Added in API level 1

Summary: Constants | Methods

Adapter

Kotlin |Java

public interface Adapter

android.widget.Adapter

Known indirect subclasses

ArrayAdapter<T>, BaseAdapter, CursorAdapter, HeaderViewListAdapter, ListAdapter, ResourceCursorAdapter, SimpleAdapter, SimpleCursorAdapter, SpinnerAdapter, ThemedSpinnerAdapter, WrapperListAdapter

ArrayAdapter<T>	You can use this adapter to provide views for an `AdapterView`, Returns a view for each object in a collection of data objects you provide, and can be used with list-based user interface widgets such as `ListView` or `Spinner`.
BaseAdapter	Common base class of common implementation for an `Adapter` that can be used in both `ListView` (by implementing the specialized `ListAdapter` interface) and `Spinner` (by implementing the specialized `SpinnerAdapter` interface).
CursorAdapter	Adapter that exposes data from a `Cursor` to a `ListView` widget.
HeaderViewListAdapter	ListAdapter used when a ListView has header views.
ListAdapter	Extended `Adapter` that is the bridge between a `ListView` and the data that backs the list.
ResourceCursorAdapter	An easy adapter that creates views defined in an XML file.
SimpleAdapter	An easy adapter to map static data to views defined in an XML file.
SimpleCursorAdapter	An easy adapter to map columns from a cursor to TextViews or ImageViews defined in an XML file.
SpinnerAdapter	Extended `Adapter` that is the bridge between a `Spinner` and its data.
ThemedSpinnerAdapter	An extension of SpinnerAdapter that is capable of inflating drop-down views against a different theme than normal views.
WrapperListAdapter	List adapter that wraps another list adapter.

An Adapter object acts as a bridge between an AdapterView and the underlying data for that view. The Adapter provides access to the data items. The Adapter is also responsible for making a View for each item in the data set.

See also:

Summary

Constants
`int`	`IGNORE_ITEM_VIEW_TYPE` An item view type that causes the `AdapterView` to ignore the item view.
`int`	`NO_SELECTION`

Public methods
`default CharSequence[]`	`getAutofillOptions()` Gets a string representation of the adapter data that can help `AutofillService` autofill the view backed by the adapter.
`abstract int`	`getCount()` How many items are in the data set represented by this Adapter.
`abstract Object`	`getItem(int position)` Get the data item associated with the specified position in the data set.
`abstract long`	`getItemId(int position)` Get the row id associated with the specified position in the list.
`abstract int`	`getItemViewType(int position)` Get the type of View that will be created by `getView(int, View, ViewGroup)` for the specified item.
`abstract View`	`getView(int position, View convertView, ViewGroup parent)` Get a View that displays the data at the specified position in the data set.
`abstract int`	`getViewTypeCount()` Returns the number of types of Views that will be created by `getView(int, View, ViewGroup)`.
`abstract boolean`	`hasStableIds()` Indicates whether the item ids are stable across changes to the underlying data.
`abstract boolean`	`isEmpty()`
`abstract void`	`registerDataSetObserver(DataSetObserver observer)` Register an observer that is called when changes happen to the data used by this adapter.
`abstract void`	`unregisterDataSetObserver(DataSetObserver observer)` Unregister an observer that has previously been registered with this adapter via `registerDataSetObserver(DataSetObserver)`.

Constants

IGNORE_ITEM_VIEW_TYPE

Added in API level 1

public static final int IGNORE_ITEM_VIEW_TYPE

An item view type that causes the AdapterView to ignore the item view. For example, this can be used if the client does not want a particular view to be given for conversion in getView(int, android.view.View, android.view.ViewGroup).

See also:

Constant Value: -1 (0xffffffff)

NO_SELECTION

Added in API level 1

public static final int NO_SELECTION

Constant Value: -2147483648 (0x80000000)

Public methods

getAutofillOptions

Added in API level 26

public CharSequence[] getAutofillOptions ()

Gets a string representation of the adapter data that can help AutofillService autofill the view backed by the adapter.

