Develop Reference

BottomNavigation View back button on pressed change state

So let me try to explain this: I have a Bottom navigation view with three buttons, each one when pressed will load a fragment. However, when pressing the back button, i have programmed the back stack to go back to the fragment it was previously. However, the colour of the navigation button does not change after the back button is changed. I know this has something to do with the state checked thing but i do not know how to implement it on my codes. Here are the codes
This is the menu page, it sets the bottomnavigation view only in which the main_frame is where the fragments are going to be:
public class menuPage extends AppCompatActivity {
BottomNavigationView mainNav;
FrameLayout mainFrame;
private MoviesFragment moviesFragment;
private HomeFragment homeFragment;
private ProfileFragment profileFragment;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_menu_page);
mainFrame= (FrameLayout) findViewById(R.id.main_frame);
mainNav = (BottomNavigationView) findViewById(R.id.main_nav);
moviesFragment= new MoviesFragment ();
homeFragment = new HomeFragment();
profileFragment = new ProfileFragment ();
removeFragment(homeFragment);
mainNav.setOnNavigationItemSelectedListener(new BottomNavigationView.OnNavigationItemSelectedListener() {
#Override
public boolean onNavigationItemSelected(#NonNull MenuItem item) {
switch (item.getItemId()) {
case R.id.nav_movies :
setFragment(moviesFragment);
return true;
case R.id.nav_home :
setFragment(homeFragment);
return true;
case R.id.nav_profile:
setFragment(profileFragment);
return true;
default:
return false;
}
}
});
}
private void setFragment(Fragment fragment) {
FragmentTransaction fragmentTransaction = getSupportFragmentManager().beginTransaction();
fragmentTransaction.replace(R.id.main_frame, fragment);
fragmentTransaction.addToBackStack("detail");
fragmentTransaction.commit();
}
private void removeFragment(Fragment fragment){
FragmentTransaction fragmentTransaction = getSupportFragmentManager().beginTransaction();
fragmentTransaction.add(R.id.main_frame, fragment);
fragmentTransaction.disallowAddToBackStack();
fragmentTransaction.commit();
}
}
Here is the codes for the Home Fragment, Movies Fragment and Profile Fragment respectively. You can ignore the codes written inside cos i know it correctly goes to another activity when launched and that has nothing to do with this issue
Home Fragment
public class HomeFragment extends Fragment {
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
// Inflate the layout for this fragment
View view= inflater.inflate(R.layout.fragment_agenda, container, false);
return view;
}
}
Movies Fragment
public class MoviesFragment extends Fragment {
ListView listofmovies;
ArrayList<String> genres;
ArrayAdapter<String> listview;
NowShowing nowShowing;
ComingSoon comingsoon;
#Override//inflate this
public View onCreateView(#NonNull LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
final View view = inflater.inflate(R.layout.fragment_movies, container, false);
listofmovies = (ListView) view.findViewById(R.id.movielist);
genres = new ArrayList<String>();
listview = new ArrayAdapter<String>(getActivity(), android.R.layout.simple_list_item_activated_1, genres);
listofmovies.setAdapter(listview);
//The types of options
genres.add("Now Showing");
genres.add("Coming Soon");
genres.add("July");
genres.add("June");
nowShowing = new NowShowing();
comingsoon = new ComingSoon();
listofmovies.setOnItemClickListener(new AdapterView.OnItemClickListener() {
#Override
public void onItemClick(AdapterView<?> parent, View view, int position, long id) {
if (position == 0) {
Intent nextPage = new Intent(view.getContext(), NowShowing.class);
startActivityForResult(nextPage,0);
}
if (position == 1){
Intent nextPage = new Intent(view.getContext(),ComingSoon.class);
startActivityForResult(nextPage,1);
}
}
});
return view;
}
}
Profile Fragment
public class ProfileFragment extends Fragment {
ListView management;
ArrayList<String> mis;
ArrayAdapter<String> Adapter;
#Override
public View onCreateView(#NonNull LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
View view = inflater.inflate(R.layout.fragment_profile,container, false );
management= (ListView) view.findViewById(R.id.management);
mis= new ArrayList<String>();
Adapter = new ArrayAdapter<String>(getActivity(), android.R.layout.simple_list_item_activated_1, mis);
management.setAdapter(Adapter);
//add management settings
mis.add("Settings");
mis.add("Favourites");
mis.add("Log Out");
userprofilefragment userprofilefragment = new userprofilefragment();
FragmentManager manager = getFragmentManager();
manager.beginTransaction()
.replace(R.id.profilelayout, userprofilefragment, userprofilefragment.getTag())
.commit();
return view;
}
Help is much appreciated. The context is that I'm just making a simple movie app for school assignment and i am still kinda beginner at Java..
Thanks

