav = (BottomNavigationView) findViewById(R.id.main_nav);
mainFrame = (FrameLayout) findViewById(R.id.main_frame);
homeFragment = new HomeFragment();
gamesFragment = new GamesFragment();
exerciseFragment = new ExerciseFragment();
galleryFragment = new GalleryFragment();
moreFragment = new MoreFragment();
setFragment(homeFragment);
mainNav.setOnNavigationItemSelectedListener(new BottomNavigationView.OnNavigationItemSelectedListener() {
#Override
public boolean onNavigationItemSelected(#NonNull MenuItem menuItem) {
switch (menuItem.getItemId()) {
case R.id.nav_home:
setFragment(homeFragment);
return true;
case R.id.nav_games:
setFragment(gamesFragment);
return true;
case R.id.nav_exercise:
setFragment(exerciseFragment);
return true;
case R.id.nav_gallery:
setFragment(galleryFragment);
return true;
case R.id.nav_more:
setFragment(moreFragment);
return true;
default:
return false;
}
}
});
}
private void setFragment(Fragment fragment){
FragmentTransaction fragmentTransaction = getSupportFragmentManager().beginTransaction();
fragmentTransaction.setCustomAnimations(R.anim.slide_in_right,R.anim.slide_out_left);
fragmentTransaction.replace(R.id.main_frame, fragment);
fragmentTransaction.commit();
}
}
I am using a navigation bottom with 4 items in my app, so I have 4 fragments.
the first fragment(home page) contains a recyclerView and other fragments don't contain any recyclerView.
The problem is here;
when I navigate to other fragments I can see the recycler view in the background.
and when I navigatie back to the first fragment there is another recycler view under the original one!
I have used this :
fm.beginTransaction().hide(active).show(fragment2).commit();
but the hide() method doesn't work.
Here is the related parts of my code:
I have globally defined these
final Fragment fragment1 = new HomeFragment();
final Fragment fragment2 = new AddFragment();
final Fragment fragment3 = new CalendarFragment();
final Fragment fragment4 = new ProfileFragment();
final FragmentManager fm = getSupportFragmentManager();
Fragment active = fragment1;
then
In the onCreate :
fm.beginTransaction().add(R.id.nav_host_fragment, fragment4, "4").hide(fragment4).commit();
fm.beginTransaction().add(R.id.nav_host_fragment, fragment3, "3").hide(fragment3).commit();
fm.beginTransaction().add(R.id.nav_host_fragment, fragment2, "2").hide(fragment2).commit();
fm.beginTransaction().add(R.id.nav_host_fragment, fragment1, "1").commit();
and at last
the navigation item listener :
private BottomNavigationView.OnNavigationItemSelectedListener mOnNavigationItemSelectedListener
= new BottomNavigationView.OnNavigationItemSelectedListener() {
#Override
public boolean onNavigationItemSelected(#NonNull MenuItem item) {
switch (item.getItemId()) {
case R.id.navigation_home:
if (active == fragment1)
return false;
fm.beginTransaction().hide(active).show(fragment1).commit();
active = fragment1;
return true;
case R.id.navigation_add:
if (active == fragment2)
return false;
fm.beginTransaction().hide(active).show(fragment2).commit();
active = fragment2;
return true;
case R.id.navigation_calendar:
if (active == fragment3)
return false;
fm.beginTransaction().hide(active).show(fragment3).commit();
active = fragment3;
return true;
case R.id.navigation_profile:
if (active == fragment4)
return false;
fm.beginTransaction().hide(active).show(fragment4).commit();
active = fragment4;
return true;
}
return false;
}
};
I have used navGraph in my fragment in the XML file previously and I've forgotten to delete the navGraph, so it was showing the first fragment in the navGraph in the background.
