I know that notifydatasetchanged updates the whole list and it is recommended to use DiffUtil to only update changed items, what I am not understanding yet after a lot of research is if it's expected that notifydatasetchanged animates list items separately when being used in a RecyclerView. Because I have one RecyclerAdapter where I replace the dataset completely and then call notifyDataSetChanged leading to list items being animated perfectly, only those added get the default added animation, removed ones get the removed animation and so on. At the same time I have another adapter where I also do the same, call notifyDataSetChanged but here the whole list flashes shortly, I am not getting any animations automatically, so I don't know from what does notifydatasetchanged make this dependent? Both adapters are too complex and long to post here.
I found the answer here:
The framework will attempt to animate views if your adapter uses
stable IDs, which provides enough data to guess which views are
removed/added/etc
Related
I need the functionality to update the data in the item in the recycler view. right now, If we notify the whole item it shows some fluctuation and we want to avoid refreshing the whole item on the UI.
I am using the ListAdapter with diff utils.
There are many ways to achieve your goal.
self-managing items. Adapter doesn't know anything about content of the items, it only puts items into RecyclerView. Content is managed by the item itself, so your problem is already solved.
custom adapter. Adapter has intricate knowledge about every item and can update selected ones accordingly.
AsyncListDiffer You can add differ to your adapter and it will take care of not updating parts that need no update.
Without seeing your code, we can't tell which way would be the most appropriate for you, but I guess adding differ is the simplest on already working code.
You need to create custom Adapter:
https://developer.android.com/develop/ui/views/layout/recyclerview
If you're talking about updating specific list items, and you're not using a DiffUtil (which will handle it for you) then you need to call the appropriate notify* method on your Adapter.
They fall into two categories, item change events (where the item list stays the same, but the displayed data for one or more of those items changes) and structural change events (where the actual list of items changes in some way, e.g. insertion/removal, or reordering).
I'm assuming you just want to update the displayed data for an item, so you should use one of the notifyItemChanged or notifyItemRangeChanged methods to inform the adapter that a certain item (or range of items) needs to update. If any of those items are currently being displayed in a ViewHolder, then onBindViewHolder will get called again for those items - which is where you set all your text, images etc depending on the item you're displaying. So you'll update them with the current data.
Both those methods have a version that takes a payload Object/Any, where you can pass in some data to be used in a partial bind - basically, onBindViewHolder can receive that data and be smarter about the update, which means you can avoid things like reloading images, etc. by passing in some stuff and checking for it during the binding process. More info about that here in the other version of onBindViewHolder you can implement, if you need to.
According to Android documentation:
Enabling Stable IDs will make the recyclerview do less work when
updating the list. Even if we call the notifyDataSetChanged(), it does
not have to handle the complete re-ordering of the whole adapter
because it can find if the item at a position is the same as before,
which results in faster performance of the recyclerview.
It also states that I should prefer notifyOnItemChanged(), notifyOnItemRemoved(), notifyOnItemInseted() etc. instead of notifyDataSetChanged() and prompts me to use it as last resort.
However, what happens if I simply want a recyclerview that doesn't support operations such as add/remove/replace at position and It is designed to replace the entire list at once? For example, I might want to display either Popular or Top Rated movies, which means that the entire content in the recyclerview will be changed. In this case, is it faster to simply:
setHasStableIDs(False);
notifyDataSetChanged();
I'm using recycler view with grid view (every item contains a grid) with thumbnail images after adding images in view it start uploading, and i need to change some values (status) in model at the time of start and finish upload.
What I'm currently doing is change values in model and call notifyDataSetChanged, but it causes to slow down application (hang some times) because it updating every child of list :(
Can any one help me with this?
Call notifydatasetchanged() for particular Gridview adapter only. Don't call notifydatasetchanged() for complete recyclerview adapter.
Try setting it again to the adapter.
gridview.setAdapter(your adapter)
-passing your new list to your adapter.
I believe notifyDataSetChanged updates all of your values regardless if they have a change or not that is why it is slow. I suggest you try using notifyItemChanged(int position) instead.
According to recyclerview docs this is what notifyDataSetChanged does:
This event does not specify what about the data set has changed, forcing any observers to assume that all existing items and structure may no longer be valid. LayoutManagers will be forced to fully rebind and relayout all visible views.
Old question but similar to what I'm experiencing.
RecyclerView is usually incredibly fast when changing list details. But manipulating a lot of images can really slow it down if you're not careul.
I'd recommend you try removing the images and repeat it so you can see if that is just as slow. I suspect this will be a lot faster.
If so, make sure you're handling the images off the UI thread. The Android docs recommend you use a library such as Glide which also handles sub-sampling the image to make sure it's the right size.
Hope that helps!
I am extending the ArrayAdapter and I provided my own OnItemClickListener where I update certain states of my data which reflects on multiple items in the list so to update the current states of those items in the list, I am calling the notifyDataSetChanged. Its working properly as how I want it to my worry is if there are any issues or negative effects on doing so. Like when the user taps many items which results in consecutive calls to notifyDataSetChanged.
If the user interaction requires views to be updated then you do need to be calling notifyDataSetChanged each time. If you're really worried you can look at debounce algorithms but that's kind of overkill, but as long as you don't have a huge number of elements and don't add a bunch of data change listeners it shouldn't be a problem.
don't worried about calling notifyDataSetChanged it only notify adapter about data change
Is there a way to call BaseAdapter.notifyDataSetChanged() on a single element in the adapter.
What I am trying to do is update the data and reflect those changes in the containing ListView. The problem is that sometimes the change is so small that it seems ridiculous that I have to refresh the whole view rather than the single item in the view that has been updated.
I am not aware of such method. If it's really important, you can always find individual item view to update. But I don't think that it worth it as Android is pretty efficient in updating list views. So it will not do much extra work (definitelly not going beyond items currently visible on the screen).