OnCreateView not called again after replacing with the same fragment

I am using a drop-down menu with the different items in the toolbar. In the activity, I am adding the fragment as soon as the menu item is clicked. The fragment OnCreateview gets called and the data is fetched from the API. The logic for the fetching of data remains same for all menu items but only the API endpoint differs. So I am trying to pass the Bundle with API endpoint name and using the same fragment for all the items. But the problem is OnCreateView gets called only first time and the request is made only for first fragment transaction even if I am replacing the same fragment for different item click.
Activity.java
public void onItemSelected(AdapterView<?> adapterView, View view, int i, long l) {
switch (i) {
case 0: //Clients
Bundle bundle1 = new Bundle();
bundle1.putString("hash-key","item1");
ReportCategoryFragment rp1 = new ReportCategoryFragment();
rp1.setArguments(bundle1);
replaceFragment(rp1,false,R.id.container);
break;
case 1:
Bundle bundle2 = new Bundle();
bundle2.putString("hash-key","item2");
ReportCategoryFragment rp2 = new ReportCategoryFragment();
rp2.setArguments(bundle2);
replaceFragment(rp2,false,R.id.container);
break;
}
}
ReportCategoryFragment
#Nullable
#Override
public View onCreateView(LayoutInflater inflater,
#Nullable ViewGroup container, #Nullable Bundle savedInstanceState) {
rootView = inflater.inflate(R.layout.fragment_runreport, container, false);
setHasOptionsMenu(true);
ButterKnife.bind(this, rootView);
presenter.attachView(this);
reportType = getArguments().getString("hash-key");
Log.v("hashkey",reportType);
presenter.fetchCategories(reportType, false, true);
return rootView;
}
replaceFragment Function
public void replaceFragment(Fragment fragment, boolean addToBackStack, int containerId) {
invalidateOptionsMenu();
String backStateName = fragment.getClass().getName();
boolean fragmentPopped = getSupportFragmentManager().popBackStackImmediate(backStateName,
0);
if (!fragmentPopped && getSupportFragmentManager().findFragmentByTag(backStateName) ==
null) {
FragmentTransaction transaction = getSupportFragmentManager().beginTransaction();
transaction.replace(containerId, fragment, backStateName);
if (addToBackStack) {
transaction.addToBackStack(backStateName);
}
transaction.commit();
}
}
EDIT: FragmentnewInstance method
public static ReportCategoryFragment newInstance() {
ReportCategoryFragment fragment = new ReportCategoryFragment();
Bundle bundle = new Bundle();
fragment.setArguments(bundle);
return fragment;
}

Simple solution is to use Broadcast Receiver
Declare this in your fragment class
BroadcastReceiver broadCastNewMessage = new BroadcastReceiver() {
#Override
public void onReceive(Context context, Intent intent) {
//extract our message from intent
String msg_for_me = intent.getStringExtra("some_msg");
}
};
Now in onCreate() of fragment register this
registerReceiver(this.broadCastNewMessage, new IntentFilter("update_fragment"));
And in onDestroyView()
unregisterReceiver(broadCastNewMessage);
Now Call this method from the service class where u want to update the activity from your menu selection
Intent intent = new Intent("update_fragment");
intent.putExtra("some_msg", message);
sendBroadcast(intent);

Try using static method in fragment to create new instance of the fragment.
public static Fragment newInstance()
{
MyFragment myFragment = new MyFragment();
return myFragment;
}

