Two view interaction, bitmap when drawing overlap

From a design standpoint, you should try to avoid overlapping views.

During a dynamic development of a new project, two views overlap during the dynamic process, and the bitmap of the two views are displayed in real time, so there is an unexpected ghosting problem. Slows down the animation and finds that the bitmap part of the upper view shows the underlying view in a transparent manner before ghosting occurs. Check the bitmap pixels and discover that the alpha channel does not exist, that is, bitmap is not transparent, and why it appears when it is drawn, for reasons not yet found.

Android provides a porterduff.mode flag for overlapping areas to set up a specific drawing of overlapping areas, thus resolving ghosting issues through this flag.

Android Color Rendering (ix) Porterduff and Xfermode detailed

Two view interaction, bitmap when drawing overlap