I\'m reading and watching UI tutorial. They all talk about the fact that you need to be aware of different devices size and resolution. Therefore export your icons into several
The answer has changed. Since version 21, Lollipop the operating system has had support for VectorDrawable. This is added to by a support library that allows you to use VectorDrawable well back into previous versions. These include support for importing most of the important SVG vector commands and having Android Studio automatically convert them to a VectorDrawable.
Use Vector Image Assets for all versions. -- Also even in older versions it's entirely possible to do fonts. Basically you give it a font asset then load up a specific letter of the font as an icon. Since fonts are glyphs and vector glyphs at that, you can very much get vector icons pretty far back.
https://fortawesome.github.io/Font-Awesome/icons/