Android length units and internal and external spacing properties (box model) settings

DPI: How many pixels are in an inch.

PX: pixels, dots on the screen, this unit is not recommended.

Dp:dp=dip (device independent pixels) devices independent pixels, easy to display the same effect on different resolution of the phone, generally set width and height. Conversion formula:

SP: Depending on the size of the system font-size the user sets, the font size is generally set.

Internal Spacing Settings properties: Layout_margin, Layout_margintop, and so on.

Outer spacing Setting properties: Padding, paddingtop, and so on.

Android length units and internal and external spacing properties (box model) settings