How big is 1dp!

Why is 1dp a fixed length?How long is it?

Why do you say px is a relative length, if you don't know dpi, you don't know how long it is.

First of all, we have to distinguish a concept

Control, text, we use dp, sp, so on different devices, it will be converted into corresponding px according to the dpi of the device

Therefore, it is guaranteed to be the same size on different devices.

For example, how big is 1dp

1dp runs on a 160dpi machine, then 1dp=1px and knowing that dpi=160 means that there are 160 pixels per inch, then the length of a pixel is 1/160 of an inch.

And 1dp runs on a 320dpi machine, then 1dp=2px knows dpi=320, that is, the length of a pixel is 1/320 inch, to display a 1dp control requires 2px, then the length is 2*1/320 Still yes1/160 of an inch, so the length is fixed.

As for the picture, since the unit of the picture is px, it needs to be adapted. It is necessary to create different folders according to different devices, and store the different pixel sizes of the same picture in different folders. When the real machine is runningThe pictures in the appropriate folder will be loaded according to the dpi of the real machine.

And if you only have one image, the px size is fixed. Naturally, when running on different devices, the displayed size of this image is different.