SelectionTracker.Builder

Artifact: androidx.recyclerview:recyclerview-selection

View Source

Added in 1.0.0

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Kotlin |Java

class SelectionTracker.Builder<K>

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Builder is the primary mechanism for create a SelectionTracker that can be used with your RecyclerView. Once installed, users will be able to create and manipulate selection using a variety of intuitive techniques like tap, gesture, and mouse lasso.

Example usage:

SelectionTrackertracker = new SelectionTracker.Builder<>(
       "my-uri-selection",
       recyclerView,
       new DemoStableIdProvider(recyclerView.getAdapter()),
       new MyDetailsLookup(recyclerView),
       StorageStrategy.createParcelableStorage(Uri.class))
       .build();

Restricting which items can be selected and limiting selection size

SelectionPredicate provides a mechanism to restrict which Items can be selected, to limit the number of items that can be selected, as well as allowing the selection code to be placed into "single select" mode, which as the name indicates, constrains the selection size to a single item.

Configuring the tracker for single single selection support can be done by supplying createSelectSingleAnything. SelectionTrackertracker = new SelectionTracker.Builder<>( "my-string-selection", recyclerView, new DemoStableIdProvider(recyclerView.getAdapter()), new MyDetailsLookup(recyclerView), StorageStrategy.createStringStorage()) .withSelectionPredicate(SelectionPredicates#createSelectSingleAnything()) .build();

Retaining state across Android lifecycle events

Support for storage/persistence of selection must be configured and invoked manually owing to its reliance on Activity lifecycle events. Failure to include support for selection storage will result in the active selection being lost when the Activity receives a configuration change (e.g. rotation) or when the application process is destroyed by the OS to reclaim resources.

Key Type

Developers must decide on the key type used to identify selected items. Support is provided for three types: Parcelable, String, and Long.

Parcelable: Any Parcelable type can be used as the selection key. This is especially useful in conjunction with android.net.Uri as the Android URI implementation is both parcelable and makes for a natural stable selection key for values represented by the Android Content Provider framework. If items in your view are associated with stable content:// uris, you should use Uri for your key type.

String: Use String when a string based stable identifier is available.

Long: Use Long when RecyclerView's long stable ids are already in use. It comes with some limitations, however, as access to stable ids at runtime is limited. Band selection support is not available when using the default long key storage implementation. See StableIdKeyProvider for details.

Usage:

     private SelectionTrackermTracker; 
     
     public void onCreate(Bundle savedInstanceState) { 
     // See above for details on constructing a SelectionTracker instance. 
     
     if (savedInstanceState != null) { 
     mTracker.onRestoreInstanceState(savedInstanceState); 
      } 
      } 
     
     protected void onSaveInstanceState(Bundle outState) { 
     super.onSaveInstanceState(outState); 
     mTracker.onSaveInstanceState(outState); 
      }

Parameters
<K>	Selection key type. Built in support is provided for String, Long, and Parcelable. StorageStrategy provides factory methods for each type: createStringStorage, createParcelableStorage, createLongStorage

Summary

Public constructors
Builder(     selectionId: String,     recyclerView: RecyclerView,     keyProvider: ItemKeyProvider<K!>,     detailsLookup: ItemDetailsLookup<K!>,     storage: StorageStrategy<K!> ) Creates a new SelectionTracker.Builder useful for configuring and creating a new SelectionTracker for use with your RecyclerView.

Public functions
SelectionTracker<K!>	build() Prepares and returns a SelectionTracker.
SelectionTracker.Builder<K!>	withBandOverlay(bandOverlayId: @DrawableRes Int) Replaces default band overlay.
SelectionTracker.Builder<K!>	withBandPredicate(bandPredicate: BandPredicate) Replaces default band predicate.
SelectionTracker.Builder<K!>	withFocusDelegate(delegate: FocusDelegate<K!>) Add focus delegate to interact with selection related focus changes.
SelectionTracker.Builder<K!>	withGestureTooltypes(toolTypes: IntArray) This function is deprecated. GestureSelection is best bound to TOOL_TYPE_FINGER, and only that tool type.
SelectionTracker.Builder<K!>	withOnContextClickListener(listener: OnContextClickListener) Adds a context click listener.
SelectionTracker.Builder<K!>	withOnDragInitiatedListener(listener: OnDragInitiatedListener) Adds a drag initiated listener.
SelectionTracker.Builder<K!>	withOnItemActivatedListener(listener: OnItemActivatedListener<K!>) Adds an item activation listener.
SelectionTracker.Builder<K!>	withOperationMonitor(monitor: OperationMonitor) Add operation monitor allowing access to information about active operations (like band selection and gesture selection).
SelectionTracker.Builder<K!>	withPointerTooltypes(toolTypes: IntArray) This function is deprecated. PointerSelection is best bound to TOOL_TYPE_MOUSE, and only that tool type.
SelectionTracker.Builder<K!>	withSelectionPredicate(     predicate: SelectionTracker.SelectionPredicate<K!> ) Install selection predicate.

