diff options
| -rw-r--r-- | core/java/android/view/View.java | 23 |
1 files changed, 14 insertions, 9 deletions
diff --git a/core/java/android/view/View.java b/core/java/android/view/View.java index 01da6b333d0e..9c388ddeaafe 100644 --- a/core/java/android/view/View.java +++ b/core/java/android/view/View.java @@ -9764,15 +9764,20 @@ public class View implements Drawable.Callback, KeyEvent.Callback, } /** - * Returns whether this View has content which overlaps. This function, intended to be - * overridden by specific View types, is an optimization when alpha is set on a view. If - * rendering overlaps in a view with alpha < 1, that view is drawn to an offscreen buffer - * and then composited it into place, which can be expensive. If the view has no overlapping - * rendering, the view can draw each primitive with the appropriate alpha value directly. - * An example of overlapping rendering is a TextView with a background image, such as a - * Button. An example of non-overlapping rendering is a TextView with no background, or - * an ImageView with only the foreground image. The default implementation returns true; - * subclasses should override if they have cases which can be optimized. + * Returns whether this View has content which overlaps. + * + * <p>This function, intended to be overridden by specific View types, is an optimization when + * alpha is set on a view. If rendering overlaps in a view with alpha < 1, that view is drawn to + * an offscreen buffer and then composited into place, which can be expensive. If the view has + * no overlapping rendering, the view can draw each primitive with the appropriate alpha value + * directly. An example of overlapping rendering is a TextView with a background image, such as + * a Button. An example of non-overlapping rendering is a TextView with no background, or an + * ImageView with only the foreground image. The default implementation returns true; subclasses + * should override if they have cases which can be optimized.</p> + * + * <p>The current implementation of the saveLayer and saveLayerAlpha methods in {@link Canvas} + * necessitates that a View return true if it uses the methods internally without passing the + * {@link Canvas#CLIP_TO_LAYER_SAVE_FLAG}.</p> * * @return true if the content in this view might overlap, false otherwise. */ |