I'm stuck at this point:
I have a RecyclerView with a list of CardViews.
When a button is pressed, the addItem(); method is called, which obviously adds an item.
Here's how:
String text = hwtext.getText().toString();
mList.add(new HomeWork_Item(the.image.I.want, text));
mAdapter.notifyItemInserted(mList.size());
Which works, great!
Now, I have added a Spinner. The spinner contains a few Subjects. If, let's say, the subject history is selected, I'd like to change the.image.I.want from the addItem(); method to another one in the drawable.
I tried using glide but this didn't work:
public void onItemSelected(AdapterView<?> parent, View view, int position, long id) {
String SpinnerText = parent.getItemAtPosition(position).toString();
Toast.makeText(getContext(), SpinnerText, Toast.LENGTH_SHORT).show();
if (SpinnerText.equals("History")) {
Glide.with(getActivity()).load(R.drawable.history).into(R.id.theImageView);
}
}
Notice: The Item would be added only when a button is pressed which calls the method to add it. After selecting a Subject it should just prepare the Image to use when the Item will be added.
Thanks!
Crash Logcat:
2019-03-08 14:59:10.328 9808-9808/com.reogen.ssr E/AndroidRuntime: FATAL EXCEPTION: main
Process: com.reogen.ssr, PID: 9808
java.lang.NullPointerException: Argument must not be null
at com.bumptech.glide.util.Preconditions.checkNotNull(Preconditions.java:31)
at com.bumptech.glide.util.Preconditions.checkNotNull(Preconditions.java:25)
at com.bumptech.glide.RequestBuilder.into(RequestBuilder.java:685)
at com.reogen.ssr.Fragments.Homework.onItemSelected(Homework.java:170)
at android.widget.AdapterView.fireOnSelected(AdapterView.java:1331)
at android.widget.AdapterView.dispatchOnItemSelected(AdapterView.java:1320)
at android.widget.AdapterView.-wrap1(Unknown Source:0)
at android.widget.AdapterView$SelectionNotifier.run(AdapterView.java:1282)
at android.os.Handler.handleCallback(Handler.java:789)
at android.os.Handler.dispatchMessage(Handler.java:98)
at android.os.Looper.loop(Looper.java:164)
at android.app.ActivityThread.main(ActivityThread.java:6938)
at java.lang.reflect.Method.invoke(Native Method)
at com.android.internal.os.Zygote$MethodAndArgsCaller.run(Zygote.java:327)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:1374)
Create an ImageView as
ImageView historyImage = findViewById(R.id.historyImage);
Then in your glide you do this :
Glide.with(view.getContext()).load(R.drawable.history).into(historyImage);
You are passing an int into the into and you should pass the ImageView directly.
Edit
Change your code to this one
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
View rootView = inflater.inflate(R.layout.fragment_homework, container, false);
insert = rootView.findViewById(R.id.insert_text);
hwtext = rootView.findViewById(R.id.hwinput);
SubjectImage = rootView.findViewById(id.HWImage);
spinner = rootView.findViewById(R.id.spinner);
buildView(rootView);
return rootView;
}
public void buildView(View rootView) {
mRecyclerView = rootView.findViewById(R.id.RecycleHW);
mRecyclerView.setHasFixedSize(true);
mManager = new LinearLayoutManager(getActivity());
mAdapter = new HomeWorkAdapter(mList);
mRecyclerView.setLayoutManager(mManager);
mRecyclerView.setAdapter(mAdapter);
}
Related
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.
You cannot call requireView() before returning a non-null value from onCreateView().
Move these lines
initWidgets();
selectedDate = LocalDate.now();
setMonthView();
(where initWidgets() calls requireView()) from onCreateView() to e.g. onViewCreated().
