notifyDataSetChange not working from custom adapter

Question

When I repopulate my ListView  I call a specific method from my Adapter   Problem   When I call updateReceiptsList from my Adapter  the data is refreshed  but my ListView doesn t reflect the change    Question   Why doesn t my ListView show the new data when I call notifyDataSetChanged   Adapter   public class ReceiptListAdapter extends BaseAdapter        public List lt Receipt gt  receiptlist      private Context context      private LayoutInflater inflater      private DateHelpers dateH       public ReceiptListAdapter Activity activity  Context mcontext  List lt Receipt gt  rl            context   mcontext          receiptlist   rl          Collections reverse receiptlist           inflater    LayoutInflater activity getSystemService Context LAYOUT INFLATER SERVICE           dateH   new DateHelpers                Override     public int getCount             try               int size   receiptlist size                return size            catch NullPointerException ex                return 0                       public void updateReceiptsList List lt Receipt gt  newlist            receiptlist   newlist          this notifyDataSetChanged                Override     public Receipt getItem int i            return receiptlist get i               Override     public long getItemId int i            return receiptlist get i  getReceiptId                private String getPuntenString Receipt r            if r getPoints   equals  1                  return  1 punt                     return r getPoints     punten               Override     public View getView int position  View convertView  ViewGroup parent            View vi convertView           final Receipt receipt   receiptlist get position           ReceiptViewHolder receiptviewholder          Typeface tf hn   Typeface createFromAsset context getAssets     helveticaneue ttf                    Typeface tf hn bold   Typeface createFromAsset context getAssets     helveticaneuebd ttf             if  vi    null      convertview  null             receiptviewholder   new ReceiptViewHolder                vi   inflater inflate R layout view listitem receipt  null               vi setOnClickListener null               vi setOnLongClickListener null               vi setLongClickable false               receiptviewholder shop    TextView  vi findViewById R id tv listitemreceipt shop               receiptviewholder date    TextView  vi findViewById R id tv listitemreceipt date               receiptviewholder price    TextView  vi findViewById R id tv listitemreceipt price               receiptviewholder points    TextView  vi findViewById R id tv listitemreceipt points               receiptviewholder shop setTypeface tf hn bold               receiptviewholder price setTypeface tf hn bold               vi setTag receiptviewholder            else   convertview is not null             receiptviewholder    ReceiptViewHolder vi getTag                       receiptviewholder shop setText receipt getShop             receiptviewholder date setText dateH timestampToDateString Long parseLong receipt getPurchaseDate               receiptviewholder price setText        receipt getPrice             receiptviewholder points setText getPuntenString receipt             vi setClickable false           return vi             public static class ReceiptViewHolder           public TextView shop          public TextView date          public TextView price          public TextView points             public Object getFilter                XXX Auto-generated method stub         return null             --EDIT   found Workaround  Just to have some functional code i do now   listview setAdapter  new ReceiptListAdapter activity mcontext  -new dataset-     Works  but not how it is supposed to work

User · Answer

As I have already explained the reasons behind this issue and also how to handle it in a different answer thread Here. Still i am sharing the solution summary here.

One of the main reasons notifyDataSetChanged() won't work for you - is,

Your adapter loses reference to your list.

When creating and adding a new list to the Adapter. Always follow these guidelines:

Initialise the arrayList while declaring it globally.
Add the List to the adapter directly with out checking for null and empty values . Set the adapter to the list directly (don't check for any condition). Adapter guarantees you that wherever you make changes to the data of the arrayList it will take care of it, but never loose the reference.
Always modify the data in the arrayList itself (if your data is completely new than you can call adapter.clear() and arrayList.clear() before actually adding data to the list) but don't set the adapter i.e If the new data is populated in the arrayList than just adapter.notifyDataSetChanged()

Hope this helps.

User · Answer

class StudentAdapter extends BaseAdapter       ArrayList lt LichHocDTO gt  studentList       private void capNhatDuLieu ArrayList lt LichHocDTO gt  list           this studentList clear            this studentList addAll list           this notifyDataSetChanged              You can try  It work for me

User · Answer

My case was different but it might be the same case for others  for those who still couldn t find a solution and tried everything above  if you re using the adapter inside fragment then the reason it s not working fragment could be recreating so the adapter is recreating everytime the fragment recreate   you should verify if the adapter and objects list are null before initializing   x000D   x000D  if adapter    null   x000D    adapter   new CustomListAdapter       x000D    x000D      x000D   x000D  if objects    null   x000D    objects   new ArrayList lt  gt     x000D    x000D   x000D   x000D