Pass data between fragments

I have one MainActivity and two fragments. In FragmentA I have a recycler view. If I click on "add" button there, the FragmentB is open. The thing I would like to is to write text into some EditTexts and send data back to FragmentA (and render that data in the recycler view). Could you suggest me something please? Thanks
FragmentB
public class NewContactFragment extends Fragment {
EditText name, number, email;
public String mName;
public String mNumber;
public String mEmail;
boolean isFavourite = false;
public NewContactFragment() {
// Required empty public constructor
}
public static NewContactFragment newInstance() {
NewContactFragment fragment = new NewContactFragment();
Bundle bundle = new Bundle();
fragment.setArguments(bundle);
return fragment;
}
#Override
public void onCreate(Bundle savedInstanceState) {
setHasOptionsMenu(true);
super.onCreate(savedInstanceState);
}
#Override
public void onViewCreated(View view, #Nullable Bundle savedInstanceState) {
super.onViewCreated(view, savedInstanceState);
ButterKnife.bind(this, view);
//set title
((MainActivity) getActivity()).getSupportActionBar().setTitle(R.string.new_contact);
}
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
View view = inflater.inflate(R.layout.fragment_new_contact, container, false);
name = (EditText) view.findViewById(R.id.ed_name);
number = (EditText) view.findViewById(R.id.ed_number);
email = (EditText) view.findViewById(R.id.ed_email);
mName = name.getText().toString();
mNumber = number.getText().toString();
mEmail = email.getText().toString();
return view;
}
#Override
public void onCreateOptionsMenu(Menu menu, MenuInflater inflater) {
inflater.inflate(R.menu.new_contact_menu, menu);
}
#Override
public boolean onOptionsItemSelected(MenuItem item) {
switch (item.getItemId()) {
case R.id.action_done:
//TODO: save editTexts and return to ContactListFragment
break;
case R.id.action_favourite:
getActivity().invalidateOptionsMenu();
//Toast.makeText(getContext(), "isFavourite is: " + isFavourite, Toast.LENGTH_SHORT).show();
break;
}
return super.onOptionsItemSelected(item);
}
FragmentA
public class ContactListFragment extends Fragment implements View.OnClickListener {
private static final String TAG = "newcontact";
FloatingActionButton fabButton;
SearchView searchView;
RecyclerView recyclerView;
ContactsAdapter contactsAdapter;
List<Contact> mContact = new ArrayList<>();
public static ContactListFragment newInstance() {
Bundle args = new Bundle();
ContactListFragment fragment = new ContactListFragment();
fragment.setArguments(args);
return fragment;
}
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setHasOptionsMenu(true);
}
#Override
public View onCreateView(LayoutInflater inflater, final ViewGroup container, Bundle savedInstanceState) {
View view = inflater.inflate(R.layout.fragment_contact_list, container, false);
searchView = (SearchView) view.findViewById(R.id.search_view);
fabButton = (FloatingActionButton) view.findViewById(R.id.fab_button);
fabButton.setOnClickListener(this);
recyclerView = (RecyclerView) view.findViewById(R.id.recycler_view);
recyclerView.setLayoutManager(new LinearLayoutManager(getContext()));
mContact = SugarRecord.listAll(Contact.class);
contactsAdapter = new ContactsAdapter(getActivity(), mContact);
recyclerView.setAdapter(contactsAdapter);
inputFilter();
return view;
}
#Override
public void onViewCreated(View view, #Nullable Bundle savedInstanceState) {
super.onViewCreated(view, savedInstanceState);
ButterKnife.bind(this, view);
//show actionBar
((MainActivity) getActivity()).getSupportActionBar().show();
//show title
((MainActivity) getActivity()).getSupportActionBar().setTitle(R.string.app_name);
}
#Override
public void onSaveInstanceState(Bundle outState) {
super.onSaveInstanceState(outState);
}
public void inputFilter() {
searchView.setOnQueryTextListener(new SearchView.OnQueryTextListener() {
#Override
public boolean onQueryTextSubmit(String query) {
return false;
}
#Override
public boolean onQueryTextChange(String newText) {
contactsAdapter.filterList(newText);
return true;
}
});
}
#Override
//Fab button listener
public void onClick(View v) {
((MainActivity) getActivity()).showFragment(new NewContactFragment(), TAG);
}