Yes it crashes because findViewById wasn't called from the fragment_calendar layout before returning inflater therefore anything called after the return statement will not be executed and will return a NullPointerException. Unless you override onViewCreated method and put down the codes
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
public class TestFragment extends Fragment {
RecyclerView calendarRecyclerView;
TextView monthYearText;
#Nullable
#org.jetbrains.annotations.Nullable
#Override
public View onCreateView(#NonNull LayoutInflater inflater, #Nullable #org.jetbrains.annotations.Nullable ViewGroup container, #Nullable #org.jetbrains.annotations.Nullable Bundle savedInstanceState) {
selectedDate = LocalDate.now();
return inflater.inflate(R.layout.fragment_calendar, container, false);
}
#Override
public void onViewCreated(#NonNull View view, #Nullable #org.jetbrains.annotations.Nullable Bundle savedInstanceState) {
super.onViewCreated(view, savedInstanceState);
initWidgets(view);
setMonthView();
}
private void initWidgets(View view) {
calendarRecyclerView = view.findViewById(R.id.calendarRecyclerView);
monthYearText = view.findViewById(R.id.monthYearTV);
}
private void setMonthView() {
monthYearText.setText(monthYearFromDate(selectedDate));
ArrayList<String> daysInMonth = daysInMonthArray(selectedDate);
CalendarAdapter calendarAdapter = new CalendarAdapter(daysInMonth, getActivity());
RecyclerView.LayoutManager layoutManager = new GridLayoutManager(getActivity(), 7);
calendarRecyclerView.setLayoutManager(layoutManager);
calendarAdapter.setAdapter(calendarAdapter);
}
}
I am making an android app based on firebase Realtime database. I am reading the data in a RecyclerView. There are three items in my RecyclerView.
Text view = Name
Text view = Number
Button = Delete
When I delete some child from my RecyclerView three things can happen:
Sometimes it deletes the targeted child normally
Sometimes it deletes some other child (often which is below the targeted child.)
Sometimes my app crashes.
This is the code for my adapter:
public class holder extends RecyclerView.ViewHolder {
public Button btnDelete;
public TextView tvName;
public TextView tvRoll;
public holder(#NonNull View itemView) {
super(itemView);
btnDelete=(Button) itemView.findViewById(R.id.idDelete);
tvName=(TextView) itemView.findViewById(R.id.idName);
tvRoll=(TextView) itemView.findViewById(R.id.idRoll);
}
}
This is the code to show items in recycler view and code for delete button:
options = new FirebaseRecyclerOptions.Builder<basic>()
.setQuery(myRef, basic.class)
.build();
adapter = new FirebaseRecyclerAdapter<basic, holder>(options) {
#SuppressLint("SetTextI18n")
#Override
protected void onBindViewHolder(#NonNull holder holder, final int i, #NonNull final basic basic) {
holder.tvName.setText(basic.getFb01name());
holder.tvRoll.setText(basic.getFb04roll());
holder.btnDelete.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
myRef.child(getRef(i).getKey()).removeValue();
}
});
}
#NonNull
#Override
public holder onCreateViewHolder(#NonNull ViewGroup parent, int viewType) {
View v = LayoutInflater.from(parent.getContext()).inflate(R.layout.items, parent, false);
return new holder(v);
}
};
//------------------------------
adapter.startListening();
Userlist.setAdapter(adapter);
//-----------------------------------
I cannot guess where is the problem.
Please also provide a practical solution.
This is the crash report:
2020-11-30 23:27:45.968 10796-10796/com.my App Name E/AndroidRuntime: FATAL EXCEPTION: main
Process: com.my App Name, PID: 10796
java.lang.IndexOutOfBoundsException: Index: 4, Size: 4
at java.util.ArrayList.get(ArrayList.java:437)
at com.firebase.ui.common.BaseObservableSnapshotArray.getSnapshot(BaseObservableSnapshotArray.java:70)
at com.firebase.ui.database.FirebaseRecyclerAdapter.getRef(FirebaseRecyclerAdapter.java:112)
at com.my App Name.ViewActivity$1$1.onClick(ViewActivity.java:72)
at android.view.View.performClick(View.java:7448)
at android.view.View.performClickInternal(View.java:7425)
at android.view.View.access$3600(View.java:810)
at android.view.View$PerformClick.run(View.java:28305)
at android.os.Handler.handleCallback(Handler.java:938)
at android.os.Handler.dispatchMessage(Handler.java:99)
at android.os.Looper.loop(Looper.java:223)
at android.app.ActivityThread.main(ActivityThread.java:7656)
at java.lang.reflect.Method.invoke(Native Method)
at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:592)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:947)
2020-11-30 23:27:46.701 1467-10685/com.google.android.googlequicksearchbox E/sb.v.u.LiteSuggestSourc: On-device lite suggest model loading error.