I have the following bottom navbar code to switch between 3 fragments:
public class MainActivity extends AppCompatActivity {
private BottomNavigationView.OnNavigationItemSelectedListener mOnNavigationItemSelectedListener
= new BottomNavigationView.OnNavigationItemSelectedListener() {
#Override
public boolean onNavigationItemSelected(#NonNull MenuItem item) {
Fragment fragment = null;
switch (item.getItemId()) {
case R.id.navigation_home:
fragment = new HomeFragment();
break;
case R.id.navigation_dashboard:
fragment = new DashboardFragment();
break;
case R.id.navigation_notifications:
fragment = new NotificationsFragment();
break;
}
return loadFragment(fragment);
}
};
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
loadFragment(new HomeFragment());
BottomNavigationView navigation = (BottomNavigationView) findViewById(R.id.navigation);
navigation.setOnNavigationItemSelectedListener(mOnNavigationItemSelectedListener);
}
private boolean loadFragment(Fragment fragment) {
//switching fragment
if (fragment != null) {
getSupportFragmentManager()
.beginTransaction()
.replace(R.id.fragment_container, fragment)
.commit();
return true;
}
return false;
}
}
In the fragments there are RecyclerViews with lists. Every time I switch between the tabs (between fragments), it looks like the fragment is reloaded, and the lists jump to the top. I want to prevent that reloading so that the user stays on the same place in the list he viewed before switching fragments
The problem is that you are creating a new instance every time. You can cache the instance like:
private Fragment mHomeFragment = new HomeFragment();
private Fragment mDashboardFragment = new DashboardFragment();
private Fragment mNotificationsFragment = new NotificationsFragment();
#Override
public boolean onNavigationItemSelected(#NonNull MenuItem item) {
Fragment fragment = null;
switch (item.getItemId()) {
case R.id.navigation_home:
fragment = mHomeFragment;
break;
case R.id.navigation_dashboard:
fragment = mDashboardFragment;
break;
case R.id.navigation_notifications:
fragment = mNotificationsFragment;
break;
}
return loadFragment(fragment);
}
As we could see, you are always replace your fragment when clicks on bottom navigation, replace means previous fragment removes and state cleans. The solution is do not create your fragment each time and use attach/detach method for showing actual fragment. Here is already described about these methods.
Problem:
Each time the BottomNavigationView is clicked the fragment is re-created.
Currently in each fragment I have Recycler View that runs only once when creating the Fragment.
In this case, the RecyclerView data is loaded every time. And that's not what I'd like.
How could I work so that the Fragment remains active after it is clicked the first time. And when you go back to the Fragment already created, just display it without recreating it every time?
My attempts:
BottomNavigationView bottomNavigationView =(BottomNavigationView) findViewById(R.id.bottomNavView_Bar);
BottomNavigationViewHelper.disableShiftMode(bottomNavigationView);
final Menu menu = bottomNavigationView.getMenu();
fragmentManager = getSupportFragmentManager();
final FragmentTransaction transaction = fragmentManager.beginTransaction();
/* Fragmento Start */
transaction.replace(R.id.content_home, new MainFragment()).commit();
bottomNavigationView.setOnNavigationItemSelectedListener(new BottomNavigationView.OnNavigationItemSelectedListener() {
#Override
public boolean onNavigationItemSelected(#NonNull MenuItem item) {
Intent in;
Fragment fragment = null;
Fragment currentFragment = getSupportFragmentManager().findFragmentById(R.id.content_home);
switch (item.getItemId()){
case R.id.ic_home:
if (!(currentFragment instanceof MainFragment)) {
fragment = new MainFragment();
toolbar.setTitle("Main");
item = menu.getItem(0);
item.setChecked(true);
}
break;
case R.id.ic_categorias:
if (!(currentFragment instanceof CategoriasFragment)) {
fragment = new CategoriasFragment();
toolbar.setTitle("Categorias");
item = menu.getItem(1);
item.setChecked(true);
}
break;
case R.id.ic_calendar:
if (!(currentFragment instanceof FeedUserFragment)) {
fragment = new FeedUserFragment();
item = menu.getItem(2);
toolbar.setTitle("Feed");
item.setChecked(true);
}
break;
case R.id.ic_explore:
if (!(currentFragment instanceof ExploreFragment)) {
fragment = new ExploreFragment();
item = menu.getItem(3);
toolbar.setTitle("Explorar");
item.setChecked(true);
}
break;
case R.id.ic_person:
if (!(currentFragment instanceof Opcoes)) {
fragment = new Opcoes();
toolbar.setTitle("Opções");
item = menu.getItem(4);
item.setChecked(true);
}
break;
}
FragmentManager manager = getSupportFragmentManager();
FragmentTransaction transaction = manager.beginTransaction();
transaction.replace(R.id.content_home, fragment);
transaction.commit();
return false;
}
});
You are replacing your fragment every time ie after your switch block
complete.
