Preference

open class Preference : Comparable<Preference!>
kotlin.Any
   ↳ androidx.preference.Preference

The basic building block that represents an individual setting displayed to a user in the preference hierarchy. This class provides the data that will be displayed to the user and has a reference to the SharedPreferences or PreferenceDataStore instance that persists the preference's values.

When specifying a preference hierarchy in XML, each element can point to a subclass of Preference, similar to the view hierarchy and layouts.

This class contains a key that that represents the key that is used to persist the value to the device. It is up to the subclass to decide how to store the value.

Developer Guides

For information about building a settings screen using the AndroidX Preference library, see Settings.

Summary

Nested classes
abstract

Interface definition for a callback to be invoked when the value of this Preference has been changed by the user and is about to be set and/or persisted.

abstract

Interface definition for a callback to be invoked when a Preference is clicked.

abstract

Interface definition for a callback to be invoked when the summary of this Preference is requested (typically when this preference is added to the hierarchy or its value is updated).

open

A base class for managing the instance state of a Preference.

Constants
static Int

Specify for setOrder(int) if a specific order is not required.

Public constructors
<init>(context: Context!, attrs: AttributeSet!, defStyleAttr: Int, defStyleRes: Int)

Perform inflation from XML and apply a class-specific base style.

<init>(context: Context!, attrs: AttributeSet!, defStyleAttr: Int)

Perform inflation from XML and apply a class-specific base style.

<init>(context: Context!, attrs: AttributeSet!)

Constructor that is called when inflating a preference from XML.

<init>(context: Context!)

Constructor to create a preference.

Public methods
open Boolean

Checks whether this preference should be selectable in the list.

open Preference.OnPreferenceClickListener!

Returns the callback to be invoked when this preference is clicked.

open Boolean

Gets whether the title of this preference is constrained to a single line.

open Unit
setFragment(fragment: String!)

Sets the class name of a fragment to be shown when this preference is clicked.

Preference.SummaryProvider<Preference!>?

Returns the SummaryProvider used to configure the summary of this preference.

open Boolean
callChangeListener(newValue: Any!)

Call this method after the user changes the preference, but before the internal state is set.

open Unit
setEnabled(enabled: Boolean)

Sets whether this preference is enabled.

open SharedPreferences!

Returns the SharedPreferences where this preference can read its value(s).

open Unit

Called when the preference hierarchy has been attached to the list of preferences.

Unit

Set a SummaryProvider that will be invoked whenever the summary of this preference is requested.

open Intent!

Return the Intent associated with this preference.

open Unit
onDependencyChanged(dependency: Preference!, disableDependent: Boolean)

Called when the dependency changes.

open Unit
setLayoutResource(layoutResId: Int)

Sets the layout resource that is inflated as the View to be shown for this preference.

Boolean

Checks whether this preference should be visible to the user.

open Unit
setWidgetLayoutResource(widgetLayoutResId: Int)

Sets the layout for the controllable widget portion of this preference.

open Unit
setIcon(icon: Drawable!)

Sets the icon for this preference with a Drawable.

open Unit
setIcon(iconResId: Int)

Sets the icon for this preference with a resource ID.

open Unit
setKey(key: String!)

Sets the key for this preference, which is used as a key to the SharedPreferences or PreferenceDataStore.

open Unit
setOrder(order: Int)

Sets the order of this preference with respect to other preference objects on the same level.

open Unit
setDefaultValue(defaultValue: Any!)

Sets the default value for this preference, which will be set either if persistence is off or persistence is on and the preference is not found in the persistent storage.

open Drawable!

Returns the icon of this preference.

open Boolean

Checks whether this preference is persistent.

open Int
compareTo(@NonNull other: Preference)

Compares preference objects based on order (if set), otherwise alphabetically on the titles.

open Unit

Binds the created View to the data for this preference.

open Unit

Sets the callback to be invoked when this preference is clicked.

open Unit

Sets the callback to be invoked when this preference is changed by the user (but before the internal state has been updated).

open String!

Gets the key for this preference, which is also the key used for storing values into SharedPreferences or PreferenceDataStore.

open Boolean

Returns whether the summary of this preference can be copied to the clipboard by long pressing on the preference.

open PreferenceManager!

Gets the PreferenceManager that manages this preference object's tree.

Boolean

Checks whether this preference is shown to the user in the hierarchy.

open Boolean

Checks whether this preference should disable its view when it's action is disabled.

Int

Gets the layout resource that will be shown as the View for this preference.

open Unit
setSelectable(selectable: Boolean)

Sets whether this preference is selectable.

open Unit

Store this preference hierarchy's frozen state into the given container.

open Unit
setShouldDisableView(shouldDisableView: Boolean)

Sets whether this preference should disable its view when it gets disabled.

open Unit

Sets the title for this preference with a CharSequence.

open Unit
setTitle(titleResId: Int)

Sets the title for this preference with a resource ID.

open Unit

Called when the preference hierarchy has been detached from the list of preferences.

open CharSequence!