2020-11-30 23:27:46.818 1467-1774/com.google.android.googlequicksearchbox E/MDD: DownloadProgressMonitor: Can't find file group for uri: android://com.google.android.googlequicksearchbox/files/sharedminusonemodule/shared/SharedMinusOneData.pb.tmp
It seems that when you access Firebase getRef(i) within the button onClick callback, it can reference a wrong position i causing IndexOutOfBoundsException
So, we'll get the key outside of the callback as below:
options = new FirebaseRecyclerOptions.Builder<basic>()
.setQuery(myRef, basic.class)
.build();
adapter = new FirebaseRecyclerAdapter<basic, holder>(options) {
#SuppressLint("SetTextI18n")
#Override
protected void onBindViewHolder(#NonNull holder holder, final int i, #NonNull final basic basic) {
holder.tvName.setText(basic.getFb01name());
holder.tvRoll.setText(basic.getFb04roll());
String refKey = getRef(i).getKey(); // <<<<<< Here is the change
holder.btnDelete.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
myRef.child(refKey)).removeValue();
}
});
}
#NonNull
#Override
public holder onCreateViewHolder(#NonNull ViewGroup parent, int viewType) {
View v = LayoutInflater.from(parent.getContext()).inflate(R.layout.items, parent, false);
return new holder(v);
}
};
What I'm using:
MVP
Navigation Component
Single Activity
Fragments
RecyclerView
Realm
Problem:
I have a MainActivity that hosts all the fragments for the application flow.
There's one fragment that has a recyclerview, the more I scroll the more API requests are made. Whenever I press one item to navigate to a different fragment and press back to return to the list, the list only has a small piece of the previous loaded recyclerview, I want everything.
Is it possible to do this with the navigation component?
Can I prevent onCreateView being called whenever I press back?
I've tried to save the View in a static variable, have a onSaveInstance (but it never gets called)
I'm using navigation this way:
#Override
public void onClick(View view) {
Navigation.findNavController(view)
.navigate(R.id.action_tripsFragment_to_tripDetailsFragment, bundle);
}
MainFragment:
#Nullable
#Override
public View onCreateView(#NonNull LayoutInflater inflater,
#Nullable ViewGroup container,
#Nullable Bundle savedInstanceState) {
View v = inflater.inflate(R.layout.trips_fragment, container, false);
mPresenter = new TripsFragmentPresenterImpl(this);
ButterKnife.bind(this, v);
navController = Navigation.findNavController(getActivity(), R.id.nav_host_fragment);
mLinearLayoutManager = new LinearLayoutManager(getContext(), RecyclerView.VERTICAL, false);
mAdapter = new PaginationAdapter(getContext());
mAdapter.setOnItemClickListener(onItemClickListener);
mPresenter.setLoadingTripsProgressBar(true);
mRecyclerView.setLayoutManager(mLinearLayoutManager);
mRecyclerView.setItemAnimator(new DefaultItemAnimator());
mRecyclerView.setAdapter(mAdapter);
mRecyclerView.addOnScrollListener(new PaginationScrollListener(mLinearLayoutManager) {
#Override
protected void loadMoreItems() {
isLoading = true;
currentPage += 1;
loadNextPage();
}
#Override
public int getTotalPageCount() {
return currentPage;
}
#Override
public boolean isLoading() {
return isLoading;
}
});
loadFirstPage();
return v;
}
What I expect:
Whenever I press back from TripDetails to Trips I want to get my recyclerview as it was, with the previous loaded items at the correct position.
Current results:
Whenever I press back from TripDetails to Trips the recyclerview cuts the items to only the items that are visible, meaning that we'll lose items previous loaded in previous pages.
For future reference I've managed to solve the issue by creating a ModelView to keep the data independent of the lifecycle of the fragment
i'm having a hard time with some code. I am using sliding tabs with 2 fragment. Inside one of my fragment i'm trying to get a LinearLayout and add some stuff in it but everytime i try to do getView().findViewByID() I got null object reference
I'm calling the function after the onCreateView() I tried making a variable of type View and putting the View that i inflate in the onCreateView in it but i keeps getting the same error. I also tried putting a if() before to check if view isnt null , but even with this , I get null object reference. Can someone help me ?
public class listAlarmFragment extends Fragment{
public View view = null;
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup vg, Bundle bundle){
View v = inflater.inflate(R.layout.list_alarm,vg,false);
view = v;
return v;
}
public void showAlarm(Cursor c){
if(view != null) { //even with that check, I got a null pointer exception
LinearLayout baseList = (LinearLayout) view.findViewById(R.id.baseList); // NullPointerException: Attempt to invoke virtual method on a null object reference
}
}
}
Replacing view with getView() doesnt change anything.
