IT. Expert System.

Android Reference

PreferenceFragment

android.preference

Class PreferenceFragment

java.lang.Object
- android.app.Fragment
- - android.preference.PreferenceFragment

All Implemented Interfaces:

ComponentCallbacks, ComponentCallbacks2, View.OnCreateContextMenuListener
```
public abstract class PreferenceFragment
extends Fragment
```
Shows a hierarchy of 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:
From an XML file specifying the hierarchy
From different Activities that each specify its own preferences in an XML file via Activity meta-data
From an object hierarchy rooted with 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).

Developer Guides

For information about using PreferenceFragment, read the Settings guide.

Sample Code

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:

See Also:: Preference, PreferenceScreen

Nested Class Summary

Nested Classes
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.

Nested classes/interfaces inherited from class android.app.Fragment
Fragment.InstantiationException, Fragment.SavedState

Field Summary
- Fields inherited from interface android.content.ComponentCallbacks2
  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 Summary

Constructors
Constructor and Description

PreferenceFragment()

Constructors
Constructor and Description
`PreferenceFragment()`

Method Summary

Methods
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.

Methods inherited from class android.app.Fragment
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

Methods inherited from class java.lang.Object
clone, finalize, getClass, notify, notifyAll, wait, wait, wait

- Constructor Detail
  - PreferenceFragment
```
public PreferenceFragment()
```
- Method Detail
  - onCreate
```
public void onCreate(Bundle savedInstanceState)
```
    Description copied from class: Fragment
    
    Called to do initial creation of a fragment. This is called after 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).
    
    Overrides:
    
    onCreate in class Fragment
    
    Parameters:
    savedInstanceState - If the fragment is being re-created from a previous saved state, this is the state.
  - onCreateView
```
public View onCreateView(LayoutInflater inflater,
                ViewGroup container,
                Bundle savedInstanceState)
```
    Description copied from class: Fragment
    
    Called to have the fragment instantiate its user interface view. This is optional, and non-graphical fragments can return null (which is the default implementation). This will be called between 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.
    
    Overrides:
    
    onCreateView in class Fragment
    
    Parameters:
    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.
    
    Returns:
    Return the View for the fragment's UI, or null.
  - onActivityCreated
```
public void onActivityCreated(Bundle savedInstanceState)
```
    Description copied from class: Fragment
    
    Called when the fragment's activity has been created and this fragment's view hierarchy instantiated. It can be used to do final initialization once these pieces are in place, such as retrieving views or restoring state. It is also useful for fragments that use 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).
    
    Overrides:
    
    onActivityCreated in class Fragment
    
    Parameters:
    savedInstanceState - If the fragment is being re-created from a previous saved state, this is the state.
  - onStart
```
public void onStart()
```
    Description copied from class: Fragment
    
    Called when the Fragment is visible to the user. This is generally tied to Activity.onStart of the containing Activity's lifecycle.
    
    Overrides:
    
    onStart in class Fragment
  - onStop
```
public void onStop()
```
    Description copied from class: Fragment
    
    Called when the Fragment is no longer started. This is generally tied to Activity.onStop of the containing Activity's lifecycle.
    
    Overrides:
    
    onStop in class Fragment
  - onDestroyView
```
public void onDestroyView()
```
    Description copied from class: Fragment
    
    Called when the view previously created by 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.
    
    Overrides:
    
    onDestroyView in class Fragment
  - onDestroy
```
public void onDestroy()
```
    Description copied from class: Fragment
    
    Called when the fragment is no longer in use. This is called after Fragment.onStop() and before Fragment.onDetach().
    
    Overrides:
    
    onDestroy in class Fragment
  - onSaveInstanceState
```
public void onSaveInstanceState(Bundle outState)
```
    Description copied from class: Fragment
    
    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. If a new instance of the fragment later needs to be created, the data you place in the Bundle here will be available in the Bundle given to 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.
    
    Overrides:
    
    onSaveInstanceState in class Fragment
    
    Parameters:
    outState - Bundle in which to place your saved state.
  - onActivityResult
```
public void onActivityResult(int requestCode,
                    int resultCode,
                    Intent data)
```
    Description copied from class: Fragment
    
    Receive the result from a previous call to Fragment.startActivityForResult(Intent, int). This follows the related Activity API as described there in Activity.onActivityResult(int, int, Intent).
    
    Overrides:
    
    onActivityResult in class Fragment
    
    Parameters:
    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").
  - getPreferenceManager
```
public PreferenceManager getPreferenceManager()
```
    Returns the PreferenceManager used by this fragment.
    
    Returns:
    The PreferenceManager.
  - setPreferenceScreen
```
public void setPreferenceScreen(PreferenceScreen preferenceScreen)
```
    Sets the root of the preference hierarchy that this fragment is showing.
    
    Parameters:
    preferenceScreen - The root PreferenceScreen of the preference hierarchy.
  - getPreferenceScreen
```
public PreferenceScreen getPreferenceScreen()
```
    Gets the root of the preference hierarchy that this fragment is showing.
    
    Returns:
    The PreferenceScreen that is the root of the preference hierarchy.
  - addPreferencesFromIntent
```
public void addPreferencesFromIntent(Intent intent)
```
    Adds preferences from activities that match the given Intent.
    
    Parameters:
    intent - The Intent to query activities.
  - addPreferencesFromResource
```
public void addPreferencesFromResource(int preferencesResId)
```
    Inflates the given XML resource and adds the preference hierarchy to the current preference hierarchy.
    
    Parameters:
    preferencesResId - The XML resource ID to inflate.
  - onPreferenceTreeClick
```
public boolean onPreferenceTreeClick(PreferenceScreen preferenceScreen,
                            Preference preference)
```
    Called when a preference in the tree rooted at this PreferenceScreen has been clicked.
    
    Parameters:
    preferenceScreen - The PreferenceScreen that the preference is located in.
    preference - The preference that was clicked.
    
    Returns:
    Whether the click was handled.
  - findPreference
```
public Preference findPreference(CharSequence key)
```
    Finds a Preference based on its key.
    
    Parameters:
    key - The key of the preference to retrieve.
    
    Returns:
    The Preference with the key, or null.
    See Also:
    PreferenceGroup.findPreference(CharSequence)
  - getListView
```
public ListView getListView()
```

IT. Expert System.

Android Reference

PreferenceFragment

Class PreferenceFragment

Developer Guides

Sample Code

Nested Class Summary

Nested classes/interfaces inherited from class android.app.Fragment

Field Summary

Fields inherited from interface android.content.ComponentCallbacks2

Constructor Summary

Method Summary

Methods inherited from class android.app.Fragment

Methods inherited from class java.lang.Object

Constructor Detail

PreferenceFragment

Method Detail

onCreate

onCreateView

onActivityCreated

onStart

onStop

onDestroyView

onDestroy

onSaveInstanceState

onActivityResult

getPreferenceManager

setPreferenceScreen

getPreferenceScreen

addPreferencesFromIntent

addPreferencesFromResource

onPreferenceTreeClick

findPreference

getListView

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