I'm developing an app on the Android platform and the main UI component used is a ListView. Now, in my case, this ListView may contain a huge amount of items (depending on the user) so with that in mind, I implemented a "infinite scrolling" feature.
Then I was thinking, if users have over 100 items then scrolling though them might take a while. So I thought of dynamically switching the normal scrollbars out for the "fast scrollbars" after, lets say, 101 items are displayed. Take the following screen shot as an example (ignore the "Section Index" image)...
Consider the "Plain old rows" image, the first phase of the ListView. Then, as the user scrolls down and more and more data is populated into the ListView, the "Fast Scrolling" phase will be enabled.
My question is, is using 'fast scrolling' a sensible approach to take? My concern is related to the consistency of the user experience. Although this idea seems to be great if someone has tons and tons of data, I'm just a little worried users may be confused with the sudden switch.