Added in [API level 1](https://developer.android.com/guide/topics/manifest/uses-sdk-element#ApiLevels) Summary: [Inherited Constants](https://developer.android.com/reference/android/widget/BaseAdapter#inhconstants) \| [Ctors](https://developer.android.com/reference/android/widget/BaseAdapter#pubctors) \| [Methods](https://developer.android.com/reference/android/widget/BaseAdapter#pubmethods) \| [Inherited Methods](https://developer.android.com/reference/android/widget/BaseAdapter#inhmethods)

# BaseAdapter

*** ** * ** ***

` public abstract class BaseAdapter `   
` extends https://developer.android.com/reference/java/lang/Object ` ` implements https://developer.android.com/reference/android/widget/ListAdapter, https://developer.android.com/reference/android/widget/SpinnerAdapter `

|---|---|
| [java.lang.Object](https://developer.android.com/reference/java/lang/Object) ||
| ↳ | android.widget.BaseAdapter |

Known direct subclasses [ArrayAdapter](https://developer.android.com/reference/android/widget/ArrayAdapter)\<T\>, [CursorAdapter](https://developer.android.com/reference/android/widget/CursorAdapter), [SimpleAdapter](https://developer.android.com/reference/android/widget/SimpleAdapter) [ArrayAdapter](https://developer.android.com/reference/android/widget/ArrayAdapter)\<T\> You can use this adapter to provide views for an `https://developer.android.com/reference/android/widget/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 `https://developer.android.com/reference/android/widget/ListView` or `https://developer.android.com/reference/android/widget/Spinner`. [CursorAdapter](https://developer.android.com/reference/android/widget/CursorAdapter) Adapter that exposes data from a `https://developer.android.com/reference/android/database/Cursor` to a `https://developer.android.com/reference/android/widget/ListView` widget. [SimpleAdapter](https://developer.android.com/reference/android/widget/SimpleAdapter) An easy adapter to map static data to views defined in an XML file. Known indirect subclasses [ResourceCursorAdapter](https://developer.android.com/reference/android/widget/ResourceCursorAdapter), [SimpleCursorAdapter](https://developer.android.com/reference/android/widget/SimpleCursorAdapter) [ResourceCursorAdapter](https://developer.android.com/reference/android/widget/ResourceCursorAdapter) An easy adapter that creates views defined in an XML file. [SimpleCursorAdapter](https://developer.android.com/reference/android/widget/SimpleCursorAdapter) An easy adapter to map columns from a cursor to TextViews or ImageViews defined in an XML file.   

*** ** * ** ***

Common base class of common implementation for an `https://developer.android.com/reference/android/widget/Adapter` that can be used in both `https://developer.android.com/reference/android/widget/ListView` (by implementing the specialized `https://developer.android.com/reference/android/widget/ListAdapter` interface) and `https://developer.android.com/reference/android/widget/Spinner` (by implementing the specialized `https://developer.android.com/reference/android/widget/SpinnerAdapter` interface).

## Summary

### Inherited constants

From interface `https://developer.android.com/reference/android/widget/Adapter` `int` `https://developer.android.com/reference/android/widget/Adapter#IGNORE_ITEM_VIEW_TYPE`

An item view type that causes the `https://developer.android.com/reference/android/widget/AdapterView` to ignore the item view.
`int` `https://developer.android.com/reference/android/widget/Adapter#NO_SELECTION`

<br />

| ### Public constructors ||
|---|---|
| ` https://developer.android.com/reference/android/widget/BaseAdapter#BaseAdapter()() ` |

