What is the difference between px, dp, and sp?

px: Pixels. Depend on screen density. On different devices, the same element defined in px will have a different physical size. Not recommended for UI element sizes.

dp (density-independent pixels): Density-independent pixels. A unit of measurement tied to the physical size on the screen. 160 dp is approximately equal to 1 inch on a screen with a density of 160 dpi (denoted as mdpi). Scales depending on device density. The preferred unit for defining UI element sizes.

sp (scale-independent pixels): Scalable pixels. Similar to dp, but additionally scales depending on the user's font settings in the system. Used exclusively for font size settings.

Comparison table:

Unit	Description	Usage
px	Screen pixel	Not recommended
dp	Density-independent pixel	UI element sizes
sp	Scalable pixel	Font sizes