DropDownPreference

Kotlin |Java

open class DropDownPreference : ListPreference

kotlin.Any
↳	androidx.preference.Preference
	↳	androidx.preference.DialogPreference
		↳	androidx.preference.ListPreference
			↳	androidx.preference.DropDownPreference

A ListPreference that presents the options in a drop down menu rather than a dialog.

Summary

Inherited constants

From class Preference

Int

DEFAULT_ORDER

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

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

Public methods
open Unit	`onBindViewHolder(view: PreferenceViewHolder!)`
open Unit	`setEntries(@NonNull entries: Array<CharSequence!>)`
open Unit	`setValueIndex(index: Int)`

Protected methods
open ArrayAdapter<Any!>!	`createAdapter()` By default, this class uses a simple `ArrayAdapter`.
open Unit	`notifyChanged()`
open Unit	`onClick()`

Inherited functions

From class Preference

`Boolean`	`callChangeListener(newValue: Any!)` 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.
`Int`	`compareTo(@NonNull other: Preference)` Compares preference objects based on order (if set), otherwise alphabetically on the titles.
`T?`	`findPreferenceInHierarchy(@NonNull key: String)` Finds a preference in the entire hierarchy (above or below this preference) with the given key. Returns `null` if no preference could be found with the given key. This only works after this preference has been attached to a hierarchy.
`Context!`	`getContext()` 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.
`String!`	`getDependency()` Returns the key of the dependency on this preference.
`Bundle!`	`getExtras()` 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.
`String!`	`getFragment()` Return the fragment class name associated with this preference.
`Drawable!`	`getIcon()` Returns the icon of this preference.
`Intent!`	`getIntent()` Return the `Intent` associated with this preference.
`String!`	`getKey()` Gets the key for this preference, which is also the key used for storing values into `SharedPreferences` or `PreferenceDataStore`.
`Int`	`getLayoutResource()` Gets the layout resource that will be shown as the `View` for this preference.
`Preference.OnPreferenceChangeListener!`	`getOnPreferenceChangeListener()` Returns the callback to be invoked when this preference is changed by the user (but before the internal state has been updated).
`Preference.OnPreferenceClickListener!`	`getOnPreferenceClickListener()` Returns the callback to be invoked when this preference is clicked.
`Int`	`getOrder()` Gets the order of this preference with respect to other preference objects on the same level.
`PreferenceGroup?`	`getParent()` 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.
`Boolean`	`getPersistedBoolean(defaultReturnValue: Boolean)` Attempts to get a persisted `Boolean` if this preference is persistent.
`Float`	`getPersistedFloat(defaultReturnValue: Float)` Attempts to get a persisted `Float` if this preference is persistent.
`Int`	`getPersistedInt(defaultReturnValue: Int)` Attempts to get a persisted `Integer` if this preference is persistent.
`Long`	`getPersistedLong(defaultReturnValue: Long)` Attempts to get a persisted `Long` if this preference is persistent.
`String!`	`getPersistedString(defaultReturnValue: String!)` Attempts to get a persisted set of Strings if this preference is persistent.
`MutableSet<String!>!`	`getPersistedStringSet(defaultReturnValue: MutableSet<String!>!)` Attempts to get a persisted set of Strings if this preference is persistent.
`PreferenceDataStore?`	`getPreferenceDataStore()` 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)`.
`PreferenceManager!`	`getPreferenceManager()` Gets the `PreferenceManager` that manages this preference object's tree.
`SharedPreferences!`	`getSharedPreferences()` 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)`.
`Boolean`	`getShouldDisableView()` Checks whether this preference should disable its view when it's action is disabled.
`CharSequence!`	`getSummary()` 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.
`Preference.SummaryProvider<Preference!>?`	`getSummaryProvider()` Returns the `SummaryProvider` used to configure the summary of this preference.
`CharSequence!`	`getTitle()` Returns the title of this preference.
`Int`	`getWidgetLayoutResource()` Gets the layout resource for the controllable widget portion of this preference.
`Boolean`	`hasKey()` Checks whether this preference has a valid key.
`Boolean`	`isCopyingEnabled()` Returns whether the summary of this preference can be copied to the clipboard by long pressing on the preference.
`Boolean`	`isEnabled()` Checks whether this preference should be enabled in the list.
`Boolean`	`isIconSpaceReserved()` Returns whether the space of this preference icon view is reserved.
`Boolean`	`isPersistent()` 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.
`Boolean`	`isSelectable()` Checks whether this preference should be selectable in the list.
`Boolean`	`isShown()` 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`.
`Boolean`	`isSingleLineTitle()` Gets whether the title of this preference is constrained to a single line.
`Boolean`	`isVisible()` 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.
`Unit`	`notifyChanged()` Should be called when the data of this `Preference` has changed.
`Unit`	`notifyDependencyChange(disableDependents: Boolean)` Notifies any listening dependents of a change that affects the dependency.
`Unit`	`notifyHierarchyChanged()` Should be called when a preference has been added/removed from this group, or the ordering should be re-evaluated.
`Unit`	`onAttached()` 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.
`Unit`	`onAttachedToHierarchy(preferenceManager: PreferenceManager!)` Called when this preference has been attached to a preference hierarchy. Make sure to call the super implementation.