Returns the title of this preference.

open PreferenceDataStore?

Returns PreferenceDataStore used by this preference.

open Unit
notifyDependencyChange(disableDependents: Boolean)

Notifies any listening dependents of a change that affects the dependency.

open Int

Gets the order of this preference with respect to other preference objects on the same level.

open String!

Returns the key of the dependency on this preference.

open Boolean

Returns whether the space of this preference icon view is reserved.

open Unit
setPersistent(persistent: Boolean)

Sets whether this preference is persistent.

open String

open Unit

Sets whether the summary of this preference can be copied to the clipboard by long pressing on the preference.

Unit
setVisible(visible: Boolean)

Sets whether this preference should be visible to the user.

open Context!

Returns the Context of this preference.

open Boolean

Checks whether this preference should be enabled in the list.

open Bundle!

Return the extras Bundle object associated with this preference, returning null if there is not currently one.

open Unit

Sets a PreferenceDataStore to be used by this preference instead of using SharedPreferences.

open Unit

Restore this preference hierarchy's previously saved state from the given container.

open Unit

Sets the summary for this preference with a CharSequence.

open Unit
setSummary(summaryResId: Int)

Sets the summary for this preference with a resource ID.

open Boolean

Checks whether this preference has a valid key.

open Unit

Initializes an android.view.accessibility.AccessibilityNodeInfo with information about the View for this preference.

Int

Gets the layout resource for the controllable widget portion of this preference.

open MutableSet<String!>!
getPersistedStringSet(defaultReturnValue: MutableSet<String!>!)

Attempts to get a persisted set of Strings if this preference is persistent.

open Bundle!

Return the extras Bundle object associated with this preference, creating a new Bundle if there currently isn't one.

open Unit
onParentChanged(parent: Preference!, disableChild: Boolean)

Called when the implicit parent dependency changes.

open Unit
setViewId(viewId: Int)

Set the ID that will be assigned to the overall View representing this preference, once bound.

open Unit
setIntent(intent: Intent!)

Sets an Intent to be used for Context#startActivity(Intent) when this preference is clicked.

open Preference.OnPreferenceChangeListener!

Returns the callback to be invoked when this preference is changed by the user (but before the internal state has been updated).

open String!

Return the fragment class name associated with this preference.

open Unit
setIconSpaceReserved(iconSpaceReserved: Boolean)

Sets whether to reserve the space of this preference icon view when no icon is provided.

open PreferenceGroup?

Returns the PreferenceGroup which is this preference assigned to or null if this preference is not assigned to any group or is a root preference.

open Boolean

Attempts to persist a set of Strings if this preference is persistent.

open Unit
setSingleLineTitle(singleLineTitle: Boolean)

Sets whether to constrain the title of this preference to a single line instead of letting it wrap onto multiple lines.

open Unit
setDependency(dependencyKey: String!)

Sets the key of a preference that this preference will depend on.

open Boolean

Checks whether this preference's dependents should currently be disabled.

open CharSequence!

Returns the summary of this preference.

Protected methods
open Boolean
getPersistedBoolean(defaultReturnValue: Boolean)

Attempts to get a persisted Boolean if this preference is persistent.

open Unit

Should be called when the data of this Preference has changed.

open Boolean
persistLong(value: Long)

Attempts to persist a Long if this preference is persistent.

open Boolean

Attempts to persist a Boolean if this preference is persistent.

open Boolean

Attempts to persist a String if this preference is persistent.

open Boolean

Checks whether, at the given time this method is called, this preference should store/restore its value(s) into the SharedPreferences or into PreferenceDataStore if assigned.

open String!
getPersistedString(defaultReturnValue: String!)

Attempts to get a persisted set of Strings if this preference is persistent.

open Unit

Processes a click on the preference.

open Boolean
persistInt(value: Int)

Attempts to persist an Integer if this preference is persistent.

open Int
getPersistedInt(defaultReturnValue: Int)

Attempts to get a persisted Integer if this preference is persistent.

open Float
getPersistedFloat(defaultReturnValue: Float)

Attempts to get a persisted Float if this preference is persistent.

open Boolean

Attempts to persist a Float if this preference is persistent.

open Unit

Should be called when a preference has been added/removed from this group, or the ordering should be re-evaluated.

open Parcelable!

Hook allowing a preference to generate a representation of its internal state that can later be used to create a new instance with that same state.

open T

Finds a preference in this hierarchy (the whole thing, even above/below your PreferenceScreen screen break) with the given key.

open Long
getPersistedLong(defaultReturnValue: Long)

Attempts to get a persisted Long if this preference is persistent.

open Unit

Called when this preference has been attached to a preference hierarchy.

open Unit

Hook allowing a preference to re-apply a representation of its internal state that had previously been generated by onSaveInstanceState.

open Any!

