Thanks for kindly quick reponse. > > 1. what is the relationship between ViewRoot and View class. > > The ViewRoot is the root of each view hierarchy. Like you said, there > is one ViewRoot per window. The ViewRoot is responsible to handling > the layout and drawing of the view hierarchy. The view hierarchy is > made of Views and ViewGroups. A ViewGroup is a special View that can > contain other Views. > > > Is all view ,its children's view and their viewRoot share the same > > canvas for draw? > > Yes, but that Canvas might change on every drawing operation. The > ViewRoot acquires a Canvas from the underlying Surface and hands that > Canvas to the top-level View.
Does the bitmap data we write to Canvas is the same as we write to the back buffer to that surface, which means surface will not copy the data in Canvas to back buffer then swap the backbuffer with front buffer, or it will do the copy operation? > > > 2. What is the relationship within View, canvas and Surface. To my > > thinking, every view will be attached a canvas and surface. > > No, the Views are not attached to the Canvas nor the Surface. The > window is tied to a Surface and the ViewRoot asks the Surface for a > Canvas that is then used by the Views to draw onto. > > > canvas hold the bitmap for view, will the actual view drawn data will > > be in canvas' bitmap. > > Yes. > > > After View draw its data to canvas, ViewRoot > > will call surface.unlockCanvasAndPost(canvas) to schedule > > surfaceFlinger::composeSurfaces() which do the actually display to > > display panel. > > Yes. > > > Where is the drawn data in canvas transfer to surface front buffer or > > backbuffer? I cannot find the code to do that. > > It's done by SurfaceFlinger. > > > Do different views within the same ViewRoot share the same surface? > > Yes, except for SurfaceViews. > > -- > Romain Guy > Android framework engineer > romain...@android.com > > Note: please don't send private questions to me, as I don't have time > to provide private support. All such questions should be posted on > public forums, where I and others can see and answer them --~--~---------~--~----~------------~-------~--~----~ You received this message because you are subscribed to the Google Groups "android-framework" group. To post to this group, send email to android-framework@googlegroups.com To unsubscribe from this group, send email to android-framework+unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/android-framework?hl=en -~----------~----~----~----~------~----~------~--~---
