Android的DisplayMetrics类中的scaledDensity和density有什么区别？

Question

TextView compute text size value with scaledDensity instead of density. so what`s the difference between these two values?

Answer 1

DisplayMetrics#scaledDensity

A scaling factor for fonts displayed on the display. This is the same as density, except that it may be adjusted in smaller increments at runtime based on a user preference for the font size.

DisplayMetrics#Density

The logical density of the display. This is a scaling factor for the Density Independent Pixel unit, where one DIP is one pixel on an approximately 160 dpi screen.

Answer 2

sp

Scale-independent Pixels – this is like the dp unit, but it is also scaled by the user's font size preference. It is recommend you use this unit when specifying font sizes, so they will be adjusted for both the screen density and user's preference.

dp

A virtual pixel unit that you should use when defining UI layout, to express layout dimensions or position in a density-independent way.

The density-independent pixel is equivalent to one physical pixel on a 160 dpi screen, which is the baseline density assumed by the system for a “medium” density screen.

you can find nice explanation here Difference of px, dp, dip and sp in Android and Android units