This is how I'm calling the function from the Main Activity
pager.addOnPageChangeListener(new ViewPager.OnPageChangeListener() {
#Override
public void onPageScrolled(int position, float positionOffset, int positionOffsetPixels) {
}
#Override
public void onPageSelected(int position) {
Fragment c = adapter.getItem(0);
((listAlarmFragment)(c)).showAlarm(dbHelper.getAlarm()); // where I call the function
}
#Override
public void onPageScrollStateChanged(int state) {
}
});
I'm opening this fragment at the beggining when my app open. It crashs when im trying to switch to another fragment.
here is the stack trace :
04-02 18:41:54.615 31584-31584/al.demo.alarmmanagerdemo E/AndroidRuntime: FATAL EXCEPTION: main
Process: al.demo.alarmmanagerdemo, PID: 31584
java.lang.NullPointerException: Attempt to invoke virtual method 'android.view.View android.view.View.findViewById(int)' on a null object reference
at al.demo.alarmmanagerdemo.fragment.listAlarmFragment.showAlarm(listAlarmFragment.java:83)
at al.demo.alarmmanagerdemo.MainActivity$1.onPageSelected(MainActivity.java:54)
at android.support.v4.view.ViewPager.dispatchOnPageSelected(ViewPager.java:1971)
at android.support.v4.view.ViewPager.scrollToItem(ViewPager.java:689)
at android.support.v4.view.ViewPager.setCurrentItemInternal(ViewPager.java:673)
at android.support.v4.view.ViewPager.onTouchEvent(ViewPager.java:2288)
at android.view.View.dispatchTouchEvent(View.java:10779)
at android.view.ViewGroup.dispatchTransformedTouchEvent(ViewGroup.java:2858)
at android.view.ViewGroup.dispatchTouchEvent(ViewGroup.java:2534)
at android.view.ViewGroup.dispatchTransformedTouchEvent(ViewGroup.java:2864)
at android.view.ViewGroup.dispatchTouchEvent(ViewGroup.java:2549)
at android.view.ViewGroup.dispatchTransformedTouchEvent(ViewGroup.java:2864)
at android.view.ViewGroup.dispatchTouchEvent(ViewGroup.java:2549)
at android.view.ViewGroup.dispatchTransformedTouchEvent(ViewGroup.java:2864)
at android.view.ViewGroup.dispatchTouchEvent(ViewGroup.java:2549)
at android.view.ViewGroup.dispatchTransformedTouchEvent(ViewGroup.java:2864)
at android.view.ViewGroup.dispatchTouchEvent(ViewGroup.java:2549)
at android.view.ViewGroup.dispatchTransformedTouchEvent(ViewGroup.java:2864)
at android.view.ViewGroup.dispatchTouchEvent(ViewGroup.java:2549)
at android.view.ViewGroup.dispatchTransformedTouchEvent(ViewGroup.java:2864)
at android.view.ViewGroup.dispatchTouchEvent(ViewGroup.java:2549)
at com.android.internal.policy.DecorView.superDispatchTouchEvent(DecorView.java:605)
at com.android.internal.policy.PhoneWindow.superDispatchTouchEvent(PhoneWindow.java:1895)
at android.app.Activity.dispatchTouchEvent(Activity.java:3241)
at android.support.v7.view.WindowCallbackWrapper.dispatchTouchEvent(WindowCallbackWrapper.java:67)
at android.support.v7.view.WindowCallbackWrapper.dispatchTouchEvent(WindowCallbackWrapper.java:67)
at com.android.internal.policy.DecorView.dispatchTouchEvent(DecorView.java:567)
at android.view.View.dispatchPointerEvent(View.java:11008)
at android.view.ViewRootImpl$ViewPostImeInputStage.processPointerEvent(ViewRootImpl.java:5155)
at android.view.ViewRootImpl$ViewPostImeInputStage.onProcess(ViewRootImpl.java:5007)
at android.view.ViewRootImpl$InputStage.deliver(ViewRootImpl.java:4532)
at android.view.ViewRootImpl$InputStage.onDeliverToNext(ViewRootImpl.java:4585)
at android.view.ViewRootImpl$InputStage.forward(ViewRootImpl.java:4551)
at android.view.ViewRootImpl$AsyncInputStage.forward(ViewRootImpl.java:4684)
at android.view.ViewRootImpl$InputStage.apply(ViewRootImpl.java:4559)
at android.view.ViewRootImpl$AsyncInputStage.apply(ViewRootImpl.java:4741)
at android.view.ViewRootImpl$InputStage.deliver(ViewRootImpl.java:4532)
at android.view.ViewRootImpl$InputStage.onDeliverToNext(ViewRootImpl.java:4585)
at android.view.ViewRootImpl$InputStage.forward(ViewRootImpl.java:4551)
at android.view.ViewRootImpl$InputStage.apply(ViewRootImpl.java:4559)
at android.view.ViewRootImpl$InputStage.deliver(ViewRootImpl.java:4532)
