RecyclerView notifyItemChanged(position) crashes the app and no animations with notifyDataSetChanged()

Question

So I have a RecyclerView and in every xml that i pull into it there is a checkbox that when pressed removes that specific item from the RecyclerView. That's what I was trying to do at least. And as I understand for it to work i need to use notifyItemChanged(position); (it's right at the bottom).

However when I use notifyItemChanged(position); it only deletes the correct item if I press the checkboxes in these orders: 1,2,3,4,5 or 5,4,3,2,1. If I try to delete the 1st item, it deletes it but then if I want to delete the 3rd one, it deletes the 4th.

Another option I found was using notifyDataSetChanged(); and it works in any order however then no animations are shown.

And I'd like to have animations when items are added and deleted, so if there's a way of doing that with notifyDataSetChanged(); I would like help with that.

public class ListAdapter extends RecyclerView.Adapter{

SharedPreferences sharedpreferences, prefs;
public static final String MyPREFERENCES = "MyPrefs";
public static final String date = "date";
@Override
public RecyclerView.ViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
    View view = LayoutInflater.from(parent.getContext()).inflate(R.layout.nd_table, parent, false);
    return new ListViewHolder(view);
}

@Override
public void onBindViewHolder(RecyclerView.ViewHolder holder, final int adapterPosition) {
    //((ListViewHolder) holder).bindView(position);
    String data = hwName.get(adapterPosition);
    String data2 = hwDesc.get(adapterPosition);
    ((ListViewHolder) holder).mItemText.setText(data);
    ((ListViewHolder) holder).mItemText2.setText(data2);
    ((ListViewHolder) holder).buttonDelete.setOnClickListener(new View.OnClickListener(){
        @Override
        public void onClick(View view){
            removeItem(adapterPosition);
            notifyItemChanged(adapterPosition);
        }
    });
}


@Override
public int getItemCount() {
    return hwName.size();
}

public class ListViewHolder extends RecyclerView.ViewHolder implements View.OnClickListener {

    private TextView mItemText, mItemText2;
    public CheckBox buttonDelete;

    public ListViewHolder(View itemView) {
        super(itemView);
        mItemText = (TextView) itemView.findViewById(R.id.pam_name);
        mItemText2 = (TextView) itemView.findViewById(R.id.pam_nd);
        buttonDelete = (CheckBox) itemView.findViewById(R.id.nd_checkbox);
        itemView.setOnClickListener(this);
    }

    public void bindView(int position) {
        String value = hwName.get(position);
        String value2 = hwDesc.get(position);

        mItemText.setText(value);
        mItemText2.setText(value2);

        //notifyItemInserted(hwName.size());
    }


    public void onClick(View view) {

    }
}

public void removeItem(int position){
    hwName.remove(position);
    hwDesc.remove(position);
    //notifyDataSetChanged();
    notifyItemRemoved(position);
    notifyItemChanged(position);
}}

Crash report:

FATAL EXCEPTION: main Process: com.sajev.slush, PID: 14166 java.lang.IndexOutOfBoundsException: Index: 5, Size: 5 at java.util.ArrayList.remove(ArrayList.java:477) at com.sajev.slush.ListAdapter.removeItem(ListAdapter.java:89) at com.sajev.slush.ListAdapter$1.onClick(ListAdapter.java:45) at android.view.View.performClick(View.java:5646) at android.widget.CompoundButton.performClick(CompoundButton.java:123) at android.view.View$PerformClick.run(View.java:22459) at android.os.Handler.handleCallback(Handler.java:761) at android.os.Handler.dispatchMessage(Handler.java:98) at android.os.Looper.loop(Looper.java:156) at android.app.ActivityThread.main(ActivityThread.java:6523) at java.lang.reflect.Method.invoke(Native Method) at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:941) at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:831)

Answer 1

There are two problems:

Don't call notifyItemChanged() after calling notifyItemRemoved()

Calling notifyItemRemoved() will tell the adapter that the item previously at position doesn't exist anymore, and that's all you need to do. Calling notifyItemChanged() tells the adapter that the item at position has been modified (perhaps its name changed, but nothing else), so it's not meant for use when you delete an item.

You're getting a crash because you call both of these in order. Imagine that you only have one item in your list, and then delete it. When you call notifyItemRemoved(), the adapter now knows that your list has zero items in it. But then you call notifyItemChanged(), and so the adapter tries to go get the first item... but the list is empty so you crash.

The position argument passed to onBindViewHolder() can not be final

(See https://www.youtube.com/watch?v=LqBlYJTfLP4 at ~43:10 for more info.)

The compiler can't stop you from adding the final keyword to the position argument of onBindViewHolder(), but it is a logical error to do so. When you call methods like notifyItemRemoved() or notifyItemInserted(), other view holders are not re-bound, and so the position argument will no longer reflect reality.

Do not use that position argument inside click listeners. Instead, look it up at runtime. Here's some updated code considering both problems:

@Override
public void onBindViewHolder(final RecyclerView.ViewHolder holder, int position) {
    ...
    ((ListViewHolder) holder).buttonDelete.setOnClickListener(new View.OnClickListener(){
        @Override
        public void onClick(View view){
            removeItem(holder.getAdapterPosition());
        }
    });
}

public void removeItem(int position){
    hwName.remove(position);
    hwDesc.remove(position);
    notifyItemRemoved(position);
}