What is RecyclerView in Android? The RecyclerView is a widget that is more flexible and advanced version of GridView and ListView.
It is a container for displaying large datasets which can be scrolled efficiently by maintaining limited number of views.
How does RecyclerView work under the hood?
- Step #1: At the initial launch, the first items x through 4 must be displayed on the screen
- Step #2: When we scroll up one item, item x moves up and a new item, item 5, enters the visible view category
- Step #3: Let’s say we scrolled up one more step
What are advantages to using RecyclerView
The major advantage of the usage of RecyclerView is the performance when loading list items in the list to the view.
RecyclerView prepares the view behind and ahead beyond the visible entries. It gives significant performance when you need to fetch the bitmap image in your list from a background task.
How do recycler views work
RecyclerView does not allocate an item view for every item in your data source.
Instead, it allocates only the number of item views that fit on the screen(Viewport) and it reuses those item layouts as the user scrolls.
When should I use RecyclerView
Use the RecyclerView widget when you have data collections whose elements change at runtime based on user action or network events.
If you want to use a RecyclerView , you will need to work with the following: RecyclerView.
Adapter – To handle the data collection and bind it to the view.
What is setHasStableIds
setHasStableIds is an optimization hint that you can give to the recycler. You’re telling it “when I provide a ViewHolder , its id is unique and will not change.”
It’s very easy to write an Adapter that does otherwise – for example, linking the id to item position.
What is difference between GridView and RecyclerView
In GridView it is recommended to use the ViewHolder but it is not compulsion but in RecyclerView it is mandatory to use ViewHolder that is the main difference between RecyclerView and GridView.
What is the ViewHolder pattern Why should we use it
The ViewHolder design pattern enables you to access each list item view without the need for the look up, saving valuable processor cycles.
Specifically, it avoids frequent call of findViewById() during ListView scrolling, and that will make it smooth.
How do you expand collapse items in RecyclerView Kotlin?
- Step 1: Create a model class
- Step 2: Create a layout for items
- Step 3: Create an adapter
- Step 4: Connect all the parts
Does RecyclerView scroll
To be able to scroll through a vertical list of items that is longer than the screen, you need to add a vertical scrollbar.
Inside RecyclerView , add an android:scrollbars attribute set to vertical
How do you inflate multiple layouts using one recycler view?
- Step 2: Implement RecyclerView in activity_main.xml
- Step 3: Add the required drawable file
- Step 4: Create all the item layouts
- Step 5: Create an Item class
Why does a RecyclerView need an adapter
RecyclerView. Adapter base class for presenting paged data from PagingData s in a RecyclerView Adapters provide a binding from an app-specific data set to views that are displayed within a RecyclerView A class that extends ViewHolder that will be used by the adapter.
What is concat adapter
ConcatAdapter is a new class available in recyclerview:1.2. 0-alpha02 which enables you to sequentially combine multiple adapters to be displayed in a single RecyclerView
Sources
https://instapage.com/blog/interstitial-ads
https://medium.com/androiddevelopers/merge-adapters-sequentially-with-mergeadapter-294d2942127a
https://www.javacodegeeks.com/2013/09/android-viewholder-pattern-example.html
https://codebun.com/how-to-get-data-from-api-in-android/