Called when a preference is being inflated and the default value attribute needs to be read.

open Unit

Called when this preference is being removed from the hierarchy.

open Unit
onSetInitialValue(restorePersistedValue: Boolean, defaultValue: Any!)

Implement this to set the initial value of the preference.

open Unit
onSetInitialValue(@Nullable defaultValue: Any?)

Implement this to set the initial value of the preference.

Constants

DEFAULT_ORDER

static val DEFAULT_ORDER: Int

Specify for setOrder(int) if a specific order is not required.

Value: Integer.MAX_VALUE

Public constructors

<init>

Preference(context: Context!, attrs: AttributeSet!, defStyleAttr: Int, defStyleRes: Int)

Perform inflation from XML and apply a class-specific base style. This constructor allows subclasses to use their own base style when they are inflating. For example, a CheckBoxPreference constructor calls this version of the super class constructor and supplies android.R.attr.checkBoxPreferenceStyle for defStyleAttr. This allows the theme's checkbox preference style to modify all of the base preference attributes as well as the CheckBoxPreference class's attributes.

Parameters
context Context!: The Context this is associated with, through which it can access the current theme, resources, SharedPreferences, etc.
attrs Context!: The attributes of the XML tag that is inflating the preference
defStyleAttr Context!: An attribute in the current theme that contains a reference to a style resource that supplies default values for the view. Can be 0 to not look for defaults.
defStyleRes Context!: A resource identifier of a style resource that supplies default values for the view, used only if defStyleAttr is 0 or can not be found in the theme. Can be 0 to not look for defaults.

<init>

Preference(context: Context!, attrs: AttributeSet!, defStyleAttr: Int)

Perform inflation from XML and apply a class-specific base style. This constructor allows subclasses to use their own base style when they are inflating. For example, a CheckBoxPreference constructor calls this version of the super class constructor and supplies android.R.attr.checkBoxPreferenceStyle for defStyleAttr. This allows the theme's checkbox preference style to modify all of the base preference attributes as well as the CheckBoxPreference class's attributes.

Parameters
context Context!: The Context this is associated with, through which it can access the current theme, resources, SharedPreferences, etc.
attrs Context!: The attributes of the XML tag that is inflating the preference
defStyleAttr Context!: An attribute in the current theme that contains a reference to a style resource that supplies default values for the view. Can be 0 to not look for defaults.

<init>

Preference(context: Context!, attrs: AttributeSet!)

Constructor that is called when inflating a preference from XML. This is called when a preference is being constructed from an XML file, supplying attributes that were specified in the XML file. This version uses a default style of 0, so the only attribute values applied are those in the Context's Theme and the given AttributeSet.

Parameters
context Context!: The Context this is associated with, through which it can access the current theme, resources, SharedPreferences, etc.
attrs Context!: The attributes of the XML tag that is inflating the preference

<init>

Preference(context: Context!)

Constructor to create a preference.

Parameters
context Context!: The Context this is associated with, through which it can access the current theme, resources, SharedPreferences, etc.

Public methods

isSelectable

open fun isSelectable(): Boolean

Checks whether this preference should be selectable in the list.

Return
Boolean: true if it is selectable, false otherwise

getOnPreferenceClickListener

open fun getOnPreferenceClickListener(): Preference.OnPreferenceClickListener!

Returns the callback to be invoked when this preference is clicked.

Return
Preference.OnPreferenceClickListener!: The callback to be invoked

isSingleLineTitle

open fun isSingleLineTitle(): Boolean

Gets whether the title of this preference is constrained to a single line.

Return
Boolean: true if the title of this preference is constrained to a single line android.R.attr#singleLineTitle

setFragment

open fun setFragment(fragment: String!): Unit

Sets the class name of a fragment to be shown when this preference is clicked.

Parameters
fragment String!: The class name of the fragment associated with this preference

getSummaryProvider

@Nullable fun getSummaryProvider(): Preference.SummaryProvider<Preference!>?

Returns the SummaryProvider used to configure the summary of this preference.

Return
Preference.SummaryProvider<Preference!>?: The SummaryProvider used to configure the summary of this preference, or null if there is no SummaryProvider set

See Also

callChangeListener

open fun callChangeListener(newValue: Any!): Boolean

Call this method after the user changes the preference, but before the internal state is set. This allows the client to ignore the user value.

Parameters
newValue Any!: The new value of this preference
Return
Boolean: true if the user value should be set as the preference value (and persisted)

setEnabled

open fun setEnabled(enabled: Boolean): Unit

Sets whether this preference is enabled. If disabled, it will not handle clicks.

