public abstract class PreferenceFragment extends Fragment
Preference
objects as
lists. These preferences will
automatically save to SharedPreferences
as the user interacts with
them. To retrieve an instance of SharedPreferences
that the
preference hierarchy in this fragment will use, call
PreferenceManager.getDefaultSharedPreferences(android.content.Context)
with a context in the same package as this fragment.
Furthermore, the preferences shown will follow the visual style of system preferences. It is easy to create a hierarchy of preferences (that can be shown on multiple screens) via XML. For these reasons, it is recommended to use this fragment (as a superclass) to deal with preferences in applications.
A PreferenceScreen
object should be at the top of the preference
hierarchy. Furthermore, subsequent PreferenceScreen
in the hierarchy
denote a screen break--that is the preferences contained within subsequent
PreferenceScreen
should be shown on another screen. The preference
framework handles showing these other screens from the preference hierarchy.
The preference hierarchy can be formed in multiple ways:
Activities
that each specify its own
preferences in an XML file via Activity
meta-data
PreferenceScreen
To inflate from XML, use the addPreferencesFromResource(int)
. The
root element should be a PreferenceScreen
. Subsequent elements can point
to actual Preference
subclasses. As mentioned above, subsequent
PreferenceScreen
in the hierarchy will result in the screen break.
To specify an Intent
to query Activities
that each
have preferences, use addPreferencesFromIntent(android.content.Intent)
. Each
Activity
can specify meta-data in the manifest (via the key
PreferenceManager.METADATA_KEY_PREFERENCES
) that points to an XML
resource. These XML resources will be inflated into a single preference
hierarchy and shown by this fragment.
To specify an object hierarchy rooted with PreferenceScreen
, use
setPreferenceScreen(PreferenceScreen)
.
As a convenience, this fragment implements a click listener for any
preference in the current hierarchy, see
onPreferenceTreeClick(PreferenceScreen, Preference)
.
For information about using PreferenceFragment
,
read the Settings
guide.
The following sample code shows a simple preference fragment that is populated from a resource. The resource it loads is:
The fragment implementation itself simply populates the preferences when created. Note that the preferences framework takes care of loading the current values out of the app preferences and writing them when changed:
Preference
,
PreferenceScreen
Modifier and Type | Class and Description |
---|---|
static interface |
PreferenceFragment.OnPreferenceStartFragmentCallback
Interface that PreferenceFragment's containing activity should
implement to be able to process preference items that wish to
switch to a new fragment.
|
Fragment.InstantiationException, Fragment.SavedState
TRIM_MEMORY_BACKGROUND, TRIM_MEMORY_COMPLETE, TRIM_MEMORY_MODERATE, TRIM_MEMORY_RUNNING_CRITICAL, TRIM_MEMORY_RUNNING_LOW, TRIM_MEMORY_RUNNING_MODERATE, TRIM_MEMORY_UI_HIDDEN
Constructor and Description |
---|
PreferenceFragment() |
Modifier and Type | Method and Description |
---|---|
void |
addPreferencesFromIntent(Intent intent)
Adds preferences from activities that match the given
Intent . |
void |
addPreferencesFromResource(int preferencesResId)
Inflates the given XML resource and adds the preference hierarchy to the current
preference hierarchy.
|
Preference |
findPreference(CharSequence key)
Finds a
Preference based on its key. |
ListView |
getListView() |
PreferenceManager |
getPreferenceManager()
Returns the
PreferenceManager used by this fragment. |
PreferenceScreen |
getPreferenceScreen()
Gets the root of the preference hierarchy that this fragment is showing.
|
void |
onActivityCreated(Bundle savedInstanceState)
Called when the fragment's activity has been created and this
fragment's view hierarchy instantiated.
|
void |
onActivityResult(int requestCode,
int resultCode,
Intent data)
Receive the result from a previous call to
Fragment.startActivityForResult(Intent, int) . |
void |
onCreate(Bundle savedInstanceState)
Called to do initial creation of a fragment.
|
View |
onCreateView(LayoutInflater inflater,
ViewGroup container,
Bundle savedInstanceState)
Called to have the fragment instantiate its user interface view.
|
void |
onDestroy()
Called when the fragment is no longer in use.
|
void |
onDestroyView()
Called when the view previously created by
Fragment.onCreateView(android.view.LayoutInflater, android.view.ViewGroup, android.os.Bundle) has
been detached from the fragment. |
boolean |
onPreferenceTreeClick(PreferenceScreen preferenceScreen,
Preference preference)
Called when a preference in the tree rooted at this
PreferenceScreen has been clicked. |
void |
onSaveInstanceState(Bundle outState)
Called to ask the fragment to save its current dynamic state, so it
can later be reconstructed in a new instance of its process is
restarted.
|
void |
onStart()
Called when the Fragment is visible to the user.
|
void |
onStop()
Called when the Fragment is no longer started.
|
void |
setPreferenceScreen(PreferenceScreen preferenceScreen)
Sets the root of the preference hierarchy that this fragment is showing.
