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abstract class FragmentStatePagerAdapter : PagerAdapter
   ↳ androidx.viewpager.widget.PagerAdapter

Implementation of PagerAdapter that uses a Fragment to manage each page. This class also handles saving and restoring of fragment's state.

This version of the pager is more useful when there are a large number of pages, working more like a list view. When pages are not visible to the user, their entire fragment may be destroyed, only keeping the saved state of that fragment. This allows the pager to hold on to much less memory associated with each visited page as compared to FragmentPagerAdapter at the cost of potentially more overhead when switching between pages.

When using FragmentPagerAdapter the host ViewPager must have a valid ID set.

Subclasses only need to implement getItem(int) and getCount() to have a working adapter.

Here is an example implementation of a pager containing fragments of lists:

The R.layout.fragment_pager resource of the top-level fragment is:

The R.layout.fragment_pager_list resource containing each individual fragment's layout is:


static Int

Indicates that only the current fragment will be in the Lifecycle.State#RESUMED state.

static Int

Indicates that Fragment#setUserVisibleHint(boolean) will be called when the current fragment changes.

Inherited constants
Public constructors
<init>(@NonNull fm: FragmentManager)

Constructor for FragmentStatePagerAdapter that sets the fragment manager for the adapter.

<init>(@NonNull fm: FragmentManager, behavior: Int)

Constructor for FragmentStatePagerAdapter.

Public methods
open Unit
destroyItem(@NonNull container: ViewGroup, position: Int, @NonNull object: Any)

open Unit
finishUpdate(@NonNull container: ViewGroup)

abstract Fragment
getItem(position: Int)

Return the Fragment associated with a specified position.

open Any
instantiateItem(@NonNull container: ViewGroup, position: Int)

open Boolean
isViewFromObject(@NonNull view: View, @NonNull object: Any)

open Unit
restoreState(@Nullable state: Parcelable?, @Nullable loader: ClassLoader?)

open Parcelable?

open Unit
setPrimaryItem(@NonNull container: ViewGroup, position: Int, @NonNull object: Any)

open Unit
startUpdate(@NonNull container: ViewGroup)

Inherited functions