Fragments should generally only communicate with their direct parent activity. Fragments communicate through their parent activity allowing the activity to manage the inputs and outputs of data from that fragment coordinating with other fragments or activities. Think of the Activity as the controller managing all interaction with each of the fragments contained within.
A few exceptions to this are dialog fragments presented from within another fragment or nested child fragments. Both of these cases are situations where a fragment has nested child fragments and that are therefore allowed to communicate upward to their parent (which is a fragment).
The important thing to keep in mind is that fragments should not directly communicate with each other and should generally only communicate with their parent activity. Fragments should be modular, standalone and reusable components. The fragments allow their parent activity to respond to intents and callbacks in most cases.
There are three ways a fragment and an activity can communicate:
Bundle - Activity can construct a fragment and set arguments
Methods - Activity can call methods on a fragment instance
Listener - Fragment can fire listener events on an activity via an interface
In other words, communication should generally follow these principles:
Activities can initialize fragments with data during construction
Activities can pass data to fragments using methods on the fragment instance
Fragments can communicate up to their parent activity using an interface and listeners
Fragments should pass data to other fragments only routed through their parent activity
Fragments can pass data to and from dialog fragments
Fragments can contain nested child fragments
Read more about Fragment and its communication at Creating and Using Fragments

Fragment is recreate on back press from other Fragment

I am facing a problem in regarding fragment.
In my scenario,
There are two fragment associated with FragmentActivity.
In FragmentActivity, there are a container layout (Frame Layout) in which all fragment will replace.
public void replaceFragment(Fragment fragmentClass) {
String selectedFragment = fragmentClass.getClass().getName();
FragmentManager fragmentManager = getSupportFragmentManager();
FragmentTransaction fragmentTransaction = fragmentManager
.beginTransaction();
fragmentTransaction
.replace(R.id.content_frame, fragmentClass);
fragmentTransaction.addToBackStack(null);
fragmentTransaction.commit();
}
First time , I set a List type fragment (Fragment A) in which get the data from web service and papulate over listview. I execute the AsyncTask from onCreateView() method.
In MainActivity: onCreate
SherlockFragment fragment = new FragmentA();
replaceFragment(fragment);
On list item click of Fragment A, Fragment A will callback the activity method to replace it to details type fragment Fragment B.
#Override
public void onAttach(Activity activity) {
// TODO Auto-generated method stub
super.onAttach(activity);
callback = (ICallBack) activity;
}
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
/*View rootView = inflater.inflate(R.layout.fragment_locate, container,
false);*/
View rootView = inflater.inflate(R.layout.fragment_a, container,
false);
ListView list = (ListView) rootView
.findViewById(R.id.listView);
adapter = new MyListAdapter();
list.setAdapter(adapter);
list
.setOnItemClickListener(new AdapterView.OnItemClickListener() {
#Override
public void onItemClick(AdapterView<?> parent,
View convertView, int position, long id) {
SherlockFragment fragment = new SalonDetailFragment();
callback.replaceFragment(fragment);
}
});
ListDataTask task = new ListDataTask();
task.execute();
return rootView;
}
class ListDataTask extends AsynTask<Void,Void,List<Data>>{
public Void doInBackground(Void parems){
List<Data> = getDataFromServer();
}
onPostExecute(List<Data> data){
adapter.addAllData(data);
adapter.notifyDataSetChanged();
}
}
When I press back button, from Fragment B then Application will show Fragment A but it execute Asynctask again and get the data to papulate the listview.
So I need to know, How to maintain the pervious state of Fragment like Activity.
Is there are any way to not to create Fragment after come back from Other activity
Have a look my pseudo code.

I got solution. Simple.... do the check null value of rootview
public class FragmentA extends Fragment {
View _rootView;
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
if (_rootView == null) {
// Inflate the layout for this fragment
_rootView = inflater.inflate(R.layout.fragment_a, container, false);
// Find and setup subviews
_listView = (ListView)_rootView.findViewById(R.id.listView);
...
} else {
// Do not inflate the layout again.
// The returned View of onCreateView will be added into the fragment.
// However it is not allowed to be added twice even if the parent is same.
// So we must remove _rootView from the existing parent view group
// (it will be added back).
((ViewGroup)_rootView.getParent()).removeView(_rootView);
}
return _rootView

I have the same problem and solved by replacing
fragmentTransaction
.replace(R.id.content_frame, fragmentClass);
to
fragmentTransaction
.add(R.id.content_frame, fragmentClass);
Replace will always create new instance on back press while Add is just add a new fragment in Stack. for more information check this link

How to refresh ActionBar navigation item during traversing the Fragment back stack?

