# PageKeyedDataSource.LoadInitialCallback

Artifact: [androidx.paging:paging-common](https://developer.android.com/jetpack/androidx/releases/paging) [View Source](https://cs.android.com/search?q=file:androidx/paging/PageKeyedDataSource.jvmAndAndroid.kt+class:androidx.paging.PageKeyedDataSource.LoadInitialCallback) Added in [2.0.0](https://developer.android.com/jetpack/androidx/releases/paging#2.0.0) Deprecated in [3.0.0](https://developer.android.com/jetpack/androidx/releases/paging#3.0.0)

*** ** * ** ***

Common/AllAndroid/JVMNative/C/iOSJavaScript
- android

  ```
  abstract class PageKeyedDataSource.LoadInitialCallback<Key : Any?, Value : Any?>
  ```

*** ** * ** ***

> [!CAUTION]
> **This class is deprecated.**   
> PageKeyedDataSource is deprecated and has been replaced by PagingSource, use this instead:
>
> ```kotlin
> PagingSource<Key, Value>
> ```

Callback for `https://developer.android.com/reference/kotlin/androidx/paging/PageKeyedDataSource#loadInitial(androidx.paging.PageKeyedDataSource.LoadInitialParams)` to return data and, optionally, position/count information.

A callback can be called only once, and will throw if called again.

If you can compute the number of items in the data set before and after the loaded range, call the five parameter `https://developer.android.com/reference/kotlin/androidx/paging/PageKeyedDataSource.LoadInitialCallback#onResult(kotlin.collections.List,kotlin.Int,kotlin.Int,kotlin.Any,kotlin.Any)` to pass that information. You can skip passing this information by calling the three parameter `https://developer.android.com/reference/kotlin/androidx/paging/PageKeyedDataSource.LoadInitialCallback#onResult(kotlin.collections.List,kotlin.Int,kotlin.Int,kotlin.Any,kotlin.Any)`, either if it's difficult to compute, or if `https://developer.android.com/reference/kotlin/androidx/paging/PageKeyedDataSource.LoadInitialParams#placeholdersEnabled()` is `false`, so the positioning information will be ignored.

It is always valid for a DataSource loading method that takes a callback to stash the callback and call it later. This enables DataSources to be fully asynchronous, and to handle temporary, recoverable error states (such as a network error that can be retried).

| Parameters |
|---|---|
| `<Key : https://kotlinlang.org/api/core/kotlin-stdlib/kotlin/-any/index.html?>` | Type of data used to query pages. |
| `<Value : https://kotlinlang.org/api/core/kotlin-stdlib/kotlin/-any/index.html?>` | Type of items being loaded. |

## Summary

| ### Public constructors |
|---|---|
| `<Key : https://kotlinlang.org/api/core/kotlin-stdlib/kotlin/-any/index.html?, Value : https://kotlinlang.org/api/core/kotlin-stdlib/kotlin/-any/index.html?> [LoadInitialCallback](https://developer.android.com/reference/kotlin/androidx/paging/PageKeyedDataSource.LoadInitialCallback#LoadInitialCallback())()` **This function is deprecated.** PageKeyedDataSource is deprecated and has been replaced by PagingSource | android |

| ### Public functions |
|---|---|---|
| `abstract https://kotlinlang.org/api/core/kotlin-stdlib/kotlin/-unit/index.html` | `[onResult](https://developer.android.com/reference/kotlin/androidx/paging/PageKeyedDataSource.LoadInitialCallback#onResult(kotlin.collections.List,kotlin.Any,kotlin.Any))(data: https://kotlinlang.org/api/core/kotlin-stdlib/kotlin.collections/-list/index.html<Value>, previousPageKey: Key?, nextPageKey: Key?)` **This function is deprecated.** PageKeyedDataSource is deprecated and has been replaced by PagingSource | android |
| `abstract https://kotlinlang.org/api/core/kotlin-stdlib/kotlin/-unit/index.html` | `[onResult](https://developer.android.com/reference/kotlin/androidx/paging/PageKeyedDataSource.LoadInitialCallback#onResult(kotlin.collections.List,kotlin.Int,kotlin.Int,kotlin.Any,kotlin.Any))( data: https://kotlinlang.org/api/core/kotlin-stdlib/kotlin.collections/-list/index.html<Value>, position: https://kotlinlang.org/api/core/kotlin-stdlib/kotlin/-int/index.html, totalCount: https://kotlinlang.org/api/core/kotlin-stdlib/kotlin/-int/index.html, previousPageKey: Key?, nextPageKey: Key? )` **This function is deprecated.** PageKeyedDataSource is deprecated and has been replaced by PagingSource | android |