Parameters
enabled Boolean: Set true to enable it

getSharedPreferences

open fun getSharedPreferences(): SharedPreferences!

Returns the SharedPreferences where this preference can read its value(s). Usually, it's easier to use one of the helper read methods: getPersistedBoolean(boolean), getPersistedFloat(float), getPersistedInt(int), getPersistedLong(long), getPersistedString(String).

Return
SharedPreferences!: The SharedPreferences where this preference reads its value(s). If this preference is not attached to a preference hierarchy or if a PreferenceDataStore has been set, this method returns null.

onAttached

open fun onAttached(): Unit

Called when the preference hierarchy has been attached to the list of preferences. This can also be called when this preference has been attached to a group that was already attached to the list of preferences.

setSummaryProvider

fun setSummaryProvider(@Nullable summaryProvider: Preference.SummaryProvider<Preference!>?): Unit

Set a SummaryProvider that will be invoked whenever the summary of this preference is requested. Set null to remove the existing SummaryProvider.

Parameters
summaryProvider Preference.SummaryProvider<Preference!>?: The SummaryProvider that will be invoked whenever the summary of this preference is requested

See Also

getIntent

open fun getIntent(): Intent!

Return the Intent associated with this preference.

Return
Intent!: The Intent last set via setIntent(Intent) or XML

onDependencyChanged

open fun onDependencyChanged(dependency: Preference!, disableDependent: Boolean): Unit

Called when the dependency changes.

Parameters
dependency Preference!: The preference that this preference depends on
disableDependent Preference!: Set true to disable this preference

setLayoutResource

open fun setLayoutResource(layoutResId: Int): Unit

Sets the layout resource that is inflated as the View to be shown for this preference. In most cases, the default layout is sufficient for custom preference objects and only the widget layout needs to be changed.

This layout should contain a ViewGroup with ID android.R.id#widget_frame to be the parent of the specific widget for this preference. It should similarly contain android.R.id#title and android.R.id#summary.

It is an error to change the layout after adding the preference to a PreferenceGroup.

Parameters
layoutResId Int: The layout resource ID to be inflated and returned as a View

isVisible

fun isVisible(): Boolean

Checks whether this preference should be visible to the user. If this preference is visible, but one or more of its ancestors are not visible, then this preference will not be shown until its ancestors are all visible.

Return
Boolean: true if this preference should be displayed

setWidgetLayoutResource

open fun setWidgetLayoutResource(widgetLayoutResId: Int): Unit

Sets the layout for the controllable widget portion of this preference. This is inflated into the main layout. For example, a CheckBoxPreference would specify a custom layout (consisting of just the CheckBox) here, instead of creating its own main layout.

It is an error to change the layout after adding the preference to a PreferenceGroup.

Parameters
widgetLayoutResId Int: The layout resource ID to be inflated into the main layout

setIcon

open fun setIcon(icon: Drawable!): Unit

Sets the icon for this preference with a Drawable. This icon will be placed into the ID android.R.id#icon within the View created by onBindViewHolder(PreferenceViewHolder).

Parameters
icon Drawable!: The optional icon for this preference

setIcon

open fun setIcon(iconResId: Int): Unit

Sets the icon for this preference with a resource ID.

Parameters
iconResId Int: The icon as a resource ID

setKey

open fun setKey(key: String!): Unit

Sets the key for this preference, which is used as a key to the SharedPreferences or PreferenceDataStore. This should be unique for the package.

Parameters
key String!: The key for the preference

setOrder

open fun setOrder(order: Int): Unit

Sets the order of this preference with respect to other preference objects on the same level. If this is not specified, the default behavior is to sort alphabetically. The PreferenceGroup#setOrderingAsAdded(boolean) can be used to order preference objects based on the order they appear in the XML.

Parameters
order Int: The order for this preference. A lower value will be shown first. Use DEFAULT_ORDER to sort alphabetically or allow ordering from XML.

setDefaultValue

open fun setDefaultValue(defaultValue: Any!): Unit

Sets the default value for this preference, which will be set either if persistence is off or persistence is on and the preference is not found in the persistent storage.

Parameters
defaultValue Any!: The default value

getIcon

open fun getIcon(): Drawable!

Returns the icon of this preference.

Return
Drawable!: The icon

isPersistent

open fun isPersistent(): Boolean

Checks whether this preference is persistent. If it is, it stores its value(s) into the persistent SharedPreferences storage by default or into PreferenceDataStore if assigned.

Return
Boolean: true if persistent

compareTo

open fun compareTo(@NonNull other: Preference): Int

Compares preference objects based on order (if set), otherwise alphabetically on the titles.

Parameters
another Preference: The preference to compare to this one
Return
Int: 0 if the same; less than 0 if this preference sorts ahead of another; greater than 0 if this preference sorts after another.

onBindViewHolder

open fun onBindViewHolder(holder: PreferenceViewHolder!): Unit

Binds the created View to the data for this preference.

