Adapter | API reference | Android Developers (original) (raw)

public interface Adapter
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Known indirect subclasses

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

An Adapter object acts as a bridge between an [AdapterView](/reference/android/widget/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](/reference/android/view/View) for each item in the data set.

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
defaultCharSequence[]	getAutofillOptions() Gets a string representation of the adapter data that can helpAutofillService autofill the view backed by the adapter.
abstract int	getCount() How many items are in the data set represented by this Adapter.
abstractObject	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.
abstractView	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 bygetView(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

public static final int IGNORE_ITEM_VIEW_TYPE

An item view type that causes the [AdapterView](/reference/android/widget/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)](/reference/android/widget/Adapter#getView%28int,%20android.view.View,%20android.view.ViewGroup%29).

Constant Value: -1 (0xffffffff)

NO_SELECTION

public static final int NO_SELECTION

Constant Value: -2147483648 (0x80000000)

Public methods

getAutofillOptions

public CharSequence[] getAutofillOptions ()

Gets a string representation of the adapter data that can help[AutofillService](/reference/android/service/autofill/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)](/reference/android/view/ViewStructure#setDataIsSensitive%28boolean%29) for more info.

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

getCount

public abstract int getCount ()

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

Returns
int	Count of items.

getItem

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

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

public abstract int getItemViewType (int position)

Get the type of View that will be created by [getView(int, View, ViewGroup)](/reference/android/widget/Adapter#getView%28int,%20android.view.View,%20android.view.ViewGroup%29) 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.

getView

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)](/reference/android/view/LayoutInflater#inflate%28int,%20android.view.ViewGroup,%20boolean%29) 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() andgetItemViewType(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

public abstract int getViewTypeCount ()

Returns the number of types of Views that will be created by[getView(int, View, ViewGroup)](/reference/android/widget/Adapter#getView%28int,%20android.view.View,%20android.view.ViewGroup%29). Each type represents a set of views that can be converted in [getView(int, View, ViewGroup)](/reference/android/widget/Adapter#getView%28int,%20android.view.View,%20android.view.ViewGroup%29). 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](/reference/android/widget/AdapterView).

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

hasStableIds

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

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

public abstract void registerDataSetObserver (DataSetObserver observer)

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

unregisterDataSetObserver

public abstract void unregisterDataSetObserver (DataSetObserver observer)

Unregister an observer that has previously been registered with this adapter via [registerDataSetObserver(DataSetObserver)](/reference/android/widget/Adapter#registerDataSetObserver%28android.database.DataSetObserver%29).

Parameters
observer	DataSetObserver: the object to unregister.