| ### Public methods ||
|---|---|
| ` boolean` | ` https://developer.android.com/reference/android/widget/BaseAdapter#areAllItemsEnabled()() ` Indicates whether all the items in this adapter are enabled. |
| ` https://developer.android.com/reference/java/lang/CharSequence` | ` https://developer.android.com/reference/android/widget/BaseAdapter#getAutofillOptions()() ` Gets a string representation of the adapter data that can help `https://developer.android.com/reference/android/service/autofill/AutofillService` autofill the view backed by the adapter. |
| ` https://developer.android.com/reference/android/view/View` | ` https://developer.android.com/reference/android/widget/BaseAdapter#getDropDownView(int,%20android.view.View,%20android.view.ViewGroup)(int position, https://developer.android.com/reference/android/view/View convertView, https://developer.android.com/reference/android/view/ViewGroup parent) ` Gets a `https://developer.android.com/reference/android/view/View` that displays in the drop down popup the data at the specified position in the data set. |
| ` int` | ` https://developer.android.com/reference/android/widget/BaseAdapter#getItemViewType(int)(int position) ` Get the type of View that will be created by `https://developer.android.com/reference/android/widget/Adapter#getView(int,%20android.view.View,%20android.view.ViewGroup)` for the specified item. |
| ` int` | ` https://developer.android.com/reference/android/widget/BaseAdapter#getViewTypeCount()() ` <br /> Returns the number of types of Views that will be created by `https://developer.android.com/reference/android/widget/Adapter#getView(int,%20android.view.View,%20android.view.ViewGroup)`. |
| ` boolean` | ` https://developer.android.com/reference/android/widget/BaseAdapter#hasStableIds()() ` Indicates whether the item ids are stable across changes to the underlying data. |
| ` boolean` | ` https://developer.android.com/reference/android/widget/BaseAdapter#isEmpty()() ` <br /> |
| ` boolean` | ` https://developer.android.com/reference/android/widget/BaseAdapter#isEnabled(int)(int position) ` Returns true if the item at the specified position is not a separator. |
| ` void` | ` https://developer.android.com/reference/android/widget/BaseAdapter#notifyDataSetChanged()() ` Notifies the attached observers that the underlying data has been changed and any View reflecting the data set should refresh itself. |
| ` void` | ` https://developer.android.com/reference/android/widget/BaseAdapter#notifyDataSetInvalidated()() ` Notifies the attached observers that the underlying data is no longer valid or available. |
| ` void` | ` https://developer.android.com/reference/android/widget/BaseAdapter#registerDataSetObserver(android.database.DataSetObserver)(https://developer.android.com/reference/android/database/DataSetObserver observer) ` Register an observer that is called when changes happen to the data used by this adapter. |
| ` void` | ` https://developer.android.com/reference/android/widget/BaseAdapter#setAutofillOptions(java.lang.CharSequence[])(https://developer.android.com/reference/java/lang/CharSequence options) ` Sets the value returned by `https://developer.android.com/reference/android/widget/BaseAdapter#getAutofillOptions()` |
| ` void` | ` https://developer.android.com/reference/android/widget/BaseAdapter#unregisterDataSetObserver(android.database.DataSetObserver)(https://developer.android.com/reference/android/database/DataSetObserver observer) ` Unregister an observer that has previously been registered with this adapter via `https://developer.android.com/reference/android/widget/Adapter#registerDataSetObserver(android.database.DataSetObserver)`. |

### Inherited methods

From class ` https://developer.android.com/reference/java/lang/Object ` ` https://developer.android.com/reference/java/lang/Object` ` https://developer.android.com/reference/java/lang/Object#clone()() `

Creates and returns a copy of this object.
` boolean` ` https://developer.android.com/reference/java/lang/Object#equals(java.lang.Object)(https://developer.android.com/reference/java/lang/Object obj) `

Indicates whether some other object is "equal to" this one.
` void` ` https://developer.android.com/reference/java/lang/Object#finalize()() `

Called by the garbage collector on an object when garbage collection determines that there are no more references to the object.
` final https://developer.android.com/reference/java/lang/Class<?>` ` https://developer.android.com/reference/java/lang/Object#getClass()() `

Returns the runtime class of this `Object`.
` int` ` https://developer.android.com/reference/java/lang/Object#hashCode()() `

Returns a hash code value for the object.
` final void` ` https://developer.android.com/reference/java/lang/Object#notify()() `

Wakes up a single thread that is waiting on this object's monitor.
` final void` ` https://developer.android.com/reference/java/lang/Object#notifyAll()() `

Wakes up all threads that are waiting on this object's monitor.
` https://developer.android.com/reference/java/lang/String` ` https://developer.android.com/reference/java/lang/Object#toString()() `

Returns a string representation of the object.
` final void` ` https://developer.android.com/reference/java/lang/Object#wait(long,%20int)(long timeoutMillis, int nanos) `

Causes the current thread to wait until it is awakened, typically by being *notified* or *interrupted*, or until a certain amount of real time has elapsed.
` final void` ` https://developer.android.com/reference/java/lang/Object#wait(long)(long timeoutMillis) `

Causes the current thread to wait until it is awakened, typically by being *notified* or *interrupted*, or until a certain amount of real time has elapsed.
` final void` ` https://developer.android.com/reference/java/lang/Object#wait()() `

Causes the current thread to wait until it is awakened, typically by being *notified* or *interrupted*.
From interface ` https://developer.android.com/reference/android/widget/ListAdapter ` ` abstract boolean` ` https://developer.android.com/reference/android/widget/ListAdapter#areAllItemsEnabled()() `

Indicates whether all the items in this adapter are enabled.
` abstract boolean` ` https://developer.android.com/reference/android/widget/ListAdapter#isEnabled(int)(int position) `

