[Android UI] The difference in pixel units: px, dp, sp, dip

very simple:

px：像素点，10px在分辨率低（像素点少）的屏幕上看上去更长
dp：让10dp在两个不同分辨率的手机上看上去差不多长
dip：=dp
sp：字体大小

Draw a very thin dividing line on the screen: px can be used to ensure that it is thin enough

Due to pixel issues, the following folders are usually prepared, in which the side length of the picture is 1.5 times the relationship:

mdpi：48*48
hdpi：72*72
xhdpi：96*96
xxhdpi：144*144
xxxhdpi：192*192