# BaseDataSource

Artifact: [androidx.media3:media3-datasource](https://developer.android.com/jetpack/androidx/releases/media3) [View Source](https://cs.android.com/search?q=file:androidx/media3/datasource/BaseDataSource.java+class:androidx.media3.datasource.BaseDataSource)

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```
@UnstableApi
abstract class BaseDataSource : DataSource
```

<br />

Known direct subclasses [AssetDataSource](https://developer.android.com/reference/kotlin/androidx/media3/datasource/AssetDataSource), [ByteArrayDataSource](https://developer.android.com/reference/kotlin/androidx/media3/datasource/ByteArrayDataSource), [ContentDataSource](https://developer.android.com/reference/kotlin/androidx/media3/datasource/ContentDataSource), [CronetDataSource](https://developer.android.com/reference/kotlin/androidx/media3/datasource/cronet/CronetDataSource), [DataSchemeDataSource](https://developer.android.com/reference/kotlin/androidx/media3/datasource/DataSchemeDataSource), [DefaultHttpDataSource](https://developer.android.com/reference/kotlin/androidx/media3/datasource/DefaultHttpDataSource), [FakeDataSource](https://developer.android.com/reference/kotlin/androidx/media3/test/utils/FakeDataSource), [FileDataSource](https://developer.android.com/reference/kotlin/androidx/media3/datasource/FileDataSource), [FileDescriptorDataSource](https://developer.android.com/reference/kotlin/androidx/media3/datasource/FileDescriptorDataSource), [HttpEngineDataSource](https://developer.android.com/reference/kotlin/androidx/media3/datasource/HttpEngineDataSource), [KtorDataSource](https://developer.android.com/reference/kotlin/androidx/media3/datasource/ktor/KtorDataSource), [MediaDataSourceAdapter](https://developer.android.com/reference/kotlin/androidx/media3/datasource/MediaDataSourceAdapter), [OkHttpDataSource](https://developer.android.com/reference/kotlin/androidx/media3/datasource/okhttp/OkHttpDataSource), [RawResourceDataSource](https://developer.android.com/reference/kotlin/androidx/media3/datasource/RawResourceDataSource), [RtmpDataSource](https://developer.android.com/reference/kotlin/androidx/media3/datasource/rtmp/RtmpDataSource), [UdpDataSource](https://developer.android.com/reference/kotlin/androidx/media3/datasource/UdpDataSource)

|---|---|
| `https://developer.android.com/reference/kotlin/androidx/media3/datasource/AssetDataSource` | A `https://developer.android.com/reference/kotlin/androidx/media3/datasource/DataSource` for reading from a local asset. |
| `https://developer.android.com/reference/kotlin/androidx/media3/datasource/ByteArrayDataSource` | A `https://developer.android.com/reference/kotlin/androidx/media3/datasource/DataSource` for reading from a byte array. |
| `https://developer.android.com/reference/kotlin/androidx/media3/datasource/ContentDataSource` | A `https://developer.android.com/reference/kotlin/androidx/media3/datasource/DataSource` for reading from a content URI. |
| `https://developer.android.com/reference/kotlin/androidx/media3/datasource/cronet/CronetDataSource` | DataSource without intermediate buffer based on Cronet API set using UrlRequest. |
| `https://developer.android.com/reference/kotlin/androidx/media3/datasource/DataSchemeDataSource` | A `https://developer.android.com/reference/kotlin/androidx/media3/datasource/DataSource` for reading data URLs, as defined by RFC 2397. |
| `https://developer.android.com/reference/kotlin/androidx/media3/datasource/DefaultHttpDataSource` | An `https://developer.android.com/reference/kotlin/androidx/media3/datasource/HttpDataSource` that uses Android's `https://developer.android.com/reference/java/net/HttpURLConnection.html`. |
| `https://developer.android.com/reference/kotlin/androidx/media3/test/utils/FakeDataSource` | A fake `https://developer.android.com/reference/kotlin/androidx/media3/datasource/DataSource` capable of simulating various scenarios. |
| `https://developer.android.com/reference/kotlin/androidx/media3/datasource/FileDataSource` | A `https://developer.android.com/reference/kotlin/androidx/media3/datasource/DataSource` for reading local files. |
| `https://developer.android.com/reference/kotlin/androidx/media3/datasource/FileDescriptorDataSource` | A `https://developer.android.com/reference/kotlin/androidx/media3/datasource/DataSource` for reading from a `https://developer.android.com/reference/java/io/FileDescriptor.html`. |
| `https://developer.android.com/reference/kotlin/androidx/media3/datasource/HttpEngineDataSource` | DataSource without intermediate buffer based on `https://developer.android.com/reference/android/net/http/HttpEngine.html` set using `https://developer.android.com/reference/android/net/http/UrlRequest.html`. |
| `https://developer.android.com/reference/kotlin/androidx/media3/datasource/ktor/KtorDataSource` | An `https://developer.android.com/reference/kotlin/androidx/media3/datasource/HttpDataSource` that delegates to Ktor's `https://api.ktor.io/ktor-client-core/io.ktor.client/-http-client/index.html`. |
| `https://developer.android.com/reference/kotlin/androidx/media3/datasource/MediaDataSourceAdapter` | A `https://developer.android.com/reference/kotlin/androidx/media3/datasource/DataSource` for reading from a `https://developer.android.com/reference/android/media/MediaDataSource.html`. |
| `https://developer.android.com/reference/kotlin/androidx/media3/datasource/okhttp/OkHttpDataSource` | An `https://developer.android.com/reference/kotlin/androidx/media3/datasource/HttpDataSource` that delegates to Square's Call.Factory. |
| `https://developer.android.com/reference/kotlin/androidx/media3/datasource/RawResourceDataSource` | A `https://developer.android.com/reference/kotlin/androidx/media3/datasource/DataSource` for reading a raw resource. |
| `https://developer.android.com/reference/kotlin/androidx/media3/datasource/rtmp/RtmpDataSource` | A Real-Time Messaging Protocol (RTMP) `https://developer.android.com/reference/kotlin/androidx/media3/datasource/DataSource`. |
| `https://developer.android.com/reference/kotlin/androidx/media3/datasource/UdpDataSource` | A UDP `https://developer.android.com/reference/kotlin/androidx/media3/datasource/DataSource`. |