`Unit`	`onBindViewHolder(holder: PreferenceViewHolder!)` 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.
`Unit`	`onDependencyChanged(dependency: Preference!, disableDependent: Boolean)` Called when the dependency changes.
`Unit`	`onDetached()` 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.
`Any!`	`onGetDefaultValue(a: TypedArray!, index: Int)` 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)`.
`Unit`	`onInitializeAccessibilityNodeInfo(info: AccessibilityNodeInfoCompat!)` Initializes an `android.view.accessibility.AccessibilityNodeInfo` with information about the View for this preference.
`Unit`	`onParentChanged(parent: Preference!, disableChild: Boolean)` Called when the implicit parent dependency changes.
`Unit`	`onPrepareForRemoval()` 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.
`Unit`	`onRestoreInstanceState(state: Parcelable!)` 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.
`Parcelable!`	`onSaveInstanceState()` 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.
`Unit`	`onSetInitialValue(restorePersistedValue: Boolean, defaultValue: Any!)` 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.
`Unit`	`onSetInitialValue(@Nullable defaultValue: Any?)` 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.
`Bundle!`	`peekExtras()` Return the extras Bundle object associated with this preference, returning `null` if there is not currently one.
`Boolean`	`persistBoolean(value: 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.
`Boolean`	`persistFloat(value: Float)` 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.
`Boolean`	`persistInt(value: Int)` 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.
`Boolean`	`persistLong(value: Long)` 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.
`Boolean`	`persistString(value: String!)` 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.
`Boolean`	`persistStringSet(values: MutableSet<String!>!)` 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.
`Unit`	`restoreHierarchyState(container: Bundle!)` Restore this preference hierarchy's previously saved state from the given container.
`Unit`	`saveHierarchyState(container: Bundle!)` Store this preference hierarchy's frozen state into the given container.
`Unit`	`setCopyingEnabled(enabled: Boolean)` Sets whether the summary of this preference can be copied to the clipboard by long pressing on the preference.
`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.
`Unit`	`setDependency(dependencyKey: String!)` 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.
`Unit`	`setEnabled(enabled: Boolean)` Sets whether this preference is enabled. If disabled, it will not handle clicks.
`Unit`	`setFragment(fragment: String!)` Sets the class name of a fragment to be shown when this preference is clicked.
`Unit`	`setIcon(icon: Drawable!)` 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)`.
`Unit`	`setIcon(iconResId: Int)` Sets the icon for this preference with a resource ID.
`Unit`	`setIconSpaceReserved(iconSpaceReserved: Boolean)` 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.
`Unit`	`setIntent(intent: Intent!)` Sets an `Intent` to be used for `Context#startActivity(Intent)` when this preference is clicked.
`Unit`	`setKey(key: String!)` Sets the key for this preference, which is used as a key to the `SharedPreferences` or `PreferenceDataStore`. This should be unique for the package.
`Unit`	`setLayoutResource(layoutResId: Int)` 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`.
`Unit`	`setOnPreferenceChangeListener(onPreferenceChangeListener: Preference.OnPreferenceChangeListener!)` Sets the callback to be invoked when this preference is changed by the user (but before the internal state has been updated).
`Unit`	`setOnPreferenceClickListener(onPreferenceClickListener: Preference.OnPreferenceClickListener!)` Sets the callback to be invoked when this preference is clicked.
`Unit`	`setOrder(order: Int)` 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.
`Unit`	`setPersistent(persistent: Boolean)` 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.
`Unit`	`setPreferenceDataStore(dataStore: PreferenceDataStore!)` 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.
`Unit`	`setSelectable(selectable: Boolean)` Sets whether this preference is selectable.
`Unit`	`setShouldDisableView(shouldDisableView: Boolean)` 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.
`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.
`Unit`	`setSummary(summary: CharSequence!)` Sets the summary for this preference with a CharSequence. You can also use a `SummaryProvider` to dynamically configure the summary of this preference.
`Unit`	`setSummary(summaryResId: Int)` Sets the summary for this preference with a resource ID. You can also use a `SummaryProvider` to dynamically configure the summary of this preference.
`Unit`	`setSummaryProvider(@Nullable summaryProvider: Preference.SummaryProvider<Preference!>?)` Set a `SummaryProvider` that will be invoked whenever the summary of this preference is requested. Set `null` to remove the existing SummaryProvider.
`Unit`	`setTitle(title: CharSequence!)` 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)`.
`Unit`	`setTitle(titleResId: Int)` Sets the title for this preference with a resource ID.
`Unit`	`setViewId(viewId: Int)` Set the ID that will be assigned to the overall View representing this preference, once bound.
`Unit`	`setVisible(visible: Boolean)` 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.
`Unit`	`setWidgetLayoutResource(widgetLayoutResId: Int)` 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`.
`Boolean`	`shouldDisableDependents()` Checks whether this preference's dependents should currently be disabled.
`Boolean`	`shouldPersist()` 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.
`String`	`toString()`

