Android RecyclerView addition removal of items

Question

I have a RecyclerView with an TextView text box and a cross button ImageView  I have a button outside of the recyclerview that makes the cross button ImageView visible   gone   I m looking to remove an item from the recylerview  when that items cross button ImageView is pressed   My adapter   public class MyAdapter extends RecyclerView Adapter lt MyAdapter ViewHolder gt  implements View OnClickListener  View OnLongClickListener        private ArrayList lt String gt  mDataset      private static Context sContext       public MyAdapter Context context  ArrayList lt String gt  myDataset            mDataset   myDataset          sContext   context              Override     public MyAdapter ViewHolder onCreateViewHolder ViewGroup parent int viewType            View v   LayoutInflater from parent getContext    inflate R layout my text view  parent  false            ViewHolder holder   new ViewHolder v           holder mNameTextView setOnClickListener MyAdapter this           holder mNameTextView setOnLongClickListener MyAdapter this            holder mNameTextView setTag holder            return holder              Override     public void onBindViewHolder ViewHolder holder  int position             holder mNameTextView setText mDataset get position                 Override     public int getItemCount             return mDataset size                 Override     public void onClick View view            ViewHolder holder    ViewHolder  view getTag            if  view getId      holder mNameTextView getId                  Toast makeText sContext  holder mNameTextView getText    Toast LENGTH SHORT  show                           Override     public boolean onLongClick View view            ViewHolder holder    ViewHolder  view getTag            if  view getId      holder mNameTextView getId                  mDataset remove holder getPosition                  notifyDataSetChanged                 Toast makeText sContext   Item     holder mNameTextView getText       has been removed from list                       Toast LENGTH SHORT  show                      return false             public static class ViewHolder extends RecyclerView ViewHolder           public TextView mNumberRowTextView          public TextView mNameTextView            public ViewHolder View v                super v                mNameTextView    TextView  v findViewById R id nameTextView                       My layout is    lt  xml version  1 0  encoding  utf-8   gt   lt LinearLayout xmlns android  http   schemas android com apk res android      android layout width  match parent      android layout height  wrap content      android orientation  horizontal      android gravity  center vertical      android id    id layout  gt        lt TextView         android id    id nameTextView          android layout width  wrap content          android layout height  wrap content          android textSize  18sp          android padding  5dp          android background   drawable greyline   gt        lt ImageView         android id    id crossButton          android layout width  16dp          android layout height  16dp          android visibility  gone          android layout marginLeft  50dp          android src   drawable cross    gt   lt  LinearLayout gt    How can I get something like an onClick working for my crossButton ImageView  Is there a better way  Maybe changing the whole item onclick into a remove the item  The recyclerview shows a list of locations that need to be edited  Any technical advice or comments   suggestions on best implementation would be hugely appreciated

User · Answer

public class MyAdapter extends RecyclerView Adapter lt MyAdapter MyViewHolder gt    private Context context  private List lt cardview widgets gt  list   public MyAdapter Context context  List lt cardview widgets gt  list        this context   context      this list   list      NonNull  Override public MyViewHolder onCreateViewHolder  NonNull ViewGroup viewGroup  int i        View view   LayoutInflater from this context  inflate R layout fragment1 one item              viewGroup  false       return new MyViewHolder view      public static class MyViewHolder extends RecyclerView ViewHolder       TextView txtValue      TextView txtCategory      ImageView imgInorEx      ImageView imgCategory      TextView txtDate       public MyViewHolder  NonNull View itemView            super itemView           txtValue  itemView findViewById R id id values           txtCategory  itemView findViewById R id id category           imgInorEx  itemView findViewById R id id inorex           imgCategory  itemView findViewById R id id imgcategory           txtDate  itemView findViewById R id id date             NonNull  Override public void onBindViewHolder  NonNull final MyViewHolder myViewHolder  int i         myViewHolder txtValue setText String valueOf list get i  getValuee          myViewHolder txtCategory setText list get i  getCategory         myViewHolder imgInorEx setBackgroundColor list get i  getImg inorex         myViewHolder imgCategory setImageResource list get i  getImg category         myViewHolder txtDate setText list get i  getDate         myViewHolder itemView setOnLongClickListener new View OnLongClickListener              Override         public boolean onLongClick View v                list remove myViewHolder getAdapterPosition                 notifyDataSetChanged                return false                        Override public int getItemCount         return list size              i hope this help you