Returns true if the item at the specified position is not a separator.
From interface ` https://developer.android.com/reference/android/widget/SpinnerAdapter ` ` abstract https://developer.android.com/reference/android/view/View` ` https://developer.android.com/reference/android/widget/SpinnerAdapter#getDropDownView(int,%20android.view.View,%20android.view.ViewGroup)(int position, https://developer.android.com/reference/android/view/View convertView, https://developer.android.com/reference/android/view/ViewGroup parent) `

Gets a `https://developer.android.com/reference/android/view/View` that displays in the drop down popup the data at the specified position in the data set.
From interface ` https://developer.android.com/reference/android/widget/Adapter ` ` default https://developer.android.com/reference/java/lang/CharSequence` ` https://developer.android.com/reference/android/widget/Adapter#getAutofillOptions()() `

Gets a string representation of the adapter data that can help `https://developer.android.com/reference/android/service/autofill/AutofillService` autofill the view backed by the adapter.
` abstract int` ` https://developer.android.com/reference/android/widget/Adapter#getCount()() `

How many items are in the data set represented by this Adapter.
` abstract https://developer.android.com/reference/java/lang/Object` ` https://developer.android.com/reference/android/widget/Adapter#getItem(int)(int position) `

Get the data item associated with the specified position in the data set.
` abstract long` ` https://developer.android.com/reference/android/widget/Adapter#getItemId(int)(int position) `

Get the row id associated with the specified position in the list.
` abstract int` ` https://developer.android.com/reference/android/widget/Adapter#getItemViewType(int)(int position) `

Get the type of View that will be created by `https://developer.android.com/reference/android/widget/Adapter#getView(int,%20android.view.View,%20android.view.ViewGroup)` for the specified item.
` abstract https://developer.android.com/reference/android/view/View` ` https://developer.android.com/reference/android/widget/Adapter#getView(int,%20android.view.View,%20android.view.ViewGroup)(int position, https://developer.android.com/reference/android/view/View convertView, https://developer.android.com/reference/android/view/ViewGroup parent) `

Get a View that displays the data at the specified position in the data set.
` abstract int` ` https://developer.android.com/reference/android/widget/Adapter#getViewTypeCount()() `

<br />

Returns the number of types of Views that will be created by `https://developer.android.com/reference/android/widget/Adapter#getView(int,%20android.view.View,%20android.view.ViewGroup)`.
` abstract boolean` ` https://developer.android.com/reference/android/widget/Adapter#hasStableIds()() `

Indicates whether the item ids are stable across changes to the underlying data.
` abstract boolean` ` https://developer.android.com/reference/android/widget/Adapter#isEmpty()() ` ` abstract void` ` https://developer.android.com/reference/android/widget/Adapter#registerDataSetObserver(android.database.DataSetObserver)(https://developer.android.com/reference/android/database/DataSetObserver observer) `

Register an observer that is called when changes happen to the data used by this adapter.
` abstract void` ` https://developer.android.com/reference/android/widget/Adapter#unregisterDataSetObserver(android.database.DataSetObserver)(https://developer.android.com/reference/android/database/DataSetObserver observer) `

Unregister an observer that has previously been registered with this adapter via `https://developer.android.com/reference/android/widget/Adapter#registerDataSetObserver(android.database.DataSetObserver)`.

## Public constructors

### BaseAdapter

```
public BaseAdapter ()
```

<br />

<br />

## Public methods

### areAllItemsEnabled

Added in [API level 1](https://developer.android.com/guide/topics/manifest/uses-sdk-element#ApiLevels)

```
public boolean areAllItemsEnabled ()
```

Indicates whether all the items in this adapter are enabled. If the value returned by this method changes over time, there is no guarantee it will take effect. If true, it means all items are selectable and clickable (there is no separator.)

<br />

| Returns ||
|---|---|
| `boolean` | True if all items are enabled, false otherwise. <br /> |

### getAutofillOptions

Added in [API level 26](https://developer.android.com/guide/topics/manifest/uses-sdk-element#ApiLevels)

```
public CharSequence[] getAutofillOptions ()
```

Gets a string representation of the adapter data that can help `https://developer.android.com/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 `https://developer.android.com/reference/android/view/ViewStructure#setDataIsSensitive(boolean)` for more info.

<br />

| Returns ||
|---|---|
| `https://developer.android.com/reference/java/lang/CharSequence` | `null` by default, unless implementations override it. <br /> |

### getDropDownView

Added in [API level 1](https://developer.android.com/guide/topics/manifest/uses-sdk-element#ApiLevels)

```
public View getDropDownView (int position, 
                View convertView, 
                ViewGroup parent)
```

Gets a `https://developer.android.com/reference/android/view/View` that displays in the drop down popup the data at the specified position in the data set.