This is a good place to grab references to custom Views in the layout and set properties on them.

Make sure to call through to the superclass's implementation.

Parameters
holder PreferenceViewHolder!: The ViewHolder that provides references to the views to fill in. These views will be recycled, so you should not hold a reference to them after this method returns.

setOnPreferenceClickListener

open fun setOnPreferenceClickListener(onPreferenceClickListener: Preference.OnPreferenceClickListener!): Unit

Sets the callback to be invoked when this preference is clicked.

Parameters
onPreferenceClickListener Preference.OnPreferenceClickListener!: The callback to be invoked

setOnPreferenceChangeListener

open fun setOnPreferenceChangeListener(onPreferenceChangeListener: Preference.OnPreferenceChangeListener!): Unit

Sets the callback to be invoked when this preference is changed by the user (but before the internal state has been updated).

Parameters
onPreferenceChangeListener Preference.OnPreferenceChangeListener!: The callback to be invoked

getKey

open fun getKey(): String!

Gets the key for this preference, which is also the key used for storing values into SharedPreferences or PreferenceDataStore.

Return
String!: The key

isCopyingEnabled

open fun isCopyingEnabled(): Boolean

Returns whether the summary of this preference can be copied to the clipboard by long pressing on the preference.

Return
Boolean: true if copying is enabled, false otherwise

getPreferenceManager

open fun getPreferenceManager(): PreferenceManager!

Gets the PreferenceManager that manages this preference object's tree.

Return
PreferenceManager!: The PreferenceManager

isShown

fun isShown(): Boolean

Checks whether this preference is shown to the user in the hierarchy. For a preference to be shown in the hierarchy, it and all of its ancestors must be visible and attached to the root PreferenceScreen.

Return
Boolean: true if this preference is shown to the user in the hierarchy

getShouldDisableView

open fun getShouldDisableView(): Boolean

Checks whether this preference should disable its view when it's action is disabled.

Return
Boolean: true if it should disable the view

getLayoutResource

fun getLayoutResource(): Int

Gets the layout resource that will be shown as the View for this preference.

Return
Int: The layout resource ID

setSelectable

open fun setSelectable(selectable: Boolean): Unit

Sets whether this preference is selectable.

Parameters
selectable Boolean: Set true to make it selectable

saveHierarchyState

open fun saveHierarchyState(container: Bundle!): Unit

Store this preference hierarchy's frozen state into the given container.

Parameters
container Bundle!: The Bundle in which to save the instance of this preference

setShouldDisableView

open fun setShouldDisableView(shouldDisableView: Boolean): Unit

Sets whether this preference should disable its view when it gets disabled.

For example, set this and setEnabled(boolean) to false for preferences that are only displaying information and 1) should not be clickable 2) should not have the view set to the disabled state.

Parameters
shouldDisableView Boolean: Set true if this preference should disable its view when the preference is disabled.

setTitle

open fun setTitle(title: CharSequence!): Unit

Sets the title for this preference with a CharSequence. This title will be placed into the ID android.R.id#title within the View bound by onBindViewHolder(PreferenceViewHolder).

Parameters
title CharSequence!: The title for this preference

setTitle

open fun setTitle(titleResId: Int): Unit

Sets the title for this preference with a resource ID.

Parameters
titleResId Int: The title as a resource ID

onDetached

open fun onDetached(): Unit

Called when the preference hierarchy has been detached from the list of preferences. This can also be called when this preference has been removed from a group that was attached to the list of preferences.

getTitle

open fun getTitle(): CharSequence!

Returns the title of this preference.

Return
CharSequence!: The title

getPreferenceDataStore

@Nullable open fun getPreferenceDataStore(): PreferenceDataStore?

Returns PreferenceDataStore used by this preference. Returns null if SharedPreferences is used instead.

By default preferences always use SharedPreferences. To make this preference to use the PreferenceDataStore you need to assign your implementation to the preference itself via setPreferenceDataStore(PreferenceDataStore) or to its PreferenceManager via PreferenceManager#setPreferenceDataStore(PreferenceDataStore).

Return
PreferenceDataStore?: The PreferenceDataStore used by this preference or null if none

notifyDependencyChange

open fun notifyDependencyChange(disableDependents: Boolean): Unit

Notifies any listening dependents of a change that affects the dependency.

Parameters
disableDependents Boolean: Whether this preference should disable its dependents.

getOrder

open fun getOrder(): Int

Gets the order of this preference with respect to other preference objects on the same level.

Return
Int: The order of this preference

See Also

getDependency

open fun getDependency(): String!

Returns the key of the dependency on this preference.