User · Answer

To Method onBindViewHolder Write This Code  holder remove setOnClickListener new View OnClickListener                  Override             public void onClick View view                    Cursor del dbAdapter ExecuteQ  delete from TblItem where Id   values get position  getId                     values remove position                   notifyDataSetChanged

User · Answer

Possibly a duplicate answer but quite useful for me  You can implement the method given below in RecyclerView Adapter lt RecyclerView ViewHolder gt   and can use this method as per your requirements  I hope it will work for you  public void removeItem  NonNull Object object            mDataSetList remove object           notifyDataSetChanged

User · Answer

Here are some visual supplemental examples  See my fuller answer for examples of adding and removing a range   Add single item  Add  Pig  at index 2     String item    Pig   int insertIndex   2  data add insertIndex  item   adapter notifyItemInserted insertIndex     Remove single item  Remove  Pig  from the list     int removeIndex   2  data remove removeIndex   adapter notifyItemRemoved removeIndex

User · Answer

String str   arrayList get position     arrayList remove str     MyAdapter this notifyDataSetChanged

User · Answer

set the position  holder cancel setTag position           click to remove an item from recycler view and an array list holder cancel setOnClickListener new View OnClickListener                Override           public void onClick View view                 int positionToRemove    int view getTag      get the position of the view to delete stored in the tag             mDataset remove positionToRemove               notifyDataSetChanged

User · Answer

Incase Anyone wants to implement something like this  in Main class instead of Adapter class  you can use   public void removeAt int position        peopleListUser remove position        friendsListRecycler getAdapter   notifyItemRemoved position       friendsListRecycler getAdapter   notifyItemRangeChanged position  peopleListUser size         where friendsListRecycler is the Adapter name

User · Answer

make interface into custom adapter class and handling click event on recycler view     onItemClickListner onItemClickListner   public void setOnItemClickListner CommentsAdapter onItemClickListner onItemClickListner        this onItemClickListner   onItemClickListner     public interface onItemClickListner       void onClick Contact contact    pass your object types         Override public void onBindViewHolder ItemViewHolder holder  int position           below code handle click event on recycler view item      holder itemView setOnClickListener new View OnClickListener              Override         public void onClick View view                onItemClickListner onClick mContectList get position                          after define adapter and bind into recycler view called below code            adapter setOnItemClickListner new CommentsAdapter onItemClickListner              Override         public void onClick Contact contact                contectList remove contectList get contectList indexOf contact                 adapter notifyDataSetChanged

User · Answer

The Problem RecyclerView is  by default  unaware of your dataset changes  This means that whenever you make a deletion addition on your data list  those changes won t be reflected to your RecyclerView directly   i e  you remove the item at index 5  but the 6th element remains in your recycler view   A  quot ok quot  Solution RecyclerView exposes some methods for you to communicate your dataset changes  reflecting those changes directly on your list items  The standard Android APIs allow you to bind the process of data removal  for the purpose of the question  with the process of View removal  The methods we talked about are  notifyItemChanged index  Int  notifyItemInserted index  Int  notifyItemRemoved index  Int  notifyItemRangeChanged startPosition  Int  itemCount  Int  notifyItemRangeInserted startPosition  Int  itemCount  Int  notifyItemRangeRemoved startPosition  Int  itemCount  Int   Better Solution If you don t properly specify what happens on each addition  change or removal of items  RecyclerView children are animated unresponsively because of a lack of information about how to move the different views around the list  Instead  the following code will precisely play the animation  just on the child that is being removed  And as a side note  it fixed any IndexOutOfBoundExceptions  marked by the stacktrace as  quot data inconsistency quot    void remove position  Int        dataset removeAt position      notifyItemChanged position      notifyItemRangeRemoved position  1     Under the hood  if we look into RecyclerView we can find documentation explaining that the second parameter we pass to notifyItemRangeRemoved  is the number of items that are removed from the dataset  not the total number of items  As wrongly reported in some others information sources                  Notify any registered observers that the  lt code gt itemCount lt  code gt  items previously        located at  lt code gt positionStart lt  code gt  have been removed from the data set  The items        previously located at and after  lt code gt positionStart   itemCount lt  code gt  may now be found        at  lt code gt oldPosition - itemCount lt  code gt                  lt p gt This is a structural change event  Representations of other existing items in the data        set are still considered up to date and will not be rebound  though their positions        may be altered  lt  p gt                 param positionStart Previous position of the first item that was removed         param itemCount Number of items removed from the data set             public final void notifyItemRangeRemoved int positionStart  int itemCount            mObservable notifyItemRangeRemoved positionStart  itemCount          Even Better Solution  Opinionated  Do not use any of those functions  That s my personal view  They are counterintuitive  error-prone and they feel really verbose and unnecessary  Let a library like FastAdapter  Epoxy or Groupie take care of this business  or use an observable recycler view with data binding

