FragmentStatePagerAdapter
abstract classFragmentStatePagerAdapter: PagerAdapter
kotlin.Any | ||
↳ | androidx.viewpager.widget.PagerAdapter | |
↳ | androidx.fragment.app.FragmentStatePagerAdapter |
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:
Summary
Constants | |
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static Int |
Indicates that only the current fragment will be in the |
static Int |
Indicates that |
Inherited constants | |
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Public constructors | |
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<init>(@NonNull fm: FragmentManager) Constructor for |
|
<init>(@NonNull fm: FragmentManager, behavior: Int) Constructor for |
Public methods | |
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open Unit |
destroyItem(@NonNull container: ViewGroup, position: Int, @NonNull object: Any) |
open Unit |
finishUpdate(@NonNull container: ViewGroup) |
abstract Fragment |
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 | |
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Constants
BEHAVIOR_RESUME_ONLY_CURRENT_FRAGMENT
static val BEHAVIOR_RESUME_ONLY_CURRENT_FRAGMENT: Int
Indicates that only the current fragment will be in the Lifecycle.State#RESUMED
state. All other Fragments are capped at Lifecycle.State#STARTED
.
Value: 1
BEHAVIOR_SET_USER_VISIBLE_HINT
static valBEHAVIOR_SET_USER_VISIBLE_HINT: Int
Deprecated: This behavior relies on the deprecated Fragment#setUserVisibleHint(boolean)
API. Use BEHAVIOR_RESUME_ONLY_CURRENT_FRAGMENT
to switch to its replacement, FragmentTransaction#setMaxLifecycle
.
Indicates that Fragment#setUserVisibleHint(boolean)
will be called when the current fragment changes.
Value: 0
Public constructors
<init>
FragmentStatePagerAdapter(@NonNull fm: FragmentManager)
Deprecated: use FragmentStatePagerAdapter(FragmentManager, int)
with BEHAVIOR_RESUME_ONLY_CURRENT_FRAGMENT
Constructor for FragmentStatePagerAdapter
that sets the fragment manager for the adapter. This is the equivalent of calling FragmentStatePagerAdapter(FragmentManager, int)
and passing in BEHAVIOR_SET_USER_VISIBLE_HINT
.
Fragments will have Fragment#setUserVisibleHint(boolean)
called whenever the current Fragment changes.
Parameters | |
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fm |
FragmentManager: fragment manager that will interact with this adapter |
<init>
FragmentStatePagerAdapter(
@NonNull fm: FragmentManager,
behavior: Int)
Constructor for FragmentStatePagerAdapter
. If BEHAVIOR_RESUME_ONLY_CURRENT_FRAGMENT
is passed in, then only the current Fragment is in the