# DiffUtil.DiffResult

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

*** ** * ** ***


```
public class DiffUtil.DiffResult
```

<br />

*** ** * ** ***

This class holds the information about the result of a `https://developer.android.com/reference/androidx/recyclerview/widget/DiffUtil#calculateDiff(androidx.recyclerview.widget.DiffUtil.Callback,boolean)` call.

You can consume the updates in a DiffResult via `https://developer.android.com/reference/androidx/recyclerview/widget/DiffUtil.DiffResult#dispatchUpdatesTo(androidx.recyclerview.widget.ListUpdateCallback)` or directly stream the results into a `https://developer.android.com/reference/androidx/recyclerview/widget/RecyclerView.Adapter` via `https://developer.android.com/reference/androidx/recyclerview/widget/DiffUtil.DiffResult#dispatchUpdatesTo(androidx.recyclerview.widget.RecyclerView.Adapter)`.

## Summary

| ### Constants |
|---|---|
| `static final int` | `https://developer.android.com/reference/androidx/recyclerview/widget/DiffUtil.DiffResult#NO_POSITION() = -1` Signifies an item not present in the list. |

| ### Public methods |
|---|---|
| `int` | `https://developer.android.com/reference/androidx/recyclerview/widget/DiffUtil.DiffResult#convertNewPositionToOld(int)(@https://developer.android.com/reference/androidx/annotation/IntRange(from = 0) int newListPosition)` Given a position in the new list, returns the position in the old list, or `NO_POSITION` if it was removed. |
| `int` | `https://developer.android.com/reference/androidx/recyclerview/widget/DiffUtil.DiffResult#convertOldPositionToNew(int)(@https://developer.android.com/reference/androidx/annotation/IntRange(from = 0) int oldListPosition)` Given a position in the old list, returns the position in the new list, or `NO_POSITION` if it was removed. |
| `void` | `https://developer.android.com/reference/androidx/recyclerview/widget/DiffUtil.DiffResult#dispatchUpdatesTo(androidx.recyclerview.widget.RecyclerView.Adapter)(@https://developer.android.com/reference/androidx/annotation/NonNull https://developer.android.com/reference/androidx/recyclerview/widget/RecyclerView.Adapter adapter)` Dispatches the update events to the given adapter. |
| `void` | `https://developer.android.com/reference/androidx/recyclerview/widget/DiffUtil.DiffResult#dispatchUpdatesTo(androidx.recyclerview.widget.ListUpdateCallback)(@https://developer.android.com/reference/androidx/annotation/NonNull https://developer.android.com/reference/androidx/recyclerview/widget/ListUpdateCallback updateCallback)` Dispatches update operations to the given Callback. |

## Constants

### NO_POSITION

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

```
public static final int NO_POSITION = -1
```

Signifies an item not present in the list.

## Public methods

### convertNewPositionToOld

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

```
public int convertNewPositionToOld(@IntRange(from = 0) int newListPosition)
```

Given a position in the new list, returns the position in the old list, or `NO_POSITION` if it was removed.

| Parameters |
|---|---|
| `@https://developer.android.com/reference/androidx/annotation/IntRange(from = 0) int newListPosition` | Position of item in new list |

| Returns |
|---|---|
| `int` | Position of item in old list, or `NO_POSITION` if not present. |

| See also |
|---|---|
| `https://developer.android.com/reference/androidx/recyclerview/widget/DiffUtil.DiffResult#NO_POSITION()` |   |
| `https://developer.android.com/reference/androidx/recyclerview/widget/DiffUtil.DiffResult#convertOldPositionToNew(int)` |   |

### convertOldPositionToNew

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

```
public int convertOldPositionToNew(@IntRange(from = 0) int oldListPosition)
```

Given a position in the old list, returns the position in the new list, or `NO_POSITION` if it was removed.

| Parameters |
|---|---|
| `@https://developer.android.com/reference/androidx/annotation/IntRange(from = 0) int oldListPosition` | Position of item in old list |

| Returns |
|---|---|
| `int` | Position of item in new list, or `NO_POSITION` if not present. |

| See also |
|---|---|
| `https://developer.android.com/reference/androidx/recyclerview/widget/DiffUtil.DiffResult#NO_POSITION()` |   |
| `https://developer.android.com/reference/androidx/recyclerview/widget/DiffUtil.DiffResult#convertNewPositionToOld(int)` |   |

### dispatchUpdatesTo

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

```
public void dispatchUpdatesTo(@NonNull RecyclerView.Adapter adapter)
```

Dispatches the update events to the given adapter.

For example, if you have an `https://developer.android.com/reference/androidx/recyclerview/widget/RecyclerView.Adapter` that is backed by a `https://developer.android.com/reference/java/util/List.html`, you can swap the list with the new one then call this method to dispatch all updates to the RecyclerView.

```
    List oldList = mAdapter.getData();
    DiffResult result = DiffUtil.calculateDiff(new MyCallback(oldList, newList));
    mAdapter.setData(newList);
    result.dispatchUpdatesTo(mAdapter);
```

Note that the RecyclerView requires you to dispatch adapter updates immediately when you change the data (you cannot defer `notify*` calls). The usage above adheres to this rule because updates are sent to the adapter right after the backing data is changed, before RecyclerView tries to read it.

On the other hand, if you have another `https://developer.android.com/reference/androidx/recyclerview/widget/RecyclerView.AdapterDataObserver` that tries to process events synchronously, this may confuse that observer because the list is instantly moved to its final state while the adapter updates are dispatched later on, one by one. If you have such an `https://developer.android.com/reference/androidx/recyclerview/widget/RecyclerView.AdapterDataObserver`, you can use `https://developer.android.com/reference/androidx/recyclerview/widget/DiffUtil.DiffResult#dispatchUpdatesTo(androidx.recyclerview.widget.ListUpdateCallback)` to handle each modification manually.

| Parameters |
|---|---|
| `@https://developer.android.com/reference/androidx/annotation/NonNull https://developer.android.com/reference/androidx/recyclerview/widget/RecyclerView.Adapter adapter` | A RecyclerView adapter which was displaying the old list and will start displaying the new list. |

| See also |
|---|---|
| `https://developer.android.com/reference/androidx/recyclerview/widget/AdapterListUpdateCallback` |   |

### dispatchUpdatesTo

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

```
public void dispatchUpdatesTo(@NonNull ListUpdateCallback updateCallback)
```

Dispatches update operations to the given Callback.

These updates are atomic such that the first update call affects every update call that comes after it (the same as RecyclerView).

| Parameters |
|---|---|
| `@https://developer.android.com/reference/androidx/annotation/NonNull https://developer.android.com/reference/androidx/recyclerview/widget/ListUpdateCallback updateCallback` | The callback to receive the update operations. |

| See also |
|---|---|
| `https://developer.android.com/reference/androidx/recyclerview/widget/DiffUtil.DiffResult#dispatchUpdatesTo(androidx.recyclerview.widget.RecyclerView.Adapter)` |   |