# ViewTreeObserver.OnDrawListener

Added in[API level 16](https://developer.android.com/guide/topics/manifest/uses-sdk-element.html#ApiLevels)

# OnDrawListener

*** ** * ** ***

Kotlin\|[Java](https://developer.android.com/reference/android/view/ViewTreeObserver.OnDrawListener "View this page in Java")  

```
interface OnDrawListener
```

|----------------------------------------------------------------------------------------------------------------------------------------------|
| [android.view.ViewTreeObserver.OnDrawListener](https://developer.android.com/reference/kotlin/android/view/ViewTreeObserver.OnDrawListener#) |

Interface definition for a callback to be invoked when the view tree is about to be drawn.

## Summary

|                                                                                                                                 Public methods                                                                                                                                  ||
|--------------------------------------------------------------------------------------|-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| abstract[Unit](https://kotlinlang.org/api/latest/jvm/stdlib/kotlin/-unit/index.html) | [onDraw](https://developer.android.com/reference/kotlin/android/view/ViewTreeObserver.OnDrawListener#onDraw())`()` Callback method to be invoked when the view tree is about to be drawn. |

## Public methods

### onDraw

Added in[API level 16](https://developer.android.com/guide/topics/manifest/uses-sdk-element.html#ApiLevels)  

```
abstract fun onDraw(): Unit
```

Callback method to be invoked when the view tree is about to be drawn. At this point, views cannot be modified in any way.

Unlike with[OnPreDrawListener](https://developer.android.com/reference/kotlin/android/view/ViewTreeObserver.OnPreDrawListener), this method cannot be used to cancel the current drawing pass.

An[OnDrawListener](https://developer.android.com/reference/kotlin/android/view/ViewTreeObserver.OnDrawListener#)listener**cannot be added or removed**from this method.  
**See Also**

- [android.view.View#onMeasure](https://developer.android.com/reference/kotlin/android/view/View#onMeasure(kotlin.Int,%20kotlin.Int))
- [android.view.View#onLayout](https://developer.android.com/reference/kotlin/android/view/View#onLayout(kotlin.Boolean,%20kotlin.Int,%20kotlin.Int,%20kotlin.Int,%20kotlin.Int))
- [android.view.View#onDraw](https://developer.android.com/reference/kotlin/android/view/View#onDraw(android.graphics.Canvas))