Return
String!: The key of the dependency

isIconSpaceReserved

open fun isIconSpaceReserved(): Boolean

Returns whether the space of this preference icon view is reserved.

Return
Boolean: true if the space of this preference icon view is reserved android.R.attr#iconSpaceReserved

setPersistent

open fun setPersistent(persistent: Boolean): Unit

Sets whether this preference is persistent. When persistent, it stores its value(s) into the persistent SharedPreferences storage by default or into PreferenceDataStore if assigned.

Parameters
persistent Boolean: Set true if it should store its value(s) into the storage

toString

open fun toString(): String

setCopyingEnabled

open fun setCopyingEnabled(enabled: Boolean): Unit

Sets whether the summary of this preference can be copied to the clipboard by long pressing on the preference.

Parameters
enabled Boolean: Set true to enable copying the summary of this preference

setVisible

fun setVisible(visible: Boolean): Unit

Sets whether this preference should be visible to the user. If false, it is excluded from the adapter, but can still be retrieved using PreferenceFragmentCompat#findPreference(CharSequence).

To show this preference to the user, its ancestors must also all be visible. If you make a PreferenceGroup invisible, none of its children will be shown to the user until the group is visible.

Parameters
visible Boolean: Set false if this preference should be hidden from the user androidx.preference.R.attr#isPreferenceVisible

See Also

getContext

open fun getContext(): Context!

Returns the Context of this preference. Each preference in a preference hierarchy can be from different Context (for example, if multiple activities provide preferences into a single PreferenceFragmentCompat). This Context will be used to save the preference values.

Return
Context!: The Context of this preference

isEnabled

open fun isEnabled(): Boolean

Checks whether this preference should be enabled in the list.

Return
Boolean: true if this preference is enabled, false otherwise

peekExtras

open fun peekExtras(): Bundle!

Return the extras Bundle object associated with this preference, returning null if there is not currently one.

setPreferenceDataStore

open fun setPreferenceDataStore(dataStore: PreferenceDataStore!): Unit

Sets a PreferenceDataStore to be used by this preference instead of using SharedPreferences.

The data store will remain assigned even if the preference is moved around the preference hierarchy. It will also override a data store propagated from the PreferenceManager that owns this preference.

Parameters
dataStore PreferenceDataStore!: The PreferenceDataStore to be used by this preference

restoreHierarchyState

open fun restoreHierarchyState(container: Bundle!): Unit

Restore this preference hierarchy's previously saved state from the given container.

Parameters
container Bundle!: The Bundle that holds the previously saved state

setSummary

open fun setSummary(summary: CharSequence!): Unit

Sets the summary for this preference with a CharSequence.

You can also use a SummaryProvider to dynamically configure the summary of this preference.

Parameters
summary CharSequence!: The summary for the preference
Exceptions
IllegalStateException If a SummaryProvider has already been set.

setSummary

open fun setSummary(summaryResId: Int): Unit

Sets the summary for this preference with a resource ID.

You can also use a SummaryProvider to dynamically configure the summary of this preference.

Parameters
summaryResId Int: The summary as a resource

hasKey

open fun hasKey(): Boolean

Checks whether this preference has a valid key.

Return
Boolean: true if the key exists and is not a blank string, false otherwise

onInitializeAccessibilityNodeInfo

@CallSuper open fun onInitializeAccessibilityNodeInfo(info: AccessibilityNodeInfoCompat!): Unit

Initializes an android.view.accessibility.AccessibilityNodeInfo with information about the View for this preference.

getWidgetLayoutResource

fun getWidgetLayoutResource(): Int

Gets the layout resource for the controllable widget portion of this preference.

Return
Int: The layout resource ID

getPersistedStringSet

open fun getPersistedStringSet(defaultReturnValue: MutableSet<String!>!): MutableSet<String!>!

Attempts to get a persisted set of Strings if this preference is persistent.

Parameters
defaultReturnValue MutableSet<String!>!: The default value to return if either this preference is not persistent or this preference is not present.
Return
MutableSet<String!>!: The value from the storage or the default return value

getExtras

open fun getExtras(): Bundle!

Return the extras Bundle object associated with this preference, creating a new Bundle if there currently isn't one. You can use this to get and set individual extra key/value pairs.

onParentChanged

open fun onParentChanged(parent: Preference!, disableChild: Boolean): Unit

Called when the implicit parent dependency changes.

Parameters
parent Preference!: The preference that this preference depends on
disableChild Preference!: Set true to disable this preference

setViewId

open fun setViewId(viewId: Int): Unit

Set the ID that will be assigned to the overall View representing this preference, once bound.

See Also

setIntent

open fun setIntent(intent: Intent!): Unit

Sets an Intent to be used for Context#startActivity(Intent) when this preference is clicked.

