Android why text size is different for all devices even if one text size in sp is specified?

Question

I'm wondering why my TextView size is different for different devices even if I set the text size in sp or dp.

Please help me. Thanks.

Answer 1

This post explains the difference:

dip/dp (density independent pixels):

an abstract unit that is based on the physical density of the screen. These units are relative to a 160 dpi screen, so one dp is one pixel on a 160 dpi screen. The ratio of dp-to-pixel will change with the screen density, but not necessarily in direct proportion. Note: The compiler accepts both "dip" and "dp", though "dp" is more consistent with "sp".

sp (scale independent pixels):

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.

And this post explains why dp and sp values may differ:

The dp has constant ratio transition to pixels: dp = px * ratio. Ratio will never change on any particular device.

The sp has scalable ratio: sp = px * ratio * scale. Ratio never changes, but scale is user configurable. This scale can be used by people who need larger font sizes, for example, to use device more comfortably.