|
dump, equals, getActivity, getArguments, getChildFragmentManager, getFragmentManager, getId, getLayoutInflater, getLoaderManager, getParentFragment, getResources, getRetainInstance, getString, getString, getTag, getTargetFragment, getTargetRequestCode, getText, getUserVisibleHint, getView, hashCode, instantiate, instantiate, isAdded, isDetached, isHidden, isInLayout, isRemoving, isResumed, isVisible, onAttach, onConfigurationChanged, onContextItemSelected, onCreateAnimator, onCreateContextMenu, onCreateOptionsMenu, onDestroyOptionsMenu, onDetach, onHiddenChanged, onInflate, onInflate, onLowMemory, onOptionsItemSelected, onOptionsMenuClosed, onPause, onPrepareOptionsMenu, onResume, onTrimMemory, onViewCreated, onViewStateRestored, registerForContextMenu, setArguments, setHasOptionsMenu, setInitialSavedState, setMenuVisibility, setRetainInstance, setTargetFragment, setUserVisibleHint, startActivity, startActivity, startActivityForResult, startActivityForResult, toString, unregisterForContextMenu
public void onCreate(Bundle savedInstanceState)
Fragment
Fragment.onAttach(Activity)
and before
Fragment.onCreateView(LayoutInflater, ViewGroup, Bundle)
.
Note that this can be called while the fragment's activity is
still in the process of being created. As such, you can not rely
on things like the activity's content view hierarchy being initialized
at this point. If you want to do work once the activity itself is
created, see Fragment.onActivityCreated(Bundle)
.
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState)
Fragment
Fragment.onCreate(Bundle)
and Fragment.onActivityCreated(Bundle)
.
If you return a View from here, you will later be called in
Fragment.onDestroyView()
when the view is being released.
onCreateView
in class Fragment
inflater
- The LayoutInflater object that can be used to inflate
any views in the fragment,container
- If non-null, this is the parent view that the fragment's
UI should be attached to. The fragment should not add the view itself,
but this can be used to generate the LayoutParams of the view.savedInstanceState
- If non-null, this fragment is being re-constructed
from a previous saved state as given here.public void onActivityCreated(Bundle savedInstanceState)
Fragment
Fragment.setRetainInstance(boolean)
to retain their instance,
as this callback tells the fragment when it is fully associated with
the new activity instance. This is called after Fragment.onCreateView(android.view.LayoutInflater, android.view.ViewGroup, android.os.Bundle)
and before Fragment.onViewStateRestored(Bundle)
.onActivityCreated
in class Fragment
savedInstanceState
- If the fragment is being re-created from
a previous saved state, this is the state.public void onStart()
Fragment
Activity.onStart
of the containing
Activity's lifecycle.public void onStop()
Fragment
Activity.onStop
of the containing
Activity's lifecycle.public void onDestroyView()
Fragment
Fragment.onCreateView(android.view.LayoutInflater, android.view.ViewGroup, android.os.Bundle)
has
been detached from the fragment. The next time the fragment needs
to be displayed, a new view will be created. This is called
after Fragment.onStop()
and before Fragment.onDestroy()
. It is called
regardless of whether Fragment.onCreateView(android.view.LayoutInflater, android.view.ViewGroup, android.os.Bundle)
returned a
non-null view. Internally it is called after the view's state has
been saved but before it has been removed from its parent.onDestroyView
in class Fragment
public void onDestroy()
Fragment
Fragment.onStop()
and before Fragment.onDetach()
.public void onSaveInstanceState(Bundle outState)
Fragment
Fragment.onCreate(Bundle)
,
Fragment.onCreateView(LayoutInflater, ViewGroup, Bundle)
, and
Fragment.onActivityCreated(Bundle)
.
This corresponds to Activity.onSaveInstanceState(Bundle)
and most of the discussion there
applies here as well. Note however: this method may be called
at any time before Fragment.onDestroy()
. There are many situations
where a fragment may be mostly torn down (such as when placed on the
back stack with no UI showing), but its state will not be saved until
its owning activity actually needs to save its state.
onSaveInstanceState
in class Fragment
outState
- Bundle in which to place your saved state.public void onActivityResult(int requestCode, int resultCode, Intent data)
Fragment
Fragment.startActivityForResult(Intent, int)
. This follows the
related Activity API as described there in
Activity.onActivityResult(int, int, Intent)
.onActivityResult
in class Fragment
requestCode
- The integer request code originally supplied to
startActivityForResult(), allowing you to identify who this
result came from.resultCode
- The integer result code returned by the child activity
through its setResult().data
- An Intent, which can return result data to the caller
(various data can be attached to Intent "extras").public PreferenceManager getPreferenceManager()
PreferenceManager
used by this fragment.PreferenceManager
.public void setPreferenceScreen(PreferenceScreen preferenceScreen)
preferenceScreen
- The root PreferenceScreen
of the preference hierarchy.public PreferenceScreen getPreferenceScreen()
PreferenceScreen
that is the root of the preference
hierarchy.public void addPreferencesFromIntent(Intent intent)
Intent
.intent
- The Intent
to query activities.public void addPreferencesFromResource(int preferencesResId)
preferencesResId
- The XML resource ID to inflate.public boolean onPreferenceTreeClick(PreferenceScreen preferenceScreen, Preference preference)
PreferenceScreen
has been clicked.preferenceScreen
- The PreferenceScreen
that the
preference is located in.preference
- The preference that was clicked.public Preference findPreference(CharSequence key)
Preference
based on its key.key
- The key of the preference to retrieve.Preference
with the key, or null.PreferenceGroup.findPreference(CharSequence)
public ListView getListView()