I am making my first app in android studio. So far I have built a bottom navigation bar using fragments. I am now trying to add a calendar feature to one of the fragments, I have copied a tutorial using activities to run the code and think there is a problem with using "View".
This is the code to open for the nav bar to open the fragment.
@Override
public boolean onNavigationItemSelected(MenuItem item) {
switch (item.getItemId()){
case R.id.home:
getSupportFragmentManager().beginTransaction().replace(R.id.container,homeFragment).commit();
return true;
case R.id.calendar:
getSupportFragmentManager().beginTransaction().replace(R.id.container,calendarFragment).commit();
return true;
case R.id.wellbeing:
getSupportFragmentManager().beginTransaction().replace(R.id.container,wellbeingFragment).commit();
return true;
}
return false;
This is java in my calendar fragment, which when opened from the navigation bar crashes the app
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
// Inflate the layout for this fragment
initWidgets();
selectedDate = LocalDate.now();
setMonthView();
return inflater.inflate(R.layout.fragment_calendar, container, false);
}
private void initWidgets()
{
calendarRecyclerView = requireView().findViewById(R.id.calendarRecyclerView);
monthYearText = requireView().findViewById(R.id.monthYearTV);
}
private void setMonthView()
{
monthYearText.setText(monthYearFromDate(selectedDate));
ArrayList<String> daysInMonth = daysInMonthArray(selectedDate);
CalendarAdapter calendarAdapter = new CalendarAdapter(daysInMonth, this);
RecyclerView.LayoutManager layoutManager = new GridLayoutManager(getContext(),7);
calendarRecyclerView.setLayoutManager(layoutManager);
calendarRecyclerView.setAdapter(calendarAdapter);
}
This is the error message I receive in my logcat
2022-05-12 12:45:05.305 10950-10950/com.example.myapplication E/AndroidRuntime: FATAL EXCEPTION: main
Process: com.example.myapplication, PID: 10950
java.lang.IllegalStateException: Fragment CalendarFragment{c4de180} (94b1c782-ca39-403f-b45b-5d0d7a042f15 id=0x7f080087) did not return a View from onCreateView() or this was called before onCreateView().
at androidx.fragment.app.Fragment.requireView(Fragment.java:1964)
at com.example.myapplication.CalendarFragment.initWidgets(CalendarFragment.java:41)
at com.example.myapplication.CalendarFragment.onCreateView(CalendarFragment.java:30)
at androidx.fragment.app.Fragment.performCreateView(Fragment.java:2963)
at androidx.fragment.app.FragmentStateManager.createView(FragmentStateManager.java:518)
at androidx.fragment.app.FragmentStateManager.moveToExpectedState(FragmentStateManager.java:282)
at androidx.fragment.app.FragmentManager.executeOpsTogether(FragmentManager.java:2189)
at androidx.fragment.app.FragmentManager.removeRedundantOperationsAndExecute(FragmentManager.java:2100)
at androidx.fragment.app.FragmentManager.execPendingActions(FragmentManager.java:2002)
at androidx.fragment.app.FragmentManager$5.run(FragmentManager.java:524)
at android.os.Handler.handleCallback(Handler.java:938)
at android.os.Handler.dispatchMessage(Handler.java:99)
at android.os.Looper.loopOnce(Looper.java:201)
at android.os.Looper.loop(Looper.java:288)
at android.app.ActivityThread.main(ActivityThread.java:7842)
at java.lang.reflect.Method.invoke(Native Method)
at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:548)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:1003)
I believe there is no error in the calendar code and is something to do with onCreateView
in the fragment code.
2
Answers
You cannot call
requireView()
before returning a non-null value fromonCreateView()
.Move these lines
(where
initWidgets()
callsrequireView()
) fromonCreateView()
to e.g.onViewCreated()
.So to avoid that, you need to override onViewCreated method or you must return view. Remember, if you want to return view then all codes or public methods must be reached before the return view statement. Else, it’ll crash due to exception
Check this codes, it’ll fix it correctly