Added in [API level 28](https://developer.android.com/guide/topics/manifest/uses-sdk-element#ApiLevels)

# ImageDecoder.OnHeaderDecodedListener

*** ** * ** ***

` public static interface ImageDecoder.OnHeaderDecodedListener `   
` `

|---|
| android.graphics.ImageDecoder.OnHeaderDecodedListener |

<br />

*** ** * ** ***

Interface for changing the default settings of a decode.

Supply an instance to `https://developer.android.com/reference/android/graphics/ImageDecoder#decodeDrawable(android.graphics.ImageDecoder.Source,%20android.graphics.ImageDecoder.OnHeaderDecodedListener)` or `https://developer.android.com/reference/android/graphics/ImageDecoder#decodeBitmap(android.graphics.ImageDecoder.Source,%20android.graphics.ImageDecoder.OnHeaderDecodedListener)`, which will call `https://developer.android.com/reference/android/graphics/ImageDecoder.OnHeaderDecodedListener#onHeaderDecoded(android.graphics.ImageDecoder,%20android.graphics.ImageDecoder.ImageInfo,%20android.graphics.ImageDecoder.Source)` (in the same thread) once the size is known. The implementation of `https://developer.android.com/reference/android/graphics/ImageDecoder.OnHeaderDecodedListener#onHeaderDecoded(android.graphics.ImageDecoder,%20android.graphics.ImageDecoder.ImageInfo,%20android.graphics.ImageDecoder.Source)` can then change the decode settings as desired.

## Summary

| ### Public methods ||
|---|---|
| ` abstract void` | ` https://developer.android.com/reference/android/graphics/ImageDecoder.OnHeaderDecodedListener#onHeaderDecoded(android.graphics.ImageDecoder,%20android.graphics.ImageDecoder.ImageInfo,%20android.graphics.ImageDecoder.Source)(https://developer.android.com/reference/android/graphics/ImageDecoder decoder, https://developer.android.com/reference/android/graphics/ImageDecoder.ImageInfo info, https://developer.android.com/reference/android/graphics/ImageDecoder.Source source) ` Called by `https://developer.android.com/reference/android/graphics/ImageDecoder` when the header has been decoded and the image size is known. |

## Public methods

### onHeaderDecoded

Added in [API level 28](https://developer.android.com/guide/topics/manifest/uses-sdk-element#ApiLevels)

```
public abstract void onHeaderDecoded (ImageDecoder decoder, 
                ImageDecoder.ImageInfo info, 
                ImageDecoder.Source source)
```

Called by `https://developer.android.com/reference/android/graphics/ImageDecoder` when the header has been decoded and the image size is known.

<br />

| Parameters ||
|---|---|
| `decoder` | `ImageDecoder`: the object performing the decode, for changing its default settings. This value cannot be `null`. <br /> |
| `info` | `ImageDecoder.ImageInfo`: information about the encoded image. This value cannot be `null`. <br /> |
| `source` | `ImageDecoder.Source`: object that created `decoder`. This value cannot be `null`. <br /> |