Develop Reference

What's the alternative to .notifyItemInserted() for multiple items?

I'm using a RecyclerView and .notifyItemInserted only inserts one item into the RecyclerView. How would I do that say, for multiple items? I want to AVOID using .notifyDataSetChanged().
Say I have 25 items, I want to insert another 20, what method would I call?

You can use notifyItemRangeInserted to notify for multiple insertion.
void notifyItemRangeInserted (int positionStart, int itemCount)
According official documentation
Notify any registered observers that the currently reflected itemCount
items starting at positionStart have been newly inserted. The items
previously located at positionStart and beyond can now be found
starting at position positionStart + itemCount.

Is there an event called by changing the count of items in the recyclerview?

Is there an event called by changing the count of items in the recyclerview?
I want to call function every time recyclerview items are added.

Update:
It turns out I misunderstood the original question. What was really asked is how to get notified when the underlying data in an Adapter has changed.
For this you could use a RecyclerView.AdapterDataObserver in conjunction with RecyclerView.Adapter's registerAdapterDataObserver(AdapterDataObserver observer) method to register for changes in the underlying list data.
Original Answer:
Your RecyclerView is backed by a RecyclerView.Adapter which owns the actual list of items being displayed.
If you change the backing list, you should call one of the notifyXXX methods on your adapter to notify your RecyclerView what has changed (and optionally where in the list the change happened.)
At the very least, you could call notifyDataSetChanged on your adapter to tell your RecyclerView that something somewhere in the list has changed. This can be expensive since you're not being specific about what changed, so the RecyclerView has to query the adapter for more information and potentially redraw its entire client area of items.
Something like:
RecyclerView.Adapter adapter = recyclerView.getAdapter();
if (adapter != null) {
adapter.notifyDataSetChanged();
}
Behind the scenes, the RecyclerView will call the RecyclerView.Adapter#getItemCount() method on the Adapter to determine what the current item count is.

How to change position of item in Recycler View

I am working on an Android app which has a recycler view. I have items ordered randomly in the recycler view. I want to move the fifth item of the list to the first position. And move the item previously at the first position to second position. Can anybody help me with this please?

You can use Collections.swap()
Swaps the elements at the specified positions in the specified list. (If the specified positions are equal, invoking this method leaves the list unchanged.)
METHOD
public static void swap(List<?> list,
int i,
int j)
Parameters:
list - The list in which to swap elements.
i - the index of one element to be swapped.
j - the index of the other element to be swapped.
SAMPLE CODE
// first swap the item using Collections.swap() method
Collections.swap(yourList, firstPosition, positionToSwap);
// than notify your adapter about change in list using notifyItemMoved() method
YourAdapter.notifyItemMoved(firstPosition, positionToSwap);

The way RecyclerView works is every time a new item comes on screen it calls your custom RecyclerView.Adapter subclass. Adapter has a reference for the dataset you take data for views from and gets passed the ViewHolder (the layout of an item) and index into onBindViewHolder(MyViewHolder holder, int position) to take dataset[position] and put the data into holder.textview.setText(dataset[position]).
As such, to swap places of elements you have 2 options:
rearrange data in the initial dataset. Chances are it's an ArrayList<> of some kind and you do TEMP=dataset[5];ArrayList.remove(TEMP);ArrayList.insert(TEMP,1); ArrayList will shift everything as required.
if it is important to keep dataset intact, you can rewrite your adapter, so that it keeps a map of { position : dataset_index } and populates items according to that map. That should be trivial.
And then you have to refresh the data with adapter.notifyDataSetChaged();

How to make specified item not update when notifyDataSetChanged in RecyclerView

I have a item in RecyclerView which does not need to be updated when I call notifyDataSetChanged.
But I didn't find any methods to make the specified item avoid updated. Is it possible to do this ?
I need to do this because the item is a WebView, it had loaded a html page, if I called notifyDataSetChanged, this item will flash.
The reason why I post this question is avoiding the flash of the WebView when notifyDataSetChanged (see this quesion). After the failure of using notifyItemRangeXXX methods, I post this question.
But after checking your answers and comments, it seems that it's impossible to avoid updating when using notifyDataSetChanged.

Yes, its actually possible to do so. notifyDataSetChanged() notifies the RecyclerView that all the elements in the data set has changed.
As you do not want that to happen and exclude specific items.
for(int i = 0; i< mAdapter.getItemCount(); i++){
if(i != itemPositionToExclude){
mAdapter.notifyItemChanged(i);
}
}
So, we need to loop through all the elements in the adapter and call notifyItemChanged() only for those positions which you do not want to exclude.

The purpose of notifyDataSetChanged IS to update ALL items. Don't use it if you don't want this behavior!
The correct approach would be to only update the data you've changed. There are some methods which will help you to only invalidate the desired data:
notifyItemChanged(int position)
notifyItemInserted(int position)
notifyItemMoved(int fromPosition, int toPosition)
notifyItemRangeChanged(int positionStart, int itemCount)
notifyItemRangeRemoved(int positionStart, int itemCount)
notifyItemRemoved(int position)

You should think in different way - which items need to be updated. To update UI of item, after data has changed use method notifyitemchanged

How to use RecyclerView.Adapter notifyItemInserted/Removed in a right way?

For instance, you have an adapter and in onBindViewHolder method you set OnClickListener to some views (and do some actions there depending on view position). You should assign final to position param of method onBindViewHolder so it could be accessible from onClick().
After changing dataset (remove or add item in list) you call onItemInserted or onItemRemoved and this really adds/removes a view in the recyclerview, BUT it does not refresh other viewitems so when you click on a neighbor viewitem it will open a screen or show data with invalid index. To avoid this I basically call notifyDatasetChanged to call onBind to all visible views and remove/add some views.
So how to refresh other views when you call notifyItemInserted/removed or how to work with these methots appropriately?

Assigning the position to a variable in onBindViewHolder will lead to an inconsistent state if items in the dataset are inserted or deleted without calling notifyDataSetChanged.
To use onItemInserted or onItemRemoved the data in the viewholder should remain consistent since it will not be redrawn and onClick would use this invalid position assigned before an item was added or removed.
For this and other use cases the RecyclerView.ViewHolder provides methods to access its position and id:
Use getAdapterPosition() or getItemId() to get valid positions and ids.
Also have a look on the other methods available in RecyclerView.ViewHolder.

So, the way I fix the problem I had is by changing the position into viewHolder.getAdapterPosition()
Cheers!

I advise you to add notifyItemRangeChanged after insert or remove list inside adapter. This work for my project.
Example in remove item :
public void removeItem (int pos) {
simpanList.remove(pos);
notifyItemRemoved(pos);
notifyItemRangeChanged(pos, simpanList.size());//add here, this can refresh position cmiiw
}

For future readers, this is what I do when inserting/removing in recyclerview
For example, my model class is CarsModel
In my adapter
ArrayList<CarsModel> carsModel;
In onBindViewHolder
CardModel model = carsModel.get(position);
When removing data in list using button in holder:
int position = holder.getAdapterPosition();
carsModel.remove(position);
notifyItemRemoved(position);
Then when inserting
carsModel.add(0, model);
notifyItemInserted(0);
or insert in last row
carsModel.add(carsModel.size() - 1 , model);
notifyItemInserted(carsModel.size()-1);