Parameters
intent Intent!: The intent associated with this preference

getOnPreferenceChangeListener

open fun getOnPreferenceChangeListener(): Preference.OnPreferenceChangeListener!

Returns the callback to be invoked when this preference is changed by the user (but before the internal state has been updated).

Return
Preference.OnPreferenceChangeListener!: The callback to be invoked

getFragment

open fun getFragment(): String!

Return the fragment class name associated with this preference.

Return
String!: The fragment class name last set via setFragment or XML

setIconSpaceReserved

open fun setIconSpaceReserved(iconSpaceReserved: Boolean): Unit

Sets whether to reserve the space of this preference icon view when no icon is provided. If set to true, the preference will be offset as if it would have the icon and thus aligned with other preferences having icons.

Parameters
iconSpaceReserved Boolean: Set true if the space for the icon view should be reserved android.R.attr#iconSpaceReserved

getParent

@Nullable open fun getParent(): PreferenceGroup?

Returns the PreferenceGroup which is this preference assigned to or null if this preference is not assigned to any group or is a root preference.

Return
PreferenceGroup?: The parent PreferenceGroup or null if not attached to any

persistStringSet

open fun persistStringSet(values: MutableSet<String!>!): Boolean

Attempts to persist a set of Strings if this preference is persistent.

The returned value doesn't reflect whether the given value was persisted, since we may not necessarily commit if there will be a batch commit later.

Parameters
values MutableSet<String!>!: The values to persist
Return
Boolean: true if the preference is persistent, false otherwise

setSingleLineTitle

open fun setSingleLineTitle(singleLineTitle: Boolean): Unit

Sets whether to constrain the title of this preference to a single line instead of letting it wrap onto multiple lines.

Parameters
singleLineTitle Boolean: Set true if the title should be constrained to one line android.R.attr#singleLineTitle

setDependency

open fun setDependency(dependencyKey: String!): Unit

Sets the key of a preference that this preference will depend on. If that preference is not set or is off, this preference will be disabled.

Parameters
dependencyKey String!: The key of the preference that this depends on

shouldDisableDependents

open fun shouldDisableDependents(): Boolean

Checks whether this preference's dependents should currently be disabled.

Return
Boolean: true if the dependents should be disabled, otherwise false

getSummary

open fun getSummary(): CharSequence!

Returns the summary of this preference. If a SummaryProvider has been set for this preference, it will be used to provide the summary returned by this method.

Return
CharSequence!: The summary

Protected methods

getPersistedBoolean

protected open fun getPersistedBoolean(defaultReturnValue: Boolean): Boolean

Attempts to get a persisted Boolean if this preference is persistent.

Parameters
defaultReturnValue Boolean: The default value to return if either this preference is not persistent or this preference is not in the SharedPreferences.
Return
Boolean: The value from the storage or the default return value

notifyChanged

protected open fun notifyChanged(): Unit

Should be called when the data of this Preference has changed.

persistLong

protected open fun persistLong(value: Long): Boolean

Attempts to persist a Long if this preference is persistent.

The returned value doesn't reflect whether the given value was persisted, since we may not necessarily commit if there will be a batch commit later.

Parameters
value Long: The value to persist
Return
Boolean: true if the preference is persistent, false otherwise

persistBoolean

protected open fun persistBoolean(value: Boolean): Boolean

Attempts to persist a Boolean if this preference is persistent.

The returned value doesn't reflect whether the given value was persisted, since we may not necessarily commit if there will be a batch commit later.

Parameters
value Boolean: The value to persist
Return
Boolean: true if the preference is persistent, false otherwise

persistString

protected open fun persistString(value: String!): Boolean

Attempts to persist a String if this preference is persistent.

The returned value doesn't reflect whether the given value was persisted, since we may not necessarily commit if there will be a batch commit later.

Parameters
value String!: The value to persist
Return
Boolean: true if the preference is persistent, false otherwise

shouldPersist

protected open fun shouldPersist(): Boolean

Checks whether, at the given time this method is called, this preference should store/restore its value(s) into the SharedPreferences or into PreferenceDataStore if assigned. This, at minimum, checks whether this preference is persistent and it currently has a key. Before you save/restore from the storage, check this first.

Return
Boolean: true if it should persist the value

getPersistedString

protected open fun getPersistedString(defaultReturnValue: String!): String!

Attempts to get a persisted set of Strings if this preference is persistent.

Parameters
defaultReturnValue String!: The default value to return if either the preference is not persistent or the preference is not in the shared preferences.
Return
String!: The value from the storage or the default return value

onClick

protected open fun onClick(): Unit

Processes a click on the preference. This includes saving the value to the SharedPreferences. However, the overridden method should call callChangeListener(Object) to make sure the client wants to update the preference's state with the new value.

persistInt

protected open fun persistInt(value: Int): Boolean

Attempts to persist an Integer if this preference is persistent.

