# RecyclerView.AdapterDataObserver

Artifact: [androidx.recyclerview:recyclerview](https://developer.android.com/jetpack/androidx/releases/recyclerview) [View Source](https://cs.android.com/search?q=file:androidx/recyclerview/widget/RecyclerView.java+class:androidx.recyclerview.widget.RecyclerView.AdapterDataObserver) Added in [1.0.0](https://developer.android.com/jetpack/androidx/releases/recyclerview#1.0.0)

*** ** * ** ***


```
public abstract class RecyclerView.AdapterDataObserver
```

<br />

*** ** * ** ***

Observer base class for watching changes to an `https://developer.android.com/reference/androidx/recyclerview/widget/RecyclerView.Adapter`. See `https://developer.android.com/reference/androidx/recyclerview/widget/RecyclerView.Adapter#registerAdapterDataObserver(androidx.recyclerview.widget.RecyclerView.AdapterDataObserver)`.

## Summary

| ### Public constructors |
|---|
| `https://developer.android.com/reference/androidx/recyclerview/widget/RecyclerView.AdapterDataObserver#AdapterDataObserver()()` |

| ### Public methods |
|---|---|
| `void` | `https://developer.android.com/reference/androidx/recyclerview/widget/RecyclerView.AdapterDataObserver#onChanged()()` |
| `void` | `https://developer.android.com/reference/androidx/recyclerview/widget/RecyclerView.AdapterDataObserver#onItemRangeChanged(int,int)(int positionStart, int itemCount)` |
| `void` | `https://developer.android.com/reference/androidx/recyclerview/widget/RecyclerView.AdapterDataObserver#onItemRangeChanged(int,int,java.lang.Object)( int positionStart, int itemCount, @https://developer.android.com/reference/androidx/annotation/Nullable https://developer.android.com/reference/java/lang/Object.html payload )` |
| `void` | `https://developer.android.com/reference/androidx/recyclerview/widget/RecyclerView.AdapterDataObserver#onItemRangeInserted(int,int)(int positionStart, int itemCount)` |
| `void` | `https://developer.android.com/reference/androidx/recyclerview/widget/RecyclerView.AdapterDataObserver#onItemRangeMoved(int,int,int)(int fromPosition, int toPosition, int itemCount)` |
| `void` | `https://developer.android.com/reference/androidx/recyclerview/widget/RecyclerView.AdapterDataObserver#onItemRangeRemoved(int,int)(int positionStart, int itemCount)` |
| `void` | `https://developer.android.com/reference/androidx/recyclerview/widget/RecyclerView.AdapterDataObserver#onStateRestorationPolicyChanged()()` Called when the `https://developer.android.com/reference/androidx/recyclerview/widget/RecyclerView.Adapter.StateRestorationPolicy` of the `https://developer.android.com/reference/androidx/recyclerview/widget/RecyclerView.Adapter` changed. |

## Public constructors

### AdapterDataObserver

Added in 1.0.0

```
public AdapterDataObserver()
```

## Public methods

### onChanged

Added in [1.0.0](https://developer.android.com/jetpack/androidx/releases/recyclerview#1.0.0)

```
public void onChanged()
```

### onItemRangeChanged

Added in [1.0.0](https://developer.android.com/jetpack/androidx/releases/recyclerview#1.0.0)

```
public void onItemRangeChanged(int positionStart, int itemCount)
```

### onItemRangeChanged

Added in [1.0.0](https://developer.android.com/jetpack/androidx/releases/recyclerview#1.0.0)

```
public void onItemRangeChanged(
    int positionStart,
    int itemCount,
    @Nullable Object payload
)
```

### onItemRangeInserted

Added in [1.0.0](https://developer.android.com/jetpack/androidx/releases/recyclerview#1.0.0)

```
public void onItemRangeInserted(int positionStart, int itemCount)
```

### onItemRangeMoved

Added in [1.0.0](https://developer.android.com/jetpack/androidx/releases/recyclerview#1.0.0)

```
public void onItemRangeMoved(int fromPosition, int toPosition, int itemCount)
```

### onItemRangeRemoved

Added in [1.0.0](https://developer.android.com/jetpack/androidx/releases/recyclerview#1.0.0)

```
public void onItemRangeRemoved(int positionStart, int itemCount)
```

### onStateRestorationPolicyChanged

Added in [1.2.0](https://developer.android.com/jetpack/androidx/releases/recyclerview#1.2.0)

```
public void onStateRestorationPolicyChanged()
```

Called when the `https://developer.android.com/reference/androidx/recyclerview/widget/RecyclerView.Adapter.StateRestorationPolicy` of the `https://developer.android.com/reference/androidx/recyclerview/widget/RecyclerView.Adapter` changed. When this method is called, the Adapter might be ready to restore its state if it has not already been restored.

| See also |
|---|---|
| `https://developer.android.com/reference/androidx/recyclerview/widget/RecyclerView.Adapter#getStateRestorationPolicy()` |   |
| `https://developer.android.com/reference/androidx/recyclerview/widget/RecyclerView.Adapter#setStateRestorationPolicy(androidx.recyclerview.widget.RecyclerView.Adapter.StateRestorationPolicy)` |   |