Public constructors

Builder

Added in 1.0.0

Builder(
    selectionId: String,
    recyclerView: RecyclerView,
    keyProvider: ItemKeyProvider<K!>,
    detailsLookup: ItemDetailsLookup<K!>,
    storage: StorageStrategy<K!>
)

Creates a new SelectionTracker.Builder useful for configuring and creating a new SelectionTracker for use with your RecyclerView.

Parameters
selectionId: String	A unique string identifying this selection in the context of the activity or fragment.
recyclerView: RecyclerView	the owning RecyclerView
keyProvider: ItemKeyProvider<K!>	the source of selection keys
detailsLookup: ItemDetailsLookup<K!>	the source of information about RecyclerView items.
storage: StorageStrategy<K!>	Strategy for type-safe storage of selection state in Bundle.

Public functions

build

Added in 1.0.0

fun build(): SelectionTracker<K!>

Prepares and returns a SelectionTracker.

Returns
SelectionTracker<K!>	this

withBandOverlay

Added in 1.0.0

fun withBandOverlay(bandOverlayId: @DrawableRes Int): SelectionTracker.Builder<K!>

Replaces default band overlay.

Returns
SelectionTracker.Builder<K!>	this

withBandPredicate

Added in 1.0.0

fun withBandPredicate(bandPredicate: BandPredicate): SelectionTracker.Builder<K!>

Replaces default band predicate.

Returns
SelectionTracker.Builder<K!>	this

withFocusDelegate

Added in 1.0.0

fun withFocusDelegate(delegate: FocusDelegate<K!>): SelectionTracker.Builder<K!>

Add focus delegate to interact with selection related focus changes.

Parameters
delegate: FocusDelegate<K!>	the delegate to be used

Returns
SelectionTracker.Builder<K!>	this

withGestureTooltypes

fun withGestureTooltypes(toolTypes: IntArray): SelectionTracker.Builder<K!>

This function is deprecated.

GestureSelection is best bound to TOOL_TYPE_FINGER, and only that tool type. This method will be removed in a future release.

Replaces default tap and gesture tool-types. Defaults are: TOOL_TYPE_FINGER.

Parameters
toolTypes: IntArray	the tool types to be used

Returns
SelectionTracker.Builder<K!>	this

withOnContextClickListener

Added in 1.0.0

fun withOnContextClickListener(listener: OnContextClickListener): SelectionTracker.Builder<K!>

Adds a context click listener. Respond to right-click.

Parameters
listener: OnContextClickListener	the listener to be used

Returns
SelectionTracker.Builder<K!>	this

withOnDragInitiatedListener

Added in 1.0.0

fun withOnDragInitiatedListener(listener: OnDragInitiatedListener): SelectionTracker.Builder<K!>

Adds a drag initiated listener. Add support for drag and drop.

Parameters
listener: OnDragInitiatedListener	the listener to be used

Returns
SelectionTracker.Builder<K!>	this

withOnItemActivatedListener

Added in 1.0.0

fun withOnItemActivatedListener(listener: OnItemActivatedListener<K!>): SelectionTracker.Builder<K!>

Adds an item activation listener. Respond to taps/enter/double-click on items.

Parameters
listener: OnItemActivatedListener<K!>	the listener to be used

Returns
SelectionTracker.Builder<K!>	this

withOperationMonitor

Added in 1.0.0

fun withOperationMonitor(monitor: OperationMonitor): SelectionTracker.Builder<K!>

Add operation monitor allowing access to information about active operations (like band selection and gesture selection).

Parameters
monitor: OperationMonitor	the monitor to be used

Returns
SelectionTracker.Builder<K!>	this

withPointerTooltypes

fun withPointerTooltypes(toolTypes: IntArray): SelectionTracker.Builder<K!>

This function is deprecated.

PointerSelection is best bound to TOOL_TYPE_MOUSE, and only that tool type. This method will be removed in a future release.

Replaces default pointer tool-types. Pointer tools are associated with band selection, and certain drag and drop behaviors. Defaults are: TOOL_TYPE_MOUSE.

Parameters
toolTypes: IntArray	the tool types to be used

Returns
SelectionTracker.Builder<K!>	this

withSelectionPredicate

Added in 1.0.0

fun withSelectionPredicate(
    predicate: SelectionTracker.SelectionPredicate<K!>
): SelectionTracker.Builder<K!>

Install selection predicate.

Parameters
predicate: SelectionTracker.SelectionPredicate<K!>	the predicate to be used.

Returns
SelectionTracker.Builder<K!>	this