ListView and RecyclerView

1. Mobile Programming
ListView & RecyclerView

2. Outline
• ListView
• RecyclerView

4. ListView
• In Android development, any time we want to show a vertical list of
scrollable items we will use a LisView which has data populated using
an Adapter
• The simplest adapter to use is called an ArrayAdapter because the
adapter converts an ArrayList of objects into View items loaded into
the ListView container.

5. ListView Illustration

7. How?
• Using ArrayAdapter
• Using Custom ArrayAdapter

8. ArrayAdapter
ArrayAdapter<String> itemsAdapter =
new ArrayAdapter<String>(this,
android.R.layout.simple_list_item_1, items);
ListView listView = findViewById(R.id.lvItems);
listView.setAdapter(itemsAdapter);

9. Custom ArrayAdapter
• Define the Model
• Create View Template
• Define the Adapter -> ArrayAdapter Inheritance
• Attaching the Adapter to a ListView
• Populating Data into ListView

10. ListView Example
• ListView

11. RecyclerView
• RecyclerView is a ViewGroup that renders any adapter-based view in a
similar way. It is supposed to be the successor of ListView and GridView.
• Each individual element in the list is defined by a view holder object. You
define the view holder by extending RecyclerView.ViewHolder.
• The RecyclerView requests those views, and binds the views to their data,
by calling methods in the adapter. You define the adapter by extending
RecyclerView.Adapter.
• The layout manager arranges the individual elements in your list. You can
use one of the layout managers provided by the RecyclerView library, or
you can define your own. Layout managers are all based on the library's
LayoutManager abstract class.

12. RecyclerView Illustration

13. LayoutManagers
• RecyclerView provides these built-in layout managers:
• LinearLayoutManager shows items in a vertical or horizontal scrolling list.
• GridLayoutManager shows items in a grid.
• StaggeredGridLayoutManager shows items in a staggered grid.

14. Adapter
• RecyclerView includes a new kind of adapter. It’s a similar approach to
the ones you already used, but with some peculiarities, such as a
required ViewHolder.
• You need to override three methods:
• onCreateViewHolder()
• onBindViewHolder()
• getItemCount()

15. Setup
// RecyclerView
def $recyclerViewVersion = “1.2.0”
implementation "androidx.recyclerview:recyclerview:$recyclerViewVersion"
Tips:
You can also drag RecyclerView widget from UI Editor directly

16. Example
• RecyclerView Sample App (Kotlin)
• RecyclerView Sample App (Java)
• RecyclerView Codelabs

17. Discussion?
• RecyclerView vs ListView