User · Answer

if still item not removed use this magic method     private void deleteItem int position            mDataSet remove position           notifyItemRemoved position           notifyItemRangeChanged position  mDataSet size             holder itemView setVisibility View GONE       Kotlin version  private fun deleteItem position  Int        mDataSet removeAt position      notifyItemRemoved position      notifyItemRangeChanged position  mDataSet size      holder itemView visibility   View GONE

User · Answer

The problem I had was I was removing an item from the list that was no longer associated with the adapter to make sure you are modifying the correct adapter you can implement a method like this in your adapter   public void removeItemAtPosition int position        items remove position       And call it in your fragment or activity like this    adapter removeItemAtPosition position

User · Answer

In the activity    mAdapter updateAt pos  text  completed   mAdapter removeAt pos        In the your adapter    void removeAt int position        list remove position       notifyItemRemoved position       notifyItemRangeChanged position  list size        void updateAt int position  String text  Boolean completed        TodoEntity todoEntity   list get position       todoEntity setText text       todoEntity setCompleted completed       notifyItemChanged position

User · Answer

you must to remove this item from arrayList of data myDataset remove holder getAdapterPosition     notifyItemRemoved holder getAdapterPosition     notifyItemRangeChanged holder getAdapterPosition    getItemCount

User · Answer

if you want to remove item you should do this  first remove item   phones remove position     in next step you should notify your recycler adapter that you remove an item by this code   notifyItemRemoved position   notifyItemRangeChanged position  phones size       but if you change an item do this  first change a parameter of your object like this   Service s   services get position   s done    Cancel service   services set position s     or new it like this    Service s   new Service    services set position s     then notify your recycler adapter that you modify an item by this code   notifyItemChanged position   notifyItemRangeChanged position  services size       hope helps you

User · Answer

In case you are wondering like I did where can we get the adapter position in the method getadapterposition    its in viewholder object so you have to put your code like this  mdataset remove holder getadapterposition

User · Answer

I tried all the above answers  but inserting or removing items to recyclerview causes problem with the position in the dataSet  Ended up using    delete getAdapterPosition     inside the viewHolder which worked great at finding the position of items

User · Answer

first of all  item should be removed from the list      mDataSet remove getAdapterPosition       then     notifyItemRemoved getAdapterPosition       notifyItemRangeChanged getAdapterPosition   mDataSet size

User · Answer

I have done something similar  In your MyAdapter   public class ViewHolder extends RecyclerView ViewHolder implements View OnClickListener      public CardView mCardView      public TextView mTextViewTitle      public TextView mTextViewContent      public ImageView mImageViewContentPic       public ImageView imgViewRemoveIcon      public ViewHolder View v            super v           mCardView    CardView  v findViewById R id card view           mTextViewTitle    TextView  v findViewById R id item title           mTextViewContent    TextView  v findViewById R id item content           mImageViewContentPic    ImageView  v findViewById R id item content pic                            imgViewRemoveIcon    ImageView  v findViewById R id remove icon            mTextViewContent setOnClickListener this           imgViewRemoveIcon setOnClickListener this           v setOnClickListener this           mTextViewContent setOnLongClickListener new View OnLongClickListener                  Override             public boolean onLongClick View view                    if  mItemClickListener    null                        mItemClickListener onItemClick view  getPosition                                       return false                                         Override     public void onClick View v              Log d  View     v toString               Toast makeText v getContext    mTextViewTitle getText       position       getPosition    Toast LENGTH SHORT  show            if v equals imgViewRemoveIcon                removeAt getPosition              else if  mItemClickListener    null                mItemClickListener onItemClick v  getPosition                        public void setOnItemClickListener final OnItemClickListener mItemClickListener        this mItemClickListener   mItemClickListener    public void removeAt int position        mDataset remove position       notifyItemRemoved position       notifyItemRangeChanged position  mDataSet size         Hope this helps   Edit   getPosition   is deprecated now  use getAdapterPosition   instead

[java] Android RecyclerView addition & removal of items

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