using notifyItemRemoved or notifyDataSetChanged with RecyclerView in Android

Question

I am creating a list of cards to display using the RecyclerView, where each card has a button to remove that card from the list.

When i use notifyItemRemoved

Answer 1

**my solution looks like this**

this way is unnecessary to use the heavy method:
 //notifyItemRangeChanged(xx,xx)

/**
 * 
 * recyclerView的item中的某一个view,获取其最外层的viewParent，也就是item对应的layout在adapter中的position
 *
 * @param recyclerView
 * @param view：can be the deep one inside the item,or the item itself .
 * @return
 */
public static int getParentAdapterPosition(RecyclerView recyclerView, View view, int parentId) {
    if (view.getId() == parentId)
        return recyclerView.getChildAdapterPosition(view);
    View viewGroup = (View) view.getParent();
    if (viewGroup != null && viewGroup.getId() == parentId) {
        return recyclerView.getChildAdapterPosition(viewGroup);
    }
    //recursion
    return getParentAdapterPosition(recyclerView, viewGroup, parentId);
}




//wherever you set the clickListener .
holder.setOnClickListener(R.id.rLayout_device_item, deviceItemClickListener);
holder.setOnLongClickListener(R.id.rLayout_device_item, deviceItemLongClickListener);


@Override
public boolean onLongClick(View v) {
    final int position = ViewUtils.getParentAdapterPosition(rVDevicesList, v, R.id.rLayout_device_item);
    return true;
}

Answer 2

You should add remove listener in ViewHolder class

 button.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {

                   onCancel(getAdapterPosition());

            }
        });

  private void onCancel(int position) {
        if (position >= issues.size())
            return;
        issues.remove(position);
        notifyItemRemoved(position);
    }

Answer 3

my mistake , notifyItemChanged(position) is helpless,the item of position can be removed ,and the item of position+1 is fine,but the items start from position+2,you will get an Exception, please use notifyItemRangeChanged(position,getItemCount()); after notifyItemRemoved(position);

like this:

public void removeData(int position) {
    yourdatalist.remove(position);
    notifyItemRemoved(position);
    notifyItemRangeChanged(position,getItemCount());
}

Answer 4

As @pskink suggested it was supposed to be (index+1) in my case with notifyItemRemoved(index+1), probably because i am reserving the top index i.e. position=0 for a header.

Answer 5

In my case I use Content Provider and a Custom RecyclerView Adapter with Cursor. This line of code is where you notify:

getContext().getContentResolver().notifyChange(uri, null);

Assuming In your recyclerView adapter (Delete Button):

Uri currentUri = ContentUris.withAppendedId(DatabaseContract.ToDoEntry.CONTENT_URI_TODO, id);
int rowsDeleted = mContext.getContentResolver().delete(currentUri, null, null);
if (rowsDeleted == 0) {
    Log.d(TAG, "onClick: Delete failed");
} else {
    Log.d(TAG, "onClick: Delete Successful");
}

And in your Database Provider:

case TODO_ID:
selection = DatabaseContract.ToDoEntry._ID + "=?";
selectionArgs = new String[] {String.valueOf(ContentUris.parseId(uri))};
rowsDeleted = database.delete(DatabaseContract.ToDoEntry.TODO_TABLE_NAME, selection, selectionArgs);
if (rowsDeleted != 0){
    getContext().getContentResolver().notifyChange(uri, null);
}
return rowsDeleted;

Answer 6

Use notifyItemRangeChanged(position, getItemCount()); after notifyItemRemoved(position);
You don't need to use index, just use position. See code below.

private List<DetectedIssue> issues = new ArrayList<DetectedIssue>();

@Override
public void onBindViewHolder(RecyclerView.ViewHolder holder, int position) {
    // - get element from your dataset at this position
    // - replace the contents of the view with that element
    if(position >0){
        RiskViewHolder riskHolder = (RiskViewHolder)holder;

        riskHolder.button.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                try {
                    issues.remove(position);
                    notifyItemRemoved(position);
                    //this line below gives you the animation and also updates the
                    //list items after the deleted item
                    notifyItemRangeChanged(position, getItemCount());

                } catch (SQLException e) {
                    e.printStackTrace();
                }
            }
        });
    }
}

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