<br />

| Parameters ||
|---|---|
| `position` | `int`: index of the item whose view we want. <br /> |
| `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. <br /> |
| `parent` | `ViewGroup`: the parent that this view will eventually be attached to <br /> |

| Returns ||
|---|---|
| `https://developer.android.com/reference/android/view/View` | a `https://developer.android.com/reference/android/view/View` corresponding to the data at the specified position. <br /> |

### getItemViewType

Added in [API level 1](https://developer.android.com/guide/topics/manifest/uses-sdk-element#ApiLevels)

```
public int getItemViewType (int position)
```

Get the type of View that will be created by `https://developer.android.com/reference/android/widget/Adapter#getView(int,%20android.view.View,%20android.view.ViewGroup)` for the specified item.

<br />

| Parameters ||
|---|---|
| `position` | `int`: The position of the item within the adapter's data set whose view type we want. <br /> |

| 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 `https://developer.android.com/reference/android/widget/Adapter#getView(int,%20android.view.View,%20android.view.ViewGroup)`. Note: Integers must be in the range 0 to `https://developer.android.com/reference/android/widget/Adapter#getViewTypeCount()` - 1. `https://developer.android.com/reference/android/widget/Adapter#IGNORE_ITEM_VIEW_TYPE` can also be returned. <br /> |

### getViewTypeCount

Added in [API level 1](https://developer.android.com/guide/topics/manifest/uses-sdk-element#ApiLevels)

```
public int getViewTypeCount ()
```

<br />

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

<br />

<br />

| Returns ||
|---|---|
| `int` | The number of types of Views that will be created by this adapter <br /> |

### hasStableIds

Added in [API level 1](https://developer.android.com/guide/topics/manifest/uses-sdk-element#ApiLevels)

```
public boolean hasStableIds ()
```

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

<br />

| Returns ||
|---|---|
| `boolean` | True if the same id always refers to the same object. <br /> |

### isEmpty

Added in [API level 1](https://developer.android.com/guide/topics/manifest/uses-sdk-element#ApiLevels)

```
public boolean isEmpty ()
```

<br />

<br />

| Returns ||
|---|---|
| `boolean` | <br /> |

### isEnabled

Added in [API level 1](https://developer.android.com/guide/topics/manifest/uses-sdk-element#ApiLevels)

```
public boolean isEnabled (int position)
```

Returns true if the item at the specified position is not a separator. (A separator is a non-selectable, non-clickable item). The result is unspecified if position is invalid. An `https://developer.android.com/reference/java/lang/ArrayIndexOutOfBoundsException` should be thrown in that case for fast failure.

<br />

| Parameters ||
|---|---|
| `position` | `int`: Index of the item <br /> |

| Returns ||
|---|---|
| `boolean` | True if the item is not a separator <br /> |

### notifyDataSetChanged

Added in [API level 1](https://developer.android.com/guide/topics/manifest/uses-sdk-element#ApiLevels)

```
public void notifyDataSetChanged ()
```

Notifies the attached observers that the underlying data has been changed and any View reflecting the data set should refresh itself.

<br />

### notifyDataSetInvalidated

Added in [API level 1](https://developer.android.com/guide/topics/manifest/uses-sdk-element#ApiLevels)

```
public void notifyDataSetInvalidated ()
```

Notifies the attached observers that the underlying data is no longer valid or available. Once invoked this adapter is no longer valid and should not report further data set changes.

<br />

### registerDataSetObserver

Added in [API level 1](https://developer.android.com/guide/topics/manifest/uses-sdk-element#ApiLevels)

```
public void registerDataSetObserver (DataSetObserver observer)
```

Register an observer that is called when changes happen to the data used by this adapter.

<br />

| Parameters ||
|---|---|
| `observer` | `DataSetObserver`: the object that gets notified when the data set changes. <br /> |

### setAutofillOptions

Added in [API level 27](https://developer.android.com/guide/topics/manifest/uses-sdk-element#ApiLevels)

```
public void setAutofillOptions (CharSequence... options)
```

Sets the value returned by `https://developer.android.com/reference/android/widget/BaseAdapter#getAutofillOptions()`

<br />

| Parameters ||
|---|---|
| `options` | `CharSequence`: This value may be `null`. <br /> |

### unregisterDataSetObserver

Added in [API level 1](https://developer.android.com/guide/topics/manifest/uses-sdk-element#ApiLevels)

```
public void unregisterDataSetObserver (DataSetObserver observer)
```

Unregister an observer that has previously been registered with this adapter via `https://developer.android.com/reference/android/widget/Adapter#registerDataSetObserver(android.database.DataSetObserver)`.

<br />

| Parameters ||
|---|---|
| `observer` | `DataSetObserver`: the object to unregister. <br /> |