It should only be set (i.e., non-null if the values do not represent PII (Personally Identifiable Information - sensitive data such as email addresses, credit card numbers, passwords, etc...). For example, it's ok to return a list of month names, but not a list of usernames. A good rule of thumb is that if the adapter data comes from static resources, such data is not PII - see ViewStructure.setDataIsSensitive(boolean) for more info.

Returns
`CharSequence[]`	`null` by default, unless implementations override it.

getCount

Added in API level 1

public abstract int getCount ()

How many items are in the data set represented by this Adapter.

Returns
`int`	Count of items.

getItem

Added in API level 1

public abstract Object getItem (int position)

Get the data item associated with the specified position in the data set.

Parameters
`position`	`int`: Position of the item whose data we want within the adapter's data set.

Returns
`Object`	The data at the specified position.

getItemId

Added in API level 1

public abstract long getItemId (int position)

Get the row id associated with the specified position in the list.

Parameters
`position`	`int`: The position of the item within the adapter's data set whose row id we want.

Returns
`long`	The id of the item at the specified position.

getItemViewType

Added in API level 1

public abstract int getItemViewType (int position)

Get the type of View that will be created by getView(int, View, ViewGroup) for the specified item.

Parameters
`position`	`int`: The position of the item within the adapter's data set whose view type we want.

Returns
`int`	An integer representing the type of View. Two views should share the same type if one can be converted to the other in `getView(int, View, ViewGroup)`. Note: Integers must be in the range 0 to `getViewTypeCount()` - 1. `IGNORE_ITEM_VIEW_TYPE` can also be returned.

See also:

IGNORE_ITEM_VIEW_TYPE

getView

Added in API level 1

public abstract View getView (int position, 
                View convertView, 
                ViewGroup parent)

Get a View that displays the data at the specified position in the data set. You can either create a View manually or inflate it from an XML layout file. When the View is inflated, the parent View (GridView, ListView...) will apply default layout parameters unless you use LayoutInflater.inflate(int, android.view.ViewGroup, boolean) to specify a root view and to prevent attachment to the root.

Parameters
`position`	`int`: The position of the item within the adapter's data set of the item whose view we want.
`convertView`	`View`: The old view to reuse, if possible. Note: You should check that this view is non-null and of an appropriate type before using. If it is not possible to convert this view to display the correct data, this method can create a new view. Heterogeneous lists can specify their number of view types, so that this View is always of the right type (see `getViewTypeCount()` and `getItemViewType(int)`).
`parent`	`ViewGroup`: The parent that this view will eventually be attached to

Returns
`View`	A View corresponding to the data at the specified position.

getViewTypeCount

Added in API level 1

public abstract int getViewTypeCount ()

Returns the number of types of Views that will be created by getView(int, View, ViewGroup). Each type represents a set of views that can be converted in getView(int, View, ViewGroup). If the adapter always returns the same type of View for all items, this method should return 1.

This method will only be called when the adapter is set on the AdapterView.

Returns
`int`	The number of types of Views that will be created by this adapter

hasStableIds

Added in API level 1

public abstract boolean hasStableIds ()

Indicates whether the item ids are stable across changes to the underlying data.

Returns
`boolean`	True if the same id always refers to the same object.

isEmpty

Added in API level 1

public abstract boolean isEmpty ()

Returns
`boolean`	true if this adapter doesn't contain any data. This is used to determine whether the empty view should be displayed. A typical implementation will return getCount() == 0 but since getCount() includes the headers and footers, specialized adapters might want a different behavior.

registerDataSetObserver

Added in API level 1

public abstract void registerDataSetObserver (DataSetObserver observer)

Parameters
`observer`	`DataSetObserver`: the object that gets notified when the data set changes.

unregisterDataSetObserver

Added in API level 1

public abstract void unregisterDataSetObserver (DataSetObserver observer)

Unregister an observer that has previously been registered with this adapter via registerDataSetObserver(DataSetObserver).

Parameters
`observer`	`DataSetObserver`: the object to unregister.