User · Answer

I have the same problem but I just finished it    you should change to  public class ReceiptListAdapter extends BaseAdapter        public List lt Receipt gt  receiptlist      private Context context      private LayoutInflater inflater      private DateHelpers dateH      private List lt ReceiptViewHolder gt  receiptviewlist       public ReceiptListAdapter Activity activity  Context mcontext  List lt Receipt gt  rl            context   mcontext          receiptlist   rl          receiptviewlist   new ArrayList lt  gt             receiptviewlist clear            for int i   0  i  lt  receiptlist size    i               ReceiptViewHolder receiptviewholder   new ReceiptViewHolder              receiptviewlist add receiptviewholder                     Collections reverse receiptlist           inflater    LayoutInflater activity getSystemService Context LAYOUT INFLATER SERVICE           dateH   new DateHelpers                Override     public int getCount             try               int size   receiptlist size                return size            catch NullPointerException ex                return 0                       public void updateReceiptsList List lt Receipt gt  newlist            receiptlist   newlist          this notifyDataSetChanged                Override     public Receipt getItem int i            return receiptlist get i               Override     public long getItemId int i            return receiptlist get i  getReceiptId                private String getPuntenString Receipt r            if r getPoints   equals  1                  return  1 punt                     return r getPoints     punten               Override     public View getView int position  View convertView  ViewGroup parent            View vi convertView           final Receipt receipt   receiptlist get position           ReceiptViewHolder receiptviewholder          Typeface tf hn   Typeface createFromAsset context getAssets     helveticaneue ttf                    Typeface tf hn bold   Typeface createFromAsset context getAssets     helveticaneuebd ttf             if  vi    null      convertview  null             ReceiptViewHolder receiptviewholder   receiptviewlist get position               vi   inflater inflate R layout view listitem receipt  null               vi setOnClickListener null               vi setOnLongClickListener null               vi setLongClickable false               receiptviewholder shop    TextView  vi findViewById R id tv listitemreceipt shop               receiptviewholder date    TextView  vi findViewById R id tv listitemreceipt date               receiptviewholder price    TextView  vi findViewById R id tv listitemreceipt price               receiptviewholder points    TextView  vi findViewById R id tv listitemreceipt points               receiptviewholder shop setTypeface tf hn bold               receiptviewholder price setTypeface tf hn bold               vi setTag receiptviewholder            else   convertview is not null             receiptviewholder    ReceiptViewHolder vi getTag                       receiptviewholder shop setText receipt getShop             receiptviewholder date setText dateH timestampToDateString Long parseLong receipt getPurchaseDate               receiptviewholder price setText        receipt getPrice             receiptviewholder points setText getPuntenString receipt             vi setClickable false           return vi             public static class ReceiptViewHolder           public TextView shop          public TextView date          public TextView price          public TextView points             public Object getFilter                XXX Auto-generated method stub         return null

User · Answer

Maybe try to refresh your ListView   receiptsListView invalidate     EDIT  Another thought came into my mind  Just for the record  try to disable list view cache    lt ListView             android scrollingCache  false      android cacheColorHint   android color transparent            gt

User · Answer

Add this code  runOnUiThread new Runnable     public void run                    adapter   new CustomAdapter anotherdata               adapter notifyDataSetChanged

User · Answer

I had the same problem using ListAdapter  I let Android Studio implement methods for me and this is what I got   public class CustomAdapter implements ListAdapter                Override     public void registerDataSetObserver DataSetObserver observer                 Override     public void unregisterDataSetObserver DataSetObserver observer                       The problem is that these methods do not call super implementations so notifyDataSetChange is never called   Either remove these overrides manually or add super calls and it should work again    Override public void registerDataSetObserver DataSetObserver observer        super registerDataSetObserver observer       Override public void unregisterDataSetObserver DataSetObserver observer        super unregisterDataSetObserver observer

User · Answer

Change your method from   public void updateReceiptsList List lt Receipt gt  newlist        receiptlist   newlist      this notifyDataSetChanged        To  public void updateReceiptsList List lt Receipt gt  newlist        receiptlist clear        receiptlist addAll newlist       this notifyDataSetChanged        So you keep the same object as your DataSet in your Adapter

User · Answer

If adapter is set to AutoCompleteTextView then notifyDataSetChanged   doesn t work      Need this to update adapter   myAutoCompleteAdapter   new ArrayAdapter lt String gt  MainActivity this           android R layout simple dropdown item 1line  myList    myAutoComplete setAdapter myAutoCompleteAdapter     Refer  http   android-er blogspot in 2012 10 autocompletetextview-with-dynamic html

User · Answer

In my case I simply forget to add in my fragment mRecyclerView setAdapter adapter

User · Answer

If by any chance you landed on this thread and wondering why adapter invaidate   or adapter clear   methods are not present in your case then maybe because you might be using RecyclerView Adapter instead of BaseAdapter which is used by the asker of this question  If clearing the list or arraylist not resolving your problem then it may happen that you are making two or more instances of the adapter for ex      MainActivity       adapter   new CustomAdapter list   adapter notifyDataSetChanged    recyclerView setAdapter adapter          and SomeFragment       adapter   new CustomAdapter newList   adapter notifyDataSetChanged           If in the second case you are expecting a change in the list of inflated views in recycler view then it is not gonna happen as in the second time a new instance of the adapter is created which is not attached to the recycler view  Setting notifyDataSetChanged in the second adapter is not gonna change the content of recycer view  For that make a new instance of the recycler view in SomeFragment and attach it to the new instance of the adapter   SomeFragment       recyclerView   new RecyclerView    adapter   new CustomAdapter    recyclerView setAdapter adapter          Although  I don t recommend making multiple instances of the same adapter and recycler view

User · Answer

I have the same problem  and i realize that  When we create adapter and set it to listview  listview will point to object somewhere in memory which adapter hold  data in this object will show in listview   adapter   new CustomAdapter data   listview setadapter adapter     if we create an object for adapter with another data again and notifydatasetchanged     adapter   new CustomAdapter anotherdata   adapter notifyDataSetChanged      this will do not affect to data in listview because the list is pointing to different object  this object does not know anything about new object in adapter  and notifyDataSetChanged   affect nothing  So we should change data in object and avoid to create a new object again for adapter

[android] notifyDataSetChange not working from custom adapter

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