at android.view.ViewRootImpl.deliverInputEvent(ViewRootImpl.java:7092)
at android.view.ViewRootImpl.doProcessInputEvents(ViewRootImpl.java:7024)
at android.view.ViewRootImpl.enqueueInputEvent(ViewRootImpl.java:6985)
at android.view.ViewRootImpl$WindowInputEventReceiver.onInputEvent(ViewRootImpl.java:7202)
at android.view.InputEventReceiver.dispatchInputEvent(InputEventReceiver.java:185)
at android.os.MessageQueue.nativePollOnce(Native Method)
at android.os.MessageQueue.next(MessageQueue.java:323)
at android.os.Looper.loop(Looper.java:136)
at android.app.ActivityThread.main(ActivityThread.java:6776)
04-02 18:41:54.615 31584-31584/al.demo.alarmmanagerdemo E/AndroidRuntime: at java.lang.reflect.Method.invoke(Native Method)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1510)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:1400)
I would do something like this,
public class listAlarmFragment extends Fragment{
//public View view = null; // no need
private LinearLayout baseList;
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup vg, Bundle bundle){
View v = inflater.inflate(R.layout.list_alarm,vg,false);
baseList = (LinearLayout) v.findViewById(R.id.baseList);
//view = v; no need
return v;
}
public void showAlarm(Cursor c){
if(baseList!=null){
//do something with your baseList
}
}
}
Also check R.id.baseList exists in the layout xml R.layout.list_alarm.
and it should be LinearLayout with
id=#+id/baseList
I have a bunch of fragments in a FragmentPagerAdapter with one ImageView in side each fragment. If I swipe really fast this error comes up:
E/AndroidRuntime: FATAL EXCEPTION: main
Process: com.wilsapp.wilsapp, PID: 21319
java.lang.NullPointerException: Attempt to invoke virtual method 'android.view.View android.view.View.findViewById(int)' on a null object reference
at com.wilsapp.wilsapp.Fragments.BuyerHomePageFragment9$DownloadImageTask.onPostExecute(BuyerHomePageFragment9.java:212)
at com.wilsapp.wilsapp.Fragments.BuyerHomePageFragment9$DownloadImageTask.onPostExecute(BuyerHomePageFragment9.java:192)
at android.os.AsyncTask.finish(AsyncTask.java:651)
at android.os.AsyncTask.-wrap1(AsyncTask.java)
at android.os.AsyncTask$InternalHandler.handleMessage(AsyncTask.java:668)
at android.os.Handler.dispatchMessage(Handler.java:102)
at android.os.Looper.loop(Looper.java:148)
at android.app.ActivityThread.main(ActivityThread.java:5417)
at java.lang.reflect.Method.invoke(Native Method)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:726)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:616)
If I swipe slowly then it works perfectly fine.
Android Code (code is the same for each fragment. Code in AsyncTask):
protected void onPostExecute(Bitmap result) {
try {
ImageView img = (ImageView) getView().findViewById(R.id.ProductOneImageView);
img.setImageBitmap(result);
}catch (Exception e){
ImageView img = (ImageView) getView().findViewById(R.id.ProductOneImageView);
int id = getResources().getIdentifier("com.wilsapp.wilsapp:drawable/" + "error", null, null);
img.setImageResource(id);
}
}
Android onCreatView method:
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
View view = inflater.inflate(R.layout.fragment_buyer_home_page, container, false);
return view;
}
how can i avoid the NullPointerException?
ImageView img = (ImageView) getView().findViewById(R.id.ProductFiveImageView);
ImageView need initialize in onCreateView. A case of you getView() return null...
Add your initialization snippet in onViewCreated method instead of onCreateView. it will ensure that imageview will be initialize after your view is inflated.
#Override
public void onViewCreated(final View view, #Nullable Bundle savedInstanceState) {
ImageView img = (ImageView) view.findViewById(R.id.ProductFiveImageView);
img.setImageBitmap(result);
}
ImageView img = (ImageView) getView().findViewById(R.id.ProductFiveImageView);
hi You can add a judgment,getView Whether to null， and Fault tolerant processing!