Is Android double-tap-zoom animation or multi-step zooming?

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http://stackoverflow.com – Does anyone know the double-tap-zoom function on normal Android application (like web view or image view) is accomplished by zoom animation or by dividing the zoom into small steps and perform them one by one? If using zoom animation, since animation is cached drawing, is there any problem when I do zoom in like this? mView.zoomTo(newScale); mView.startAnimation(zoomInAnimation); Should I only set the new scale after animation finished? And if using multiple steps of zooming, is this really a good approach? How to perform each step? Send messages multiple times? What is exactly the best (HowTos)