## Public constructors

### LoadInitialCallback

android

```
<Key : Any?, Value : Any?> [LoadInitialCallback](https://developer.android.com/reference/kotlin/androidx/paging/PageKeyedDataSource.LoadInitialCallback#LoadInitialCallback())()
```

> [!CAUTION]
> **This function is deprecated.**   
> PageKeyedDataSource is deprecated and has been replaced by PagingSource, use this instead:
>
> ```kotlin
> PagingSource<Key, Value>
> ```

| Parameters |
|---|---|
| `<Key : https://kotlinlang.org/api/core/kotlin-stdlib/kotlin/-any/index.html?>` | Type of data used to query pages. |
| `<Value : https://kotlinlang.org/api/core/kotlin-stdlib/kotlin/-any/index.html?>` | Type of items being loaded. |

## Public functions

### onResult

android Added in [2.0.0](https://developer.android.com/jetpack/androidx/releases/paging#2.0.0)

```
abstract fun [onResult](https://developer.android.com/reference/kotlin/androidx/paging/PageKeyedDataSource.LoadInitialCallback#onResult(kotlin.collections.List,kotlin.Any,kotlin.Any))(data: List<Value>, previousPageKey: Key?, nextPageKey: Key?): Unit
```

> [!CAUTION]
> **This function is deprecated.**   
> PageKeyedDataSource is deprecated and has been replaced by PagingSource, use this instead:
>
> ```kotlin
> PagingSource<Key, Value>
> ```

Called to pass loaded data from a DataSource.

Call this from `https://developer.android.com/reference/kotlin/androidx/paging/PageKeyedDataSource#loadInitial(androidx.paging.PageKeyedDataSource.LoadInitialParams)` to initialize without counting available data, or supporting placeholders.

It is always valid to pass a different amount of data than what is requested. Pass an empty list if there is no more data to load.

| Parameters |
|---|---|
| `data: https://kotlinlang.org/api/core/kotlin-stdlib/kotlin.collections/-list/index.html<Value>` | List of items loaded from the `https://developer.android.com/reference/kotlin/androidx/paging/PageKeyedDataSource`. |
| `previousPageKey: Key?` | Key for page before the initial load result, or `null` if no more data can be loaded before. |
| `nextPageKey: Key?` | Key for page after the initial load result, or `null` if no more data can be loaded after. |

### onResult

android Added in [2.0.0](https://developer.android.com/jetpack/androidx/releases/paging#2.0.0)

```
abstract fun [onResult](https://developer.android.com/reference/kotlin/androidx/paging/PageKeyedDataSource.LoadInitialCallback#onResult(kotlin.collections.List,kotlin.Int,kotlin.Int,kotlin.Any,kotlin.Any))(
    data: List<Value>,
    position: Int,
    totalCount: Int,
    previousPageKey: Key?,
    nextPageKey: Key?
): Unit
```

> [!CAUTION]
> **This function is deprecated.**   
> PageKeyedDataSource is deprecated and has been replaced by PagingSource, use this instead:
>
> ```kotlin
> PagingSource<Key, Value>
> ```

Called to pass initial load state from a DataSource.

Call this method from your DataSource's `loadInitial` function to return data, and inform how many placeholders should be shown before and after. If counting is cheap to compute (for example, if a network load returns the information regardless), it's recommended to pass data back through this method.

It is always valid to pass a different amount of data than what is requested. Pass an empty list if there is no more data to load.

| Parameters |
|---|---|
| `data: https://kotlinlang.org/api/core/kotlin-stdlib/kotlin.collections/-list/index.html<Value>` | List of items loaded from the `https://developer.android.com/reference/kotlin/androidx/paging/DataSource`. If this is empty, the `https://developer.android.com/reference/kotlin/androidx/paging/DataSource` is treated as empty, and no further loads will occur. |
| `position: https://kotlinlang.org/api/core/kotlin-stdlib/kotlin/-int/index.html` | Position of the item at the front of the list. If there are `N` items before the items in data that can be loaded from this DataSource, pass `N`. |
| `totalCount: https://kotlinlang.org/api/core/kotlin-stdlib/kotlin/-int/index.html` | Total number of items that may be returned from this DataSource. Includes the number in the initial `data` parameter as well as any items that can be loaded in front or behind of `data`. |
| `previousPageKey: Key?` | Key for page before the initial load result, or `null` if no more data can be loaded before. |
| `nextPageKey: Key?` | Key for page after the initial load result, or `null` if no more data can be loaded after. |