*** ** * ** ***

Base `https://developer.android.com/reference/kotlin/androidx/media3/datasource/DataSource` implementation to keep a list of `https://developer.android.com/reference/kotlin/androidx/media3/datasource/TransferListener`s.

Subclasses must call `https://developer.android.com/reference/kotlin/androidx/media3/datasource/BaseDataSource#transferInitializing(androidx.media3.datasource.DataSpec)`, `https://developer.android.com/reference/kotlin/androidx/media3/datasource/BaseDataSource#transferStarted(androidx.media3.datasource.DataSpec)`, `https://developer.android.com/reference/kotlin/androidx/media3/datasource/BaseDataSource#bytesTransferred(int)`, and `https://developer.android.com/reference/kotlin/androidx/media3/datasource/BaseDataSource#transferEnded()` to inform listeners of data transfers.

## Summary

| ### Protected constructors |
|---|
| `https://developer.android.com/reference/kotlin/androidx/media3/datasource/BaseDataSource#BaseDataSource(boolean)(isNetwork: https://kotlinlang.org/api/core/kotlin-stdlib/kotlin/-boolean/index.html)` Creates base data source. |

| ### Public functions |
|---|---|
| `https://kotlinlang.org/api/core/kotlin-stdlib/kotlin/-unit/index.html` | `@https://developer.android.com/reference/kotlin/androidx/media3/common/util/UnstableApi https://developer.android.com/reference/kotlin/androidx/media3/datasource/BaseDataSource#addTransferListener(androidx.media3.datasource.TransferListener)(transferListener: https://developer.android.com/reference/kotlin/androidx/media3/datasource/TransferListener!)` Adds a `https://developer.android.com/reference/kotlin/androidx/media3/datasource/TransferListener` to listen to data transfers. |

| ### Protected functions |
|---|---|
| `https://kotlinlang.org/api/core/kotlin-stdlib/kotlin/-unit/index.html` | `https://developer.android.com/reference/kotlin/androidx/media3/datasource/BaseDataSource#bytesTransferred(int)(bytesTransferred: https://kotlinlang.org/api/core/kotlin-stdlib/kotlin/-int/index.html)` Notifies listeners that bytes were transferred. |
| `https://kotlinlang.org/api/core/kotlin-stdlib/kotlin/-unit/index.html` | `https://developer.android.com/reference/kotlin/androidx/media3/datasource/BaseDataSource#transferEnded()()` Notifies listeners that a transfer ended. |
| `https://kotlinlang.org/api/core/kotlin-stdlib/kotlin/-unit/index.html` | `https://developer.android.com/reference/kotlin/androidx/media3/datasource/BaseDataSource#transferInitializing(androidx.media3.datasource.DataSpec)(dataSpec: https://developer.android.com/reference/kotlin/androidx/media3/datasource/DataSpec!)` Notifies listeners that data transfer for the specified `https://developer.android.com/reference/kotlin/androidx/media3/datasource/DataSpec` is being initialized. |
| `https://kotlinlang.org/api/core/kotlin-stdlib/kotlin/-unit/index.html` | `https://developer.android.com/reference/kotlin/androidx/media3/datasource/BaseDataSource#transferStarted(androidx.media3.datasource.DataSpec)(dataSpec: https://developer.android.com/reference/kotlin/androidx/media3/datasource/DataSpec!)` Notifies listeners that data transfer for the specified `https://developer.android.com/reference/kotlin/androidx/media3/datasource/DataSpec` started. |

### Inherited functions

From [androidx.media3.common.DataReader](https://developer.android.com/reference/kotlin/androidx/media3/common/DataReader) `abstract https://kotlinlang.org/api/core/kotlin-stdlib/kotlin/-int/index.html` `https://developer.android.com/reference/kotlin/androidx/media3/common/DataReader#read(byte[],int,int)(buffer: https://kotlinlang.org/api/core/kotlin-stdlib/kotlin/-byte-array/index.html<https://kotlinlang.org/api/core/kotlin-stdlib/kotlin/-byte/index.html>!, offset: https://kotlinlang.org/api/core/kotlin-stdlib/kotlin/-int/index.html, length: https://kotlinlang.org/api/core/kotlin-stdlib/kotlin/-int/index.html)`

Reads up to `length` bytes of data from the input.
From [androidx.media3.datasource.DataSource](https://developer.android.com/reference/kotlin/androidx/media3/datasource/DataSource) `abstract https://kotlinlang.org/api/core/kotlin-stdlib/kotlin/-unit/index.html` `@https://developer.android.com/reference/kotlin/androidx/media3/common/util/UnstableApi
https://developer.android.com/reference/kotlin/androidx/media3/datasource/DataSource#close()()`

Closes the source.
`(https://kotlinlang.org/api/core/kotlin-stdlib/kotlin.collections/-mutable-map/index.html)https://kotlinlang.org/api/core/kotlin-stdlib/kotlin.collections/-map/index.html<https://kotlinlang.org/api/core/kotlin-stdlib/kotlin/-string/index.html!, (https://kotlinlang.org/api/core/kotlin-stdlib/kotlin.collections/-mutable-list/index.html)https://kotlinlang.org/api/core/kotlin-stdlib/kotlin.collections/-list/index.html<https://kotlinlang.org/api/core/kotlin-stdlib/kotlin/-string/index.html!>!>!` `@https://developer.android.com/reference/kotlin/androidx/media3/common/util/UnstableApi
https://developer.android.com/reference/kotlin/androidx/media3/datasource/DataSource#getResponseHeaders()()`

When the source is open, returns the response headers associated with the last `https://developer.android.com/reference/kotlin/androidx/media3/datasource/DataSource#open(androidx.media3.datasource.DataSpec)` call.
`abstract https://developer.android.com/reference/android/net/Uri.html?` `@https://developer.android.com/reference/kotlin/androidx/media3/common/util/UnstableApi
https://developer.android.com/reference/kotlin/androidx/media3/datasource/DataSource#getUri()()`

When the source is open, returns the `https://developer.android.com/reference/android/net/Uri.html` from which data is being read.
`abstract https://kotlinlang.org/api/core/kotlin-stdlib/kotlin/-long/index.html` `@https://developer.android.com/reference/kotlin/androidx/media3/common/util/UnstableApi
https://developer.android.com/reference/kotlin/androidx/media3/datasource/DataSource#open(androidx.media3.datasource.DataSpec)(dataSpec: https://developer.android.com/reference/kotlin/androidx/media3/datasource/DataSpec!)`

Opens the source to read the specified data.

## Protected constructors

### BaseDataSource

