RecyclerView
is a more advanced and flexible version of ListView.
This widget is a container for large sets of views that can be
recycled and scrolled very efficiently. Use the RecyclerView
widget when you have lists with elements that change dynamically.RecyclerView
is easy to use, because it provides:- A layout manager for positioning items
- Default animations for common item operations
You
also have the flexibility to define custom layout managers and
animations for this widget.
To
use the
RecyclerView
widget, we have to specify an adapter and a layout manager.
LayoutManager
The
LayoutManager
is probably the most interesting part of the RecyclerView.
This class is responsible for the layout of all child views. There is
one
default implementation
available: LinearLayoutManager
which you can use for vertical as well as horizontal lists. To
create a custom layout, you extend the RecyclerView.LayoutManager
class.
//
use a linear layout manager
mLayoutManager
= new
LinearLayoutManager(this);
mRecyclerView.setLayoutManager(mLayoutManager);
//
improve performance if you know that changes in content
//
do not change the size of the RecyclerView
mRecyclerView.setHasFixedSize(true);
Animations
Animations
for adding and removing items are enabled by default in
RecyclerView.
use
the
RecyclerView.setItemAnimator
method
for animations, to customize just extend the
RecyclerView.ItemAnimator
class
Android
provide DefaultItemAnimator
and we can customize according to our needs.
mRecyclerView.setItemAnimator(new
DefaultItemAnimator());
Adapter:
To
create an adapter, you extend the
RecyclerView.Adapter
class.
The
RecyclerView.Adapter class contains few
notifyItemXXXX()methods.
Which help us in modifying the View.
Two
methods used in the example are insert and remove and they are
notifyItemInserted(position);
notifyItemRemoved(position);
mRecyclerView.setAdapter(mAdapter);
//
insert or remove item from the view. This methods are in the adapter
class.
public void addToList(String name) {
int position = 0;
if (mDataset.size() > 1) {
position = new Random().nextInt(mDataset.size() - 1);
}
mDataset.add(position, name);
notifyItemInserted(position);
}
public void removeItemFromList(String name) {
int position = mDataset.indexOf(name);
if (position != -1) {
mDataset.remove(position);
notifyItemRemoved(position);
}
}
Source Code
You can download the source code by clicking here: Sample RecyclerView . This project is built using eclipse IDE. Unzip and import the project into Eclipse, it’s a good idea to use the Project by clean and rebuild from the project menu.
Screenshot:
Initial screen with four items.
 |
| Added two rows to the recyclerView |
 |
| Removed one item which is added from RecyclerView |
Thanks for reading :)
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