What screen sizes should I type to support most of the screens of the Android devices most used today?

Question

Android

I am new to android development. Finishing my first big application, but the problem is that at the moment the application is displayed correctly only on one type of screen dimension. The application was written and tested on only one device. Such a question, you need to typeset for each screen density mdpi hdpi xhdpi xxhdpi xxxhdpi. The application will only support portrait orientation and should only work on smartphones (up to 7 inches approximately), not on tablets. How to do it better?
What about pictures? I know that they must be scaled by yourself. For example, I have a big picture 700*1500 px.
Unfortunately, there is no way to test on various physical devices, is it possible to do all this in Genymotion. On what devices to test in the emulator. There is a chance that something in the application will not work in the emulator as it would on a physical device. Share your experience.

Answer 1

Count on screen width >640px (from 320dp). But in general, write values ​​everywhere in dp and sp, add scrolls to the screens and there should not be many problems. + in the studio, in the xml editing screen, you can drag the layout to different widths and see what happens to it.