```
protected BaseDataSource(isNetwork: Boolean)
```

Creates base data source.

| Parameters |
|---|---|
| `isNetwork: https://kotlinlang.org/api/core/kotlin-stdlib/kotlin/-boolean/index.html` | Whether the data source loads data through a network. |

## Public functions

### addTransferListener

```
@UnstableApi
fun addTransferListener(transferListener: TransferListener!): Unit
```

Adds a `https://developer.android.com/reference/kotlin/androidx/media3/datasource/TransferListener` to listen to data transfers. This method is not thread-safe.

| Parameters |
|---|---|
| `transferListener: https://developer.android.com/reference/kotlin/androidx/media3/datasource/TransferListener!` | A `https://developer.android.com/reference/kotlin/androidx/media3/datasource/TransferListener`. |

## Protected functions

### bytesTransferred

```
protected fun bytesTransferred(bytesTransferred: Int): Unit
```

Notifies listeners that bytes were transferred.

| Parameters |
|---|---|
| `bytesTransferred: https://kotlinlang.org/api/core/kotlin-stdlib/kotlin/-int/index.html` | The number of bytes transferred since the previous call to this method (or if the first call, since the transfer was started). |

### transferEnded

```
protected fun transferEnded(): Unit
```

Notifies listeners that a transfer ended.

### transferInitializing

```
protected fun transferInitializing(dataSpec: DataSpec!): Unit
```

Notifies listeners that data transfer for the specified `https://developer.android.com/reference/kotlin/androidx/media3/datasource/DataSpec` is being initialized.

| Parameters |
|---|---|
| `dataSpec: https://developer.android.com/reference/kotlin/androidx/media3/datasource/DataSpec!` | `https://developer.android.com/reference/kotlin/androidx/media3/datasource/DataSpec` describing the data for initializing transfer. |

### transferStarted

```
protected fun transferStarted(dataSpec: DataSpec!): Unit
```

Notifies listeners that data transfer for the specified `https://developer.android.com/reference/kotlin/androidx/media3/datasource/DataSpec` started.

| Parameters |
|---|---|
| `dataSpec: https://developer.android.com/reference/kotlin/androidx/media3/datasource/DataSpec!` | `https://developer.android.com/reference/kotlin/androidx/media3/datasource/DataSpec` describing the data being transferred. |