The Android 4.1 ActionBar provides a useful navigation mode as a list or tab. I am using a SpinnerAdapter to select from three fragments to be displayed in view android.R.id.content.
The onNavigationItemSelected() listener then inflates each fragment to the view and adds it to the back stack using FragmentTransaction.addToBackStack(null).
This all works as advertised, but I don't know how to update the ActionBar to reflect the current back stack. Using the ActionBar.setSelectedNavigationItem(position) works but also triggers a new OnNavigationListener() which also creates another FragmentTransaction (not the effect I want). The code is shown below for clarification. Any help with a solution is appreciated.
public class CalcActivity extends Activity {
private String[] mTag = {"calc", "timer", "usage"};
private ActionBar actionBar;
/** An array of strings to populate dropdown list */
String[] actions = new String[] {
"Calculator",
"Timer",
"Usage"
};
/** Called when the activity is first created. */
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
this.actionBar = getActionBar();
actionBar.setNavigationMode(ActionBar.NAVIGATION_MODE_LIST);
// may not have room for Title in actionbar
actionBar.setDisplayOptions(0, ActionBar.DISPLAY_SHOW_TITLE);
actionBar.setListNavigationCallbacks(
// Specify a SpinnerAdapter to populate the dropdown list.
new ArrayAdapter<String>(
actionBar.getThemedContext(),
android.R.layout.simple_list_item_1,
android.R.id.text1,
actions),
// Provide a listener to be called when an item is selected.
new NavigationListener()
);
}
public class NavigationListener implements ActionBar.OnNavigationListener {
private Fragment mFragment;
private int firstTime = 0;
public boolean onNavigationItemSelected(int itemPos, long itemId) {
mFragment = getFragmentManager().findFragmentByTag(mTag[itemPos]);
if (mFragment == null) {
switch (itemPos) {
case 0:
mFragment = new CalcFragment();
break;
case 1:
mFragment = new TimerFragment();
break;
case 2:
mFragment = new UsageFragment();
break;
default:
return false;
}
mFragment.setRetainInstance(true);
}
FragmentTransaction ft = getFragmentManager().beginTransaction();
if (firstTime == 0) {
firstTime++;
ft.add(android.R.id.content, mFragment, mTag[itemPos]);
} else {
ft.replace(android.R.id.content, mFragment, mTag[itemPos]);
ft.addToBackStack(null);
}
ft.commit();
Toast.makeText(getBaseContext(), "You selected : " +
actions[itemPos], Toast.LENGTH_SHORT).show();
return true;
}
}
public static class CalcFragment extends Fragment {
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
View v = inflater.inflate(R.layout.fragment_calc, container, false);
return v;
}
}
public static class TimerFragment extends Fragment {
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
View v = inflater.inflate(R.layout.fragment_timer, container, false);
return v;
}
}
public static class UsageFragment extends Fragment {
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
View v = inflater.inflate(R.layout.fragment_usage, container, false);
return v;
}
}

You could do something like this:
Create a boolean to track when you are selecting a navigation item based on the back button:
private boolean mListIsNavigatingBack = false;
Override onBackPressed, in the override, check if the backstack has items, if so handle yourself, if not call the superclass:
public void onBackPressed() {
if(getFragmentManager().getBackStackEntryCount() > 0){
mListIsNavigatingBack = true;
//You need to get the previous index in the backstack through some means
//possibly by storing it in a stack
int previousNavigationItem = ???;
getActionBar().setSelectedNavigationItem(previousNavigationItem);
}
else{
super.onBackPressed();
}
}
Inside NavigationListener, handle the mListIsNavigatingBack state, manually pop the back stack and unset the state:
if(mListIsNavigatingBack){
if(fm.getBackStackEntryCount() > 0){
fm.popBackStack();
}
mListIsNavigatingBack = false;
}