Solution: Replace only when condition meets and use addToBackStack which helps to maintain stacks. You can read more about from this site
Try this,
bottomNavigationView.setOnNavigationItemSelectedListener(new BottomNavigationView.OnNavigationItemSelectedListener() {
#Override
public boolean onNavigationItemSelected(#NonNull MenuItem item) {
Intent in;
Fragment fragment = null;
Fragment currentFragment = getSupportFragmentManager().findFragmentById(R.id.content_home);
switch (item.getItemId()){
case R.id.ic_home:
if (!(currentFragment instanceof MainFragment)) {
fragment = new MainFragment();
toolbar.setTitle("Main");
item = menu.getItem(0);
item.setChecked(true);
loadFragment(fragment,"mainMenu");
}
break;
case R.id.ic_categorias:
if (!(currentFragment instanceof CategoriasFragment)) {
fragment = new CategoriasFragment();
toolbar.setTitle("Categorias");
item = menu.getItem(1);
item.setChecked(true);
loadFragment(fragment,"categories");
}
break;
case R.id.ic_calendar:
if (!(currentFragment instanceof FeedUserFragment)) {
fragment = new FeedUserFragment();
item = menu.getItem(2);
toolbar.setTitle("Feed");
item.setChecked(true);
loadFragment(fragment,"feedUsers");
}
break;
case R.id.ic_explore:
if (!(currentFragment instanceof ExploreFragment)) {
fragment = new ExploreFragment();
item = menu.getItem(3);
toolbar.setTitle("Explorar");
item.setChecked(true);
loadFragment(fragment,"explore");
}
break;
case R.id.ic_person:
if (!(currentFragment instanceof Opcoes)) {
fragment = new Opcoes();
toolbar.setTitle("Opções");
item = menu.getItem(4);
item.setChecked(true);
loadFragment(fragment,"opcoes");
}
break;
}
return false;
}
});
/**
* Create new method which replace your old fragment
*/
public void loadFragment(Fragment fragment, String tag){
FragmentManager manager = getSupportFragmentManager();
FragmentTransaction transaction = manager.beginTransaction();
transaction.replace(R.id.content_home, fragment);
transaction.addToBackStack(tag);
transaction.commit();
}
I would try transaction.add() and search for fragments in back stack with this method findFragmentByTag. https://developer.android.com/reference/android/support/v4/app/FragmentManager.html#findFragmentByTag(java.lang.String).
How can I limit a tap on a BottomNavigatioView item to just once, so that my mapfragment doesn't have to reload itself when someone spamms the item?
My current Solution is this one:
fragmentManager = getSupportFragmentManager();
bottomNavigation.setOnNavigationItemSelectedListener(new BottomNavigationView.OnNavigationItemSelectedListener() {
#Override
public boolean onNavigationItemSelected(#NonNull MenuItem item) {
Fragment fragment = null;
Fragment currentFragment = fragmentManager.findFragmentById(R.id.main_container);
int id = item.getItemId();
switch (id){
case R.id.World:
if (!(currentFragment instanceof MapsFragment)) {
fragment = new MapsFragment();
}
break;
case R.id.Friends:
fragment = new FriendsFragment();
break;
case R.id.Chats:
fragment = new You_Fragment();
break;
}
final FragmentTransaction transaction = fragmentManager.beginTransaction();
transaction.replace(R.id.main_container, fragment).commit();
return true;
}
});
but it doesn't work since the fragment throws a Nullpointer.
What can i change to achieve the above?
Try this! Worked for me:
fragmentManager = getSupportFragmentManager();
bottomNavigation.setOnNavigationItemSelectedListener(new BottomNavigationView.OnNavigationItemSelectedListener() {
#Override
public boolean onNavigationItemSelected(#NonNull MenuItem item) {
Fragment fragment = null;
Fragment currentFragment = getSupportFragmentManager().findFragmentById(R.id.main_container);
int id = item.getItemId();
switch (id){
case R.id.World:
if (currentFragment instanceof MapsFragment) {
return false;
} else {
fragment = new MapsFragment();
}
break;
case R.id.Friends:
fragment = new FriendsFragment();
break;
case R.id.Chats:
fragment = new You_Fragment();
break;
}
final FragmentTransaction transaction = fragmentManager.beginTransaction();
transaction.replace(R.id.main_container, fragment).commit();
return true;
}
});