Difference between “screen size” and “screen density” in Android?

Question

I have a few questions:

1. What is the screen size?

2. What is the screen density?

3. What is a differenc

Answer 1

There are different terms and can't be used interchangeably

density = how many pixels appear within a constant area of the display, dots per inch = dpi or ppi(pixels per inch )

size = amount of physical space available for displaying an interface, screen's diagonal, inch

resolution = number of pixels available in the display, scale-independent pixel = sp