The returned value doesn't reflect whether the given value was persisted, since we may not necessarily commit if there will be a batch commit later.

Parameters
value Int: The value to persist
Return
Boolean: true if the preference is persistent, false otherwise

getPersistedInt

protected open fun getPersistedInt(defaultReturnValue: Int): Int

Attempts to get a persisted Integer if this preference is persistent.

Parameters
defaultReturnValue Int: The default value to return if either this preference is not persistent or this preference is not in the SharedPreferences.
Return
Int: The value from the storage or the default return value

getPersistedFloat

protected open fun getPersistedFloat(defaultReturnValue: Float): Float

Attempts to get a persisted Float if this preference is persistent.

Parameters
defaultReturnValue Float: The default value to return if either this preference is not persistent or this preference is not saved.
Return
Float: The value from the storage or the default return value

persistFloat

protected open fun persistFloat(value: Float): Boolean

Attempts to persist a Float if this preference is persistent.

The returned value doesn't reflect whether the given value was persisted, since we may not necessarily commit if there will be a batch commit later.

Parameters
value Float: The value to persist
Return
Boolean: true if the preference is persistent, false otherwise

notifyHierarchyChanged

protected open fun notifyHierarchyChanged(): Unit

Should be called when a preference has been added/removed from this group, or the ordering should be re-evaluated.

onSaveInstanceState

protected open fun onSaveInstanceState(): Parcelable!

Hook allowing a preference to generate a representation of its internal state that can later be used to create a new instance with that same state. This state should only contain information that is not persistent or can be reconstructed later.

Return
Parcelable!: A Parcelable object containing the current dynamic state of this preference, or null if there is nothing interesting to save. The default implementation returns null.

findPreferenceInHierarchy

protected open fun <T : Preference!> findPreferenceInHierarchy(key: String!): T

Finds a preference in this hierarchy (the whole thing, even above/below your PreferenceScreen screen break) with the given key.

This only functions after we have been attached to a hierarchy.

Parameters
key String!: The key of the preference to find
Return
T: The preference that uses the given key

getPersistedLong

protected open fun getPersistedLong(defaultReturnValue: Long): Long

Attempts to get a persisted Long if this preference is persistent.

Parameters
defaultReturnValue Long: The default value to return if either this preference is not persistent or this preference is not in the SharedPreferences.
Return
Long: The value from the storage or the default return value

onAttachedToHierarchy

protected open fun onAttachedToHierarchy(preferenceManager: PreferenceManager!): Unit

Called when this preference has been attached to a preference hierarchy. Make sure to call the super implementation.

Parameters
preferenceManager PreferenceManager!: The PreferenceManager of the hierarchy

onRestoreInstanceState

protected open fun onRestoreInstanceState(state: Parcelable!): Unit

Hook allowing a preference to re-apply a representation of its internal state that had previously been generated by onSaveInstanceState. This function will never be called with a null state.

Parameters
state Parcelable!: The saved state that had previously been returned by onSaveInstanceState.

onGetDefaultValue

protected open fun onGetDefaultValue(a: TypedArray!, index: Int): Any!

Called when a preference is being inflated and the default value attribute needs to be read. Since different preference types have different value types, the subclass should get and return the default value which will be its value type.

For example, if the value type is String, the body of the method would proxy to TypedArray#getString(int).

Parameters
a TypedArray!: The set of attributes
index TypedArray!: The index of the default value attribute
Return
Any!: The default value of this preference type

onPrepareForRemoval

protected open fun onPrepareForRemoval(): Unit

Called when this preference is being removed from the hierarchy. You should remove any references to this preference that you know about. Make sure to call through to the superclass implementation.

onSetInitialValue

protected open fun onSetInitialValue(restorePersistedValue: Boolean, defaultValue: Any!): Unit

Implement this to set the initial value of the preference.

If restorePersistedValue is true, you should restore the preference value from the SharedPreferences. If restorePersistedValue is false, you should set the preference value to defaultValue that is given (and possibly store to SharedPreferences if shouldPersist() is true).

In case of using PreferenceDataStore, the restorePersistedValue is always true but the default value (if provided) is set.

This may not always be called. One example is if it should not persist but there is no default value given.

Parameters
restorePersistedValue Boolean: True to restore the persisted value; false to use the given defaultValue.
defaultValue Boolean: The default value for this preference. Only use this if restorePersistedValue is false.

onSetInitialValue

protected open fun onSetInitialValue(@Nullable defaultValue: Any?): Unit

Implement this to set the initial value of the preference.

If you are persisting values to SharedPreferences or a PreferenceDataStore you should restore the saved value for the preference.

If you are not persisting values, or there is no value saved for the preference, you should set the value of the preference to defaultValue.

Parameters
defaultValue Any?: The default value for the preference if set, otherwise null.