From class ListPreference

`Int`	`findIndexOfValue(value: String!)` Returns the index of the given value (in the entry values array).
`Array<CharSequence!>!`	`getEntries()` The list of entries to be shown in the list in subsequent dialogs.
`CharSequence!`	`getEntry()` Returns the entry corresponding to the current value.
`Array<CharSequence!>!`	`getEntryValues()` Returns the array of values to be saved for the preference.
`CharSequence!`	`getSummary()`
`String!`	`getValue()` Returns the value of the key. This should be one of the entries in `getEntryValues()`.
`Any!`	`onGetDefaultValue(a: TypedArray!, index: Int)`
`Unit`	`onRestoreInstanceState(state: Parcelable!)`
`Parcelable!`	`onSaveInstanceState()`
`Unit`	`onSetInitialValue(defaultValue: Any?)`
`Unit`	`setEntries(@ArrayRes entriesResId: Int)`
`Unit`	`setEntryValues(entryValues: Array<CharSequence!>!)` The array to find the value to save for a preference when an entry from entries is selected. If a user clicks on the second item in entries, the second item in this array will be saved to the preference.
`Unit`	`setEntryValues(@ArrayRes entryValuesResId: Int)`
`Unit`	`setSummary(summary: CharSequence!)`
`Unit`	`setValue(value: String!)` Sets the value of the key. This should be one of the entries in `getEntryValues()`.

From class DialogPreference

`Drawable!`	`getDialogIcon()` Returns the icon to be shown on subsequent dialogs.
`Int`	`getDialogLayoutResource()` Returns the layout resource that is used as the content view for subsequent dialogs.
`CharSequence!`	`getDialogMessage()` Returns the message to be shown on subsequent dialogs.
`CharSequence!`	`getDialogTitle()` Returns the title to be shown on subsequent dialogs.
`CharSequence!`	`getNegativeButtonText()` Returns the text of the negative button to be shown on subsequent dialogs.
`CharSequence!`	`getPositiveButtonText()` Returns the text of the positive button to be shown on subsequent dialogs.
`Unit`	`onClick()`
`Unit`	`setDialogIcon(dialogIcon: Drawable!)` Sets the icon of the dialog. This will be shown on subsequent dialogs.
`Unit`	`setDialogIcon(dialogIconRes: Int)` Sets the icon (resource ID) of the dialog. This will be shown on subsequent dialogs.
`Unit`	`setDialogLayoutResource(dialogLayoutResId: Int)` Sets the layout resource that is inflated as the `View` to be shown as the content view of subsequent dialogs.
`Unit`	`setDialogMessage(dialogMessage: CharSequence!)` Sets the message of the dialog. This will be shown on subsequent dialogs. This message forms the content view of the dialog and conflicts with list-based dialogs, for example. If setting a custom `View` on a dialog via `setDialogLayoutResource(int)`, include a `android.widget.TextView` with ID `android.R.id#message` and it will be populated with this message.
`Unit`	`setDialogMessage(dialogMessageResId: Int)`
`Unit`	`setDialogTitle(dialogTitle: CharSequence!)` Sets the title of the dialog. This will be shown on subsequent dialogs.
`Unit`	`setDialogTitle(dialogTitleResId: Int)`
`Unit`	`setNegativeButtonText(negativeButtonText: CharSequence!)` Sets the text of the negative button of the dialog. This will be shown on subsequent dialogs.
`Unit`	`setNegativeButtonText(negativeButtonTextResId: Int)`
`Unit`	`setPositiveButtonText(positiveButtonText: CharSequence!)` Sets the text of the positive button of the dialog. This will be shown on subsequent dialogs.
`Unit`	`setPositiveButtonText(positiveButtonTextResId: Int)`

Public constructors

<init>

DropDownPreference(context: Context!)

<init>

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

<init>

DropDownPreference(
    context: Context!, 
    attrs: AttributeSet!, 
    defStyle: Int)

<init>

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

Public methods

onBindViewHolder

open fun onBindViewHolder(view: PreferenceViewHolder!): Unit

setEntries

open fun setEntries(@NonNull entries: Array<CharSequence!>): Unit

setValueIndex

open fun setValueIndex(index: Int): Unit

Protected methods

createAdapter

protected open fun createAdapter(): ArrayAdapter<Any!>!

By default, this class uses a simple ArrayAdapter. But if you need a more complicated adapter, this method can be overridden to create a custom one.

Note: This method is called from the constructor. Overridden methods will get called before any subclass initialization.

Return
`ArrayAdapter<Any!>!`	The custom `ArrayAdapter` that needs to be used with this class

notifyChanged

protected open fun notifyChanged(): Unit

onClick

protected open fun onClick(): Unit