I recently came across the android
RecyclerView which was released with Android 5.0 and it seems that
RecyclerView is just an encapsulated traditional
ListView with the ViewHolder pattern incorporated into it, which promotes the reuse of the view, rather than creating it every single time.
What are the other benefits of using
If both have the same effect in terms of performance, why would one prefer RecyclerView` ?
I found that people have asked similar question and the answers are not conclusive, adding them here for record keeping.
The other plus of using
RecycleView is animation, it can be done in two lines of code
RecyclerView.ItemAnimator itemAnimator = new DefaultItemAnimator(); recyclerView.setItemAnimator(itemAnimator);
But the widget is still raw, e.g you can't create header and footer.
Okay so little bit of digging and I found these gems from Bill Philips article on
RecyclerView can do more than ListView, but the RecyclerView class itself has fewer responsibilities than ListView. Out of the box, RecyclerView does not:
- Position items on the screen
- Animate views
- Handle any touch events apart from scrolling
All of this stuff was baked in to ListView, but RecyclerView uses collaborator classes to do these jobs instead.
The ViewHolders you create are beefier, too. They subclass
RecyclerView.ViewHolder, which has a bunch of methods
ViewHoldersknow which position they are currently bound to, as well as which item ids (if you have those). In the process,
ViewHolderhas been knighted. It used to be ListViews job to hold on to the whole item view, and
ViewHolderonly held on to little pieces of it.
Now, ViewHolder holds on to all of it in the
ViewHolder.itemViewfield, which is assigned in ViewHolders constructor for you.
More from Bill Phillip's article (go read it!) but i thought it was important to point out the following.
In ListView, there was some ambiguity about how to handle click events: Should the individual views handle those events, or should the ListView handle them through OnItemClickListener? In RecyclerView, though, the ViewHolder is in a clear position to act as a row-level controller object that handles those kinds of details.
We saw earlier that LayoutManager handled positioning views, and ItemAnimator handled animating them. ViewHolder is the last piece: its responsible for handling any events that occur on a specific item that RecyclerView displays.
I used a
ListView with Glide image loader, having memory growth. Then I replaced the
ListView with a
RecyclerView. It is not only more difficult in coding, but also leads to a more memory usage than a
ListView. At least, in my project.
In another activity I used a complex list with
EditText's. In some of them an input method may vary, also a
TextWatcher can be applied. If I used a
ViewHolder, how could I replace a
TextWatcher during scrolling? So, I used a
ListView without a
ViewHolder, and it works.
Reuses cells while scrolling up/down - this is possible with implementing View Holder in the listView adapter, but it was an optional thing, while in the RecycleView it's the default way of writing adapter.
Decouples list from its container - so you can put list items easily at run time in the different containers (linearLayout, gridLayout) with setting LayoutManager.
mRecyclerView = (RecyclerView) findViewById(R.id.recycler_view); mRecyclerView.setLayoutManager(new LinearLayoutManager(this)); //or mRecyclerView.setLayoutManager(new GridLayoutManager(this, 2)); mRecyclerView.setLayoutManager(new GridLayoutManager(this, 3));
Animates common list actions.
Animations are decoupled and delegated to
There is more about RecyclerView, but I think these points are the main ones.
i) LinearLayoutManager - which supports both vertical and horizontal lists,
ii) StaggeredLayoutManager - which supports Pinterest like staggered lists,
iii) GridLayoutManager - which supports displaying grids as seen in Gallery apps.
And the best thing is that we can do all these dynamically as we want.
RecyclerView was created as a ListView improvement, so yes, you can create an attached list with ListView control, but using RecyclerView is easier as it:
Reuses cells while scrolling up/down : this is possible with implementing View Holder in the ListView adapter, but it was an optional thing, while in the RecycleView it's the default way of writing adapter.
Decouples list from its container : so you can put list items easily at run time in the different containers (linearLayout, gridLayout) with setting LayoutManager.
mRecyclerView = (RecyclerView) findViewById(R.id.my_recycler_view); mRecyclerView.setLayoutManager(new LinearLayoutManager(this)); mRecyclerView.setLayoutManager(new GridLayoutManager(this, 2));
- Animates common list actions : Animations are decoupled and delegated to ItemAnimator. There is more about RecyclerView, but I think these points are the main ones.
So, to conclude, RecyclerView is a more flexible control for handling "list data" that follows patterns of delegation of concerns and leaves for itself only one task - recycling items.
If you use RecycleView, first you need more efford to setup. You need to give more time to setup simple Item onclick, border, touch event and other simple thing. But end product will be perfect.
So decision is yours. I suggest, if you design simple app like phonebook loading, where simple click of item is enough, you can implement listview. But if you design like social media home page with unlimited scrolling. Several different decoration between item, much control of individual item than use recycle view.